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Vertebrates. Which of these is most closely related to you?

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Presentation on theme: "Vertebrates. Which of these is most closely related to you?"— Presentation transcript:

1 Vertebrates

2 Which of these is most closely related to you?

3

4 Echinoderms and Chordates are the only two phyla of deuterostomes. Vertebrates

5 Chordata fish, amphibians, reptiles, birds, mammals Deuterostome coelomates Notochord serves as axis of body Dorsal, hollow nerve cord Tails. Human coccyx is vestigial tail. Birds & mammals = homeotherms (constant body temperature) All others are poikilotherms (cold-blooded) though some reptiles are endothermic.

6 Mammals class Nurse their young with milk Have hair or fur made of keratin Homeotherms Placental = develops in womb Marsupial = born early, develops in pouch Monotreme = egg-laying (duck-billed platypus and spiny anteater).

7 Primates order Hands with opposable thumbs Claws have become nails Eyes are in front and close together for binocular vision Nurture their young for a long time.

8 Chordate Characteristics

9 A flexible rod between the nerve cord and the digestive tube All chordates have this as embryos Most develop later into complex, jointed skeleton. Notochord Chordate Characteristics

10 Develops from a plate of ectoderm that rolls into a tube Unique to chordates. (Other phyla have solid, ventral nerve cords) Develops into central nervous system, spinal cord, and brain. Dorsal, hollow nerve cord Chordate Characteristics

11 Just posterior to the mouth Used for suspension feeding and gas exchange (gills) In land animals, they develop into parts of the ear. Pharyngeal slits or clefts Chordate Characteristics

12 Lost during embryonic development in many species Provides propulsion for many aquatic species. Muscular, post-anal tail Chordate Characteristics

13 Classes of Chordates

14 Tunicates Classes of Chordates

15 Tunicates Classes of Chordates

16 Tunicates Classes of Chordates

17 Tunicates Classes of Chordates

18 Lancelets Classes of Chordates

19 Lancelets Classes of Chordates

20 Hagfish Classes of Chordates Craniate (has brain and skull) No jaws No vertebrae

21 Hagfish Classes of Chordates

22 Hagfish Classes of Chordates

23 Hagfish Classes of Chordates

24 Lamprey Classes of Chordates Vertebrate (has backbone) Still no jaws

25 Lamprey Classes of Chordates

26 Lamprey Classes of Chordates

27 Lamprey Classes of Chordates

28 Sharks and Rays Classes of Chordates Gnathostomes (“jaw-mouths”) Bones have some mineralization but are still mostly cartilage Acute senses (lateral line, nostrils, black-and-white vision) Oviparous, ovoviviparous, or viviparous.

29 Sharks and Rays Classes of Chordates

30 Sharks and Rays Classes of Chordates

31 Sharks and Rays Classes of Chordates

32 Ray-Finned Fishes Classes of Chordates

33 Lobe-Finned Fishes Classes of Chordates

34 Lungfishes Classes of Chordates

35 Tetrapods

36 Classes of Tetrapods Amphibians Urodela (“tailed ones”) Salamanders Anura (“tailless ones”) Frogs and toads Apoda (“legless ones”) Caecilians

37 Classes of Tetrapods Amphibians Adaptations: Camouflage Poison Metamorphosis / paedomorphosis Complex social behavior Eggs lack shells, dehydrate quickly Gas exchange through moist skin

38 Amniotes

39 Amniotic egg may be laid on land. Contains extra-embryonic membrane May be calcified (birds) or leathery (reptiles) or may implant in the uterus (mammals)

40 Phylogeny of Amniotes Ancestral amniote Synapsidia Diapsidia Anapsidia

41 Phylogeny of Amniotes Mammals Turtles Lizards & Snakes Crocodiles Dinosaurs Birds Ancestral amniote Synapsidia Diapsidia Anapsidia

42 Phylogeny of Amniotes Mammals Turtles Lizards & Snakes Crocodiles Dinosaurs Birds Ancestral amniote Synapsidia Diapsidia Anapsidia

43 Reptiles Adaptations: Keratinized skin Lungs Leathery shells on eggs Ectotherms.

44 Birds began as feathered reptiles Adaptations: Feathers Honeycombed bones Missing some organs Gizzard instead of teeth Endothermic Four-chambered heart Good vision Relatively large brains.

45 Mammals diversified in the wake of the Cretaceous extinctions Adaptations: Mammary glands Hair Four-chambered heart Endothermic Placenta / live birth Large brains Differentiated teeth.

46 Primates and Human Evolution Adaptations: Brain size Jaw shape Bipedal posture Size difference between sexes Long-term pair bonding Long-term infant dependency.

47 Multiregional Hypothesis African European Asian Austalasian Homo erectus In Africa interbreeding 1-2 million years ago

48 Replacement Hypothesis African European Asian Austalasian Homo erectus In Africa 100,000 years ago 1-2 million years ago


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