Download What is an animal - Whitewater Middle School

What is an animal
Definition: an animal is a many-celled organism that feeds on other organisms
Structure of Animals
Many-celled organisms.
These cells are organized into higher levels of structure including tissues, organs and systems.
-a group of similar cells that perform a specific function is called a tissue (ex: nerve, bone, muscle tissue)
-Tissue may combine to form organs = a group of several different tissues (ex: frog’s thigh bone is made up
of bone tissue, nerve tissue and blood.) An organ performs much more complicated functions than tissues
could perform alone.
-Groups of structures that perform very broad functions are called systems. (ex: skeletal, nervous system…)
Function of Animals
Major functions are to:
obtain food and oxygen
keep internal conditions stable
move
reproduce.
Structure or behaviors that allow animals to perform these functions in their environment are called adaptations
Animal Symmetry
- a balanced arrangement of parts in some animals is called symmetry
- bilateral symmetry – two sides are mirror images of each other (humans, fish)
o tend to be larger and more complex than radial.
o Distinct front end with sense organs streamlined bodies that help them move.
- radial symmetry – many line of symmetry (think of spokes on a wheel or slices of pizza – sea star,
jellyfish).
o No distinct front or rear end.
o All of them live in water
o most do not move fast
- some animals have no symmetry (sponges)