Natural selection
- Created by: Kittykatty2000
- Created on: 27-09-17 17:39
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Selection pressures:
- the environmental factors that limit the population of a species
Gene pool:
- the total number of all the alleles of all the genes of all the individuals within a particular population at a given time
Carrying capacity:
- refers to the resources available, enabling a population to survive
Fundamental niche:
- refers to the resources available to species in the absence of competition
Realised niche:
- refers to the resources available to species as an outcome of competition
The process of evolution by means of natural selection depends upon a number of factors including:
- organisms produce more offspring that can be supported by the available supply of food, light, space etc
- there is genetic variety within the populations of all species
- a variety of phenotypes that selection operates against
Evolution through natural selection:
1 - because the individuals of a species population vary genetically, their characteristics are slightly different from one other
2 - resources (food, space, mates) enabling species populations to survive are limited
3 - organisms have the potential to over-reproduce. however, species populations fluctuates in numbers but, on average, numbers remain stable in the medium term because the individuals of…
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