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Animal diversity
Chapters 33 & 34
Coelomates
Deuterostome Endoskeleton Enchinodermata & Chordata
Enchinoderms
600 myaOceans StarfishBrittle starsSea urchinsSand dollarSea cucumber
Enchinoderms
“spiny” skinEndoskeleton made up of calciumPlates enclosed in living tissueAdults plates fuseCreates hard shellWater-vascular system----move Central ring canal with canals that extend into the arms
Body plan
Bilateral symmetry larva Develop-radial symmetryNerve ring: central ring5 branches arise from central ringTube feetPart of water-vascular systemHelps attach itself to somethingReproduction, sexual & external Regenerate parts
Chordates
Bilateral symmetryNotochordJointed appendagesSegmentationBirds, reptiles, amphibians, fishes, & mammals
Chordates
Common features of chordatesPresent at some point in development1. Nerve cordHollowEctodermBeneath dorsal surfaceVertebrates (brain & spinal cord)
Chordates
2. NotochordDorsal side of primitive gut in embryoFluid filled cellsEnclosed in stiff fibrous tissuePersists in someSupportReduced to vertebral discs in others
Chordates
3. Pharyngeal slits: Connect pharynx & esophagus to outsideGills stay connect to outsidePharyngeal pouches:Slits do not connect to outsideTerrestrial vertebratesPresent in embryos4. Postanal tailAt least during embryo development
Chordates
HumansNerve cord staysNotochord is replaced by spinal column (discs)Pharyngeal pouches are lost Except one forms Eustachian tubeTail regresses tail bone
Chordates
Other featuresMuscles arranged in segmented blocksWork against internal skeletonHelps movement
Chordates
Phylum Chordata includes three subphyla, Vertebrates Two phyla of invertebratesUrochordates
Cephalochordates.
Fig. 34-2
Lobed fins
Legs
Amniotic egg
Milk
Jaws, mineralized skeleton
Lungs or lung derivatives
Vertebral column
Head
Notochord
Commonancestor ofchordates
ANCESTRALDEUTERO-STOME
Echinodermata(sister group to chordates)
Chondrichthyes(sharks, rays, chimaeras)
Cephalochordata(lancelets)
Urochordata(tunicates)
Myxini(hagfishes)
Petromyzontida(lampreys)
Mammalia(mammals)
Actinopterygii(ray-finned fishes)
Actinistia(coelacanths)
Amphibia (frogs,salamanders)
Dipnoi(lungfishes)
Reptilia(turtles, snakes,crocodiles, birds)
Ch
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Chordates
NonvertebratesNotocord but no backboneTunicates (urochordates)Marine, shallow watersSessileAdults no cavity or segmentationTadpole shows characteristics Tunic: sac of cellulose secreted by adultsSurrounds the animal
Chordates
Lancelets (cephalochordata)Shallow waters in oceanBuried in sand Anterior end sticking outPlanktonGill slitsClosest relative to vertebrate
Fig. 34.4
(b)(a)
Vertebrates
1. Vertebral column2. HeadBrain is enclosed in a bony skull or cranium Craniate chordates
Vertebrates
Other characteristics1. Neural crestCells that develop on crest of neural tube Form other structures (teeth, neurons, dermis)2. Internal organsLiver, kidney, endocrine glands3. EndoskeletonCartilage & bone helps with movement
Neural crest
Fig. 34-7
Migrating neuralcrest cellsNotochord
Dorsal edgesof neural plate
Neuralcrest
Neuraltube
Neural crest
Vertebrates
470 myaJawless fishJaw developedGave rise to Amphibians Were first vertebrate moved to landFirst reptiles 300 myaBirds (descendants of dinosaurs)Mammals 220 mya
Vertebrates
65 mya dinosaurs disappeared Gave rise to larger mammalsNine classes of vertebrae5 fish (2 are extinct)4 tetrapods (animals with 4 limbs)Amphibians, reptiles, birds, mammals
Fish
Marine & freshwater1. Vertebral column2. Jaws & paired appendagesHelps eat larger & active preyPaired fins help with swim
Fish
3. GillsExtract oxygen dissolved in waterVessels rich in bloodSupported by cartilage4. Single-loop blood circulationBlood pumped from heart to gillsOxygenated blood to body Returns to heart
Fish
5. Nutritional deficienciesCannot make certain aaMust consume them
Fish evolution
First fish jawless Internal skeleton made of cartilageSucked up small food particlesHagfish: Present day jawless fish
Fig. 34-10
Fish
Jaw 410 myaCartilage, supported gillsTeeth evolvedSpiny fish with scales had boneNo longer exist Bony & sharks developed nextSharks dominated for awhile
Fish
Skeleton cartilage with calcium carbonate Lighter skeletonShark teeth first to be developed Not firmly attached so fall out easilyReproduction advanced with internal fertilization Most females give birth to pups
Fish
Bony fishCartilage is replaced by bone OssificationEarly fish evolved in freshwater unlike sharkFirst bony fish were smallFins of thin scalesSymmetrical tails
Fish
Bony fish most dominant Swim bladderGas filled sac-keeps them floatingSharks have to keep moving or they sinkLateral line systemHelps fish detect movement of objectsHelps orient the fishGill cover
Fig. 34-16
Intestine
Adipose fin(characteristicof trout)
Cut edgeof operculum
Swimbladder Caudal
fin
Lateralline
UrinarybladderPelvic
fin
Anus
Dorsal finSpinal cord
Brain
Nostril
Gills
Kidney
Heart
Liver
Gonad
Anal fin
Stomach
Fig. 34-18
Fig. 34-19
Tetrapodlimbskeleton
Bonessupportinggills
Amphibians
First vertebrae to walk on landDescendants of fishSmallMore species than mammalsFrogs, salamanders & caccileansKey role in terrestrial food chains
Amphibians
Characteristics1. Legs4 legs helps movement (tetrapods)2. Cutaneous respirationRespiration occurs across their skinMoist skin3. LungsPair of lungs, poorly developedLower mouth-suck in air
Amphibians
4. Pulmonary veinsReturn aerated blood to heartRe-pumps to body5. Partially divided heartTwo chambers separatedPrevents un-aerated/aerated blood mixing
Amphibian evolution
Amphibia Greek “both lives”Evolved from lobe-finned fishAdaptations due to movement on land1. Legs2. Lungs3. Heart4. Reproduction5. Keep body from drying out
Amphibians
370 mya in GreenlandPresent day 3 ordersAnura Frogs & toadsFrogs smooth, moist skin, long hind legs Live in or near waterToads dry skin, short legsReproduce in water (tadpoles)Eggs fertilized externally
Amphibians
Urodela (Caudata)SalamandersLong tails, moist skinFertilization external, eggs in waterApodaTropical burrowing amphibiansResemble worms
Fig. 34-23
Reptiles
Reptiles
Characteristics1. Amniotic egg (Amniotes)Chorion: outer layer of eggBelow shell (gas exchange)Amnion: encases the embryo (cushions)Yolk sac: supplies food (blood supply)Allantois: surrounds a cavity in which wastes from the embryo goes
Fig. 34-26
Reptiles
2. Dry skinWatertight skinScales3. Thoracic breathingExpand & contract rib cagePulls air into lungs
Reptiles
Evolution 4 major groups of reptiles dominated for 250 million yearsDinosaursPresent day reptilesTurtles, lizards, snakes, & crocodiles
Fig. 34-27d
(d) Eastern box turtle (Terrapene carolina carolina)
Reptiles
Other characteristicsInternal fertilization4 chambered heartEctothermic: Body temperature determined by environmentRegulate temperature by behavior
Birds
Fig. 34-29
Airfoil wingwith contourfeathers
Toothed beak Wing claw
Long tail withmany vertebrae
Birds
Birds successful due to structure of the featherDerived from reptilian scalesBones are thinHollow
Birds
Bird’s anatomy modified to enhance flight.Reduce weightMissing of some organs.Females-only one ovary. Modern birds-toothless Grind food in a muscular gizzard Near stomach.
Birds
Descended from dinosaursAdaptations1. Efficient respiration2. Efficient circulation3. Endothermy Generate heat internally4. Amniotic egg
Mammals
Mammals
5300 living speciesSmallest # of species of vertebraeCharacteristics1. Mammary glandsNewborns nurseMilk is rich in fat, sugar, protein, vitamins & minerals
Mammals
2. HairConsists of proteinSensitive to touch (cat)Avoid colliding with objects3. EndothermyFat layer under skin4. PlacentaCarry & nourish babies
Mammals
5. TeethVariety of teeth to match diet6. Middle ear
Fig. 34-31
(b) In mammals, the articular and quadrate bones are incorporated into the middle ear.
(a) In Biarmosuchus, an early synapsid, the articular and quadrate bones formed the jaw joint.
Middle ear
Temporalfenestra
Jaw joint
Eardrum
Present-day reptile Present-day mammal
Malleus (articular)
Incus (quadrate)Sound
Stapes
Inner ear
Eardrum Middle ear
Sound
Inner earStapes
Key
Quadrate
Articular
Squamosal
Dentary
Mammals
1. Egg-layingMonotremes: duck-billed platypusFound in Australia2. MarsupialsPouched mammals3. Placental mammals
Marsupials