Animal Reproduction Flashcards
r-strategy
Lots of energy is used up in making many offspring and little energy is used in care (many offspring die)
K-strategy
Few offspring are produced but lots of energy used to care for offspring (better chance of survival)
Courtship
Behaviour pattern of a male and female animal with the ultimate purpose of mating and fertilization
Mating
The process leading to fertilization and is either brought about externally or internally
Fertilization
Fusing of the haploid egg and sperm to form a diploid zygote
Characteristics of external fertilisation
Happens outside the female’s body
Courtship and mating ensure eggs and sperm are released simultaneously into water
zygote develops into larva that lives on yolk
Current ensures dispersal minimizing competition
Characteristics of internal fertilisation
Occurs inside the female’s body
Does not require water
Fewer gametes produced because of higher chance of fertilisation
Sperm released by a penis in a fluid medium and swim to the egg
Fewer offspring produced
Aquatic oviparity
Development inside soft egg in water
External fertilisation
r-strategy
Terrestrial oviparity
Development in shelled egg
Internal fertilisation
Large food supply in eggs
K-strategy
Ovoviviparity
Embryo surrounded by thin membrane shell inside female
Egg contains yolk
Internal fertilisation
Egg laid when embryo is fully developed - hatch very shortly after
Protected inside female
K-strategy
Viviparity
Egg develops into an embryo without a shell
Embryo connected directly to mother and receives nutrients via placenta
Internal fertilization
K-strategy
Young born through birth and require a lot of care
Structure and function of the amnion
Fluid filled membrane that surrounds the embryo Protects it from: shock injuries temperature dehydration
Structure and function of the allantois
Sac that grows from the embryo’s intestines
Collects waste products
Exchanges gases
Structure and function of the chorion
Outermost membrane of the egg
Allows gas exchange in oviparous animals
Forms part of placenta (nutrients), allows gas exchange and waste excretion in viviparous animals
Structure and function of the yolk sac
Filled with yolk
Provides food for the embryo
