Variation & Evolution
- Created by: beth-marie2511
- Created on: 15-06-16 08:30
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- Variation & Evolution
- Over-production
- More offspring are produced than survive
- Many die without reproducing
- Why?
- Competition
- Interspecific
- Competition between two different species
- Intraspecific
- Competition within the same species
- For different resources (food, water, shelter, mates, territory etc.)
- Interspecific
- Natural Selection
- Depends of 'survival of the fittest'
- Selection pressures increase the chance
- Competition
- Why?
- Many die without reproducing
- More offspring are produced than survive
- Selection Pressures
- The environmental force altering the frequency of alleles in a population
- The factor which has a direct effect on the numbers of individuals in a population of organism
- Examples
- Lack of food
- Lack of water
- Overcrowding
- Increase in predation
- Increase in disease
- A change in environmental factors would have an effect on the frequency of alleles in a population
- A change in environmental factors can either make a once un-advantageous allele advantageous and therefore its frequency within a species increases, or visa versa
- The environmental force altering the frequency of alleles in a population
- Populations
- A population is a group of the organisms of the same species living in the same habitat at the same time
- A population can also be described as a group of organisms that can interbreed, occupying the same habitat
- Gene pool
- The total number of available alleles in a population in a specific habitat
- Allele Frequency
- Relative proportion of alleles (in a population)
- A population is a group of the organisms of the same species living in the same habitat at the same time
- Over-production
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