c hapter 3: a nimal s tructure and f unction. a im : h ow are animals classified into groups ?
TRANSCRIPT
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
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
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
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
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
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