Taxonomy 2201 Unit 2.pdf

Taxonomy 2201 Unit 2.pdf

Prokaryotic Cell

Eukaryotic Cell

• Autotrophs capture the light energy from

sunlight and convert it to chemical energy

they use for food.

• Heterotrophs must get energy by eating

autotrophs or other heterotrophs.

• Decomposers, aka saprobes, are heterotrophs

that recycle dead organisms by breaking them













•Common name














Taxonomy is the science of grouping

and naming organisms.

• Classification the grouping of

information or objects based on


•We only know about a fraction of the

organisms that exist or have existed on Earth.

•Taxonomists give a unique scientific name to

each species they know about whether it’s alive

today or extinct.

• The scientific name comes from one of two

“dead” languages – Latin or ancient Greek.

Why use a dead language?

Devil Cat

Ghost Cat

Mountain Lion

Screaming Cat


Florida Panther


•There are at least 50 common names for

the animal shown on the previous 7 slides.

•Common names vary according to region.

•Soooo……why use a scientific name?

Binomial Nomenclature

•a two name system for writing scientific names.

•The genus name is written first (always Capitalized).

•The species name is written second (never capitalized).

•Both words are

italicized if typed or underlined if hand written.

Example: Felis concolor or F. concolor

Which is the genus? The species?

"Formal" scientific names should have a third

part, the authority.

The authority is not italicized or underlined.

The authority is written as an abbreviation of

the last name of the person responsible for

naming the organism. Since Carolus Linnaeus

was the first person to name many plants, the L.

for Linnaeus is very common in plant scientific


An example is Quercus alba L.

Phylogeny, the evolutionary history of an

organism, is the cornerstone of a branch of

biology called systematic taxonomy.

Systematics, as systematic taxonomy is

commonly called, is the study of the

evolution of biological diversity.

A phylogenetic tree is a family tree

that shows a hypothesis about the

evolutionary relationships thought to

exist among groups of organisms. It

does not show the actual evolutionary

history of organisms.

Why a hypothesis?

Phylogenetic trees are usually based on a

combination of these lines of evidence:

Fossil record


Embryological patterns of


Chromosomes and DNA








Adaptive Radiation -

Modifies homologous structures

Convergent Evolution

These animals have evolved similar adaptations

for obtaining food because they occupy similar

niches. What can you infer about their

phylogeny from their geographic locations?

Convergent evolution leads to……….

Analogous Structures -

•Traits that are morphologically and

functionally similar even though there

is no common ancestor.


Cladistics - is a relatively new

system of phylogenetics

classification that uses shared

derived characters to establish

evolutionary relationships. A

derived character is a feature

that apparently evolved only

within the group under



There are three basic assumptions

in cladistics:

1.Organisms within a group are

descended from a common


2.There is a bifurcating pattern of


3.Change in characteristics

occurs in lineages over time.

A phylogenetic tree based on a

cladistic analysis is called a


What derived character is shared by

all the animals on the cladogram on

the next slide?

The acacia and its

ants are an example

of coevolution. Each

influences the others


Can you think of any

other examples of


Punctuated Equilibrium

“instead of a slow, continuous movement,

evolution tends to be characterized by long

periods of virtual standstill ("equilibrium"),

"punctuated" by episodes of very fast

development of new forms”

The "punctuated equilibrium" theory of Niles

Eldredge and Stephen Jay Gould was proposed

as a criticism of the traditional Darwinian

theory of evolution…what is it called?

The Dichotomous Key

• A key is a device for easily and quickly


an unknown organism.

• The dichotomous key is the most widely used

type in biological sciences.

• The user is presented with a sequence of

choices between two statements, couplets,

based on characteristics of the organism. By

always making the correct choice, the name of

the organism will be revealed.

A. one pair of wings


B. Two pairs of wings

• Domain Archaea

– Includes newly discovered cell types

– Contains 1 kingdom – the Archaebacteria

The Three Domains

•Domain Bacteria

– Includes other members of old kingdom Monera

– Has 1 kingdom – the Eubacteria

•Domain Eukarya

– Includes all kingdoms composed of organisms made

up of eukaryotic cells

– Protista

– Fungi

– Animalia

– Plantae

The major classification levels,

from most general to most specific

(several of these have subdivisions)

A group at any level is a taxon.

Categories within Kingdoms

Kingdoms are divided into groups called phyla

Phyla are subdivided into classes

Classes are subdivided into orders

Orders are subdivided into families

Families are divided into genera

Genera contain closely related species

Species is unique

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