Reproductive strategies Flashcards
Fertilisation
The action or process of fertilizing an egg of a female animal or plant, involving the fusion of male and female gametes to form a zygote.
Advantages of external fertilisation
It results in increased genetic variations.
It produces a larger number of offsprings.
The gametes released can drift and therefore it is easy to find mates.
Disadvantages of external fertilisation
Chances of fertilization are diminished by environmental hazards and Predators
Eggs and sperms, essentially, may not come in contact
Dessication of zygote or gametes
Advantages of internal fertilisation
Increased chance of gametes meeting
Less gametes are needed thus less energy is expended in production
Protection from environment
Disadvantage of internal fertilisation
Harder to bring both male and female into intimate contact
Limited amount of offspring being produced at any given time
Higher risk of sexually transmitted diseases being passed on
Example of external fertilisation
Salmon
Trout
Examples of internal fertilisation
Mammals
Reptiles
Courtship
Courtship can be defined as the behavior used to obtain copulation with a partner. E.g. Blue footed boobies
Ovipary
Species that produce eggs that are protected by a shell after fertilisation in order to protect the embryo from desiccation. (Chickens, penguins)
Vivipary
An animal that is viviparous gives birth to developed live young. (Humans, cattle)
Ovovivipary
Organisms that lay eggs that hatch as they are being laid. (Snakes, Sharks)
Amniotic egg
Amniotic eggs allowed for reptiles and birds to colonise different habitats as they no longer needed to return to water to breed.
