3.4.5 - Phenotypes & Variation

Question 1

What Is Meant By ‘Phenotypes’?

Answer 1

Observable characteristics of an organism.

Question 2

What Is Meant By ‘Phenotypic Variation’?

Answer 2

Difference in phenotypes, between organisms of the same species.

Question 3

What Is Phenotypic Variation, Influenced By?
(2 Points)

Answer 3

~ Genetic variation.

~ Environmental factors.

Question 4

Describe ‘Genetic Variation’ As A Factor Phenotypic Variation, Is Influenced By
(4 Points)

Answer 4

~ Organisms of the same species, have similar genotypes, but slight differences.

~ Genetic variation is transferred from one generation to another, generating phenotypic variation.

~ Some characteristics are monogenic, usually showing discontinuous variation.

~ Another characteristics are polygenic, usually showing continuous variation.

Question 5

What Is Meant By ‘Monogenic’?

Answer 5

Phenotypes, controlled by a single gene.

Question 6

What Is Meant By ‘Polygenic’?
(2 Points)

Answer 6

~ Phenotypes, controlled by several genes.

~ Different alleles an organism has, at a single gene locus, determines the phenotype.

Question 7

Describe ‘Environmental Factors’ As A Factor Phenotypic Variation, Is Influenced By
(3 Points)

Answer 7

~ Changes in environmental factors, can affect growth and development.

~ E.g. Height, hair colour.

~ Changes in phenotypes, caused by environmental pressures, cannot be inherited.

Question 8

Describe Continuous Variation
(3 Points)

Answer 8

~ Individuals within a population, vary within a range.

~ There are no distinct categories.

~ E.g. Mass or height.

Question 9

Describe Discontinuous Variation
(3 Points)

Answer 9

~ Two or more distinct categories.

~ Each individual falls within one category.

~ E.g. Blood type.