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Chapter 34 Notes Vertebrate Evolution and Diversity.

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Presentation on theme: "Chapter 34 Notes Vertebrate Evolution and Diversity."— Presentation transcript:

1 Chapter 34 Notes Vertebrate Evolution and Diversity

2 Concept 34.1 Deuterosomes - two main phyla: chordates and echinoderms (sea stars) Four anatomical features characterize the phylum Chordata - notochord, dorsal nerve chord, pharyngeal slits, and a postanal tail

3 Concept 34.1

4 There are two subphylums for invertebrate chordates Urochrodates - aka tunicates - sessile filter feeders; use pharyngeal slits as a siphon

5 Concept 34.1

6 Cephalochordates - aka lancets - suspension feeders

7 Concept 34.1

8 Concept 34.2 Class Agnatha - jawless fish - ex hagfish and lampreys - oval shaped mouth; lack jaws and paired fins - evolution of jaws occurred with modification of supporting structures of gill slits

9 Concept 34.2


11 Concept 34.4 Advantages of having a jaw - increase range for prey capture - increase size of prey - increased energy content of prey Allowed jawed species to become larger

12 Concept 34.4

13 Class Condrichthyes - sharks, skates, and rays - skeleton made of cartilage. Teeth and vertebrae may be strengthened with mineralized granules - very dense; must continue to swim - carnivorous; teeth evolved from scales

14 Concept 34.4

15 Sexual reproduction w/ internal fertilization -Oviparous: lay egg, then fertilize; embryo develops within egg after laying - Ovoviviparous: fertilized egg develops in mother, but mother and egg are separated; born live after hatching

16 Concept Viviparous: live young born; embryo develops inside of body; nourished by placenta

17 Concept 34.4 Class Osteichthyes - ray finned and lobed finned fish - boney fish; endoskeleton w/ calcium phosphate - 2 chambered heart (1 atria, 1 ventricle) - buoyancy maintained w/ swim bladder

18 Concept 34.4

19 - gills for gas exchange; operculum allow fish to breathe while remaining still - most species are oviparous

20 Concept 34.4


22 Concept 34.5 Tetrapods: “four feet” - all, except for modified species such as snakes, have four limbs with the same basic structure - used for movement

23 Concept 34.5 Class Amphibia - means “two lives” - frogs, toads, and salamanders - thought to have evolved from lobed finned fishes - 3 chambered heart (2 atria, 1 ventricle)

24 Concept most are oviparous; some exhibit other forms - eggs lack a shell and will dehydrate quickly in dry air

25 Concept 34.5


27 Concept 34.6 Development of the amniotic egg allowed animals to move further away from water 4 parts to the amniotic egg - amnion: prevents dehydration and cushions against shock - yolk sac: stockpile of nutrients for the embryo

28 Concept allantois: disposal sac for metabolic waste - chorion: allows O 2 and CO 2 to diffuse freely across the egg’s shell - found in birds, reptiles

29 Concept 34.6

30 Class Reptilia - scales are made of keratin (waterproof) - 3 chambered heart (2 atria and 1 partially separated ventricle) - nitrogenous waste excreted as uric acid (low water loss)

31 Concept internal fertilization; most lay an amniotic egg - ectotherms: obtain heat by external absorption; not “cold blooded”

32 Concept 34.6

33 Class Aves - flightless (ratites) and flight (carinate) - thought to have evolved from dinosaurs - body is designed to enhance flight - endothermic: maintain high body temp through metabolism

34 Concept 34.6 Why did flight evolve? - to help escape predators - to help catch prey - to help move from place to place - gain access to new food sources

35 Concept 34.6

36 Adaptations for flight - shortened tails - lack teeth - hollow, thin bones - air sacs - feathers are highly modified scales

37 Concept 34.6

38 Concept 34.7 Class Mammalia Monotremes: ex. platypus -lay eggs - have hair and produce milk Marsupials: ex. kangaroos, koalas - born early in development

39 Concept 34.7


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