Reproduction in vertebrates Flashcards
Fertilisation that occurs outside the body, usually in water
External Fertilisation
Development of a fertilised egg that has been laid
Ovipary
Development of a fertilised egg that is retained in the mothers body
Ovovivipary
Development of an embryo within the females body
Vivipary
Sperm are released into the females body and swim towards the egg where fertilisation occurs
Internal Fertilisation
Occurs when a sperm fuses with a egg to form a zygote
Fertilisation
Function of the yolk sac
Encloses the yolk
Yolk provides embryo with nutrients
Function of the chorion
Allows for gaseous exchange
Function of the egg shell
Porous to allow for gas exchange
Prevents egg from drying out
Function of albumen (egg-white)
Stores proteins for developing embryo
Provides embryo with water
Function of allantois
Bladder like structure
Collects and stores nitrogenous wastes produced by embryo
Function of amnion
Surrounds embryo except on ventral side
Secretes amniotic fluid which provides moisture to embryo, allows embryo freedom of movement, acts as a shock absorber
Function of the air pocket
Gaseous exchange
Describe Precocial Development
This type of chick development is mainly found in birds that make their nest on the ground. The eggs have a high amount of energy resulting in well developed hatchlings. The young chicks are able to move immediateley after hatching and leave the nest two days later. The hatchlings are easy prey for predators. Ostriches, Ducks and Turkeys display Precocial Development
Describe Altricial Development
This is typical of birds that build nests high up on trees. The eggs have little energy so the young chicks are poorly developed when they hatch and their eyes are closed. They are helpless and are totally dependent on their parents for food and protection. Most Flying birds display Altricial Development.
