L6 Bevan - Reptiles Flashcards
What 3 orders make up Lissamphibia?
- Urodela
- Anura
- Gymnophnia
What structure do Lissamphiban eyes contain?
Choroidal hyaline cartilage - supports the eye
How many photoreceptor types do adult amphibians typically have?
4
1 - red rods - contain rhodopsin and absorb green wavelengths
2 - green rods - unique to amphibians - absorb blue wavelengths
3 - single comes - contain pigment that has peak absorbance at yellow wavelength
4 - double cones - consists of 2 cones fused together - one contains rhodopsin, the other the yellow pigment of the single cone
What are the 2 types of pigmented cells for amphibian colouration?>
Melanophores - black, brown, red
Xanthophores - yellow, orange, red
Give an examples of a Urodela who has paedomorphosis
Axolotl
- larvae fail to metamorphose so therefore adults stay aquatic and gilled
Give 6 characteristics of Urodela
- unspecialised body form
- undulate swimming
- paedomorphosis
- 400 species
- lots live in caves
- precise courtship ritual for spermatophores transfer
What 2 characteristics turned the vertebrates into amniotes?
- Eggshell impermeable to water (but allows GE)
- Water loss reduction - combination of traits
- skin is impermeable to water
- kidneys that could excrete concentrated urine
What is the out part of an amniote egg like?
Either:
- leathery
- calcium impregnated eggshell
both of these prevent evaporation of fluids, but allow for GE
Describe the inside of an amniote egg
Stores large amounts of yolk, allows the embryo to develop to quite an advanced stage before it hatches
What are the 4 extra embryonic membranes in an amniote egg?
- Amnion - surrounds the egg itself
- Chorion - surrounds the embryo and the yolk sac
- Yolk sac - surrounds the yolk that nourishes the embryo
- Allantois - evolved o store nitrogenous waste, and aid GE between embryo and egg surface
What are the 2 main groups of Reptilia?
Synapsids - mammal like reptiles, including the ancestors of mammals
Sauropsids - lizard like reptiles
What are the 2 types of Sauropsids?
Anapsids - para reptiles, including Testudines (turtles etc.)
Diapsids:
- Archosaurs (dinosaurs, crocodiles, birds)
- Lepidosaurs (lizards and snakes)
What number of temporal fenestra (windows) do each have?
a) Turtles
b) Mammals
c) Crocodiles
a) Turtle = Anapsids - no hole
B) Mammals = Synapsids = single hole
c) Crocodiles = Diapsids = double hole
When did reptiles diversify from amniotes?
Carboniferous period (360-290mya)
Describe the physiology of reptiles
Reptiles have:
- skin covered in keratinised scales to reduce water loss
- exchange gas by the lungs
- have a heart divided into chambers that separate oxygenated and deoxygenated blood