Selection

Question 1

List the three conditions necessary for natural selection to occur.

Answer 1

Variation: A variation in phenotype

Inheritance: Phenotypic traits what are genetically inheritable

Competition: Phenotypic variation, which is advantageous in terms of survival or reproductive success amongst a population.

Question 2

Describe phenotypic (phenotype).

Answer 2

A set of observable traits of an individual resulting from the interaction of its genotype with the environment.

Question 3

Out of: Directional Selection, Stabilising Selection and Disruptive Selection. Which ones increase variations amongst populations?

Answer 3

Directional selection and disruptive selection.

Question 4

What are the major physiological differences between males and makes in the animal kingdom?

Answer 4

Males produce small motile gametes in the form of sperm. Females produce fewer larger eggs. Females usually care for young.

Question 5

What effect does the difference in gametes between male and females of the animal kingdom, have on the mating dynamics of some species of males?

Answer 5

Males compete with one another to obtain access to females by using 1 of 2 techniques:

1. They physically control females directly or control the resources females acquire; or they physically dominate or control other males, restricting their access to females
2. They advertise to females and females choose a mating partner

Question 6

How would you define intrasexual selection?

Answer 6

Intrasexual selection, is a selection pressure which acts upon males who compete amongst each-other for the mating rights of females that favour individuals with weaponry and those with the largest weaponry could outcompete individuals with smaller weaponry thereby gaining access to females.

Question 7

How do you define intersexual selection (also known as female choice)?

Answer 7

Intersexual selection amongst males is best described using the Peacock as an example. The brightly coloured plumage (or ornaments) attracts a female. Like intrasexual selection, in wild habitats males are constantly developing bigger and more impressive ornaments to entice females for mating rights to them.

Question 8

What is the difference between artificial selection and natural selection?

Answer 8

Artificial selection is the selective breeding of organisms to encourage desirable phenotype traits.
Natural selection is the continuing survival and reproduction of a population due to advantageous phenotypic traits.

Question 9

Why does piebald syndrome happen?

Answer 9

Because pigment-forming skin cells which develop from he neural crest, either fail to migrate to the skin of the embryo or die. Thus leaving the section of skin with no pigment.

Question 10

List the three types of natural selection.

Answer 10

Directional selection

Stabilising selection

Disruptive selection