Animal Kingdom

ANIMAL KINGDOM

CHAPTER

03

“In natural science the principles of truth ought to be confirmed by

observation”.

“ CARL LINNAEUS (1707-1778)”

INTRODUCTION

When we look around we see wide range of different animals with different structure,

body and forms. You see parrots, cockroaches, cats, elephants, dogs, cow, buffalo,

crow, piegon, hen, monkey, sparrow, butterflies, mosquito, frogs,human beings, etc.

We see them some creep, jump, walk or some swim. All these organisms we are

observing in our day to day life, can you imagine these all livings come under Kingdom

Animalia.

As over a million species have been described till now, the need for classification

becomes more important. But before classifying them, let’s study the basic features

of all the animals that distinguish them from other living organisms.

BIOLOGY FOR NEET & AIIMS

ANIMAL - CLASSIFICATION (PORIFERA TO ECHINODERMATA)

BRIEF HISTORY OF ANIMAL TAXONOMY

TAXONOMY

Taxonomy is the branch which deals with the study of nomenclature, classification and their principles. Three steps:

(1) Identification (2) Nomenclature (3) Classification

Taxonomy word was given by “Candole. It is a Greek word.

Taxis - arrangements (systematics)

Nomos - Law / Rules

Outline of Animal-classification

Animal-Kingdom

I - Protozoa

On the basis of body-organisation

II - Metazoa

Animals of Protoplasmic level

Animals of cellular level

Sub - Kingdom

(1) Mesozoa (3) Enterozoa or Eumetazoa

(2) Parazoa

(1) Small, worm like

parasites, only 1 phylum -

Mesozoa - Tissues absent

e.g. Dicyemia

(1) Body organisation of

cellular level

(2) Diploblastic

(3) Well developed mouth

with a pore, phyla porifera

alimentary canal absent

e.g. Sponge sycon, Scypha

Eumetazoa has been divided into 2 divisions on the basis of body symmetry

Divisions

(3) Eumetazoa

(i) Body organisation

tissue or organ grade.

(ii) Well developed mouth,

alimentary canal present.

(A) Radiata

(A) Division Radiata -

(i) Diploblastic / Triploblastic

(ii) Radial symmetry is found, body is bilayered and tissue-grade.

(iii) Mouth and digestive cavity present - Coelentron / Gastrovascular cavity

(iv) Anus absent i.e. alimentry canal incomplete.

Radiata includes two phyla -

(i) Cnidaria or Coelenterata (eg. Hydra) - Diploblastic, radial

(ii) Ctenophora (e.g. Beroe) - Triploblastic, biradial (According to modern view.)

(B) Bilateria

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(B) Division Bilateria -

ANIMAL KINGDOM

Body triploblastic - Bilateral symmetry is found i.e. body can be divided into two equal-halves length – wise

only on the middle line. Body organisation organ-grade.

On the basis of embryological development Bilateria has been divided into 2 sub-division.

Subdivision Protosomia

Subdivision Deuterostomia

1. Blastopore gives rise to the mouth. 1. Blastopore gives rise to the anus

2. Cleavages is spiral and determinate 2. Cleavages is radial and indeterminate

3. Mesodermis formed from a single blastomere 3. Mesodermis made of many blastomeres. Two

called Teloblast. Due to the cleavage of Teloblasta rows of sacs are formed in the archentron of embryo.

mesodermal plate is formed later on it ruptures from All the sacs unite together to form a large cavity

the center to form cavity.This is a true coelom and called "Enterocoelic Coelom" This is developed type

this type of coelom is called "Schizocoelic-coelom" of coelom.

On the basis of body-cavity, Subdivision Protostomia has been divided into three sections

Sec. (A)

Acoelomata

– Body-cavity absent

– a loose mesodermal tissue

parenchyma is present between

the body-cavity and the internal

organ. It has 3 phylum

(i) Platyhelminthes

(ii) Nemertinea

(iii) Gnathostomulida

Sec. (B)

Pseudocoelomata

– False body cavity is present

called the Pseudocoel

– It directly develops from the

blastocoel. It has 7 phyla

(1) Entoprocta

(2) Rotifera

(3) Gastrotricha

(4) Kinorhyncha

(5) Nematoda /

Nemathelminthes

(6) Nematomorpha

(7) Acanthocephala

Protostomia

Eucoelomate

13-Phyla

Schizocoel

Sec. (C)

Eucoelomata

– True coelom

– Coelom develops

from the mesoderm

Deuterostomia

Eucoelomate

4-Phyla

Enterocoel

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Deuterostomia

Radial cleavage, Blastopore gives rise to anus, Enterocoelic coelom

Phylum - Echinodermata ———————— to ———————— Phylum - Chordata

Section A - Acoelomata

Coelom absent

Divided into 3 phyla

(1) Platyhelminthes - flat-worms, leaf or ribbon - shaped. Anus - absent, hermaphrodite. Most of them are internal or

external parasites, e.g. Fasciola hepatica, Taenia-solium.

(2) Gnathostomulida -Anus absent

Jaws present - e.g. Hapagnatha.

(3) Nemertinea -

(i) Ribbon - worms

(ii) Anus-present, body unsegmented

(iii) Mostly unisexual

(iv) Locomotary organs are Rhynchocoel

e.g.

(i) Cerebratulus

(ii) Stichostemma - Anus is absent

Section B - Pseudocoelomata

These have a false coelom which develops from embryonal blastocoel.

Mesodermal epithelium absent

Anus present

Cuticle present

No. of cells is fixed

It has 8-phyla in it.

(1) Entoprocta -

(i) Fixed aquatic animals

(ii) Sucking organ is called calyx

(iii) Alimentary canal is U - shaped

(iv) Pseudocoel cavity is filled with parenchyma

e.g. - Pedicellina, Loxosoma

(2) Rotifera-

(i) These are called “Wheel animalcules”

(ii) Mainly in wet soil or water without salts

(iii) Body is microscopic, cylindrical and present inside a shell of hard-cuticle.

(iv) At the anterior end wheel organor the “Corona” is present

(v) Corona helps in feeding & locomotion

e.g. - Philodina, Rotaria

(3) Gastrotricha -

(i) Body unsegmented, long thin & flexible

(ii) Unisexual / Bisexual

(iii) Mouth at anterior end and is surrounded by spines

e.g - Chaetonotus.

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(4) Kinorhyncha -

(i) Body canal shaped, divided into 13 or 14 coin like segments called Zonites

e.g. - Echinoderes

(5) Nematoda / Nemathelminthes -

(i) Body unsegmented, thin, long tubular also called. “Thread-worms” or “Round worm”

(ii) Unisexual

(iii) Parasites on other animals or plants

e.g. - Ascaris

(6) Nematomorpha-

ANIMAL KINGDOM

These are called “Horse-hair worms” or “Hair snakes”. Body unsegmented. Parasites on insects in juvenile

stages

e.g. - Gordius.

(7) Acanthocephala - spiny headed worms

(i) Internal parasites of vertebrates

(ii) Alimentary canal absent

(iii) Unisexual

e.g. - Echinorhynchus, Acanthocephalus

SECTION C -Eucoelomata

- These have a true coelom which is lined by mesodermal epithelium or peritoneum. It includes 17 phyla. The

members of 13-phyla are protostomians and that of 4 phyla are Deuterostomians.

(I) Protostomia eucoelomata - 13 phyla

(I)

Protostomial Eucoelomate

(1) Bryozoa / Ectoprocta / Sea mosses Bugula

(II) Duetcrostomia eucoelomata - 4 phyla

(2) Phoronida :- Worm like animals, alimentary canal U-shaped, Anterior end is in the form of a Lophophore-organ.

bisexual, e.g. Phoronis.

(3) Brachiopoda (lamp shell animal):- Anus present / absent, two lophophores with ciliary tentacles. Unisexual.

Marine-animal enclosed in a Bivalved calcified shell, e.g. Lingula

(4) Mollusca (soft body animal) :- Shelled, it is the second largest phylum of the animal kingdom, e.g. Unio, Snail.

(5) Annelida :- Segmented worms e.g. Earthworm , Leeches, Nereis

(6) Sipunculoidea :- “Peanut-worms” e.g. -Sipunculus.

(7) Echiuroidea :- Adder-tailed worm, spoon worm : e.g. Echiurus

(8) Priapulida :- e.g. Priapulus

(9) Pogonophora :- “Marine Beard-worm”. Alimentary canal absent, e.g. Polybrachia, Spirobrachia.

(10) Onychophora :- Female is viviparous. Unisexual, Unsegmented body.

e.g. Peripatus walking worm - It is a connecting - link between annelida and arthopoda.

(11) Arthropoda :- This is the largest phylum of the animal kingdom. 4 or more jointed appendages, chitinous

exoskeleton, unisexual (mostly) e.g. Crab, Prawn, housefly, Mosquito.

(12) Pentastomida :- Parasites of vertebrates (tracheal parasite). Unisexual e.g. Linguatula

(13) Tardigrade :- Known as “Water-bears”, Unisexual, e.g. Echiniscus.

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(II) Deuterostomial Eucoelomate :

(1) Chaetognatha :- Arrow worm. Bisexual, have fins for swimming. Mouth is surrounded by spines, e.g. Sagitta

(2) Echinodermata :- These have water vascular system. Pentaradial and unsegmented marine animals. Have tubefeet

for locomotion. Mostly unisexual e.g. Asterias, Echinus.

(3) Hemi-chordata :- Marine “Tongue worms”, acorn worms e.g. Balanoglossus.

(4) Chordata :- Presence of Notocord. Paired pharyngeal gill -clefts. Clear tail behind the anus.

e.g. Fish, Frog, Lizard, Birds, Animals, Man. Chordata is the smallest phylum of the animal kingdom in which

3 - 5 % animals are included

The words vertebrates & invertebrate were given by “Lamarck”.

Family, genera and species words were given by John-Ray.

The words class and order were given by “Linnaeus “, Storer and Usinger have divided the whole animal

kingdom into 31 phyla, out of which 10 are major and 21 are minor phyla.

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PHYLUM - PROTOZOA

The study of protozoans is termed as protozoology. Protozoa is the 3rd largest phylum in which 30,000 species

are present. In this phylum those first animals have been included whose whole body is made up of a eukaryotic

type of cell. There one-celled body performs all the biological-activities like multicellular animals, so these are

termed as “Acellular-unicellular” organisms. This was first proposed by “Dobell”. Protozoan animals were first

studied by “Leeuwenhoek” (father of Protozoology). The word protozoa was first used by “Goldfuss”. Protozoa

phylum was established by Von Siebold.

Rhizopoda given by Dujardin

Ciliata given by Perty

Sporozoa is given by Leuckart

Leder-Muller” termed protozoa as “Infusoria”.

Main Characters :-

(1) Protozoa are universal and cosmopolitan in distribution. Mostly microscopic organisms.

(2) The animals of this phylum are free living or parasites in plants or animals. These are solitary or colonial.

(3) These are the simplest and most primitive animals. Their body organisation is of Protoplasmic level.

(4) Their shape is of different types ie. irregular, elongated or round.

(5) The body of most animals is naked and some have pellicle, test or shell on their body as exo-skeleton.

(6) Body is unicellular which has one or more nucleus which may be monomorphic or dimorphic

(i) small-micronucleus – control genetic activities, (ii) Large-macronuclues – physiological activities

(7) Unicellular body performs all the necessary biological activities, so in them “subcellular - physiological division of

labour” is found.

(8) In them many types of locomotary organs are found. Finger like pseudopodias, cilia, flagella, tentacles or absent.

(9) Protozoans which are found in fresh water have one or more contractile-vacuoles for water-balance or osmoregulation.

1 contractile - vacuole - e.g. Amoeba, 2 Paramecium.

(10) Nutrition is of different types, like Holozoic, Holophytic, Mixotropic like in euglena, Parasitic in plasmodium,

saprozoic. These have cytostome and cytopyge e.g. Paramecium or These may be absent. Digestion is intracellular

and it takes place in the food-vacuoles. Coprozoic nutrition also present in some animals.

(11) In these, excretory and respiratory organs are absent. Both these processes take place through general body

surface; and by the process of simple-diffusion. These are ammonotelic animals.

(12) Reproduction may be sexual or asexual. Asexual reproduction is more common; and takes place by Binary fission

(longitudinal transverse Budding or Multiple-fission (through spore formation). Sexual reproduction takes place by

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Hologamy / conjugation in adults eg. Paramaecium and by syngamy in plasmodium.

ANIMAL KINGDOM

(13) Life-cycle is simple in most animals. In some animals alternation of asexual and sexual generations is found.

(14) They have more capability of encystment for protection from environmental conditions and also for dispersal.

(15) They don’t have natural-death because in unicellular animals there is no division of Somatoplasm and germplasm

and so these are considered immortal.

(16) On the body of some protozoans, an exoskeleton of CaCO 3

or silica is found e.g. Radiolaria group. - Foraminifera

group.

Classification -

Protozoans are classified on the basis of locomotary organelles. It has been divided into 4 sub-phyla

(1) Sarcomastigophora

(2) Sporozoa

(3) Cnidospora

(4) Ciliophora

SUB PHYLUM - SARCOMASTIGOPHORA

(i)

Locomotary organs are pseudopodia or flagella or both,

(ii) Nucleus one or many and similar type. These are divided into 3 classes -

Class -1

Mastigophora or Flagellata :-

(i) Locomotary organs are one or many thin thread like flagella.

(ii) Many members have chlorophyll just like plants e.g. Euglena.

(iii) Their body has pellicle and so they have a definite shape.

(iv) Nucleus is only one

(v)

Binary fission is longitudinal. Sexual reproduction is absent.

(vi) Contractile - vacuole is present for osmoregulation.

(vii) Nutrition is mixotropic e.g. Euglena.

Example

(i)

Euglena :- It is a connecting link between plants and animals.

(ii) Proterospongia :- This is a colonial protozoan. It is a connecting link between protozoa and porifera (flagellated

collar cells).

(iii) Mastigamoeba :- It is a connecting link between Mastigophora and Sarcodina.

(iv) Leishmania donovani :- This parasite is responsible for kala-azar disease is man. This disease spreads through

sand fly (Phlabotamus). This parasite is dimorphic and digenetic. Disease caused by this is also known as Dumdum

fever or viscera Leishmaniasis or Tropical splenomegaly. [L.Tropica] causes - Delhi Boils (cutaneous disease)

or oriental sores disease – liver & spleen enlarges].

(v)

Trypanosoma gambiense :- This parasite causes ‘African sleeping sickness” in man. This disease spreads through

Tse-Tse fly (Glossina palpalis). T.gambiens is polymorphic- Leptomonad form, crithidial form, Trypanosomal

forms..

(vi) Trypanosoma cruzi :- It causes the disease Chagas cause American sleeping sickness, carrier - a bug Triatoma.

(vii) Giardia intestinalis :- It is termed a Grand-old man of Intestine. It causes diarrhoea Back Packer’s disease in man /

Giardiasis.

(viii) Trichomonas vaginalis :- It is a parasite in the vagina of females. It causes “Vaginitis = Leucorrhoea.”carrier -

male.

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Termites + cockroach Trichonympha symbiosis

(ix) Triconympha :- This is an symbiont in the intestine of termite and cockroach. It helps in the digestion of cellulose.

(x)

Noctiluca :- Free living / swimming, marine. It shows bioluminiscense due to Luciferic protein. Its is also called the

Fire of Sea.”

Class - 2

Sarcodina or Rhizopoda:

(1) Locomotary organs are different types of pseudopodia like

(i) Lobopodia – in Amoeba

(ii) Filopodia – in Euglypha

(iii) Reticulopodia – in Globigerina

(iv) Axopodia – in Actinophrys

Actonophrys is termed “Sun animalcule”.

(2) Body in naked so shape is changeable, some animals have different types of shells.

(3) Pseudopodia also help in feeding.

(4) Nutrition is Holozoic or Saprozoic

(5) Cytoplasm is divided into Ectoplasm and Endoplasm.

(6) Nucleus is one or many but monomorphic animals may be free-living or parasite.

(7) Contractile vacuole found in only fresh water species like amoeba. But in parasites and marine animals the

contractile-vacuoles are absent. e.g. Entamoeba histolytica

(8) Asexual reproduction normally takes place by Binary-fission, which is transverse. Sexual reproduction is

absent.

Example:-

(i)

Amoeba :- Simplest animal

(ii) Pelomyxa - chaos - This is the largest amoeba. Size = 6 mm. It is multinuceate.

(iii) Entamoeba-histolytica - It is parasite in the colon of man. If causes amoebic dysentery in man. In it contractile

vacuoles are absent. It is dimorphic (i) Magnum-Pathogenic - trophozoite stage (ii) Minuta-Nonpathogenic

(iv) Entamoeba gingivalis - It is found in between the teeth of man. It increases Pyrea disease but does not cause it.

Pyrea is caused by “Trichomonas tinax”- cause KTD - Kissing Transmitted disease..

(v)

Arcella - It has an exo-skeleton of tactin.

(vi) Elphidium Polystomella - It has multichambered shell of CaCO 3

silica and magnesium sulphate.

(vii)

(viii)

Dimorphic -

(a) Micro spheric (asexual)

(b) Megalospheric (sexual) Metagenesis (alternation of generation)

Thalassicole

Both of these haveCaCO 3,shell

Acanthometra

(ix) Allogromia - It has internal skeleton.

(x)

Actinophrys - It is termed as the “Sun animalcule” Shine like glass - Heliozoans - fresh water animal.

(xi) Entamoeba - coli - It is found in the intestine of man. It shows commensalism.

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ANIMAL KINGDOM

Class - 3

Opalinata or Protociliata -

(1) Locomotary organs are flagella which are found on the whole surface of body

(2) Body has pellicle over it

(3) Nuclei many but isomorphic

(4) Binary fission is found, sexual reproduction takes place by syngamy.

(5) Contractile-vacuole is a absent

(6) All flat and parasite in the intestine of amphibia

(7) Cytostome absent

e.g. “Opalina” - It is found as a parasite in the intestine of frog.

Characteristics :-

SUB PHYLUM·2 - SPOROZOA

(1) All the members of this group are endoparasite. These are found in cells (called cytozoic) tissues, (called histozoic)

or in vacuoles (called coelozoic).

(2) Locomotary organs are absent

(3) A thick pellicle is present in the body

(4) Cytostome, cytopyge and contractile vacuoles are absent.

(5) Binary-fission is absent, in place of that asexual reproduction takes place with the help of multiple fission.

(6) Sexual reproduction takes place by syngamy. Spore formation takes place in most of the members.

(7) Life-cycle is complex. Polar filaments are absent in spores.

Class-l

Sub-phylum sporozoa is divided into four classes on the basis of presence or absence of spores in life cycle.

Telosporea:

Sporozoites elongated and mostly find in spores Examples :-

(1) Plasmodium - Its four species spread malaria fever in man. Female anopheles is carrier of Plasmodium. Plasmodium

falciparum causes – “Malignant Malaria” or Black water fever” (cannot digest iron so passed in urine, so urine

appears black) or “Cerebral Malaria”( affect brain /madness)

(2) Monocystis :- It is found in seminal vesicle of earthworm, and causes sterility in earthworm. It is monogenetic in

nature.Main food - sperm

(3) Eimeria - It is found in epithelial cells of liver of rabbit. Cause coccidiosis

Class - 2

Piroplasmea :

(i)

Microscopic parasites of the RBC of animals in which spores are not formed, the sporozoites are naked.

Example:- Babesia - It causes the “Texas cattle fever” in animals. ,This disease also called “Red water fever” or

“Haemoglobin-uric fever”.Cannot digest Hb.

Class - 3

Toxoplasma & Sarcocystis: Muscular Parasite (Histozoic)

Example - Toxoplasma & Sarcocystis

Class - 4

Haplosorea – Holozoic

Example – Coelosporidium, Ichthyosporidium (Coelozoic)

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SUB PHYLUM 3 - CNIDOSPORA

1. Parasites of other animals like sporozoa.

2. Absence of locomotary organs and also contractile vacuoles.

3. Spore-formation takes place in life-cycle and spores are formed but unlike sporozoa, the spores have polar -

filaments.

Class - 1

Cnidospora has been classified into 2 classes on the basis of development of spores

Mixosporea :- Spores develop from many nuclei. Spore shell made of 2 or 3 valves, large size of spores.

Example - Ceratomyxa, Myxidium.

Class - 2

Microsporea :- Spores develop from 1 nucleus. Spore shell made of only 1 valve small size of spores.

Example :- Nosema - It is an endoparasite of the tissues of silk-worm. It causes harm to “Sericulture”. This disease is

called “Pebrine disease”. (Nosema bombycis)

(Nosema apis - in honey bee cause nosemiasis - affect apiculture)

1. These are very complex.

SUB PHYLUM 4 - CILIOPHORA

2. In at least one stage of life cycle cilia are present for locomotion or for feeding in adults sucking tentacles are

necessarily found.

3. Nuclei are dimorphic i.e. of two types, the bigger called Macronucleus and the smaller called Micro nucleus.

4. Body surface has a rigid-pellicle.

5. Asexual reproduction by binary fission and sexual reproduction by conjugation. Ciliophora is divided into two

classes -

Class-l

Ciliata -

1. Life-cycle is complex and a rigid-pellicle is found.

2. Locomotary organs are cilia and present on the whole body surface

3. Nutrition is Holozoic.

4. Nuclei are dimorphic, small nucleus is the micronucleus which is related to reproduction. The other is large called

Macronucleus. It regulates the vegetative functions of the animal.

5. Asexual reproduction takes place by Transverse binary fission and sexual reproduction takes place by Conjugation.

Conjugation is of different types - like - Autogamy, Hemimixis, Endomixis, Cytogamy

6. 2 contractile -vacuoles are found; present at the anterior and posterior ends of the body. These help in osmoregulation.

7. For the ingestion and egestion of food permanent pores are present. For ingestion cytostome is present and for

egestion cytopyge or cytoproct or also cell-anus is present.

8. Below the pellicle on the circumference of ectoplasm. “Trichocysts” .are found which are defence organelles.

Example

(i)

Paramecium - It is termed as the “Slipper-animalcule”. In the cytoplasm of paramecium some toxic particles are

found called “Kappa particles” and “Sigma particles”. Both these particles show cytoplasmic inheritence. Kappaparticles

produce “Paramecin which destroys the sensitive species. Paramecium which have Kappa-particles are

called killer and which don’t have them are called Non Killer.Lambda Mu Pi particles are also present in cytoplasm.

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(ii) Vorticella - It is called “Bell animalcule”. It is a pedicellate protozoan, sessile.

(iii) Didinium - It is called “Water - Bear”

(iv) Spirostomum - It is the largest living ciliate. It is 4 mm long.

(v)

ANIMAL KINGDOM

Balantidium coli- This parasite causes ulcer in the colon of man and given rise to diarrhoea. Balantidiasis.

(vi) Nyctotherus - It is a parasite in the rectum of frog. It is also found in the rectum of cockroach.

(vii) Nummulites - In the form of largest member of protozoa in the form of fossil.

Class-2

Suctoria -

1. The members of this class are sessile and stalked.

2. Locomotary organs is adults are the “Sucking -tentacles”.

3. Pellicle is found

4. Cytostome and cytopyge are absent.

5. Asexual reproduction by external budding.

6. Binary fission is absent.

7. Nuclei are dimorphic i.e. a macronucleus and a micronucleus are present, but the macronucleus is branched.

8. Only 1 contractile vacuole is present.

Example - Arcineta, Ephelota

9. All animals are sessile - pedicellate

Special facts about protozoa -

1. “Pelomyxa palustris” is the largest living protozoan.Its size is 6 mm.

2. Fastest running protozoan is “Monas stigmata”

3. Some protozoans have a loose exoskeleton called “Lorica-house” on them

4. The fastest reproducing protozoan is “Glaucoma”. It produces 6-generation within 24 hrs.

5. The longest living protozoan is “Euglena gracilis “. It lives for 20 years.

6. “Ceratium and “Noctiluca” show bioluminescense.

7. The largest euglena is “E. oxyuris”.

8. When Euglena is kept in dark, then its chlorophyll disappears.

9. Flagellates are the simplest protozoan and ciliates the most complex protozoans.

10. Polystomella is a dimorphic rhizopod which shows metagenesis or alternation of generation in its life-cycle. (i)

Megalospheric (ii) Microspheric

11. Trypanosoma when in blood causes the “Gambien-fever” and when in brain and spinalcord causes the “Sleeping -

sickness”.

12. “Heliozoans” are mainly fresh-water rhizopods and are termed “Sun - animalcules”.

13.

Mastigophora

Zoomastigophora

Phytomastigophora

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PHYLUM - PORIFERA

The animals of this phylum are of lower level multicellular, whose body is perforated. Body organisation is cellular.

Tissue system is absent. The members are commonly called sponges. Robert-grant gave the name porifera to the group

of sponges and Ellis proved that sponges are animals. The study of sponges is “Parazoology”. Poriferan and coelentrates

were classified into Zoophyta by Lamark. Robert Grant showed true animal nature.

Main - characters:

1. All members are aquatic, some are found in fresh-water while most are marine.

2. All are sessile, solitary or colonial.

3. Sponges are asymmetrical. Some sponges show radial-symmetry e.g. Leucosolenia.

4. They are either cup-shaped, cylindrical, vase-shaped or spherical.

5. Two types of pores are found on the body one through which water enter inside the body, are small and numerous

called “Ostia” (equivalent to mouth of animlas) and pores through which water goes out are called “Osculum” (large

anus).

6. Body organisation is of Cellular -grade i.e. tissues are absent.

7. Body wall is “Diploblastic”. Outer layer is ectodermal and made up of .flat cells called “Pinacocyte cells”. Inner layer

is endodermal made of peculiar collar cells called “Choanocyte-cells”(Discovered by H.J. Clarke) or the “Collarcells”.

These are found only in the sponges.

8. In between both the layers, jelly like middle layer or mesenchyme is present. In it various types of amoebocyte cells

(Highly totipotent) are present like-

(i) Archaeocytes

(ii) Collenocytes (iii) Chromocytes

(iv) Myocytes (v) Thesocytes (vi) Scleroblast & (vii) Trophocytes.

9. Canal-system is found inside the body which is of 4 types- Ascon, Sycon and Leucon and Rhagon type.

10. A big cavity is present in the body of sponges called Spongocoel or Paragastric cavity.

11. Canal system of sponges helps in excretion (ammonotelic), respiration and feeding.

12. Exoskeleton if present is made of CaCO 3

spicules or silica-spicules or spongin fibres or absent.

13. Scleroblast - cells form.

14. Digestion is intracellular and choanocyte cells help in it. Digestion takes place with the help of vacoule.

Trophocytes - distribute food in the body. Thesocytes - extra food is stored.

15. Respiratory, excretory, circulatory and nervous-systems are absent.

16. Asexual reproduction takes place by budding, segmentation or “Gemmules” (help in perennation).

Gemmules” are formed by Archaeocytes. Archaeocytes are totipotent cells. They can form any cells. The reproductive

cells of sponges are derived from archaeocyte.

17. Fertilization in sponges is “Internal” Sponges are “Bisexual” and have in them “Protogynous condition”, so in

sponge “Cross-fertilisation” is found.

18. “Myocyte cells “ surround the osculum to form a sphincter.

19. Sponges have a high capacity of regeneration.

20. They have holoblastic type of cleavage.

21. Development in sponges is indirect i.e. larva stage is found in sponges. Their larva is free-swimming

22. Larva- (i) Amphiblastula

(ii) Parenchymula

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ANIMAL KINGDOM

There are 4 types of spicules in sponges

(1) Monoaxon (2) Triaxon (3) Tetraaxon (4) Polyaxon

Diaxon spicules are absent in sponges. Sponges are “Ammonotelic”.

Porifera has been divided into 3 classes on the basis of endoskeleton.

(A) ClASS - CALCAREA OR CALCISPONGIAE

(1) All members of this class are marine.

(2) They are small in size, Length till 10 cm.

(3) They may be solitary or colonial.

(4) Skeleton is of CaCO 3

spicules. Mainly spicules are tri-radiate; some may be quadriradiate and rest monoaxon.

(5) Canal-system is of Ascon, Sycon or Leucon type.

(6) Collar cells are relatively larger.

Examples

(1) Leucosolenia (Most primitive) [Exceptionally - protandrous sponge

(2) Sycon or Scypha (Crown-sponge) or Urn sponge

(3) Clathrina

(4) Leucilla Protogynous

(5) Grantia

(6) Leucan

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[B] ClASS - HEXACTINELLIDA OR HYALOSPONGIAE

1. All members are marine.

2. These are of moderate shape and upto 1 m in length.

3. Body is rase or bell or cup-shaped.

4. Endoskeleton is made of silica-spicules, spicules are 6-rayed. These are colourless, shining and also

transparent so called “Glass-sponges”.

5. Choanocytes are in finger shaped chamber.

6. Canal system is complex leucon type.

Examples

(i) Euplectella - “Venus’s flower basket”. In Japan given as a Bridal-gift. Male and Female shrimps live in it till death.

(ii) Hyalonema - Glass-rope sponge

(iii) Pheronema - Bowl-sponge

(iv) Monorhaphis

(C) CLASS - DEMOSPONGIAE –

1. Majority are marine but some species are found in fresh water. Mostly large and asymmetrical sponges

which may be solitary or colonial.

2. In some skeleton is absent, in some of siliceous spicules, in some made up of Sulphur-containing Spongin

protein fibres skeleton, and in some skeleton is made of both spongin fibres and siliceous spicules.

3. Spicules if present are mono or tetra axon.

4. Canal-system Leucon or Rhagon type.

5. They have the capacity of contraction due to special Fibrocytes.

Example

1. Euspongia – Bath sponge

2. Spongilla - Fresh water sponge. It has zoochlorella living in it as a symbiont.

3. Ephydatia - Fresh water sponge.

4. Cliona - Boring - sponge.

5. Chalina - Mermaid’s gloves

6. Hippospongia - Horse sponge or Horny sponge

7. Phyllospongia - Leaf sponge

8. Patreon - Cup shaped sponge.

9. Oscarella - Skeleton is absent.

10. Halichondria - Bread sponge.

11. Chondrosia - Skeleton is absent.

12. Haliclona - Finger sponge.

13. Spongia officinalis - Turkish bath sponge - Great economic value.

KEY S KEY PO POINTS

E

T TS

OO IN

1. Chromocytes are pigmented amoebocytes which provide colour to the animal.

2. Gemmules are formed as endogenous buds.

3. Choanocytes of sponges were discovered by H.J. Clark.

4. Sponges have a high power of regeneration due to archaeocyte cells.

5. Several sponges pass, during their embryonic development, through a structure, called olynthus. It is

called hypothetical ancestor of sponges.

6. Monoaxon spicules are found around the osculum.

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ANIMAL KINGDOM

PHYLUM - COELENTERATA / CNIDARIA

Due to the stinging nature of coelenterate animals. Aristotle called them as Akalephe or Cnidae Members of this

phylum have a central cavity called coelenteron. So Leukart gave the name coelenterata to this phylum. Study of

members of coelenterata is termed as “Cnidology”. Hatschek on the.basis of stinging cells (cnedoblast) gave the

name “Cnidaria” to this phylum. Peyssonnel and Trembly established animal nature of colentrates.

Main - Characters

1. All aquatic mostly marine while some are fresh water species.

2. Solitary or colonial and free-living or sessile. Parasitic mode of living is absent.

3. Body organisation is of cell-tissue grade.

4. These animals have radial or biradial type of symmetry.

5. Body is diploblastic. Outer layer is termed as Epidermis or ectoderm and the inner layer is termed as gastrodermis

(endodermis). In between these two layers, cellular or acellular mesoglea is present. It is secreted by both layers.

6. In the centre of their body a large cavity is present called the coelenteron or also the gastrovascular cavity. In some

animals this cavity is divided into 6-8 chambers by septa/ mesentry. Cavity extends till the tips of tentacles.

7. Coelenteron opens to the outside through one aperture called the Mouth. Through it food is ingested and undigested

food is egested. So, alimentary canal is incomplete in them.

8. Mouth is surrounded by hollow tentacles which help in holding the prey and also in locomotion (main function).

9. In epidermis or gastrodermis or in both some special type of self regulatory cells called the Cnidoblast or nematoblast

are present. Presence of stinging cells/Nematoblasts is a characteristic feature of this phylum. These help in attack

and defence, holding the prey and also in locomotion.

10. Digestion is of two types i.e. both extra cellular as well as intracellular.

11. Respiratory, excretory and circulatory systems are absent. Exchange of gases and excretion take place through

general body surface.

12. Distinct division of labour starts from coelentrates

13. They have a primitive type of diffused nervous system. (But no system is present only tissues are present) Begining

of nervous system from coelentrates. Neurons are non-polar. Only cyton is present.

14. Members of this phylum are dimorphic and termed as Zooids. One is cylindrical and sessile polyp form and the other

is umbrella shaped and free-living medusa form. In some species polymorphism is found. If Polyp and Medusae

both are found in a group is called cormidia.

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Polyps (Asexual zooids)

1. Habit: Sedentary and colonial

2. Position: They are attached to vertical branches

of the colony.

3. Shape: They are like hollow conical sacs or

wine glass-shaped.Cylindrical structure.

4. Velum is lacking.

5. Mesoglea is like a thin layer between ectoderm

and endoderm.

6. Statocyst are absent

7. They reproduce asexually by the process of budding.

Medusa (Sexual zooids)

1. Free swimming and solitary.

2. They are formed by budding from blastotyles

and finally detach from it and become free swimming.

3. They are disc-shaped or umbrella-like structure.

4. It is present (rudimentary) around the margin of

umbrella.

5. Mesoglea is thick.

6. 8 statocyst situated at the bases of adradial tentacles

are present. They are sensory (balancing organs).

7. They reproduce sexually by the process of gametogenesis.

Polyps and Medusa are of the following types -

(A) Type of Polyp -Mostly sessile, but sometimes motile.

(l) Gastrozooids - provide nutrition/nutritive polyps /Hydranthes.

(2) Dactylozooids - provide protection/ protective polyps.

(3) Gonozoids - for asexual reproduction.

(B) Type of Medusa -

(1) Phyllozooids - For protection - protactive medusa

(2) Nectophores - For swimming/floating medusa - a bladder is present in which gas glands produce gas/air

(3) Gonophores - For sexual reproduction.

(4) Pneumatophore - Swimming medusae/free swimming

14. Reproduction is sexual as well as asexual. Asexual reproduction takes place by budding and sexual reproduction by

gametes.

15. Animal may be unisexual or bisexual.

16. In the life-cycle, there is an alternation of the asexual polyp phase and the sexual medusa phase and it is termed as

Metagenesis.

17. Have a high capacity of regeneration.

18. Development is of the indirect type. Cleavage- Holoblastula, In some animals ephyra larva is present. Ciliated free

-living “Planula” larva present. On the basis of presence and dominance of polyp and medusa form in the lifecycle

coelenterata is divided into 3 classes :-

(a) Hydrozoa (b) Scyphozoa (c) Anthozoa

CLASS (A) – HYDROZOA

1. Mostly marine, some fresh water.

2. Solitary or colonial.

3. In most members, metagenesis is found which is the alternation of the asexual polyp and sexual medusa form in the

life cycle. In some only polyp form is found e.g. Hydra.

4. Mesoglea is acellular.

5. Coelenteron is undivided.

6. Medusa is umbrella shaped and on its corners muscular folds are present called Velum. Medusa with Velum is

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termed as “Craspedote” medusa. In members of this class, polymorphism is very common.

7. Reproductive cells usually arise from the interstitial cells of the epidermis.

8. Nematoblasts absent in Gastrodermis.

Example:

1. Hydra - Freshwater animal, only polyp form. Medusa absent

ANIMAL KINGDOM

2. Obelia - “Sea fur”. It is colonial. The colony is covered by a covering of cuticle called Perisarc. The colony is

polymorphic. It has both polyp and medusa in it. Polyp is of 3 types -

(i) Hydranth or Gastrozoids - These polyp provide nutrition for the colony.

(ii) Blastostyles or Gonozoids- These are reproductive polyps and help is reproduction.

(iii) Dactylozooids - These are protective.

3. Velella - Little sail

4. Porpita.

5. Millepora - Sting coral

6. Physalia - Its different types of zooids look like war-ships, so it is called “Portugese man of war”. It also shows

polymorphism. Poison is present in cnidoblast.

7. Campanularia

8. Bougainvillea - Colonial

9. Tubularia.

ClASS [B] - SCYPHOZOA

1. All are marine and solitary.

2. Mostly free living medusa-forms, polyps is either absent or ill developed or supressed.

3. Commonly called “Jelly -fish” as in them mesoglea is thick and jelly like mesoglea contains cells and fibres.

4. Velum is absent in medusa, so also called “Acraspedote-medusa”. In place of velum 8 balancing organ statocyst or

Tentaculocyst are found.

5. Nematoblasts are present in both epidermis and gastrodermis.

6. Reproductive cells develop from the interstitial cells of gastrodermis.

7. Development indirect. “Ephyra” larval stage is found.

Example

1. Aurelia- “Jelly - fish” (Ephyra larva present)

2. Rhizostoma - Many mouths present

3. Cyanea - “Sun - Jelly” Its diameter is 2m and length of tentacles = 40 m (Largest).

4. Atolla

5. Periphylla

6. Chrysaora.

CLASS(C) - ANTHOZOA

1. All are marine.

2. Only polyp phase present. Medusa phase absent.

3. Coelenteron is divided into chambers by mesenteries.

4. Mesoglea has cells and fibres.

5. Nematoblasts present in both the epidermis and the gastrodermis.

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6. Reproductive cells form from the interstitial cells of the gastrodermis.

7. Fertilization is external. Development is indirect and Planula larval stage is found.

8. Metagenesis absent.

This class has 2 types of animals.

(i)

Anemones - External skeleton is absent.

e.g. Adamsia, Sagartia & Metridium – shows commensal with Eupagurus.

(ii) Coral- Body has an exo-skeleton made up of CaCO 3

. The exo-skeleton of one polyp is termed as the “Corallite”

and that of whole colony is termed as “Corallium”. Corals form rocks in the sea called the coral reefs. The largest

coral reef is the Great-Barrier reef which is 2200 miles long and surrounds Australia completely.

Examples

1. Madrepora - Stag-Horn coral 2. Alcyonium – Dead mans fingers.

3. Meandrina - Brain - coral. 4. Astrea – Star coral.

5. Fungia - Mushroom coral.

6. Corallium – Red – coral (economically important ( very very expensive)

7. Heliopora - Blue -coral(very expensive). 8. Antepethos – Black coral

9. Gorgonia – Sea – fan

10. Pennatula - Sea pen 11. Renilla – Sea pansy

12. Virgularia / Cavernularia - Sea walkingstick 13. Tubipora – Organ-pipe coral

14. Pteroides - Sea - feather. 15. Oculina – Eye coral

PHYLUM - CTENOPHORA

1. Ctenophora is the smallest phylum of marine animals.

2. Name ctenophora by Eschscoltz.

3. Body organisation is tissue-grade.

4. Animals acoelomate and triploblastic. Mesoglea contains like amoeba mesodermal cells called “Colloblast”. Due to

presence of colloblast, body of ctenophora becomes triploblastic.

5. They·have a “Biradial” symmetry.

6. All animals of this phylum are marine and pelagic (float on sea surface).

7. Animals are carnivorous. They feed on the eggs and larvae of Molluscs, fishes and crustaceans. Anus is absent,

8. They may be spherical, cylindrical or Pear-shaped.

9. Body is soft transparent jelly like.

10. These animals are known for their beauty and delicate nature. In sunlight their comb-plate give the effect of a

rainbow.

11. Nematoblasts are absent, so also called “acnidaria”.

12. In place of nematoblasts on the tentacles a special type of cells are present called “Lasso-cells’ which help in

catching the prey.

13. Their main characteristic feature is the presence of 8 ciliary comb plates on the body surface. These help in

locomotion so are also called “Comb-jellies”.

14. On the opposite ends of these animals a pair of long solid tentacles are present.

15. Skeletal, Excretory and Respiratory systems are absent.

16. Diffused type of nervous system, non-polar neuron.

17. All animal of this phylum are Bisexual.

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ANIMAL KINGDOM

18. Asexual reproduction is absent. Only a complex type of sexual reproduction is found. Metagenesis is absent.

19. The animals of this phylum are known as “Sea-gooseberries” or “Comb-jellies” or “Sea-walnuts”.

20. Regeneration and “Paedogenesis” is normally found.

21. Development is indirect type, life cycle involves a free living “Cydippid” larval stage.

22. Cleavage is Holoblastic, determinate and unequal.

Ctenophora is divided into 2 classes on the basis of tentacles :-

CLASS (1) - TENTACULATA

1. On the adult animals of this class 2 long solid tentacles are present. In some animals, tentacles are present only in

the larval-stages.

2. On their upper surface oral lobe and on the lower surface sensory organ statocyst is present.

Examples :-

(i) Pleuropbrachia - most primitive ctenophora

(ii) Velamen

(iii) Cestum - “Venus’s girdle”

(iv) Ctenoplana – Commensal with Alcyonea.

CLASS (2) - NUDA

1. Body of these animals is long cone like and flattened on the dorsal surface.

2. Tentacles and oral-lobes absent.

3. Mouth broad and pharynx long.

Example

1. Beroe - Swimming eye of cat.

Exception - Euchlora rubra - with cnidoblast ctinophore (Tentaculata).

PHYLUM - PLATYHELMINTHES

Platyhelminthes means Flat worms: their body is flat on dorsoventral axis. “Linnaeus” first kept them

in vermis. Phylum platyhelminthes was established by “Gagenbaur”.

Main characters -

1. Most members of this phylum are the parasites of vertebrate. Some are found in aquatic habitat.

2. Body organisation is of tissue grade level or Tissue-organ grade. i.e. cells of the body unite to form tissues which

in turn unite to form organs.

3. Body is Triploblastic i.e. body is formed from 3 germinal layers i.e. Ectoderm, Endoderm & Mesoderm

4. Body is Bilaterally symmetrical. Anterior and posterior parts are clear.

5. Locomotary organs are absent in these animals but adhesive organs are present like suckers, hook etc.

6. Their epidermis is syncytial and is sometimes ciliated. On the body wall of parasitic animals a thick cuticle is present.

Their body wall is called Tegument. Thick cuticle protects the arasite from the digestive-enzymes of the host. It is

secreted by epidermis.

7. Below epidermis muscles in the body-wall are mesodermal. Below the endodermis longitudinal circular and oblique

muscles are present (facultative aerobes).

8. Nervous system is Ladder-like and made of ganglia and nerves.

9. These are acoelomate. In between various organs a solid, loose mesodermal tissue called Mesenchyme or Parenchyma

is present.

10. Respiratory organs are absent.

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11. Except class cestoda the body of animals of the remaining 2 classes is unsegmented.

12. In turbellaria and trematoda class an incomplete, branched and without anus digestive system is present. In animals

of class cestoda, digestive system is completely absent.

13. Skeleton respiratory and circulatory systems are absent.

14. Excretory organs are protonephridia or flame-cells. Flame - cells are also termed as the “Solenocytes”. They help in

osmoregulation.

15. Sensory organs are Papillae and Amphiods.

16. Pseudometamerism.

17. All animals of this phylum are Bisexual. Reproductive system is complex and well-developed.

18. Fertilization may be self or cross and internal, cleavage-holoblastic.

19. Differentiation of head begins from this phylum (cephalization).

20. Development may be direct (in free living members / ectoparasite) or indirect (endoparasite). In indirect development,

larva may be one or of more types.

21. Anus is absent. Incomplete and branched alimentary canal.

In these animals yolk/vitelline lands are present which provide nutrition to the eggs. Phylum platyhelminthes has

been divided into 3 classes on the basis of nature and mode of life -

CLASS [1] - TURBELLARIA

1. Most animals of this class are aquatic may be marine or fresh water.

2. These are free-living and carnivorous. Some are ectoparasites.

3. Body wall has cilia which help in crawling and swimming.

4. Body is flat on dorso-ventral surface. .

5. Many cells of the epidermis of body wall secrete mucous. Epidermis has many rod shaped structure called the

“Rhabdites”.

6. Mouth aperture is far from the ends and located on the ventral-surface.

7 . Suckers are absent.

8. Body is unsegmented.

9. Reproduction is sexual, but asexual in some. Majority are bisexual.

10. Digestive system present. Alimentary canal without anus and is branched.

11. Normally members called “Eddy-worm”

12. Development is direct. Larva absent.

13. High capacity of Regeneration.

Examples

1. Planaria or Dugesia - Primitive type of helminth. If cut by a knife, then also is immortal due to regeneration power.

Cannabalism is found. It is fresh water free living animal.

2. Mesostoma

3. Macrostomum

4. Microstomum - “Enemy of Hydra.

5. Gunda

6. Convoluta - Symbiont on zoochloreila and Diatoms, algae.

7. Ichthyophaga - Parasite on fishes.

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CLASS [2] - TREMATODA

1. Members of this class are called the “Flukes” because are leaf -like.

2. All members are parasites. Some are ectoparasites while majority are endoparasites.

3. Body wall has a thick resistant covering called Tegument.

4. To attach with the tissues of the host suckers and hooks are present.

5. Sensory organs absent in adults.

6. Body unsegmented.

7. Alimentary canal dibranched. Mouth present but anus absent.

8. Majority animals bisexual.

ANIMAL KINGDOM

9. Direct development in ectoparasites and indirect development in endoparasites many larval stages are found.

Eamples

1. Fasciola - called “Liver-fluke”. It causes “Liver-rot disease in sheep. It is a digenetic parasite. Polyembryony and

metagenesis present.

Primary host - Sheep, secondary host - garden snail. Following sequential larva stage are found in Fasciola. Enter in

snail in 8 - 10 hours.

(i)

Miracidium – Free swimming stage.

(ii) Sporocyst - 5 - 8 Redia

(iii) Redia - 12 - 14 Cercaria

(iv) Cercaria - 70- 160 Metacercaria

(v)

Metacercaria

Infective stage in primary host - Metacercaria - Infective stage in sec. host - Miracidium.

Schistosoma - “Blood fluke”- digenetic [man & snail] and sexual dimorphism is found. Females are highly reduced

and are permanently present in “Gynophoric canals” of males.lt causes schistosomiasis or Bilharzia disease. Cercaria

larva enter through skin while swimming in pond.

Diplozoon - Ectoparasite on the gills of fishes. It is X shaped.

Paragonimus - Parasite in the lungs of Man, Cheetah, Pig etc. It is commonly called “Lung fluke”.

Opisthorchis - Human liver fluke or chinese-liver fluke. (most common infection in China)

CLASS [3] – CESTODA

1. All members are endoparasite’s,mainly in the alimentary canal of vertebrates.

2. Body of most animals is tape - like so called “Tape-worms”

3. Body is long and divided into segments called the Proglottids. According to modern scientists, of the body segment

represents a complete animals. So called linear colony of animals. segmentation is also termed as “False segmentation”.

4. At the anterior end a knob-like structure is present called Scolex. Scolex has 4 suckers on it. Head of the scolex is

cone-like and called “Rostellum”, it has hooks on it.

5. Digestive system is completely absent. The general body surface takes in the digested food of host in liquid form

by the process of diffusion.

6. Sensory organs are absent.

7. Thick tegument is found on the body-wall.

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8. In each body segment a complete bi-sexual reproductive system is present. In each segment complete set of male

and female reproductive organs are present. Fertilization is self and intemal.

9. The segments of the anterior body are immature and middle part are mature. In the proglottids of posterior part

fertilized eggs are filled and are called the “gravid-proglotlids”. Gravid-proglottids keep on breaking and separate

from the body. This process is called “Apolysis”. Formation of segments at anterior end by budding of is called

“Strobilization”.

10. Excretory and Nervous system present.

11. Development is indirect. Many larval stages are found.

Examples

1. Taenia solium - “Pork tapeworm”- measly pork - piece of pork which cause infection on being eaten. It is digenetic

parasite. Its has hooked embryo. Cause taeniasis

Primary host - Man - In intestine. Secondary host - pig. name of the larva of tape-worm

1. Onchophere

2. Hexacanth

3. Bladderworm

4. Cysticercus - Cause cysticerosis (more dangerous)

Infective stage in man - “Cysticercus”

Infective stage in pig - “Onchospheri”.

2. Taenia - saginata – “Beef tape worm”. It is also a digenetic parasite. Primary host - Man. It is also known as

“unarmed tape worm”. Scolex without hooks. (Rostellum also absent) Secondary host - Cow.

3. Moniezea - Endoparasite of ruminants

4. Echinococcus - “Dog tape worm”. It has only 2 or 3 proglottids. It is also called “Hydatid worm”. Hydatid cyst.

5. Hymenolepis- Endoparasite of the intestine of man. Smallest tape worm.

6. Raillietina - “Bird’s tape worm”

7. Amphilina -

PHYLUM - NEMATODA / NEMATHELMINTHES

“Linnaeus” kept them under vermis. “Rudolphi” kept the animals of this group under Nematoida.

The phylum Nemathelminthes was established by “Gagenbaur’.

Helminthology - study of flat worm + round worm.

Main - Characters -

1. Members of this phylum are thread likes so called “Thread-worms” or “Round worms”.

2. Most animals are parasite, some are terrestrial, freeliving or aquatic.

3. Majority animals are microscopic, some 1m or more in length.

4. Body organisation is of “Organ-system grade”.

5. Body is unsegmented, triploblastic and billaterally symmetrical.

6. Body is thin long, cylindrical and has pointed ends.

7. They have pseudocoel which is not lined by mesoderm. This pseudocoel develops from the embryonal blastocoel.

(beginning of coelom)

8. On the anterior part of the body, mouth and sensory organs are found but there is a lack of head.

9. A covering of thick cuticle (secreted by epidermis) is present on the body which protects the animal from the

digestive enzymes of the host.

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ANIMAL KINGDOM

10. Epidermis is syncytial and on the inner side a muscle layer divided into 4 quadrants is present, made up of

longitudinal muscles.

11. Respiratory and circulatory systems are absent.

12. Excretory system is made of excretory canals or Protonephridia. (Renette cells - H shape)

13. Nervous system has 1 brain or the nerve-ring and Anterio-posterior nerves. (Beginning of brain formation)

14. Reproductive system is developed. Animal is unisexual. Male and female are separate. Male smaller than the

females. Sexual dimorphism is found. Fertilization is internal.

15. Alimentary canal is complete. At one end mouth is present and at the other end anus is present .Phary nx is more

developed and muscular.

16. Development is direct or indirect.

17. The no. of cells is fixed in their body. The no. of the cells are formed during larval form which remains same in the

systems of the adult is called “eutely”. Nematoda has been divided into classes on the basis of caudal receptors or

phasmids.

18. Cleavage holoblastic, spiral and determinate type.

1. Members of this class lack phasmids.

2. Anterior receptors or amphids are of many types.

3. Excretory tubules less developed or absent.

4. Caudal adhesive glands present.

5. Most of them free living marine animals.

Examples

1. Desmoscolex

2. Trilobus

3. Enoplus

4. Capillaria

1. Phasmids are present

2. On the anterior part pore like amphids are present.

CLASS [1] - APHASMIDIA / ADENOPHOREA

ClASS (2) - PHASMIDIA / SECERNENTEA

3. In excretory system 1 pair of lateral tubules are found.

4. Caudal adhesive glands are absent.

Examples

1. Ascaris - Round - worm - Larva is called “Rhabditoid”.

2. Trichuris - Whip -worm

3. Trichinella - Trichina -worm- It causes Trichinosis disease.

4. Enterobius - Pin worm- It causes “Enterobiasis” or “Oxyurosis”.

5. Dracunculus - Guinea - worm

6. Loa - Loa - Eye worm, move through complete body and finally set in intestine.

7. Ancylostoma - Hook worm. It cause “sever anaemia”. Infection from moist soil.

8. Wuchereria - Filarial worm (lymph node)

It causes “Elephantiasis” is man :

This worm is “viviparous” . This worm is Digenetic. Primary host - Man, Secondary host Female - Culex, it is a carrier

of elephantiasis disease.

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PHYLUM - ANNELIDA

1. Linnaeus put all the worms (with soft body) in a separate class vermes.

2. Lamarck coined and states the phylum Annelida.

3. In annelid worms, body composition is organ system grade.

4. Members of this phylum are mostly found in sea, in fresh water or on land.

5. These animals are triploblastic, bilaterally symmetrical and true coelomate. Their long, thin and metamerically

segmented.

6. Their body cavity is true coelom and is divided into chambers by septa. This coelom ischizocoel. A fluid is filled in

coelom, it is called coelomic fluid, cells or granules are found coelomic fluid.

7. The whole structure of their “body is tube within tube” because their body itself is tube and their alimentary canal

is also tube like and alimentary canal his tube like body.

8. Digestive system is complete and digestion is extracellular.

9. Respiration is by moist skin or parapodia or gills present at head.

10. Circulatory system in annelids is complex and closed type, Respiratory pigment is haemoglobin which is dissolved

in blood plasma. It is called Erythrocruorin or intercellular haemoglobin.

11. Excretion is by nephridia which are present in segments of body.

12. Chitinous setae or parapodia or suckers are present for locomotion.

13. Nervous system is made up of a nerve ring and nerve cord. Nerve cord is situated at mid ventral side of body. Nerve

cord is double and solid.

14. Animal is unisexual or bisexual gonads are formed by coelomic cover.

15. Receptors include tentacles, taste buds, photosensitive cells, eye with lens.

16. Cleavage is spiral and determinate type. Regeneration is normally found in all annelids. Most of the members of

this phylum do not have larval stage in their life-cycles, but some members have trochophore larva in their lifecycle.

Phylum annelida is classified into 4 classes on the basis of presence or absence and position of setae.

PHYLUM ANNELIDA

Class (1) Polychaeta (2) Oligochaeta (3) Hirudenia (4) Archeannelida

Clam worm / rag worm

1. Most of the members are found in sea water.

CLASS -1 - POLYCHAETA

2. In these annelids, cephalisation is more distinct. Head is distinct with well developed eyes, tentacles and olfactory

palps.

3. In the polychaets, no of setae is numerous (poly = so many), and these setae are present on parapodia, Locomotion

is by parapodia, these also help in respiration.

4. Clitellum is absent in their members.

5. Animals are unisexual and gonads are formed only during breeding season.

6. Metamorphosis is indirect. Larval stage is called trochophore.

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ANIMAL KINGDOM

Examples

1. Nereis – It is also called Neanthes, and sand worm. During breeding season it is called Heteronereis, because

during breeding season, its body is divided into two parts, anterior asexual part of body is called Atoke and

posterior sexual portion of body is called Epitoke. This change is called “epitoky”.

2. Aphrodite – “Sea-mouse”

3. Chaetopterus – “Paddle-worm” - It shows bio-florescence.

4. Arenicola – “Lugworm”

5. Polynoe – “Scale-worm”

6. Sebella – “Peacock – worm” - contain chlorocruorim.

7. Terebella – body worm like and gills are branched.

8. Eunice – “Palalo - worm.

9. Glycera – Smooth blood worm.

CLASS -2 - OLIGOCHAETA

1. Most of the members are terrestrial, but some are aquatic also

2. Setae are found for locomotion. Number of setae is limited (oligo few). Seta is situated in microbags present in body

wall, a single seta is present in a bag. Parapodia and suckers are absent.

3. Cephalisation is absent in oligochaets, distinct head, eyes, tentacles and olfactory palps are absent.

4. Clitellum is present permanently for cocoon formation. Fertilization is external and is held in cocoon.

5. All the members are bisexual or hermaphrodite.

6. Metamorphosis is direct because larval stage is absent.

Examples

All earthworms

1. Pheritima

2. Eutyphacus - Found in north India

3. Dravida

4. Megascolex Found in south India, Megascolex is the longest earth worm.

5. Lumbricus (Ellropian earthworm)

6. Dero

7. Nais

8. Tubifex.6 , 7 & 8 are fresh water forms of class oligoclaeta. Tubifex is called “Blood worm”.

All the leeches are included in this class.

CLASS -3 - HIRUDINEA

1. Members of this class are aquatic, terrestrial, ectoparasite and sanguivorous.

2. Suckers are present at both the ends of body.

3. Saw like chitinous teeth are present in buccal-cavity.

4. Number of segments in the body is fixed ie. 33 segments are present in body. Each segment is subdivided into

numberous rings this phenomenon is called “Secondary external annulation”..

5. Hirudin - the anticoaggulant is present in the saliva.

6. Parapodia and setae are absent.

7. Citellum is temporary, which is developed only in breeding season clitellum is formed in 9-11 segments of body.

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8. Haemocoelomic system is present in leeches coelom is divided in tubes, and coelomic fluid and haemoglobin is

found in these tubes. In between the tubes, a special mesodermal tissue is filled that is called Botryoidal tissue. It

is made up of adipose tissue in which fat is stored.

9. Animals of this class are bisexual.

10. Fertilization is external.

11. Metamorphosis is direct, i.e. larval stage is absent.

Examples

1. Hirudinaria - Fresh water leechs / Indian cattle leech

Hirudo medicinalis (Medicinal leech) - Phlebotomy process of sucking impure blood by leech.

2. Glossiphonia - Fresh water leech

3. Haemadipsa - .Terrestrial leech

4. Haemopis – Horse Leech

5. Pontobdella - (Skate-suckers) - This leech is found as ectoparasite on elasmobronchi fishes of sea.

6. Acanthobdella - sctoparasite of salmon fish.

7. Bonnelia - (Sea - leech). Marine, male animal is well developed and lives permanently in the uterus (modification of)

of female. Special sex potential, larva if developed independently than form female, if in contact with female than

form male. It is unisexual animal.

1. In this class archiannelids are present.

2. External segmentation is not very distinct.

3. Parapodia and setae are absent.

4. Animals are unisexual

CLASS -4 - ARCHIANNELIDA

5. Members of this class are salt water animals with small body.

Examples

1. Polygordius - Primitive Archiannelid or living fossil

2. Protodrillus.

3. Annelids are first protostomi eucoelomate animals.

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ANIMAL KINGDOM

ANIMAL-CLASSIFICATION (ARTHOPODA TO ECHINODERMATA)

[Gr.] Arthos - joints + poda - legs / Appendages.

Aristotle classified some arthropods like crabs.

PHYLUM - ARTHOPODA

Linneaus grouped all these alike animals in a class Insecta (largest class 75%).

Von Siebold established a separate phylum Arthropoda for such animals.

This phylum includes approximately 900,000 species. 90% species of animal kingdom are included in phylum

Arthropoda.

Phylum Arthropoda is the biggest phylum of animal kingdom.

Special Features:

(1) Animals of this phylum are found in all habitat like in water, on land, in air, in earth and on trees.

(2) Their body is bilaterally symmetrical, three layered (triploblastic), and metamerically segmented and external

segmentation like annelids.

(3) Presence of jointed appendages is the main character of this phylum.

(4) “Organ - System Grade” type of level of organisation is found in this group.

(5) Body is divided into head, thorax and abdomen. Sometimes head and thorax fuse to form cephalothorax e.g.

crustaceans.

(6) Body is covered externally by thick hard chitinous cuticle. External skeleton is dead, which is secreted by hypodermis.

Body grows only after removal of external cuticle. It is called moulting.

Main compound of pro cuticle is chitin -

(i) Its molecular weight is higher and it is just like cellulose.

(ii) It is the acetate of polysaccharide, which contains Glycosamine [C 32

H 54

N 4

O 21

]

(iii) It always combined with protein.

(iv) Metabolic source of chitin is glycogen .

Flexible part of cuticle is called suture.

(7) Due to the presence of joints in arthropods, muscles are separate, where as, in annelids, continuous muscular layer

is present.

Almost all the muscles are striped. Straited muscles first of all developed in Arthoropods

(8) Modified jointed appendages are present almost at each segment for different work.

(9) Digestive system is complete.

Different types of mouth parts (oral- appendages) are found in insects, that help in intake of food.

Example:

Mouth parts

1. Chewing & bitingtype

2.Spongy type

3. Piercing type

4.Siphoning type

-

-

-

-

Example

In Periplaneta,Cymex,Romelea

In Muska

In Female Anopheles

In Butterfly,Moth

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(10) Their body cavity is called haemocoel, because it is filled with haemolymph. True coelom is reduced which is

restricted to only gonads and excretory organs. Coelom of gonads is called gonocoel and of nephrons is called

nephrocoel.

(11) Respiratory organs are of different types. e.g. in aquatic animals gills are present for respiration, in terrestrial animals

respiration is done by trachea (cockroach) or by book lungs (scorpion). In some animals respiration is held by the

diffusion from bodywall.

(12) Excretory organs are of different types. e.g. coelomoduct or special type of malpighian tubules or green glands or

coxal glands for excretion.

(13) Blood vascular system is open type in which heart and blood sinuses are found at dorsal surface and blood is

colourless but haemocyanin pigment is found in crustaceans.

(14) Cilia and flagella are totally absent in this phylum.

(15) Their structure is small due to external skeleton.

High degree of cephalization.

(16) Central nervous system includes a nerve ring and double nerve cords. Segmental ganglia are found in each segment

of nerve cord. Nerves come out from these ganglia.

(17) Their sense organs include ocelli, compound eyes, chemoreceptors, and tangoreceptor.

(18) Most of the species are unisexual i.e. male and female are separate, sexual dimorphism is present.

(19) Fertilisation is internal normally. Gonads and their ducts are paired.

(20) Animals of phylum arthropoda are most successful invaders of terrestrial environment in invertebrates. Due to the

presence of (A) Cuticle, (B) Appendages and (C) Wings

(21) These animals are oviparous or ovoviviparous.

(22) Metamorphosis is direct or indirect with one or more larval stages.

Classification :-

Storer and Eusinger have classified phylum Arthropoda into six subphyla and several classes on the basis of divisions

of body, antennae and jaws.

1. SUB PHYLUM - TRILOBITE

(1) All the members of this subphylum were (Salt water) marine animals.

(2) Their fossils are found from the bottom of sea.

(3) Body was divided into three lobes by two longitudinal fissures.

(4) Their head was not distinct.

(5) Abdomen was divided into 2 to 29 segments ..

(6) Respiration through gills and biramous legs are present on each segments except last segment. Example - Triarthrus.

2. SUB PHYLUM - CHELICERATA

(1) The animals of this sub phylum are mostly terrestrial, some aquatic.

(2) Body is divided into two parts -

Cephalothorax or Prosoma and Abdomen or Opisthosoma.

(3) On the prosoma simple eyes, a pair of chelicera, a pair of pedipalp and 4 pairs or more then four pairs of legs are

present.

On the abdomen appendages are absent.

(4) Respiration is through gills, trachea or book lungs.

(5) Excretion is through coxal - glands or malpighian - tubules.

(6) Animals are unisexual.

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(7) Most of then are oviparous & some viviparous.

This subphylum includes 3 classes -

Class (1) Merostomata

Class (2) Pycnogonida

Class (3) Arachnida.

The basis of classification of the 3 classes is respiratory - organ.

ClASS (1) MEROSTOMATA

(1) All members of this class are found in marine water of the sea.

(2) Respiration is through gills.

(3) Normally, 5 or 6 pairs of appendages are present.

(4) Telson is found on the last part of the abdomen.

(5) On its mesosoma part plate like flat appendages are found.

Example

(1) Limulus : “King - Crab” or “Horse shoe crab”. It is an example of living - fossil.

ClASS (2) ARACHNIDA

(1) Members of this class are terrestrial.

(2) They are small in size and solitary.

ANIMAL KINGDOM

(3) Body is made up of two segments, anterior segment is called cephalothorax or prosoma and posterior segment is

called abdomen or opisthosoma.

(4) On the prosoma 6 pairs of jointed appendages are present.

1 - Pair - Chelicera

1 - pair - Pedipalps

4 - Pairs - Jointed legs.

On the basis of 4 pairs of legs, Arachnida is also termed as Octapoda.

(5) Normally no appendage is found on the abdomen.

(6) Four pairs of simple eyes are present.

(7) Antennae and jaws completely absent.

(8) Respiratory organs are Book lungs or Tracheas.

(9) Heart is dorsal and tubular.

(10) Excretion is through coxal - glands or malpighian tubules. Coxal - glands are found at the base of the legs.

(11) These are unisexual. Fertilization is internal. Development is direct. Larval stage is absent.

12) These are oviparous or viviparous.

Examples

(1) Palamnaeus : Scorpion - Touch receptor is present on second segment of sternum is called Pectene. – It is

viviparous and in it cannibalism is found. After copulation female scorpion kills and feeds on the male scorpion.

(2) Book - Scorpion: Chelifer :- Telson is absent in it.

(3) Ticks : Ixodes Ectoparasites on animals, also called “Sheep - mite”

(4) Mite - Sarcoptes - Itchmate - 5 Scabies

(5) Spiders :-

(i) Cteniza - Trapdoor spider.

(ii) Lycosa - Wolf spider.

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(iii) Pholcus - House spider.

(iv) Agelena - Funnel web spider.

Spiders make web from the secretion of the glands present in the posterior part of the abdomen .

(6) Buthus

(7) Salticus

(8) Aranea - “orb webbed spider” - Book lungs for respiration and coxal gland for excretion.

CLASS (3) PYCNOGONJDA

(1) This class includes small “Sea - spiders”

(2) Body made up of cephalothorax, abdomen is less developed.

(3) Suctorial mouth is present on the proboscis.

(4) On the head 3 pairs of appendages and 4 eyes are present.

(5) Mostly 8 pairs of walking - legs are present.

(6) Respiratory and Excretory organs are absent.

Examples

(1) Nymphon : “Sea - spider” . The male conducts the eggs laid by the female.

(2) Pycnogonum

Most developed Arthropods are included in sub-phylum mandibulata.

(3) SUB PHYLUM - MANDIBULATA/ ANTENNATA

(1) Body is divided into head, thorax and abdomen.

(2) On the head, 1 or 2 pairs of antennae, 1 pair of mandibles and 2 pairs of maxillae are present.

(3) Respiration is through trachea or gills / body wall

(4) Excretion is through malpighian tubules or Antennal - glands / green gland.

(5) Eyes mostly compound.

(6) High degree of cephalisation.

This subphylum is divided further into 6 classes

Class - (1) Crustacea

Class - (3) Chilopoda

Class - (5) Symphyla

ClASS (1) CRUSTACEA

(1) Most animals of this class are aquatic.

Class - (2) Diplopoda

Class - (4) Insecta

Class - (6) Pauropoda.

(2) Body is divided into cephalothorax and abdomen.

The skeleton on the dorsal part of the cephalothorax is more thick and termed as Carapace which is made up of

Chitin + CaCO3.

(3) 5 - segments are found in the head of crustaceans which have 5 pairs of appendages –

2 Pairs - Antennae

1 Pair - Mandible

2 Pairs - Maxillae

(4) All appendages are “Biramous”. On the thorax and abdomen 12 - 19 pairs of legs are present.

(5) The legs of the abdomen are called as “Pleopods” and these are adapted for swimming.

(6) Respiration is through gills or through the body - wall.

(7) Excretion is through the coxal- glands. In some malpighian tubules are also present for excretion .

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ANIMAL KINGDOM

On the antenna of some animals, “Green - glands” are found which help in excretion e.g. Palaemon-Prawn.

(8) Eyes are compound and stalked.

(9) Animals are unisexual. Sexual - dimorphism is found. Animals are oviparous.

(10) In life - cycle many juvenile - stages are present. e.g. Nauplius, Cypris, Zoea, Mysis, Metanauplius Megalopa,

Schizopod etc.

Examples

(1) Cancer : Crab

(2) Palaemon: Prawn

(3) Eupagurus: “Hermit - Crab”

It is found in empty-shells of mollusca; and is an example of commensalism.

(4) Astacus : “Cray-fish”

(5) Hippa : Mole-crab.

(6) Daphnia : Water - flea.

It is the favourite food of hydra.

(7) Apus - Tadepole fish

(8) Palinurus: Lobster.

(9) Balanus: Rock - barnacle

(10) Cyclops: “Husband of 100 wives” only 1 eye is found.

(11) Sacculina: It is a parasite on crab. It makes the crab sterile (e.g. of parasitic castration)

(12) Cypris: Mussel- shrimp.

Note - In crustacean, respiratory pigment is haemocyanin dissolved in blood plasma.

ClASS (2) DIPLOPODA

(1) Members of this class are terrestrial.

(2) Body is long, cylindrical, worm like.

Body is divided into head, thorax and abdomen. Following appendages are found on them-

5 - segments are found 4 segments are present "9 to 100" segments present

Head has 1 pair of atennae Each segment has 1 pair Each segment is made by the fusion of

1 pair of mandible, and of jointed - legs.

1 pair of maxilla

Head Thorax Abdomen

2 segments; and so each segment has

2 pairs of jointed legs

(3) Genital opening on 3rd segment behind the head so they are called progoneate.

(4) In these poisonous claw is absent.

(5) Respiration through trachea, excretion by malpighian - tubules, unisexual, oviparous.

Examples

(1) Thyroglutus: Millipede also called the thousand leggers.

(2) Glomeris

CLASS (3) CHILOPODA

(1) Terrestrial members.

(2) Body is divided into head and trunk.

(3) Head has 1 pair antenna, 1 pair of mandibles and 2 pairs of maxillae.

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(4) Trunk is divided into 15 to 173 segments. On each segment of the trunk 1- 1 pair of jointed legs are present. On the

legs poison - glands are present.

(5) Respiration is through trachea and excretion by malpighian - tubules. Unisexual, females lay eggs.

(6) Genital opening situated at hind end of the body so that they are called Opisthogoneate.

Example:

(1) Scolopendra : Centipede

Diplopoda and Chilopoda are together kept in Myriapoda.

Word Myriapoda was given by “Laterille”.

CLASS (4) INSECTA

Characters :-

This is the largest class of the animal- kingdom.

7.5 lakh species are known. 75% of the total animals are insects.

Insecta is also termed as Hexapoda.

(1) Members of this class (insects) are found in all types of environment.

(2) Body is divided into 3 parts - Head, Thorax and Abdomen.

(3) In the thoracic part, the presence of 3 pairs of jointed legs is the main feature of class insecta.

(4) Head has 6, thorax has 3 and abdomen has 7-11 segments.

(5) In insects, 1 or 2 pairs of wings are also present:

(6) On the head a pair of compound - eyes, a pair of antennae and different types of mouth - parts are present.

(7) Salivary - glands are found.

(8) Respiration is through trachea.

(9) Excretion is by malpighian - tubules. Insects are Uricotelic.

(10) Insects are unisexual. Their eggs are centrolecithal type.

(11) Fertilization is mostly internal. Development is direct and indirect type.

Many larval stages are found -

Larva Caterpillar In silk worm.

Larva Grub In honey bee.

Larva Maggot In house fly.

Larva Wriggler In mosquito.

The pupa of mosquito is termed as tumbler

The mouth - parts of insects are the best examples of Homologous - organs.

On the basis of presence or absence of wings class insecta is further divided into 2 sub - classes-

Sub - Class (1) Pterygota

It includes winged insects.

Example

(1) Bombyx - Silk - worm

(2) Apis - Honey - bee. It is a social insect.

(3) Mosquitoes - Johnston’s organ is present on antenae which is sensitive to vibration

– Anopheles

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Culex – Are the carriers of many diseases - Such as Malaria, Elephantiasis and

}

ANIMAL KINGDOM

Aedes Dengue fever etc.

(4) “Romalea” - Grasshopper

(5) Schistocerca - Locust

This insect is “Group - dwelling” and “Migratory”.

(6) Kalotermes - termites

Social - insect. This insect harms wood.

(7) Tacnarida laca - “Lac - insect” - Lac - called shellec

(a) bangles

(b) gramophone disc

(c) printing ink

It lives on shrub; and there only secretes lac. Lac is secreted by the dermal - glands.

Sub-Class (2) Apterygota

This ·subclass has wingless insects.

Examples

(1) Pediculus - Louse

(2) Cimex - Bed - bug

(3) Lepisma - Silver fish - Ametaboly (metamorphosis absent)

(4) Xenopsylla cheopsis - Rat bug / Rat flee

This insect is the carrier of the disease, Bubonic Plague.

CLASS (5) PAUROPODA .

(1) All members are terrestrial.

(2) Minute and soft, tubular, worm like body divided into head and trunk.

(3) Trunk is divided into 11 - 12 segments and united in the dorsal paired segments.

(4) 9 - 10 pairs of legs are present.

(5) Eyes are absent.

Example -

(i) Pauropus

CLASS (6) SYMPHYlA

(1) All members are terrestrial, and their body is about 6 mm long.

(2) Eyes are absent on the head but the antennae are present.

(3) 10 - 12 pairs of locomotary organs present.

(4) Trunk divided into 15 - 22 segments.

Example - Scutigerella

SUB PHYLUM 4 - PENTASTOMIDA

(1) The members of this subphylum are the endoparasites in trachea of mammals.

(2) Body is soft, unsegmented, worm-like.

(3) Antennae and Locomotory organs are absent.

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Example-

(1) Linguatula - “Tracheal- parasite”

SUB PHYLUM 5 - TARDIGRADA

(1) Members are called “Water - bears”

(2) These are 1 mm long

(3) Body is tubular and unsegmented.

(4) 4 pairs of unsegmented, small, knob like and clawed locomotory legs are present.


Example-

(1) Echiniscus : “Water - bear”

SUB PHYLUM 6 - ONYCHOPHORA

(1) The members of this subphylum are terrestrial, thin, long and worm - like.

(2) Body is like caterpillar and unsegmented.

(3) Head not distinct but antennae and palps present.

(4) On the body 14 to 44 pairs of small knob-like legs, that are clawed, are present.

(5) Respiration is through trachea.

(6) Excretion is through nephridia.

(7) Unisexual and viviparous.

Examples -

(1) Peripatus: It is a connecting link between Annelida and Arthropoda.

Insects are useful as well as harmful.

Useful Insects

(1) Honey bee - Honey, wax. (5) Blister beetle - Cantheridine oil

(2) Silk - worm - Silk (6) Red Ants - Formic acid

( 3) Lac insect - Lac (7) Dragon flies - Larvivorous -

(4) Coccineal bug - Tannin colour (mosquitoes)

Harmful Insects

(1) Disease carrier insects -

Anopheles - Malaria fever

Culex - Elephantiasis

Tse - Tse fly - African sleeping sickness

Sand fly - Kala - azar disease

House-fly - Cholera, Diarrhoea, Dysentry, Intestinal fever.

Bed - bug - Relapsing fever

Louse - Trench fever

(2) Poisonous insects - Honey - bee, ant, bed-bug, mosquito, wasp etc.

(3) Domestic article destroying insect - termite, silver-fish, ants, crickets and cockroach.

(4) Insects harmful to crops - Locust, Pyrila

(1) Culex and Anopheles can be identified on the basis of sitting-positions. Anopheles is bent at 45° from the base.

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(2) Metamorphosis in House-fly and Mosquito is “Holometabody” type.

(3) In Periplaneta (cockroach), metamorphosis is “Paurometaboly” type.

(4) In House - fly (Musca domestica) the nutrition is “Saprozoic”

(5) Carl Van Frish got nobelprize for translation of language of Honey bee.

(6) Honey bees communicate to other members of the colony by dance and sound.

Bee message includes :

(i) Source of food supply

(ii) Food source direction in relation to sun and distance from colony

(iii) Richness of food source

ANIMAL KINGDOM

If the source is near the hive (less then 75 meters) it is conveyed by “Round dance”. But no indication of direction

of source.

Long distance source – convey distance of new source and also its direction in relation to position of sun.

[Gr.] Malacus - soft body.

“Aristotle” described few members of this phylum.

“Johnston” coined the name mollusca.

PHYLUM - MOLLUSCA

Mollusca phylum is the second largest phylum in animal kingdom. It includes approximately 80,000 species.

The study of this phylum is called Malacology, and study of the shells of molluscan animals is known as conchology.

Main characters :-

(1) Members of this phylum are found in marine water, fresh water or damp soil. These are free living or found attached

with rocks.

(2) Body organisation in these animals is of organ-system grade.

(3) Their body is bilaterally symmetrical, having three germinal layers and is unsegmented (triploblastic)

[Body is segmented in Monoplacophora.]

Most of the animals of this phylum are having asymmetrical body due to torsion. e,g, members of class

gastropoda.

(4) Body of these animals is soft and slimy, due to a thin covering of mucous all over the body. Body surface is ciliated.

(5) Body is divided into four parts - (i) head, (ii) foot, (iii) visceral mass and (iv) mantle.

Mantle is envelop like structure over the body wall, which secretes hard calcium shell.

Shell is made up of CaCO 3

and Conchiolin protein .

(6) Mouth, eye, tentacles and other sensory organs are situated on head.

[Head is absent in Pelecypoda and scaphopoda.]

(7) Foot is situated at ventral side, which is muscular, and helps creeping or swimming.

(8) All the organs are present in visceral mass.

(9) [Foot is absent in oyster]

(10) Alimentary canal is straight or U - shaped or coiled. Radula is present in the buccal cavity for grinding the food.

(11) Digestive system is well developed Digestive glands (hepatopancreas) and liver are present in these animals.

(12) Gills or ctenidia or lungs are present as respiratory organs.

(13) Circulatory system is of open type. It open in some places in Lacuna.

[Cephalopoda has closed type of circulatory system.]

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(14) Blood is colourless.

Respiratory pigment absent, but in gastropoda animals, blood has Heamocyanin pigment. This is a Cu-containing

bluish or greenish pigment.

(15) Body cavity in molluscans is called Heamocoel .

True body cavity or coelom is highly reduced type.

Real coelom is restricted only to the pericardial cavity (pericardiocoel), cavity of the gonads (gonocoel) and the

cavity of excretory organs (nephrocoel).

(16) Excretory organs are kidneys or Metanephridia.

Kidneys of Molluscans are known as “Organs of Bojanus” or Keber’s organ”

(17) Nervous system consists of paired - ganglion, connective and nerves.

(18) Eyes and tentacles are present as sensory organs.

“Statocyst” balancing organ .

“Lithocyst” is found inside the statocyst in the foot.

At the base of the gills “Osphradium” are found which are olfactory organs .

Osphradium is a “Chemoreceptor” It also helps in the selection of food and test the water current also

(19) The shell is univalved or bivalved.

Radula is absent in “Bivalvia”

(20) Reproduction of sexual. Majority members are unisexual (bisexual – snails / slugs).

(21) Fertilization may be internal or external.

(22) Asexual reproduction is absent, cleavage is spiral, determinate, unequal and holoblastic type.

(23) In the life-cycle of mollusca, one of the following larval stages are present –

(1) Veliger

Classification :-

(2) Glochidium (parasites on fish)

(3) Trochophore

The presence of chewing organ Radula and “Mantle” is the universal feature of Molluscan animals.

The animals of mollusca are classified on the following basis -

(1) Symmetry of the body

(2) Shape of the body

(3) Character of foot

(4) Mantle

(5) Respiratory organ

(6) Nervous - system

(7) Muscle.

Phylum - Mollusca is further divided into the following classes :-

CLASS (1) MONOPLACOPHORA

(1) Members of this class are found in sea water.

(2) These have characters of both Annelida and Arthropoda.

(3) Like annelids, equal segmental arrangement of 8 pair muscles, 5 or 6 pair of gills and 5 pairs of nephridia.

Body is bilaterally symmetrical and segmented; but then also these are considered as Molluscans because

(i) Presence of Mantle and dome-shaped shell on the body and

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(ii) Broad and flat muscular foot for locomotion.

Example

These animals are probably a connecting link between Annelida and mollusca.

ANIMAL KINGDOM

(1) Neopilina - This is a connecting link between annelida and mollusca. It is an example of a living fossil and most

primitive molluscan.

CLASS (2) APLACOPHORA

(1) Lower grade, worm like marine-molluscs.

(2) Body is smalls and covered by a thick mantle.

(3) Shell absent, spicules containing calcium present in mantle.

(4) Foot reduced or absent.

(5) Mostly unisexual.

Example –

(1) Neomenia

CLASS (3) POLYPLACOPHORA

“Von Ihering” gave a new name “Amphineura” to this class.

(1) All members found in sea-water.

(2) Body billaterally symmetrical. Absence of distinct head.

(3) Shell may be present or absent.

(4) Radula is present.

Example -

(1) Chiton - “Sea - micca” or mice

CLASS (4) SCAPHOPODA

(1) All members are found in sea-water.

(2) Shell is tubular and open at both the ends.

(3) Distinct head, eyes are absent.


(5) Foot is cylindrical, adapted for burrowing habit.

Example -

(1) Dentalium - “Tusk - shell”

ClASS (5) GASTROPODA

(1) This class includes snails, whelks, cyprea.

(2) Members of this class are found in fresh water, sea- water or moist-soil.

(3) Body of the members is coiled and asymmetrical due to torsion. Shell is also mostly coiled.

(4) Head is distinct. Eyes and tentacles are present.

(5) Radula is present.

(6) Foot is large, flat, muscular and strong and is used for crawling.

(7) Gills or pulmonary sacs or both may be present for respiration. Gills are termed as tenidia.

(8) Nervous system has 4 pairs of paired ganglia.

(9) May be unisexual or bisexual. In some bisexual members (like underground snail), in one gonad both male and

female parts are present. Such gonad is termed as the “Ovotestis”.

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(10) Mostly “Trochophore” or “Veliger” larval stages are found in the life - cycle.

Example

(1) Pila - “Apple-snail”

(2) Aplysia - “Sea - hare”

(3) Doris - “Sea - lemon”

(4) Turbinella - “Shankh”

(5) Cyprea - “Cowrie” old units of money

(6) Limax - “Slug”; Bisexual

(7) Patella - “Limpet”

(8) Fissurella - “Key-hole limpet”

(9) Planorbis - “Garden-snail”

(10) Xancus - The holychank

(11) Turbo - Cat’s eye

CLASS (6) PELECYPODA OR BIVALVIA OR LAMELLIBRANCHIATA

[Highest economic class] .

(1) Marine or fresh - water mussel.

(2) Body billaterally symmetrical and flat on the lateral sides.

(3) The mantle and the shell are divided into 2 valves. so called bivalvia.

(4) Head, eye, tentacles and Radula absent.

(5) Foot is plough-shaped.

(6) Nervous system has 3 pairs of main ganglia.

(7) Gills are “W” shaped.

(8) Animals are unisexual

(9) Life-cycle includes “Trochophore” or “Glochidium” larval stages.

Example

(1) Solen - “Blade-fish”

(2) Teredo - “Ship-worm”

[This mollusc bores the wood]

(3) Unio - “Fresh-water mussel”

[Detritus feeder]

(4) Mytilus - “Marine mussel”

(5) Pecten - “Scallop”

(6) Spondylus - Edible oyster

(7) Pinctada vulgaris & Pteria -”Indian Pearl oysters”

Pearl is obtained from it.

Mantle secretes many layers around sand particles to form a pearl.

(8) Ensis - “Razor-clam”

(9) Lamellidens

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CLASS (7) CEPHALOPODA

(1) Found in marine water. The members of this class are the most developed molluscs.

These are free-living.

(2) Exo and endoskeleton may be present or absent.

(3) Body is billaterally symmetrical.

(4) Mantle is thick and muscular.

ANIMAL KINGDOM

(5) Most members have “Exhalant - siphon” for locomotion, for this they fill the mantle-cavity with water and give a fast

jet of water out and swim along with this jet of water (This is jet like mechanism).

(6) Just like vertebrates, large eyes are present on the developed head. Radula is present.

(7) Foot surround the head and is divided into many arms on which many small suckers are present.

(8) On the arms, ink-glands are present which help in protection.

(9) Majority animals don’t have a shell

External shell may be present in some like Example - Nautilus, Argonauta

Some have internal shells like - Sepia

All have an endoskeleton made up of cartilage.

(10) Nervous system is highly developed

(11) Larval stage is absent in the life-cycle

(12) Animals are unisexual

(13) Members of this class are the “Largest invertebrates”

Example:-

(1) Sepia - “Cuttle - fish”- Inside the body of sepia, chromatophores are present on entire surface

It has 10 arms.

(2) Octopus - “Devil-fish”

It has 8 arms and is devoid of shell

(3) Argonauta - “Paper-shell”

(4) Nautilus

(5) Pachydiscus

(6) Loligo - Squid or Sea - arrow

(7) Tethys - “Sea - fly”

Architeuthis – Members of this class are giant-squids. These are the “Largest invertebrates”

These are 18 m long and 6 m thick. It is also called “Giant Atlantic squid”

Important point about molluscs -

(1) Precious pearl of the size of tennis-ball is made by a mollusc - Tridacna.

(2) A structure called “Hectocotyl” is present in the members of the class cephalopoda, which is a modified arm. This

structure helps in Sperm-transfer.

(3) “Planorbis” and “Lymnaea” are the secondary hosts of Fasciola hepatica.

(4) Shell is multivalved in Polyplacophora.

(5) “Nacre layer” is called “Mother of Pearl: This layer is made up of CaCO 3

and chonchiolin protein

(6) Dentalium has a cylindrical foot.

(7) Complete close blood vascular system is found in Cephalopods and blue blood is found in Octopus and Loligo.

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The phylum was given this name by Jacab Klein.

PHYLUM - ECHINODERMATA

Lamarck put its members under order Echinodermis of class Radiata.

Leuckart designated this group as phylum.

Almost 6000 live and 20,000 extinct species are known in this phylum.

Main characters :-

(1) Except Synapta similis, the whole phylum is marine.

(2) Body is multicellular, triploblastic and bilaterally symmetrical in larval stage but after metamorphosis, pentamerous,

radial symmetry is found in adults.

(3) Their skin is spiny in which calcium spines are found.

(4) Body is unsegmented, globe-shaped, round like a star, polyp shaped or elongated.

(5) Distinct head and brain absent.

(6) Most animals are pentamerous body having a centraldisc. five arms are attached with the central-disc.

On the central - disc, mouth and anus are present.

The surface having mouth is termed as the oral-surface.

On the oral surface radial-fissures are present which extend from the centre to the circumference and called the

“Ambulacral grooves”

In these fissures tube-feet are present which help in locomotion, feeding, stimuli-reception and also helps in

respiration.

(7) The body surface of these animals is rough and leathery. On the body wall movable spines of CaCO 3

are present.

(8) On the body wall “Pedicellariae” are found which are organs of defense.

(9) They have a true body - cavity which is enterocoelic type. Coelom is surrounded by ciliated peritoneum.

Coelom is divided into many tubes and sinuses, which together form 3 systems -

(i) Water vascular system.

(ii) Haemal system.

(iii) Perihaemal system.

Haemal and perihaemal systems are related to blood - conduction.

Blood is colourless and devoid of respiratory pigments.

(10) Respiratory organs include “Bronchial”, Tube - feet” , “Respiratory tree” .

(11) Alimentary canal is straight or coiled. Digestion is “extra - cellular”

(12) For locomotion it has tube feet, water vascular system and mostly one madreporite.

(13) Members of this phylum don’t have the excretory - organs. Excretion takes place through general body - surface.

(14) Nervous - system and sensory - organs are less developed. Central nervous system is absent.


(16) Fertilization is external.

(17) These have a high power of regeneration.

(18) Development is indirect. Life - cycle also includes some larval stages like -

Bipinnaria

Auricularia

Doliolaria

Pluteus

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Echinopluteus

Ophiopluteus

(19) No parasitic forms are present. No animal is microscopic.

Classification :-

ANIMAL KINGDOM

On the basis of shape of body, characters of skin skeleton, position of anus, functions of vascular system and

digestive system. “Fell” classified this phylum into 4 subphyla.

But all members of subphylum Homalozoa have become extinct.

SUB PHYLUM (1) ECHINOZOA

(1) Body of animals is round and stalkless

(2) Arms are absent.

(3) Suckers are present on tube feet.

Present species are divided into 2 dasses -

CLASS (A) HOLOTHUROIDEA

(1) These are normally called as the “Sea - Cucumbers”.

(2) Arms are absent. Body is long, thick and tubular like the cucumber.

(3) On the anterior end mouth and on the posterior end anus is present.

(4) Around the mouth hollow tentacles are present.

(5) Tube - feet are present and have suckers on them.

(6) Spines and pedicellaiae are absent on the skin.

(7) For respiration and excretion , two long branched tubules are extended into the coelom called the Respiratory - tree.

Example

Their larval stage is termed as the “Auricularia”.

(1) Holothuria

(2) Synapta

(3) Cucumaria - “ Sea - cucumber”

(4) Thyone

CLASS (B) ECHINOIDEA

(1) This class includes “Sea - urchins” and “Sand - dollars”.

(2) Body is round (like sea - urchin) or disc - shaped (Sea - cakes).

(3) On the body surface movable spines are present. Pedicillariae has 3 jaws.

(4) Arms are absent.

(5) Mouth is on the lower pole and is surrounded by 5 hard teeth which are used for chewing the food and they form

an apparatus called the - “Aristotle’s lantern” (eg - sea - urchin)

(6) Locomotion is through tube - feet having suckers.

(7) Anus is present.

(8) Larval stage is Pluteus or Echinopluteus.

Example

(1) Echinus - “Sea - Urchin”

(2) Salmacis - “Sea - cake”

(3) Clypeaster - “Sand - dollars”

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(4) Diadema

(5) Echinocardium - “Heart urchin” - Lophophores are present

SUB PHYLUM (2) CRINOZOA

All the living members of this sub phylum are classified in a single class -

CLASS (A) CRINOIDEA

(1) From the central disc, 5 or in the multiples of 5, branched arms come out.

(2) Around the central disc, a cup shaped shell of calcium plates is present called the calyx.

Calyx is attached to any object by a stalk or lower aboral surface.

(3) On the upper surface of the calyx on one side mouth and on one side anus is present.

(4) Five ambulacral fissures extend from the mouth till the end of arms.

(5) Central - disc has tube - feet without suckers on them.

(6) Pedicellarie and spines are absent on the skin.

(7) Larval stage is “Doliolaria”

Example :-

(1) Antedon - “Sea - lily” or “Feather - star”

(2) Holopus

SUB PHYLUM (3) ASTEROZOA

(1) Freely motile

(2) Arms highly developed

Classified into 2 main classes –

ClASS (A) ASTEROIDEA

(1) Members of this class have a flat and star like body.

(2) Commonly called “Star - fishes”

(3) Arms 5 or in multiples of 5. Arms are small and unbranched.

(4) Mouth on the lower surface of the central- disc and anus on the upper surface of the central disc.

Mouth is 5 - angled and called the Actinostome.

(5) Near the anus a sieve - plate is present called Madreporite. It is a part of water - vascular system.

(6) Tube - feet with suckers.

(7) Skin has spines and pedicellaiea.

(8) Larval stage - Bipinnaria or Brachiolaria.

Example

(1) Asterias- “Star-fish” or Asteropectin

(2) Solaster - “Sea - star”

(3) Pentaceros - “Oreaster” or “Sea pentagen”

It destroys oyster; so it harms the “pearl industry”.

(4) Asterina.

ClASS (B) OPHIUROIDEA

(1) From the central-disc, 5 arms originate. Arms are long and jointed.

(2) Mouth is present on the upper surface at the centre. On the lower surface madreporite is present.

(3) Anus and pedicellariae absent.

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(4) Tube-feet are arranged in 2 rows. Tube-feet don’t have suckers. They don’t help in locomotion.

(5) Larva - Ophiopluteus.

Example

(1) Ophiothrix - “Brittle - star”

(2) Ophiura

(3) Ophioderma

(4) Gorgonocephalus - “Basket - star”

(5) Ophiopholis.

Largest star fish - Pycnopodia helianthoides.

Largest urchin - Echinostome holacantha

Echinoderm is termed as the lateral branch of the animal-tree.

ANIMAL KINGDOM

As a result of biological development, primary characters can be seen again so they show retrogressive

evolution.

Water vascular system helps in locomotion, respiration and feeding.

These are the only deuterostomians in Invertebrates.

Star fish shows the process of removal of self-organs. This is termed as Autotomy.

Tied man’s bodies projecting inwards from the ring canal and madreporite opens into the ring canal through the

stone canal.

Endoskeleton is formed by many dermal plates are called Ossicles.

At the time of anger or irritation, Sea cucumber throw away its all visceral organs, except body wall. This

phenomenon is known as Evisceration. Immediate new organs are formed by regeneration.

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Kingdom

ANIMALIA

Level of

organization

Cellular

level

Tissue/Organ system

Symmetry

Body cavity

or coelom

Mostly

asymmetric

Radial

Cnidaria

Ctenophora

Bilateral

Acoelomates Pseudocoelomates Coelomates

Phylum

Porifera

Platyhelmin Aschelminthes Annelida

Arthropoda

Mollusca

Echinodermata

Chordata

1. INTRODUCTION

Animals show different types of of body organisation

(i) Protoplasmic level

Eg. - Protozoa

(ii) Cellular level

Eg. - Porifera

(iii) Tissue level

Eg. - Coelenterata & Ctenophora

(iv) Organ/organ system level Eg. - Platyhelminthes onwards to Chordata.

Animals can be Asymmetric, Radial and Bilateral symmetric.

Most of the animals are triplobastic.

Flatworms are Acoelomate, Round worms are pseudocoelomate where as rest of the animals are coelomates. Digestive

tract is incomplete in coelenterata, ctenophora and platyhelminthes where as it is complete in rest of the phyla.

Modes of respiration can be Body surface, cutaneous branchial and pulmonary.

Circulatory system is open in Arthropoda, Mollusca, Echinodermata, Hemichordata and in Urochordata where as it

is closed in annelida and rest of the chordates

Modes of Excretory system includes Flame cells, Nephridia. Malpighian tubules, Green glands and Kidneys in

animals.

2. PORIFERA

Mostly marine, cellular level body organistation with water transport system / Canal system having ostia, osculum

and choanocytes (Collar cell) etc.

Sponges are hermaphrodite and their Fertilization is internal.

Eg. - Sponges, Like - Sycon (Scypha), Spongilla (Fresh water sponge), Euspongia (Bath sponge)

3. COELENTERATA

Mostly marine, radially symmetrical with stinging cell known as Cnidoblast. Mainly two forms i.e. polyp & medusa

which exibit alternation of generation (Metagenesis)

Eg. - Hydra Aurelia (Jelly Fish), Adamsia (Sea anemone), Pennatula (Sea pen), Gorgonia (Sea Fan), Meandrina (Brain

coral), Physalia (Portuguese man-of-war).

4. CTENOPHORA

Exclusively marine popularly known as sea walnuts or comb jellies due to presence of 8-cillary comb plates which

help in locomotion. They show Bioluminescence.

Eg. Ctenoplana, Pleurobrachia

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ANIMAL KINGDOM

5. PLATYHELMINTHES

They are known as Flatworms and mostly endoparasitc. Hooks and suckers are found.

Eg. Taenia, (Tape worms), Planaria, (High regeneration of capacity), Fasciola (Liver Fluke), etc.

6. ASCHELMINTHES / NEMATODA

They are known as round worm. Complete Alimentary Canal with muscular Pharynx. Sexual dimorphism is well

marked. Often male is small with curved tail where as Female is large & straight.

Eg. Ascaris (Round worm), Wuchereria (Filaria worm), Ancyclostoma (Hook worm).

7. ANNELIDA

Body surface with segments or metamere. Possess Longitudinal and circular muscles. Parapodia help in swimming.

In Nervous system, nerve cord is double, mid ventral, solid and gangliated

Eg. Nereis, Pheretima (Earthworm), Hirudinaria (Blood sucking Leech).

8. ARTHROPODA

Arthropoda is the largest phylum with jointed appendages and chitinous exoskeleton. Mainly body is divided into

head, Thorax and Abdomen. Few Arthropods have economic importance and few are vectors for various pathogens

statocysts balance organs are present.

Eg. (i) Economically important insects - Apis, Bombyx, Laccifer

(ii) Vector - Anopheles, Culex, Aedes.

(iii) Gregarious pest - Locusta (Locust)

(iv) Living fossil - Limulus (king crab)

9. MOLLUSCA

It is the second largest phylum. Basically they are soft body and hence covered with calcareous shell. Normally

body is divided into Head, muscular foot and visceral hump. Spongy fold mantle and rasping organ for feedingradula

is also found “Eg. Pila, Pinctada, Sepia, Loligo, Octopus, Aplysia, Dentalium, Chaetopleura (Chiton)

10. ECHINODERMATA

An exclusively marine phylum and having spiny body. Their larva is bilateral symmetrical where are adult is radially

symmetrical. They have an endoskeleton of calcareous ossicus. “Unique water vascular system helps in locomotion,

nutrition and respiration “Eg. Asterias (Star fish), Echinus (Sea urchin) Antedon (Sea lily), Cucumaria, Ophiura

(Brittle star)

11. HEMICHORDATA

Earlier considered as sub-phylum of chordata. Body is divided into proboscis, collar & Trunk. Animals are worm like

Eg. Balanoglossus, Saccoglossus.

CHORDATA

PROTOCHORDATA

(Acrania)

EUCHORDATA

(Craniata)

UROCHORDATA CEPHALOCHORDATA VERTEBRATA

Sub-phylum

AGNATHA

(Lacks Jaw)

class

GNATHOSTOMATA

(bears Jaw)

CYCLOSTOMATA

PISCES

classes

TETRAPODA

classes

Chondrichthyes

& Osteichthyes

Amphibia

Reptilia

Aves

Mammalia

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12. CHORDATA

Chordata are fundamentally characterised by presence of Notochord, dorsal hollow Nerve cord and paired pharyngeal

gills slits.

There are three sub-phylas of chordata -

(i) Urochordata - Eg. Herdmania, Ascidia, Salp

(ii) Cephalochordata Eg. Amphioxus or Branchiostoma (Lancelet)“Urochordata and Cephalochordata are also

known as Protochordata.

(iii) Vertebrata - This subphylum is divided as Agnatha and Gnathostomata.

Agnatha do not possess jaw where as Gnathostomata possess Jaw.

Cyclostomata are agnatha and considered as most primitive vertebrates. Gnathostomata has two super classes Pisces &

Tetrapoda

Class chondrichthyes (Cartilaginous) and osteichthyes (Bony) are pisces classes and bear fins for locomotion.

Tetrapoda divides into four classes - Amphibia, Reptilia, Aves and Mammalia. They have two pairs of Limbs and thus

grouped under tetrapoda.

Amphibian have adapted for both on Land and water where as reptiles are characterised by the presence of dry and

cornified skin and thus considered as successful terrestrial animals.

Fishes, Amphibians and Reptiles are poikilothermic (cold blooded) where as Aves and mammals are Homothermic (warm

blooded). Birds with feathers on their bodies.

Their fore limbs modified into wings where as hind limb are adapted for walking, swimming and clasping .

The most unique mammalian charateristic is the presence of mammary glands. Skin is hairy and presence of diaphragm

are salient features of mammals. Pinna are also present. All are homeothermic animals.

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Animal Kingdom

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