Reptiles

Question 1

What set of traits allowed the evolution of a tetrapod without the dependence on water? What are these vertebrates called?

Answer 1

• egg with a shell impermeable to water
  These reduced water loss:
• skin that is impermeable to water
• kidneys that could excrete concentrated urine
  These are called amniotes (after the egg they produce)

Question 2

What are amniotes eggs like?

Answer 2

Leathery or have calcium shell
This prevents evaporation, but allows O2 and CO2 to diffuse
Contain a lot of yolk allowing the embryo to become relatively advanced before hatching

Question 3

What are the 4 extra embryonic membranes in amniote eggs?

Answer 3

Amnion - surrounds embryo itself
Yolk sac - surrounds yolk
Chorion -surrounds embryo and yolk sac
Allantois - evolved to store nitrogenous waste and aid gas exchange between embryo and egg surface

Question 4

What are the main groups of the reptilia?

Answer 4

• Synapsids (mammal like, including ancestors of mammals)

- sauropsids (lizard like)

Question 5

What are the 2 types of sauropsids?

Answer 5

Anapsids
- testudines
Dispsids
- archosaurs (dinosaurs, crocodiles, birds)
- lepidosaurs (lizards, snakes)

Question 6

What is anapsid synapsid or diapsid?

Answer 6

Relates to number of temporal fenestra

• anapsid (no holes) testudines
• synapsid (one hole) mammals
• diapsid (two holes) dinosaurs, lizards snakes crocs birds

Question 7

What is the early amniote lineage that diversified 360-290mya?

Answer 7

Reptiles (not actually a class, a paraphyletic group)

Question 8

What is ovo-viviparity?

Answer 8

When the egg doesn’t have a shell and is kept inside the females body until they hatch, some reptiles

Question 9

What is reptiles skin covered in?

Answer 9

Ketatinised scales that reduce water loss

Question 10

What is the new finding about the origins of mammals and reptiles?

Answer 10

They are sister groups, rather than mammals being derived from reptiles

Question 11

What are the 2 subdivision of dinosauria?

Answer 11

Saurischians
-diplodocus
- velociraptor, trex birds
Ornithischians

Question 12

Why are ornithischians called that?

Answer 12

Because their pelvis is bird like, but DID NOT give rise to the birds

Question 13

What lineage of the saurischians did birds evolve from?

Answer 13

Therapods

Question 14

What are the archosaurs?

Answer 14

‘Old lizards’
Only extant group are crocodiles
Tropical and warm temperate environments
Most of time in water but build nests on land

Question 15

What are the testudines?

Answer 15

Turtles, tortoises and terrapins

Shell - carapace (dorsal) and plastron (ventral)

Question 16

What are the 2 groups of testudines?

Answer 16

Cryptodires
- tortoises turtles and terrapins
- retract head vertically 
Pleurodires
- matamata 
- retract head horizontally

Question 17

What is different about testudines vertebral column and ribs?

Answer 17

Fused to carapace

Question 18

Do testudines have diaphragm ventilation

Answer 18

Yes

Question 19

Where are testudines limb girdles

Answer 19

Inside shell

Question 20

What determines sex?

Answer 20

Temperature of brood, cool for males, warm for females

Question 21

What marine lineages of diapsid reptiles are there? (All extinct)

Answer 21

Plesiosaurs - ribbon reptiles

Ichthyosaurs - fish reptiles

Question 22

What are the terrestrial lineages?

Answer 22

Lepidosaurs (all living diapsid reptiles in this lineage)

• squamata (lizards and snakes)
• tuatara

Question 23

What are tuataras?

Answer 23

Sister group of lizards, 2 species, endemic to new Zealand

Question 24

What are included in the Squamata?

Answer 24

Lizards
Snakes
Amphisbaenians

Question 25

What do snakes specialise in?

Answer 25

Locomotion
Prey capture
Swallowing

Question 26

What ecological types of snakes are there?

Answer 26

Fossorial (burrowing)
Epigean (soils surface)
Aquatic

Question 27

What are the consequences of diameter reduction

Answer 27

• left lung reduced or absent
• gall bladder posterior to liver
• right kidney anterior to left
• gonads offset

Question 28

What locomotory types in snakes are there?

Answer 28

• lateral undulation: S movement of body pushing against ground
• rectilinear: movement of scales, only in straight line
• concertina: S shape moves through body
• side winding: allows snake to have little contact with hot sand

Question 29

In what ways are snakes specialised for eating?

Answer 29

• skull with 8 flexible links
• each side can move independent of the other
• constriction
• venom (all snakes)

Question 30

What are the 4 morphologies of snake teeth

Answer 30

• aglyphous: ancestral, no specialisation, sharp backward pointing teeth
• opisthotlyphous: bAck fanged, one or two enlarged teeth near rear of maxilla
• proteroglyphous: hollow fangs on front of maxilla, permanently erect (so limit to length), short teeth behind
• solenoglyphous: only teeth on maxilla are long hollow fangs, maxilla rotates to allow jaw closure