amniotic egg

Question 1

animals

Answer 1

• early vertebrates (fish, amphibians) : lay eggs in/near water
• later vertebrates (amniotes : birds and reptiles) : lay eggs in terrestrial environment

Question 2

amniotes

Answer 2

• mammals are amniotes but don’t lay eggs
• produce eggs after fertilisation
• develop extra-embryonic membranes
• membranes develop after fertilisation (internal)

Question 3

how does the amniotic egg maximis reproductive success?

Answer 3

• fluid filled amnion : protects
• fluid filled amnion : hydration
• allantois : acts as reservoir for nitrogenous waste
• yolk sac : nutrients
• chorion : surrounds membranes - mammals (placenta with endometrium); birds and reptiles (shell allows gaseous exchange)