Content Outline for Teaching - Potosi School District - Home

17
Section 4
Content Outline
for Teaching
Arthropods and Echinoderms
Invertebrate Animals
Underlined words and
phrases are to be filled
in by students on the
Note-taking Worksheet.
A. Arthropods—have appendages such as claws, legs, and antennae plus an
exoskeleton
1. Insects—such as ants have three body regions called the head, the thorax,and
the abdomen
a. Open circulatory system transports food and waste but spiracles gather
oxygen.
b. Insects change body form in process called metamorphosis.
2. Arachnids—such as spiders have two body regions called the cephalothorax
and the abdomen plus four pairs of legs
3. Centipedes and millipedes—long, thin, segmented animals
a. Centipedes—predators with one pair of jointed legs per segment
b. Millipedes—plant eaters with two pairs of jointed legs per segment
4. Crustaceans—water animals such as lobsters usually having two pairs of
antennae, three types of chewing appendages, and five pairs of legs
B. Echinoderms—have radial symmetry
1. Diets vary—some are predators, some are filter feeders, some eat rotting material
2. Echinoderms have spiny skin covering an internal skeleton of plates.
3. Echinoderms have a water-vascular system to help them move and eat.
4. Some echinoderms can reproduce through regeneration from parts.
Discussion Question
How do arthropods differ from echinoderms in symmetry? Arthropods tend to be bilateral;
echinoderms are radial
Invertebrate Animals 58