new mod 5

Question 1

define sexual reproduction

Answer 1

The process of forming a new organism from the fusion of the offspring’s parents’ males and female gametes. The offspring that is formed is not genetically identical to either parent.

Question 2

define external fertilisation

Answer 2

External fertilisation involves the fusion of gametes outside the body of a parent.

Question 3

what animals is external fertilisation is most common in and why?

Answer 3

It is most common in aquatic animals, where the water acts as a medium in which the gametes can travel.

Question 4

are large or small quantities of gametes produced in external fertilisation?

Answer 4

They usually release large quantities of gametes to compensate for losses.

Question 5

what are environmental influences that external fertilisation is susceptible to?

Answer 5

This method of fertilisation is susceptible to environmental influences, such as predators and pH changes

Question 6

define internal fertilisation

Answer 6

Internal fertilisation involves the fusion of gametes inside the body of a parent

Question 7

what animals is internal fertilisation most common in?

Answer 7

Terrestrial animals typically use internal fertilisation to avoid desiccation (drying out) of gametes or embryos.

Question 8

why can internal fertilisation be advantageous?

Answer 8

Internal fertilisation offers more protection ot the gametes and embryos, but as a potential survival cost to the parent.

Question 9

list advantages of sexual reproductions

Answer 9

Sexual reproduction  Combination of chromosomes from two organisms increases variation, which assists with survival
Sexual reproduction via internal  Increased likelihood of fertilisation as egg and sperm are in close proximity, with increased protection from the environment leading to higher survival rates of offspring. Less chance of desiccation of gametes
Sexual reproduction via external  Large number of gametes produced generally means more off spring. It is also a simpler behavioural process which does not require mating rituals. More genetic variation

Question 10

list disadvantages of sexual reproduction

Answer 10

Sexual reproduction  Requires mating of two organisms which is dependent on syncing fertility cycles, and the production of offspring is lower and less prolific than asexual reproduction – greater time and energy involved – in finding a mate etc.
Sexual reproduction via internal  Fewer offspring are produced, and it is more difficult to bring males and females into contact. There is higher risk of sexually transmitted infections passing between organisms.

Sexual reproduction via external  Species must produce larger numbers of gametes, which requires extra energy. It also requires a watery environment (may be difficult for amphibians )