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. Vertebrate Evolution

3. Why did vertebrates begin to move onto land 380 million years ago?
Competition for food and habitat in aquatic ecosystems
Escape predators
Availability of new food source and terrestrial niches

4. Transitional tetrapods

5. Transition from Sea to Land

6. Coelacanth

7. Eusthenopteron

8. Panderichthys

9. Tiktaalik http://www.youtube.com/watch?v=HyJAV-Jf9do

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

13. https://www. youtube. com/watch

14. Struggles to Survive On Land
Water conservation
Gas exchange
Reproduction
Gravity
Separation of head, flexion of a neck to pick up food

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

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

17. Evolution of Circulation
Fish
Amphibian

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

19. 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

20. AMPHIBIAN METAMORPHOSIS
Egg- tadpole- adult
external fertilization with no parental care
lay eggs without shells in water
larvae are herbivores, adults carnivores

21. Fig. 25.8

22. Fig

23. Amphibian Body Plan Bilateral symmetry 3 chambered heart
Breathe through thin, moist skin (produces mucus)

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

25. Class Amphibia Order Caudata
Caudata- “have a tail”
2 pairs walking legs
Live in freshwater or
leaf litter
Ex. Salamanders and newts

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

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

31. 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
metanephric kidney- produces uric acid to reduce water loss
Large cerebrum as compared to rest of brain-
behaviors- 1. instinct learned

32. 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.

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

34. 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 and gas exchange.
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.

37. Checkpoint
List basic traits of reptiles.
How do reptiles reproduce? Explain fertilization type, type of eggs, egg development.
Which class of animals is better adapted for life on land, Amphibia or Reptilia?
4. Explain how your chosen class of vertebrates is better adapted for life in terrestrial ecosystems.

38. 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

39. Turtle Shell Anatomy

41. Fusion of ribs, vertebrae, & carapace

43. Turtle Life Cycle

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

45. 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
dichotomous key

46. Evidence suggests that Snakes descended from tetrapod ancestor
Pythons, and other species of snakes are sometimes born with vestigial hindlimbs
Snakes have DNA to code for a pelvis, and limbs, but genes are turned off early in development

47. 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

48. Crocodilians
Crocodiles, Alligators, Caimans, & Gavials

50. Gavial(gharial) Carnivores, “ghara”- pot- bulb on snout
ft. long
Rivers of India, Nepal, Pakistan, Bhutan, Bangladesh
Critically Endangered

51. Alligator Live in and around freshwater- wetlands and rivers
East china, southern US and gulf of mexico
Teeth do not interlock, can only see teeth of upper jaw when mouth is closed

52. Crocodile Largest, best predators Interlocking teeth
Live in/near Salt water
American Crocodile- Endangered
Most in Australia

54. Caiman Rivers/swamps of Central and South America
3ft- 16 ft. (only in black caiman species)

55. Crocodilian Reproduction

56. 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.

57. http://www. animalplanet

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