Implantation- the eggconnecting to theuteruslining
Gestation- pregnancy
Parturition- giving birth
Lactation- producing milk
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Delayed Implantation
Facultative Diapause- this is a mechanism that is associated with metabolic stress(lactation). If a female becomes pregnant while still lactating for her original youngster, the suckling stimulus will cause the embryos to enterdiapause.
Obligate Diapause- this is a mechanism to allow mammals to time the birth of their youngsters with favourable environmental conditions
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Oviparous
Lay eggs which develop and hatch outside the body. The young inside develops using the nourishment from the yolk.
Advantages
easier to hide
lots of young
less likely the mum will die
might not need parental care
no lack of mobility
Disadvantages
eggs are vulnerable
mums can become egg bound
low success rate
can't tell if they're fertilised
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Ovoviviparous
Producing young with eggs that hatch inside the body. The category includes certain types offish, reptilesandinvertebrates.
Advantages
young are alive
mother doesn't have to give nourishment
can still have a lot of young
nutrientscan be reabsorbed
the eggis safer
Disadvantages
easier to see because of the movement
still have to carry them around for a period
more complicated
if the parent dies, the young will most likely die
less young thanoviparous
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Viviparous
Give birth to live young. The young gain nourishment from the mother's blood via theplacenta.
Advantages
fully developed
protected in the parent
warm environment
Disadvantages
Mum is slowed down
needs nourishment from the mum constantly
complications because of a larger baby
relies on mother after birth
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Monotremes
A mammal that lays eggs, usually have acloaca.Monotremes have pores in their armpits for milk production.
Advantages
able to provide milk
can leave young in the nest
Disadvantages
in the nest for a long period
need yolk and milk production
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Marsupials
Give birth to partially developed young and the young then develop inside a pouch. Females have twovaginas (both open via the same external orifice but enter different parts of the uterus).Males have a prolongedpenisandtesticlesare situated in front of thepenis.
Advantages
protection from predators
no complications at birth
short pregnancy
can have offspring at different stages (for example, Kangaroos can have one joey in the womb, one new-born joey in the pouch and one larger joey outside the pouch)
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