Chapter 32 34 Animals Domain Eukarya Domain Eubacteria

Chapter 32 -34: Animals Domain Eukarya Domain Eubacteria AP Biology Domain Archaea Domain Eukarya 2007 -2008 Common ancestor

Animal Characteristics § Heterotrophs u must ingest others for nutrients § Multicellular u complex bodies § No cell walls u allows active movement § Sexual reproduction no alternation of generations u no haploid gametophyte u AP Biology

Animal Evolution Cnidaria Porifera sponges jellyfish Nematoda Platyhelminthes Annelida Mollusca Echinodermata Arthropoda flatworms roundworms mollusks segmented worms redundancy, segmentation specialization, mobility insects spiders starfish Chordata vertebrates body & brain backbone size, mobility body size endoskeleton coelom digestive sys radial body cavity body complexity digestive & repro sys bilateral symmetry tissues multicellularity AP Biology Ancestral Protist distinct body plan; cephalization specialized structure & function, muscle & nerve tissue specialization & body complexity bilateral

Body Cavity § Space for organ system development u increase digestive & reproductive systems § increase food capacity & digestion § increase gamete production § Coelem mesoderm & endoderm interact during development u allows complex structures to develop in digestive system acoelomate ectoderm mesoderm endoderm pseudocoel u § ex. stomach AP Biology coelomate ectoderm mesoderm coelom cavity endoderm protostome vs. deuterostome

Invertebrate: Porifera § Sponges u no distinct tissues or organs § do have specialized cells no symmetry u sessile (as adults) u AP Biology food taken into each cell by endocytosis

Invertebrate: Cnidaria § Jellyfish, hydra, sea anemone, coral tissues, but no organs polyp u two cell layers u radial symmetry u predators u § tentacles surround gut opening § extracellular digestion w release enzymes AP Biology into gut cavity w absorption by cells lining gut medusa

Stinging cells of Cnidarians mouth tentacles sensory cell stinging cell hydra AP Biology trigger stinging cell with nematocyst discharged nematocyst undischarged nematocyst

Invertebrate: Platyhelminthes § Flatworms u u u tapeworm, planaria mostly parasitic bilaterally symmetrical § have right & left & then have head (anterior) end & posterior end Animals now w cephalization = development of brain face the world w concentration of sense organs in head on! § increase specialization in body plan ectoderm AP Biology acoelomate mesoderm endoderm

Invertebrate: Nematoda § Roundworms u u bilaterally symmetrical body cavity C. elegans § pseudocoelom = simple body cavity § digestive system w tube running through length of body (mouth to anus) u many are parasitic § hookworm AP Biology

Invertebrate: Mollusca § Mollusks u u slugs, snails, clams, squid bilaterally symmetrical (with exceptions) soft bodies, mostly protected by hard shells true coelem § increases complexity & specialization of internal organs AP Biology

Invertebrate: Annelida § Segmented worms u u earthworms, leeches segments § increase mobility § redundancy in body sections u u AP Biology bilaterally symmetrical true coelem fan worm leech

Invertebrate: Arthropoda § Spiders, insects, crustaceans u u u most successful animal phylum bilaterally symmetrical segmented § specialized segments § allows jointed appendages u exoskeleton § chitin (carbohydrate) + protein AP Biology

Arthropod groups arachnids 8 legs, 2 body parts spiders, ticks, scorpions crustaceans gills, 2 pairs antennae crab, lobster, barnacles, shrimp AP Biology insects 6 legs, 3 body parts

Invertebrate: Echinodermata § Starfish, sea urchins, sea cucumber u u u AP Biology radially symmetrical as adults spiny endoskeleton loss of bilateral symmetry? deuterostome

Invertebrate quick check… Invertebrates: Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Mollusca, Arthropoda, Echinodermata § Which group includes snails, clams, and squid? § Which group is the sponges? § Which are the flatworms? …segmented worms? …roundworms? § Which group has jointed appendages & an exoskeleton? § Which two groups have radial symmetry? § What is the adaptive advantage of bilateral symmetry? AP Biology § Which group has no symmetry?

Chordata § Vertebrates fish, amphibians, reptiles, birds, mammals hollow dorsal nerve cord u internal bony skeleton u § backbone encasing spinal column § skull-encased brain u deuterostome Oh, look… your first baby picture! AP Biology vertebrate embryo becomes brain & spinal cord becomes gills or Eustachian tube pharyngeal pouches postanal becomes tail or tailbone becomes vertebrae notochord

450 mya Vertebrates: Fish § Characteristics u body structure § bony & cartilaginous skeleton § jaws & paired appendages (fins) § scales u body function § gills for gas exchange § two-chambered heart; single loop blood circulation § ectotherms u AP Biology reproduction § external fertilization § external development in aquatic egg salmon, trout, sharks gills body

Transition to Land Evolution of tetrapods Humerus Femur Pelvis Tibia Ulna Shoulder Radius Lobe-finned fish Fibula Pelvis Femur Fibula AP Biology Humerus Tibia Early amphibian Ulna Shoulder Radius Tiktaalik

350 mya frogs salamanders toads lungs Vertebrates: Amphibian § Characteristics u body structure § legs (tetrapods) § moist skin w gas exchange u lung buccal cavity glottis closed body function § lungs (positive pressure) & diffusion through skin for gas exchange § three-chambered heart; veins from lungs back to heart § ectotherms u AP Biology reproduction § external fertilization § external development in aquatic egg § metamorphosis (tadpole to adult) heart body

250 mya Vertebrates: Reptiles § Characteristics u body structure dinosaurs, turtles lizards, snakes alligators, crocodile lungs § dry skin, scales, armor u body function § § u lungs for gas exchange heart thoracic breathing; negative pressure three-chambered heart ectotherms reproduction leathery embryo shell § internal fertilization § external development in amniotic egg chorion AP Biology allantois yolk sac body amnion

150 mya finches, hawk ostrich, turkey lungs Vertebrates: Birds (Aves) § Characteristics u body structure § feathers & wings § thin, hollow bone; flight skeleton u heart body function § very efficient lungs & air sacs § four-chambered heart § endotherms u reproduction § internal fertilization § external development in amniotic egg AP Biology heart body trachea lung anterior air sacs posterior air sacs

220 mya / 65 mya Vertebrates: Mammals § Characteristics u body structure § hair § specialized teeth muscles u body function reproduction § internal fertilization § internal development in uterus w nourishment through placenta § birth live young § mammary glands make milk AP Biology heart contract § lungs, diaphragm; negative pressure § four-chambered heart diaphragm § endotherms contracts u mice, ferret elephants, bats whales, humans lungs body

Vertebrates: Mammals § Sub-groups u monotremes § egg-laying mammals § lack placenta & true nipples § duckbilled platypus, echidna u marsupials § pouched mammals w offspring feed from nipples in pouch § short-lived placenta § koala, kangaroo, opossum u placental § true placenta w nutrient & waste filter § shrews, bats, whales, humans AP Biology

Vertebrate quick check… § § § § Which vertebrates lay eggs with shells? Which vertebrates are covered with scales? What adaptations do birds have for flying? What kind of symmetry do all vertebrates have? Which vertebrates are ectothermic and which are endothermic Why must amphibians live near water? What reproductive adaptations made mammals very successful? What characteristics distinguish the 3 subgroups of mammals? AP Biology

That’s the buzz! Any Questions? AP Biology