CHAPTER 3: ANIMAL STRUCTURE AND FUNCTION

AIM: HOW ARE ANIMALS CLASSIFIED INTO GROUPS?

Study cells in order to best classify them

Cells make up tissuesTissues come together to make an

organGroups of organs work together to

form an systemCells, tissues, organs, and organ

systems are compared very carefully

Divided into 2 phlya:VertebratesInvertebrates

AIM: WHAT ARE THE CLASSES OF

INVERTEBRATES?

INVERTEBRATES 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 flatHave heads and tailsHave organs, no true organ systemSome live in water, some inside other

animalsExamples: marine flatworm, planarian

4. Nematoda: (Roundworms)round bodiesDigestive systemSimple nervous systemLive all over Earth-in plants and animals

5. Annelida: (Earthworms, leeches)Have eyes, jaws or gillsCirculatory, digestive and nervous

system

6. Mollusca: (snails, clams, octopus)Most have shells-inside or out of bodyThree main body parts- kind of foot,

tissue covering called a mantle, and compartment holding internal organs

GillsJaws or other organs to capture foodCirculatory systemSome have a well-developed brain-

octopus

7. Arthropoda: (insects, spiders, centipedes, millipedes, lobsters, crabs)More arthropods on Earth than any other

animalTough outer skeletonJointed legsBody made up of several sections

8. Echinodermata: (starfish)Skeleton inside bodySpiny skinTubelike feet with suction cups

AIM: WHAT ARE THE CLASSES OF VERTEBRATES?

VERTEBRATES: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 bonesMovable flap over gillsOrgan called air sac-allows them to

hover at any depthEx: tropical fish

4. Amphibians: (frogs, toads, salamanders)Adults have four legsAdults’ skin doesn’t have scalesAdults breathe with lungs not gillsEarly stages live in water

5. Reptiles: (snake, crocodile, turtle)First vertebrates to grow and

develop out of waterBreathe through lungsMost have waterproof scalesEggs have leathery or hard covering

6. Aves: (ostrich, frigate bird)Have feathersWalk on two hind limbsFront limbs are wingsBones are strong, but lightweight

7. Mammals: (humans, whale, shrew)Feed their young milkHave some hair or furHave larger brains than other

vertebrates

AIM: HOW DOES MIMICRY HELP ANIMALS SURVIVE?

MIMICRYIs an adaptation that helps animals keep

away from predatorsThe animal looks like something else and

has a better chance of not being eatenExamples:

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

AIM: HOW DOES CAMOUFLAGE HELP AN

ANIMAL SURVIVE?

CAMOUFLAGEAn 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 ColorationDark moths vs. light colored

mothsDark moths could not be seen on

the tree trunks-black from smokeLight colored moths could be

seen-were eaten more

AIM: HOW ARE ANIMAL BEHAVIORS THAT ARE INHERITED DIFFERENT FROM THOSE THAT ARE LEARNED?

Some animal behaviors are learnedExample: animals learn that some insects are bad tasting

Some animals behaviors are inheritedInherited behavior is done

automatically, it does not need to be learnedexample: bird building a nest

Passing of inherited traits from parents to offspring is called heredity

Many physical traits are inheritedExample: color of a bird’s feathers

Some physical traits are not inheritedExample: weight and size

AIM: WHAT 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

Hybrids Crossbreeding