D4.1 Natural Selection

Reproductive potential

The maximum number of offspring an organism can produce in the absence of offspring mortality

Steps to Natural Selection

1. Overpopulation

2. Variation in population

3. Struggle for survival

4. Survival of the fittest

5. Reproduction

Acquired characteristics

Something that is acquired during the lifetime of an organism

Lamarckism

Organisms can inherit acquired characteristics from their parents (FALSE)

Sexual selection

When the reproductive success of an individual results in more offspring comped to others in the population who do not have as much success in finding a mate

Cryptic colouration

Dull or dark colours that blend in with shadows of the forest

Sexual dimorphism

When morphological differences exist between males and females of a species

Intrasexual competition

Competition between males for access to females

Gene pool

All the genetic information present in the reproducing members of a population at a given time

Inbreeding

When closely related organisms mate with each other

Allele frequency

A measure of the proportion of a specific version of a gene in a population

Polymorphic

When a group of genes show multiple variations

Directional Selection

When one phenotype is favoured over another by natural selection

Stabilizing Selection

When one phenotype is favoured over two extreme phenotype

Disruptive selection

When two extreme phenotypes are favoured by natural selection rather than one intermediate phenotype

Hardy-Weinburg equation

An equation used to calculate the frequency of alleles within a population