What is an Animal?

• There are about 1 million species of animals. • About 95 percent of them are invertebrates,

animals without a backbone.• Examples: jellyfish, insects

• Any animal with a skull and

backbone is a vertebrate.

• Examples: fish, birds

Animals share characteristics that separate them from all other living things:

• All animals are multicellular. The cells are eukaryotic and do not have a cell wall.

• Animals usually use sexual reproduction. A few animals, such as sponges and sea stars, can reproduce asexually by budding or fragmentation.

• Animals have specialized body parts. When a fertilized egg cell divides to form an embryo, some cells become skin cells, others may become muscle, nerve, or bone cells. Most animals also have organs, a combination of two or more tissues.

• Animals move. Some other organisms move, but animals are more likely to move quickly in a single direction. A few animals do not move much, such as sea anemones and clams.

• Animals are consumers. They eat other organisms because they cannot make their own food.

Animal Behavior- activities that help animals stay alive

• Innate behavior- doesn’t depend on learning or experience, it’s in the genes. It may be present at birth or years later.

Examples: whales can swim, birds can sing

• Learned behavior- learned from experience or watching other animals, can modify innate behavior

• For example: Humans are born knowing how to speak, but the language is learned not inherited

Survival Behaviors:

• Finding Food

Predators- animals that

eat other animals

Prey- the animal

being eaten

• Camouflage- blending in with the background

• Defenses- horns, spines, chemicals

• Animals with a chemical defense often have warning coloration

Seasonal Behaviors:• Some animals migrate- travel from one

place to another to find food, water, or safe nesting grounds

• Hibernation- having a period of inactivity and decreased body temperature to deal with food and water shortage.

• Estivation- period of reduced activity in the summer, some desert squirrels and mice do in the hottest part of the summer.

Social Behaviors:

• Communication- signal traveling from one animal to another and the receiver responds

• Examples: find food, avoid enemies, protect homes, warn of danger

• Pheremones- chemicals

• Noises- sound can reach a large number of animals over a large area

• Body language

• Touch