by Miller & Levine
[complete Table of Contents]
the pull-down menu to jump to any of the Book's 40 Chapters:
American rubyspot [Hetaerina
americana] from "The
Damselflies of Texas."
Arthropods and Echinoderms
chapter, students will read about the general characteristics and major
types of arthropods and echinoderms, with special emphasis on insects.
The links below lead to additional resources to help you with this chapter.
These include Hot Links to Web sites related to the topics in this chapter,
the Take It to the Net activities referred to in your textbook, a Self-Test
you can use to test your knowledge of this chapter, and Teaching Links
that instructors may find useful for their students.
28-1: Introduction to the Arthropods
a segmented body, a tough exoskeleton, and jointed appendages.
In many groups
of arthropods, continuing evolution has led to fewer body segments and
highly specialized appendages for feeding, movement, and other functions.
When they outgrow
their exoskeletons, arthropods undergo periods of molting.
28-2: Groups of Arthropods
classified based on the number and structure of their body segments and
appendages, particularly their mouthparts.
have two pairs of branched antennae, two or three body sections, and chewing
mouthparts called mandibles.
mouthparts called chelicerae and two body sections, and most have four
pairs of walking legs.
jaws, one pair of antennae, and unbranched appendages.
Insects have a
body divided into three partshead, thorax, and abdomen. Three pairs
of legs are attached to the thorax.
The growth and
development of insects usually involve metamorphosis, which is a process
of changing shape and form. Insects undergo either incomplete metamorphosis
or complete metamorphosis.
Ants, bees, termites,
and some of their relatives form complex associations called societies.
characterized by spiny skin, five-part radial symmetry, an internal skeleton,
a water vascular system, and suction-cup-like structures called tube feet.
The water vascular
system carries out many essential body functions in echinoderms, including
respiration, circulation, and movement.
Classes of echinoderms
include sea lilies and feather stars, sea stars, brittle stars, sea urchins
and sand dollars, and sea cucumbers.