Reptiles

Question 1

characteristics of amniotes?

Answer 1

• Monophyletic group within vertebrata
• Includes
• Nonavian reptiles
• Birds
• mammals
• Amniotic membrane around the embryo
• Lack gilled larvae
• Internal fertilization
• Lay eggs on land or retained within the mother

Question 2

characteristics of anamniotes

Answer 2

• Vertebrates that lacks an amniotic membrane
• Informal group that includes fishes and amphibians
• Tend to lay their eggs in water
• Smaller, slower growing embryos compared to amniotic egg of same size

Question 3

what are the 7 adaptations of amniotes?

Answer 3

1. Amniotic egg
2. Thicker and more waterproof skin
3. Rib ventilation of the lungs
4. Stronger jaws
5. High-pressure cardiovascular systems
6. Water-conserving nitrogen excretion
7. Expanded brain and sensory organs

Question 4

amnion

Answer 4

• encloses embryo in fluid (aqueous medium for growth) • cushions embryo

Question 5

Chorion

Answer 5

• surrounds the entire egg and is highly vascularized
• Participates in gas exchange (02 in, C02 out)
• In most mammals, it contributes to the placenta

Question 6

Allantois

Answer 6

• Participates in gas exchange and stores metabolic waste (uric acid) in birds and nonavian reptiles
• Role in development of the placenta in most mammals

Question 7

yolk sac

Answer 7

• Also found in anamniotes (tends to be larger in amniotes)
• Stores nutrients
• In marsupials and placental mammals the yolk sac doesn’t store yolk, but contributes to the placenta

Question 8

Shell

Answer 8

• Many amniotic eggs have a shell (e.g. reptiles, birds)
• Shell is mineralized, but often flexible
• Provides mechanical support
• Semipermeable barrier
• Allows passage of gases but limited water loss (especially in birds)
• Eggs of some lizards, some snakes, and most mammals lack a shell

Question 9

Waterproof skin

Answer 9

Amphibians:
• thin, moist skin to permit effective gas exchange
• Vulnerable to dehydration and physical trauma (on land)
Change in skin morphology in amniotes
• Thicker, tougher, more waterproof
• Few use skin for respiration
• protected by hair, feathers, scales

Question 10

Rib ventilation of the lungs

Answer 10

amphibians use positive ventilation breathing

amniotes use negative pressure breathing

Question 11

Nitrogen excretion

Answer 11

amphibians - ammonia
mammals - urea
birds and nonavian reptiles - uric acid

Question 12

characteristics of non-avian reptiles

Answer 12

• ectothermic
• dioecious
• body covered in keratinized epidermal scales
• parental care typically absent
• tetrapod

Question 13

testudines

Answer 13

• Enclosed in shell
• Dorsal carapace
• Ventral plastron (breastplate)
• Outer layer composed of keratin
• Inner layer composed of bone
• Bony layer is a fusion of ribs, vertebrae and other bone
• Unique among vertebrates – turtle limbs are located inside the ribs
Reproduction: oviparous, internal fertilization, bury eggs
sex determination: low temperature = male, high temp = female

Question 14

Squamata

Answer 14

body covered in keratinized scales

kinetic skull - enables it to swallow large prey

Question 15

lizards

Answer 15

moveable eyelids

successful in warm climates with low productivity

Question 16

snakes

Answer 16

no moveable eyelids
limbless
no external ear opening
skull is more kinetic than a lizard skull

Question 17

Jacobson’s organ

Answer 17

paired organs located at the roof of the mouth
used for smell
tongue flicks air past the sensory organs

Question 18

Tuatara

Answer 18

lizardlike

Question 19

Crocodilians

Answer 19

teeth can be replaced
oviparous
extensive parental care
Incubation temperature determines the sex ratio of the offspring - Low nest temperature produces only females
- High nest temperature produces only males