Flashcards in Reptiles Deck (24):
Amniotes developed the cleidoic egg to give freedom from the water. What is the shell made of in both archosaurs and lepidosaurs?
Archosaurs = 95% calcium carbonate
Lepidosaurs = leathery shell made of protein
What is diapsida composed of?
The archosaurs and lepidosaurs.
What is archosauria composed of?
The crurotarsans and ornithodirans.
What is lepidosauria composed of?
The squamates and the rhyncocephalians.
Eggs display temperature dependant sex determination. In crocodiles how does this work?
Hotter = makes
Colder = females
This is the opposite in turtles.
The diapsids have 2 major ways of giving birth. What are they?
1. Oviparity = egg laying
2. Ovivivaparity = mother gives birth to live young from eggs that have hatched within her body
All lepidosaurs and crocodiles are ectothermic. What advantages does this have?
They do not need to expend energy on thermoregulation. As all energy is derived from a free source more can be converts to biomass, so they need less food.
How do ectothermic diapsids thermoregulate?
1. Behavioural methods
2. Physiological methods
How do nocturnal reptiles obtain heat?
Why do reptiles shed their skin?
Keratin is a dead protein that cannot grow to accommodate size changes.
Water loss across the eyes is substantial. How have reptiles solved this problem?
Evolved the Brille, a scale that grows across the eyelid.
Scaly skin is derived from the epidermis, but where is body armour derived from?
Osteoderms (dermal bone cells)
Reptiles are said to have 'respiration with locomotion'. What does this mean?
In a sprawling gait, the body waggled from side to side due to axial muscle contraction. This alternately ventilates each lung due to compression with each step.
Do reptiles have a diaphragm?
What kind of breathing do crocodiles have?
In chelonians the ribs are fused in the shell and cannot expand/contract in breathing. How have they overcome this?
They have muscles that attach from the inside of the shell to the stomach. These push the stomach into the lungs to expel the air.
Snakes have reduced/lost their left lung as a result of elongation. How do they breathe?
The right lung is v. long but only the anterior part is oxygenated. The posterior part acts as a bellow.
What kind of heart do reptiles have?
A 4-chambered heart
What is the lens like in the reptilian eye?
Thin, soft and distortable. It DOES NOT MOVE but can change shape.
What is the parietal organ?
A light-sensing/seasonality organ.
How do reptiles 'taste the air'?
Via the vomal nasal organ.
Secondary limb loss is v. common in reptiles. How many times has it occurred independently?
Do reptiles masticate?
No, but static feeding pressure on the anterior teeth means they can powerfully close their jaws and eat a wide range of prey.