Biodiversity 7: Reptiles and birds Flashcards

1
Q

Describe the amniotic egg

A

A self contained waterproof chamber for development
Eliminates larval stage = freed ancestors from need to return to water to breed

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2
Q

What is the amniotic egg shell like in reptiles?

A

Leathery

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3
Q

What is the amniotic egg shell like in birds?

A

calcium carbonate (protected from drying out)

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4
Q

What are the 5 membranes present in the amniotic egg?

A
  • Shell
  • Amnion
  • Chorion
  • Yolk sac
  • Allantois
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5
Q

Describe the shell of an amniotic egg

A

Shell is waterproof but allows gas exchange so embryo can get O2

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6
Q

Describe the amnion of an amniotic egg

A

fluid cushions and protects embryo

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7
Q

Describe the chorion of an amniotic egg

A

surrounds embryo and regulates gas exchange

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8
Q

Describe the yolk sac of an amniotic egg

A

surround egg yolk mass

yolk mass = accumulation of nutrients from mother

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9
Q

Describe the allantois of an amiotic egg

A

Stores nitrogenous waste (toxic to embryo)

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10
Q

What is a fenestra?

A

openings in the skull for attachment of jaw muscles, enables the jaw to open widely

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11
Q

Define anapsid

A

No fenestra
Extinct forms

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12
Q

Define synapsid

A

1 fenestra
Mammals

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13
Q

Define diapsid

A

2 fenestra
Birds and reptiles

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14
Q

Why did anapids go extinct?

A

probably due to poor bite power

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15
Q

‘reptiles are paraphyletic’

What does this statement mean?

A

multiple lineages, don’t have a single ancestor that distinguishes them from non-reptiles

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16
Q

Describe reptiles + examples

A

Lack a single defining characteristic:
Have amniotic eggs but no feathers (not birds)
Don’t have mammary glands/hair (not mammals)
E.g Turtles, lizards, snakes, crocodile, tuatara

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17
Q

Describe the features of reptiles

A

Heavier ossified skeleton, strong joints, clawed toes
Skin covered in keratinised scales or scutes
Ectotherm (cold blooded) → eat less: only need 10% of calories of an endotherm
Internal fertilisation, eggs laid on land
Efficient predators

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18
Q

What covers a reptiles skin and how are these adapted to life on land?

A

Skin covered in keratinised scales or scutes → prevent dessication

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19
Q

What type of fertilsation do reptiles use?

A

Internal, lay eggs on land

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20
Q

In which age were early reptiles dominant?

A

Mesozoic ‘Age of the Reptiles’

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21
Q

When and why did Ichthyosaurs go extinct?

A

~95 mil yrs ago
couldn’t evolve fast enough to deal with global warming

22
Q

What did early forms of reptiles probaby feed on?

A

Invertebrates = little competition

23
Q

When and why did the plesiosaurs, pterosaurs and dinosaurs go extinct?

A

~65 mil yrs ago

Potentially:
Mammals outcompeted
Massive volcanic eruption
Massive asteroid impact
= Most likely due to climate change, triggered by asteroid ash blocking sunlight
→ only 4 orders survived this

24
Q

Which order do turtles, terrapins and tortoises belong to?

A

Chelonia

25
Q

Describe the Chelonia

A

Includes marine (turtle), freshwater (terrapin) and terrestrial (tortoise) forms
Teeth replaced by sharp horny plates
No fenestra = weaker jaws
Bony dermal plates fuse to form carapace (top shell) and plastron(bottom shell)
Tortoises have retractable neck and limbs to protect against predators

26
Q

Which order do lizards and snakes belong to?

A

Squamata

27
Q

Describe snakes

A

Loss of limbs, elongate body form
Probably evolved from a burrowing lizard-like ancestor (convergent evolution with earthworms)
Eyelid lost, spectacle clear
Jaws extremely flexible, moveable joints for large prey

28
Q

Which order do alligators and crocodiles belong to?

A

Crocodillia

29
Q

Describe Crocodilia

A

Adapted for life in water
Broad flattened tail = powerful propulsion
Eye, ear, nose openings on the top of the flat head
Most closely related group to the dinosaurs

30
Q

How are crocodilia adapted for life on water?

A

Broad flattened tail = powerful propulsion
Eye, ear, nose openings on the top of the flat head

31
Q

Describe the differences between ailligators and crocs

A

Difference between alligators and crocs:
Alligators lower teeth not visible when mouth is shut
Crocs lower teeth stick up (always 4th one)
Alligators: prefer freshwater
Crocs: prefer saltwater
Crocs: more aggressive

32
Q

What order does the Tuatara belong to?

A

Sphenodontia

33
Q

Describe the Tutara

A

2 species, both in NZ
Very slow growing, 35 yrs to reach full size
Mean lifespan 60yrs, one male reproduced successfully at 111 yrs
Some biologists predict that in captivity they could live up to 200 yrs

34
Q

What are birds defined by?

A

Defined by presence of feathers

35
Q

Describe birds modifications to flight

A

Hollow bones with cross struts
Reduced organs (e.g females have 1 ovary)
No teeth, food ground in gizzard
Lightweight keratin bill
Large pectoral muscle anchored to keel (enlarged sternum)= gives power for flight

36
Q

Describe a birds wing

A

Aerofoil shaped wing
Pentadactyl limb

37
Q

What are a birds feathers held together by?

A

held together with barbs and hooked barbules = link together to give continuous flat mat of feathers

38
Q

what are a birds feathers made from?

A

Keratin = not living

39
Q

What are the 5 types of feathers on a bird?

A

Filoplumes
Down
Flight
Contour

40
Q

Describe filoplume feathers

A

hair-like structures, accompany contour feathers, suggested sensory function

41
Q

Describe down feathers

A

lie under contour feathers, lack barbules, long fluffy barbs. Trap air for insulation

42
Q

Where are flight feathers on the wing?

A

posterior

43
Q

Describe contour feathers

A

overlay body and give bird outershape, cover anterior edges of wings

44
Q

Flight carries a high energetic requirement, what does this necessitate?

A

Necessitates endothermy, fat and feather circulation
Efficient circulation, 4 chambered heart

45
Q

Birds have larger brains than reptiles, give some examples of what this facilitates

A

Complex behaviours: courtship, flight, navigation
Some capable of learning and solving problems
Colour vision

46
Q

Describe the kind of dinosaur birds evolved from

A

Bipedal theropod dinosaur

47
Q

What are 3 hypothesis for possible origins of flight?

A

1: Ancestors chased insect prey
Feathers aided running, jumping then gliding

2: Wings and feathers aided running up inclines, then gliding

3: Ancestors were climbers, feathers evolved as an adaptation for gliding to the ground

48
Q

What does ratite mean?

A

Any bird with a flat breastbone
→ Cassowary & emu, kiwi, ostrich, rhea

49
Q

Describe the ratites

A

Lack keel but wide sternum, suggests lost flight
Vestigial wings, large powerful legs
Has evolved at least 4 times → not monophyletic

50
Q

Give some examples of carinates

A

Penguins, waders, raptors