Lecture 9 RH - Reptiles Flashcards Preview

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Flashcards in Lecture 9 RH - Reptiles Deck (54)
1

What kind of grouping are amniotes?

Monophyletic group within tetrapods.

2

What lifestyle do amniotes have?

A terrestrial lifestyle; some colonised air and some returned to water

3

What type of fertlization do amniotes have?

Internal fertilization

4

What kinds of animals are the amniotes?

Reptiles/Birds

Mammals

5

What are the general features of amniotes?

Thicker and more waterprood skin

Rib-ventilation of the lungs

Stronger Jaws

High-pressure cardiovascular system

Water-conserving nitrogen excretion

Expanded brain and sensory organs

Amniotic egg

6

What are the layers of membranes surronding the amniotic egg?

Yolk sac: Contains nutrients

Chorion: Allows gas exchange with environment

Amnion: Surrounds and cushions embryo with the help of fluid

Allantois: Stores wastes and allows gas exchange

7

Why is the shell of an egg porous?

Shell contains pores so that the embryo could breath

8

What does the layer between the egg's shell and the chorion contain?

Albumin

9

In what order does everything happen with egg production?

fertilization -> membranes around embryo -> shell

10

What are the general features of reptiles?

Tetrapods with 5 digits per limb

Internal fertilization

Amniotic with calcareious or leathery shelled egg

No aquatic larval stage

Respiration by lungs

Cloaca

Ectothermic and poikilothermic (birds are homeothermic and enothermic)

Epidermal keratin forms scales (this forms feathers in birds and hair in mammals)

Skull with one occipital condyle

11

How many occipital condyles do reptile skulls have?

1; compared to 2 in mammals

12

Are reptile and fish scales homologous?

No, reptilian scales are epidermal whereas fish scales are mesodermally derived (from the dermis of the skin)

13

What is the function of reptile scales?

Physical protection and prevention of dessication

Some reptiles have bony dermal plates with added strength

14

What do reptile hearts look like?

All reptiles have a septum between left and right atria.

Most reptiles have a partial septum dividing the ventricle into 2 chambers.

Crocodilians have a complete septum between left and right ventricles.

15

What are the developments in locomotion seen in reptiles?

Improved body structure and support and limbs.

Ancestral form of locomotion is by lateral undulations of trunk which compresses lungs alternatingly in order to run.

Improvements include bipedal locomotion, movements of ribs, pelvis, organs, and limb movement independent of trunk bending.

16

What are the developments that reptiles have in order to respire more efficiently?

Larger and more efficient lungs

Lungs are inflated by negative pressure by enlarging body cavity (without using a diaphragm)

Turtles move their visceral organs around in order to create the negative pressure.

Lizards ventilate the lungs by compressing and expanding the rib cage

Crocodiles inhale by expanding the rib cage and pulling the liver back and rotating pubic bones.

17

What developments in the reptiles have allowed more efficient metabolism to take place?

More effient circulatory system with 4 chambered hearts.

18

What are the advantages and disadvantage of ectothermy?

Advantages:
Efficient conversion of food into biomass

Can thrive in ecosystems of low productivity

Can survive with low metabolic rate

Disadvantages:
External temperature limits activity

Requires behavioural adaptations for finding thermal microenvironments

Becoming inactive for part of the year

Limitations on latitudinal range

19

How long ago did amniotes arise from amphibians?

300 mya

20

What are the 3 groups of amniotes?

Anapsids: No temporal bone holes posterior to orbits. (earliest reptiles)

Synapsids: One pair of temporal holes posterior to orbits for attachment of jaw muscles. (gave rise to therapsid reptiles and mammals.

Diapsids: 2 pairs of temporal holes posterior to orbits for attachments of jaw muscles. They gave rise to all other reptiles including dinosaurs and birds. Turtles secondarily lost these openings

21

What basis is there for amniote division?

Skull structure

22

Are turtles considered anapsids, synapsids, or diapsids?

Anapsids (secondarily)

23

Interesting fact:

Crocodilians are more closely related to birds than to other reptiles

24

What are the 3 main clades of reptilians?

Turtles

Snakes, lizards, tuataras

Crocodiles, birds, dinosaurs

25

What order are tortoises/turtles?

Testudines

26

Where does the shell attach to the turtle body?

Shell is fused to the ribs and vertebrae of the thorax

27

How is the lung ventillated in turtles?

Muscular contractions of the thorax, abdomen, and limbs.

Viscera are moved in a way where pressure is created to open the lungs for ventillation

28

What are tortoises referring to?

Terrestrial turtles

29

Fact

Turtles are endangered

30

What is the turtle's life cycle?

Egg buried in the sand

Sand travels to the water and hatchlings must travel to the water

31

What determines the sex of a turtle?

Nesting temperature of the egg

32

How are turtles guided between feeding and nesting grounds?

Scents

Currents

Lights

Magnetic field

33

What order are snakes and lizards a part of?

Squamata

34

Which reptiles are the most recently evolved?

Squamata

35

Why can snakes open their mouth so wide?

They have a kinetic skull with movable quadrate bone which allows large mouth opening.

Very strong jaw muscles

36

Are squamates viviparous?

Some are by retaining egg in oviduct until it hatches

37

What suborder of squamata are lizards?

Suborder sauria

38

Which are more primitive, lizards or snakes?

Lizards

39

How are sauria eyes different to snakes?

Lizards have movable eyes and very good vision

40

Where are saurians typically found?

low productivity environments such as dry forests, deserts, or grasslands

41

What are worm lizards?

No limbed lizards that burrow in soil and are poorly studied

42

Which suborder are snakes?

Serpentes

43

What are the features of snakes?

No limbs

Excellent olfactory and vibration senses (olfactory organs in roof of mouth known as jacobson's organs

Pit vipers have a pit organ which senses temperature with 0.003 degrees sensitivity

Fused, transparent eyelids

No external ear openings (unlike worm lizards)

44

How can worm lizards be excluded from snakes?

Worm lizards have external ear openings

45

What type of diet do snakes have?

Carnivorous

46

What percentage of snakes are venomous?

20%

80% of Australian snakes are venomous

47

Are snakes ovi or viviparous?

Most are oviparous

48

Which snake has the most toxic venom of all land snakes?

Tiger snake

49

What superorder are snakes a part of?

Lepidosauria

50

What order are tuataras a part of?

Sphenodonta

51

What are the features of tuataras?

1 genus remains

Nocturnal, live in burrows associated with nesting sea brds

Most primitive living reptiles, similar to 200 million year old fossils

Have a primitive third eye on the top of their head used to regulate sun exposure

52

What are the differences between alligators and crocodiles?

Crocodiles have a broader snout and visible upper teeth when mouth is closed

Alligators have a narrow snouth and both upper and lower teeth visible when mouth is closed

53

What are the largest crocodilians?

Salties; they extend up to 7m

54

What is interesting about crocodilians and birds in relation to dinosaurs?

Crocodilians and birds are survivors of the lineage that gave rise to the dinosaurs and have changed very little in 200 million years