C HAPTER 3: A NIMAL S TRUCTURE AND F UNCTION

A IM : H OW ARE ANIMALS CLASSIFIED INTO GROUPS ?

Study cells in order to best classify them Cells make up tissues Tissues come together to make an organ Groups of organs work together to form an system Cells, tissues, organs, and organ systems are compared very carefully Divided into 2 phlya: Vertebrates Invertebrates

A IM : W HAT ARE THE CLASSES OF INVERTEBRATES ?

I NVERTEBRATES 98% of animals are invertebrates 8 classes: 1. Porifera: (Sponges) body is like a hallow tube with lots of pores No organs, some tissues Live in water 2. Cnidaria : (Hydras, sea anemones, jellyfish) No heads or tails Live in water Soft bodies and tentacles Cells make poisons-inject into animals they eat

3. Platyhelminthes: (Flatworms) Bodies are flat Have heads and tails Have organs, no true organ system Some live in water, some inside other animals Examples: marine flatworm, planarian 4. Nematoda: (Roundworms) round bodies Digestive system Simple nervous system Live all over Earth-in plants and animals

5. Annelida: (Earthworms, leeches) Have eyes, jaws or gills Circulatory, digestive and nervous system 6. Mollusca: (snails, clams, octopus) Most have shells-inside or out of body Three main body parts- kind of foot, tissue covering called a mantle, and compartment holding internal organs Gills Jaws or other organs to capture food Circulatory system Some have a well-developed brain-octopus

7. Arthropoda: (insects, spiders, centipedes, millipedes, lobsters, crabs) More arthropods on Earth than any other animal Tough outer skeleton Jointed legs Body made up of several sections 8. Echinodermata: (starfish) Skeleton inside body Spiny skin Tubelike feet with suction cups

A IM : W HAT ARE THE CLASSES OF VERTEBRATES ?

V ERTEBRATES : 7 classes: 1. Agnatha: (lamprey, hagfish) Simplest fish Skeletons made of cartilage No backbone Tough nerve cord 2. Chondrichthyes: (shark, reef sting ray) Skeleton made of cartilage Jaws, paired fins Cartilage in back made of vertebraes

3. Osteichtheez: (Bony Fish) have bones Movable flap over gills Organ called air sac-allows them to hover at any depth Ex: tropical fish 4. Amphibians: (frogs, toads, salamanders) Adults have four legs Adults’ skin doesn’t have scales Adults breathe with lungs not gills Early stages live in water

5. Reptiles: (snake, crocodile, turtle) First vertebrates to grow and develop out of water Breathe through lungs Most have waterproof scales Eggs have leathery or hard covering 6. Aves: (ostrich, frigate bird) Have feathers Walk on two hind limbs Front limbs are wings Bones are strong, but lightweight

7. Mammals: (humans, whale, shrew) Feed their young milk Have some hair or fur Have larger brains than other vertebrates

A IM : H OW DOES MIMICRY HELP ANIMALS SURVIVE ?

M IMICRY Is an adaptation that helps animals keep away from predators The animal looks like something else and has a better chance of not being eaten Examples: 1. Yellow jacket-stings, syrphid fly-harmless Look alike, so insect eating animals avoid both 2. Monarch Butterfly-awful tasting, Viceroy- tastes good Birds avoid eating the viceroy

A IM : H OW DOES CAMOUFLAGE HELP AN ANIMAL SURVIVE ?

C AMOUFLAGE An animal blends in with its surroundings and moves very slowly Adaptation that helps animals avoid predators 2 kinds: 1. Animal’s shape: Leaf butterflies-wings are shaped like leaves Hard for a bird to see when on a leaf

2. Protective Coloration Dark moths vs. light colored moths Dark moths could not be seen on the tree trunks-black from smoke Light colored moths could be seen- were eaten more

A IM : H OW ARE ANIMAL BEHAVIORS THAT ARE INHERITED DIFFERENT FROM THOSE THAT ARE LEARNED ?

Some animal behaviors are learned Example: animals learn that some insects are bad tasting Some animals behaviors are inherited Inherited behavior is done automatically, it does not need to be learned example: bird building a nest Passing of inherited traits from parents to offspring is called heredity

Many physical traits are inherited Example: color of a bird’s feathers Some physical traits are not inherited Example: weight and size

A IM : W HAT IS THE DIFFERENCE BETWEEN HYBRIDS AND CROSSBREEDING ?

Have 2 different parents Breeding of a male donkey and a female horse= mule Cross between 2 different animals Product of mating organisms of the same species with desired traits crossbreed to produce an organism with a desirable trait HybridsCrossbreeding