Internal & External Fertlisation, & How Reproductive Success Is Ensured Flashcards
(18 cards)
What two types of fertilizations are there?
Internal and external.
External fertilization requires what type of an environment?
One where the eggs will not dry out, the sperm can swim to the female gametes and fertilise without drying out. An aquatic environment.
What species are commonly associated with external fertilization?
Frogs and Fish.
What reproductive strategy can externally fertilizing organisms be associated with, and why?
R-Strategy, many egg and sperm cells are released into water, and many offspring are born, however few survive due to low energy expenditure on parental care.
How is reproductive success maximized in external fertilization? Name 4 reasons.
- Egg and sperm released simultaneously into water
- Will not dry out in aquatic environments
- Brings sperm cells into contact with egg cells
- Many sperm and egg cells are released
How does external fertilization maximize a sessile organism’s reproductive success?
Sessile organisms are unable to move/ fixed in a certain position and through external fertilization in aquatic environments can ensure that their egg and sperm cells make contact and fertilize.
Why is external fertilization not particularly successful? Name 4 reasons.
- Egg and sperm drift apart
- Egg cells destroyed, eaten by predators or damaged
- Embryos left unprotected — many organisms that externally fertilize are r-strategists with low parental care
- Unfavourable environmental conditions.
Advantage of external fertilization?
No additional energy spent on formation of a protective shell or parental care.
Explain the term, a complete metamorphosis, in relation to frogs?
Offspring do not directly compete with parents. In frogs, offspring (tadpoles) are herbivores and parents (frogs) are carnivores.
Which type of fertilization often involves courtship and why is it related to seasons of the year?
Internal fertilization. Favourable environmental conditions as the offspring are born to ensure survival.
How does internal fertilization maximize reproductive success?
- Courtship dictates offspring are born during a time when the environmental conditions are favorable to their survival
- Fertilization occurs in a contained space
- Embryos not exposed to predation, cannot dry out
- Sperm more likely to fertilize eggs as placed in close proximity.
What does the term copulation mean?
Internal fertilization by which the makes penis enter the females vagina/ cloaca
What is the function of the cloaca?
Similar to a vagina it is found commonly in birds, and is a female reproductive organ which allows the male to inseminate the female within her body. (Copulation, internal fertilization)
Whether internal or external fertilization, other than in mammals, what provides the developing embryo with nutrients?
The egg, in the form of the yolk
Do some internally fertilizing vertebrates have little parental care?
Yes.
What reproductive strategy is commonly associated with internal reproduction and why?
K-Strategy, low offspring count, high survivorship in the offspring/ young, high energy invested into parental care. Many mammals and most birds.
What species exhibit internal fertilization?
Insects, reptiles, birds, and mammals (including humans)
In some vertebrae’s__________is not present. (Internal or external fertilization)
Parental care
