Types of variation (f)

Question 1

What is variation?

Answer 1

The differences in characteristics between organisms

Question 2

What are the types of variation?

Answer 2

Interspecific - The differences between organisms of a different species
Intraspecific - The differences between organisms of the same species

Question 3

What are the causes of variation?

Answer 3

Genetic - differences in the genetic material an organisms inherits from its parents
Environmental - caused by the environment in which the organism lives

Question 4

Genetic causes of variation

Answer 4

• alleles - genes have different alleles, producing different effects of the same characteristic
• mutations - changes DNA sequence + thus proteins. if mutation occurs in somatic (body) cells, only the individual is affected; in gametes it can be passed to offspring
• meiosis - crossing over and independent assortment leads to gametes showing variation in an individual
• sexual reproduction - offspring produces from 2 individuals inherits alleles from each of the parents, thus differing
• chance/random fertilisation - many different gametes are produced from the parental genome - the combination is chance

Question 5

How is variation created in asexually reproducing organisms?

Answer 5

• genetic variation in clones can only be increased due to mutation

Question 6

Environmental causes of variation

Answer 6

• all organisms are affected by the environment that they live in
• plants affected more than animals due to their lack of mobility
• e.g. amount of sunlight a plant gets, body scars etc

Question 7

Environmental and genetic causes

Answer 7

• difficult to investigate combinations of the causes to draw conclusions about the cause
• ‘nature versus nurture’ argument - e.g. studies investigating the primary cause variation in intelligence