1. Vertebrate Movement to Land
SZ2- Students will explain evolutionary history of animals over the history of life on earth.
Tetrapods- Animals with 4 limbs
Amphibians
Reptiles
Birds
Mammals
Evolved from fish

2. Transition from Sea to Land

3. Coelacanth

4. Eusthenopteron

5. Panderichthys

6. Tiktaalik

8. Transitional Tetrapods
Skull, teeth, limbs similar to lobe-finned fish
Acanthostega
Ichthyostega

11. Fig. 25.CO
Amphibians

12. Adaptations to live on land
Gills are usually lost
Lungs function
Breathe through skin
Secrete mucus
Prevent dehydration
Aids in respiration

13. More Adaptations to live on land
Skeleton
Fins evolve into limbs
Vertebral column supports body underneath it
AIR IS NOT AS BOUYANT AS WATER.

14. Evolution of Circulation
Fish
Amphibian

15. Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class Amphibia
1st land vertebrates
Ex: frogs, toads, & salamanders

16. Class Amphibia – “Double Life” frogs, toads, salamanders, & newts
Characteristics
“Double Life” -lives part of its life in water and part on land
Ectothermic- “outside heat”- body temp. regulated by environment
no scales or claws
Have thin, moist skin

17. AMPHIBIAN METAMORPHOSIS
Egg- tadpole- adult
larvae are herbivores, adults carnivores
larva have tails to move in water
external fertilization with no parental care
lay eggs without shells in water

18. Fig. 25.8

19. Fig

20. Amphibian Body Plan Bilateral symmetry 3 chambered heart
Larvae breathe through gills; adults breathe through lungs
Breathe through thin, moist skin (produces mucus)
Changes from larva to adult through
the process of metamorphosis

21. Class Amphibia Order Anura
Anura- an=without, ura= tail
Tailless
Hindlegs adapted for jumping and swimming
Tympanum (ear drum) and larynx well developed
Ex. Frogs and toads
frog dissection intro-

22. Class Amphibia Order Caudata
Caudata- “have a tail”
Long tail
2 pairs of limbs
Ex. Salamanders and newts

23. Class Amphibia: Order Gymnophiona(Apoda)
Gymnos- naked
ophis- snake
live in tropics
Elongated body
Limbless
carnivores
Ex. Caecilians – “blind”-small eyes

26. Kingdom Animalia Phylum Chordata Class Reptilia
Ex: snake, turtle, lizards
crocodile, dinosaurs

27. 3 chambered heart (except for crocodilians- imperfect 4) Ectothermic
Reptilian Traits:
3 chambered heart (except for crocodilians- imperfect 4)
Ectothermic
Paired limbs with five toes and claws
Tough, dry, scaly skin (horny epidermal scales)
Jaws adapted for crushing and gripping
Breathe with lungs
Solid nitrogen wastes - due to metanephric kidney
Large cerebrum as compared to rest if brain-
behaviors- 1. instinct learned

28. Reptile Legs Short tetrapods for walking
Positioning of the legs more directly under the animal. This position provided more support than the splayed arrangement of the Amphibian legs.

29. Reproduction:
Internal fertilization (to avoid desiccation of gametes), oviparous
Lay amniotic eggs on land- no dependence on water
Shells leathery, sometimes calcareous

30. Amniotic Egg Structures & Functions
Chorion provides a special hard covering that is permeable to respiratory gases (O2 and CO2) while being impermeable to water vapor.
Allantois is a storage reservoir for metabolic waste products such as nitrogenous compounds.
Amnion is a fluid filled sac that acts as a cushion for the embryo and also prevents desiccation.
Yolk sac contains food for the embryo, thus eliminating the need for a larval stage.

33. Order Testudine: Body in a bony case dorsal carapace(top of shell)
Phylum Chordata
Subphylum Vertebrata
Class Reptilia
Order Testudine:
Body in a bony case
dorsal carapace(top of shell)
ventral plastron(bottom of shell)
Jaws with a horny beak, no teeth
Vertebrae and ribs fused
Ex. Turtles and tortoises

34. Turtle Shell Anatomy

36. Fusion of ribs, vertebrae, & carapace

38. Turtle Life Cycle

39. Phylum Chordata Subphylum Vertebrata Class Reptilia Order Sphenodonta
Primitive reptile
closely related to dinosaur
Looks like lizard
Diapsid skull
Ex. Tuatara- only living species

40. Order Squamata Diapsid skull with two temporal openings
Phylum Chordata
Subphylum Vertebrata
Class Reptilia
Order Squamata
Diapsid skull with two temporal openings
Skin is shed with horny epidermal scales
Jacobson’s organ- sense of smell
Movable skin, kinetic skull
Poisonous- hemotoxins (blood) , neurotoxins(nervous system)
EX. Snakes and lizards
Lizards have movable eyelids
Snakes- descended from tetrapod ancestor

41. Elongated massive skull Imperfect 4 chambered heart
Phylum Chordata Subphylum Vertebrata Class Reptilia Order Crocodilia
Elongated massive skull
Imperfect 4 chambered heart
crocodiles, alligators, and caimans, gavials

42. Crocodilians
Crocodiles, Alligators, Caimans, & Gavials

44. Gavial

45. Alligator

46. Crocodile

48. Caiman

49. Crocodilian Reproduction

50. The temperature inside the nest of several crocodilian species decides the sex of the young. ~50-80 eggs
If the nest temperature is 30ºC, females will hatch
If the temperature is above 34ºC - males.
If the temperature is in between- young of both sexes.

52. Land Adaptations for Reptiles
Legs underneath bodies (tetrapods)
Lungs
more efficient circulatory system
Scales- prevents dehydration, protection
Claws
Amniotic egg
The excretory waste of the reptiles is uric acid unlike the dilute, water wasting ammonia in the urine of Amphibians