Fertilisation

Question 1

What is fertilisation?

Answer 1

the fusion of nuclei of 2 gametes. This allows for DNA from both the male and female gametes to come together to create a zygote.

Question 2

Describe internal fertilisation.

Answer 2

Internal fertilisation occurs inside the body. This happens in mid land dwelling organisms such as reptiles, birds and mammals.

Question 3

What does it mean for fertilisation to occur internally

Answer 3

it means there is a high chance of fertilisation occurring and that the zygote will be protected from the external environment.

Question 4

Describe External fertilisation.

Answer 4

External fertilisation occurs outside the body.

Question 5

Describe how External fertilisation can take place and the risks.

Answer 5

In fish and amphibians the sperm and the eggs are released into the surrounding water so fertilisation can take place, this means there’s a higher risk of gametes being destroyed or washed away

Question 6

Why do organisms in which fertilisation occurs externally produce a high number of gametes?

Answer 6

To try and ensure fertilisation occurs.

Question 7

Compare external and internal fertilisation.

Answer 7

Compared to external fertilisation, internal fertilisation has a higher chance of fertilisation occurring and a lower chance of gametes and the zygote being swept away and destroyed as they have more protection from external environment. plus, less gametes are released in internally fertilising organisms.