Types of variation

Question 1

Variation

Answer 1

Differences in characteristics between organisms

Question 2

interspecific variation

Answer 2

• Variation between species —> useful in identifying and classifying different species

Question 3

Intraspecific variation

Answer 3

• Variation within species
• in relation to Natural selection variation refers to the differences that exist between individuals of the same species

Question 4

Genetic variation

Answer 4

Variation in genotypes between species or within a species

Question 5

Phenotypic variation

Answer 5

The variation in phenotypes between species or within a species

Eg. Height , mass , shape

Question 6

2 factors that cause variation

Answer 6

• an organisms genetic material - differences in the genetic material an organism inherits from its parents lead to genetic variation
• the environment in which the organism lives - causes environmental variation

Question 7

Generic causes of variation

Answer 7

• alleles
• mutations
• meiosis
• sexual reproduction
• chance

Question 8

Chance

Answer 8

• Many different gametes are produced from the parental genome
• during sexual reproduction it is a result of chance as to which two combine
• the individuals produced therefore also differ from their siblings as each contains a unique combination of genetic material

Question 9

Sexual reproduction

Answer 9

• offspring produced from two individuals inherits genes from each of the parents
• each individual produced therefore differs from the parents

Question 10

Meiosis

Answer 10

• gametes are produced by the process of meiosis In organisms that reproduce sexually
• each gamete 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 11

Mutations

Answer 11

• 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 Judy the individual is affected
• however if a mutation occurs in the gametes it may be passed on to the organisms offspring
• both can result in variation

Question 12

Alleles

Answer 12

• genes have different alleles
• with a gene for particular characteristic different alleles produce different effects
• individuals In a species population may inherit different alleles of a gene

Question 13

Environmental causes of variation

Answer 13

Eg of a characteristic that is determined purely by environmental variation is the presence or absence of any scars on your body

They will have occurred as a result of an accident or disease and have no genetic origin

Scars cannot be inherited from a parent