1. Amphibians and Reptiles
Test #3

2. Class: Amphibia First vertebrates on land were in Class Amphibia
Amphibian-means “two lives”
About 4,000 species of frogs, salamanders, and caecilians (limbless animals that burrow in tropical forests and fresh water lakes)

3. Devonian Time Period
Cycles of drought and then heavy rainfall then drought again
Lobe-finned fish were at an advantage because the bones in their fins are like that in the arms and legs of early amphibians
They were able to come to land to escape predators or to get food.

4. 3 Orders of Amphibians 1. Urodela 2. Anura 3. Apoda “tailed ones”
salamanders
2. Anura
“tail-less ones”
frogs & toads
3. Apoda
“leg-less ones”
caecilians

5. Order: Urodela (Salamanders)
400 species
Some are entirely aquatic and some live on land
Most walk by bending their body from side to side

6. Order: Anura (Frogs and Toads)
3,500 species
More specialized for living on land
Use strong legs to hop
Flick tongue to catch insect

7. What is the difference between frogs and toads?
Frogs are in the family Ranidae and have the following characteristics:
Bulging eyes
Webbed feet and longer legs for swimming
Smooth or slimy skin
Lay eggs in clusters

9. Toads
Toads are in the family Bufonidae and have the following characteristics:
Stubby bodies with short hind legs for walking instead of hopping
Warty dry skin
Poison glands behind the eyes
Lay eggs in chains

10. Defense from predators
Camouflage
Secrete mucous that is bad tasting or poisonous
Many with poison have a bright color to warn predators

11. Order: Apoda (Caecilians)
Legless
Nearly blind
Look like earthworms

12. Amphibian Characteristics
Frogs
Tadpole Adult
Aquatic with gills Gills & tail disappear
Lateral line Lateral line
Finned tail Develops legs

14. Frogs
Frogs have air breathing lungs, eardrums, and a digestive system (carnivorous diet)
Some frogs do not go through the tadpole phase
Some are strictly aquatic and some are strictly land
Salamanders and caecilians resemble adults when born
Even land-dwelling amphibians need a moist habitat
Some breathe through skin and mouth b/c they have no lungs

15. Frogs Social life Eggs do not have a shell and dehydrate in air
Male causes female to release eggs and spills sperm while she does this
Some incubate eggs on back, mouth, or in stomach
Some are ovivaporons (eggs hatch in uterus) and viviparons (young develop in uterus)
Social life
Frogs are usually quiet, but many call during mating season
Many want to protect territory or attract females

17. Class: Reptilia 7,000 species Many extinct species
Mainly lizards, snakes, turtles, and crocodilians
Birds are closely related

18. Reptile Characteristics
Scales create waterproof skin
(Helps prevent dehydration in air)
Have lungs because they can’t breathe through moist skin
Some turtles have gas exchange through their moist cloaca
Most lay shelled eggs on land
Internal fertilization

19. Reptile Characteristics
Called “cold-blooded” or ectothermic because they don’t use their metabolism to control their body temperature
they regulate their temperature in other ways
Ectotherms body temperature changes with their surroundings

20. Extinct Reptiles 1. Dinosaurs 2. Pterosaurs
lived on land flying reptiles
different sizes wings were a membrane
up to 45 m long of skin stretched from the body wall to the tip of an elongated finger
many were very fast
social and give parental care

22. Modern Reptiles 3 Largest Orders 1. Chelonia (turtles)
2. Squamata (lizards and snakes)
3. Crocodilia (crocodiles and alligators)

23. Order: Chelonia Have not changed much since the Mesozoic era
What is the difference between a turtle and a tortoise?
Turtles are any reptile that lives in a shell.
A tortoise is a turtle that lives on land but enters the water for various reasons.

25. Order: Squamata Lizards- most numerous and diverse
May have survived cold by nesting in crevices to maintain heat

26. Order: Squamata
Snakes- descendants of lizards that adopted a burrowing lifestyle
Today, most snakes live above ground
Boa’s have vestigial pelvic and limb bones (primitive snakes)
Snakes are carnivorous
They have chemical sensors on their tongue that helps them detect prey
have no ear drums
feel vibrations on the ground
they have heat detecting organs between the eyes and nostrils
they inject poison through hollow teeth
They have loose jaws that help swallow prey

27. Crocodilians (crocodiles and alligators)
Largest living reptiles
Spend most of their time in water breathing through upturned nostrils
Live in warmer areas
Most closely related to dinosaurs of all the reptiles
Birds are the closest relatives to reptiles

28. What is the difference between a crocodile and an alligator?
Has a long V shaped snout
Upper and lower jaws are the same width so teeth show interlocking when mouth is shut

30. What is the difference between a crocodile and an alligator?
Wide U shaped snout
Have a wider upper jaw so that the teeth from the upper portion only show when the mouth is closed.