Section 1- What is an Animal? Chapter 1 Section 1- What is an Animal?

Structure of Animals Cell – Basic unit of structure and function in living things Group of cells – tissue – organ Groups of structures that perform the broadest functions of an animal are systems.

Functions of Animals The major functions of animals are to obtain food and oxygen, keep internal conditions stable, move, and reproduce.

Obtaining Food and Oxygen Obtains food by eating other organisms Food provides animals with raw materials for growth To release energy from food, the body’s cells need oxygen.

Keeping Conditions Stable Animals must maintain a stable environment within their bodies. If the balance is lost, the animal cannot survive for long. Cells that get too hot start to die = dogs panting

Swimming, walking, hopping Movement Swimming, walking, hopping Movement is related to meeting the basic needs of survival and reproduction.

Reproduction Sexual reproduction – develops from the joining of 2 sex cells (fertilization) Asexual reproduction – process by which a single organism produces a new organism identical to itself.

Classification Of Animals 35 major groups each of which is called a phylum Animals are classified according to how they are related to other animals. These relationships are determined by an animal’s body structure, the way the animal develops, and its DNA

Invertebrates – Without a backbone Vertebrates – Have a backbone Classification Invertebrates – Without a backbone Vertebrates – Have a backbone 97 percent are invertebrates

Section 2 Animal Symmetry

Bilateral – 1 line that divides it into halves that are mirror images Animal Symmetry Bilateral – 1 line that divides it into halves that are mirror images Radial – many lines that all go through a central point

Symmetry and Daily Life Depending on their symmetry, animals share some general characteristics. Animals with symmetry – complex Animals without symmetry – simple body plans

Animals With Radial Symmetry The external body parts of animals with radial symmetry are equally spaced around a central point, like spokes on a bicycle. Examples: sea stars, jellyfishes, sea urchins All live in water Don’t move fast = move along with the current

Animals With Bilateral Symmetry More complex, larger, move quickly Have a front and back Most animals have bilateral symmetry Have sense organs in their front ends that pick up information about what is in front of them Examples: nose, eyes, whiskers