1. A Phylogeny of the Animal Phyla
Porifera
No true tissues
Cnidaria
radial symmetry
diploblastic
Ctenophora
Acoelomates
Rotifera
Pseudocoelomates
Nematoda
Nemertea
Mollusca
Protostomes
true tissues
Annelida
Arthropoda
Bilateral symmetry
triploblastic
Bryozoa
Lophophorate phyla
Body cavity
Phoronida
Coelomates
Brachiopoda
Echinodermata
Chordata
Deuterostomes

2. Animal Diversity
-Vertebrates -

3. Evolution of Vertebrates
-from one lineage of craniates
1. Increased in bony layers around skull and spinal column
Cartilaginous precursors of vertebrae

4. Early Vertebrates
Conodonts

5. Conodonts

6. Jawless armoured vertebrates
Hemicyclapsis
Drepanaspis
Anglapsis
Pterapsis

7. Vertebrate Jaw
First fish with jaws - Placoderms

8. Vertebrate Jaw
First fish with jaws - Placoderms

9. Vertebrate Jaw

10. Vertebrate Jaw

11. Vertebrate Jaw

12. Vertebrate Jaw

13. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes
- most primitive group - Chondrichthyes - sharks, skates and rays
-skeleton is made of cartilage not bone

14. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Chondrichthyes - sharks, skates and rays
Jaw of a shark - mineralized
Rows of forward-moving teeth

15. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
So far:
Cephalochordates
Lampreys – jawless animals with the beginnings of vertebrae
Conodonts – vertebrates with jaw-like elements
Placoderms – extinct vertebrates with well developed jaws
Chondrichthyes – jawed fish with largely cartilaginous skeletons

16. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Now - fish with jaws and bony skeletons
Lobed fin
Divided into two groups
Ray fin

17. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - the fish (Osteichthyes)
Lobe fins
(Latimeria)

18. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - the fish (Osteichthyes)
Lobe fins
Lungfish

19. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - the bony fish (Osteichthyes)
Ray fins

20. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - the bony fish (Osteichthyes)
Bouyancy

21. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - the bony fish (Osteichthyes)
Bouyancy

22. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - the bony fish (Osteichthyes)
Labyrinth organ
Sound wave
Swim bladder
Weberian ossicles

23. Next move for vertebrates
Invasion of land

24. Move onto Land - Legs Humerus Radius Ulna Lobed fin fish
Fossil amphibian

25. Move onto Land - Legs
Lungfish

26. Move onto Land - Legs Pelvic and pectoral girdles Latimeria
Ichthyostega
No contact with spinal column
Contact with spinal column

27. Invading Land
Ichthyostega

28. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - Tetrapoda - Amphibia
Amphibians
- first living vertebrates with legs than can support their weight
first vertebrates on land -BUT still must
return to the water to reproduce

29. AMPHIBIA GROUPS
1. Urodela (Caudata)
Salamanders

30. AMPHIBIA GROUPS
1. Urodela (Caudata)
Salamanders

31. AMPHIBIA GROUPS
1. Urodela (Caudata)
Salamanders - Reproduction
spermatophore

32. AMPHIBIA GROUPS
1. Urodela (Caudata)
Salamanders - Reproduction
Must return to the water to lay eggs

33. AMPHIBIA GROUPS
2. Salientia (Anura)
Frogs and Toads

34. AMPHIBIA GROUPS
2. Salientia (Anura)
Frogs and Toads
Amplexus

35. Loss of limbs and girdles
AMPHIBIA GROUPS
3. Gymnophiona (Apoda)
Loss of limbs and girdles

36. AMPHIBIA GROUPS
3. Gymnophiona (Apoda)
Normal mating – female guards eggs

37. Next step
Breaking the reliance on water
Opens up terrestrial habitats to vertebrates

38. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - Tetrapoda - Reptilia
Reptiles
development of a scaly skin to prevent water loss

39. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - Tetrapoda - Reptilia
Reptiles
development of a scaly skin to prevent water loss
development of amniote egg that doesn’t have to be laid in water

40. Chordata - Chordate evolution - Vertebrates - craniates with a backbone
Jawed vertebrates - Gnathostomes - Tetrapoda - Reptilia
Reptiles
development of a scaly skin to prevent water loss
development of amniote egg that doesn’t have to be laid in water
Salamander egg
Reptile egg

41. Amniote Egg Amnionic sac – protects embryo
Allantois – disposal sac for embryonic waste, works with chorion in gas exchange
Chorion – with membrane of the allantois exchanges O2 and CO2 with the air
Yolk sac – storage and transfer of nutrients to developing embryo

42. REPTILIA GROUPS

43. Next time:
Reptiles
Mammals