Ch. 10.5 : Types of Variation

Question 1

Define variation ( in this context )

Answer 1

The differences in characteristics between organisms

Question 2

What is interspecific and intraspecific variation?

Answer 2

Interspecific : variation between members of different species
Intraspecific : variations between organisms of the same species

Question 3

What are the causes of variation?

Answer 3

An organisms genetic material - differences in the genetic material an organism inherits from its parents leads to genetic variation.

The environment in which the organism lives - this causes environmental variation.

Question 4

What are the causes of genetic variation?

Answer 4

Alleles
Mutations 
Meiosis 
Sexual reproduction 
Change

Question 5

How do alleles cause genetic variation?

Answer 5

With a gene for a particular characteristic, different alleles produce different effects. Individuals in a species population may inherit different alleles of a gene.

Question 6

How do mutations cause genetic variation?

Answer 6

Changes to the DNA sequence and therefore to genes can lead to changes in the proteins that are coded for. These protein changes can affect physical and metabolic characteristics. If a mutation occurs in somatic ( body ) cells, just the individual is affected. If a mutation occurs in the gametes it may be passed on to the organisms offspring.

Question 7

How does meiosis cause genetic variation?

Answer 7

Gametes are produced by meiosis. Each gametes receives half the genetic content of a parent cell. Before the nucleus divides and chromatids of a chromosome separate, the genetic material inherited from the two parents is ‘mixed up’ by independent assortment and crossing over. This leads to the gametes of an individual showing variation.

Question 8

How does sexual reproduction cause genetic variation?

Answer 8

The offspring produced from two individuals inherits genes ( alleles ) from each of the parents. Each individual produced therefore differs from the parents.

Question 9

How does chance cause genetic variation?

Answer 9

Many different gametes are produced from the parental genome. During sexual reproduction it is a result of chance as to which two combine ( random fertilisation ). The individuals produced therefore also differ from their siblings as each contains a unique combination of genetic material.

Question 10

How does the environment cause variation?

Answer 10

It causes variation that cannot be inherited e.g. Scars that have occurred as a result of an accident or disease.