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Name ___________________________________________________________________
Date ____________
Class ______________
Content Mastery
CHAPTER
28
WHAT IS AN ANIMAL?
Get the Big Picture
Read the paragraph in the box. Then study the picture and answer the questions.
There are so many kinds of animals that it is nearly impossible to describe just what an
animal is. All animals, however, have some things in common. All animals have some kind of
shape. Scientists often identify animals by their shape and symmetry—the balance in their body
proportions. All animals go through a developmental stage when they go from a single cell to an
adult. They also have a life cycle they pass through as they grow. All animals have some way to
reproduce. Most animals interact with their environment in some way. And all animals must
reproduce if their species is going to survive.
Some Characteristics of Animals
Shape or Symmetry
None
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Sponge
Radial
Bilateral
Starfish
Human
Development
One cell
Blastula
Animals
Protection and Support
Crab
exoskeleton
Cat
endoskeleton
a single cell
1. What do all adult animals develop from? ______________________________________________
2. A sea urchin is related to a starfish. What kind of symmetry do you think a sea urchin would
radial symmetry
have? ____________________________________________________________________________
3. What kind of skeleton do you have? __________________________________________________
I have an endoskeleton because it is on the inside of my body.
__________________________________________________________________________________
BIOLOGY: The Dynamics of Life CHAPTER 28
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