1. Charles Darwin’s Theory of Natural Selection and its significance as a mechanism of Evolution

2. Linking Natural Selection to Evolution Darwin observed four things that happened in nature, which meant that species could change.

3. . Natural Selection is based on Darwin’s observations and deductions 1 Organisms produce more young than the population needs to survive. 2 There is competition between individuals for survival. 3 There is variation between individuals. 4 Some individuals are more likely to survive and breed than others.

4. Student Task Your group needs to choose one of these underpinning points and discuss why it is central to allowing evolution to occur. Evolution is defined as a change in the allele frequency of a gene pool over time.

5. Group 1 Competition for survival. If there is no pressure to compete for the essential resources, no individuals have an advantage over any other individual. All will be able to breed and all characteristics will be passed on to the next generation. The population will not change.

6. When some resource is in short supply, the individual with the characteristic that allows it to take that resource enough to breed will have more descendants in the next generation. Other individuals that cannot get enough of the resource will die and their characteristics will not be in the next generation.

7. How does this connect to the definition of Evolution? The features that allow the parent to compete for the resources are controlled by the alleles of the parents. When these parents breed they pass their alleles on to their offspring. More successful alleles will become more frequent in the gene pool of a population. Less successful parents will not pass on their less successful version of the gene, so that allele will become less frequent.

8. Group 2 Variation within the Population Variation between individuals is important because the parents with the most favourable traits are able to survive longer (because they compete better for the resources that are limited).

9. They survive longer therefore they are able to breed and pass on their traits to their offspring, Which allows the next generation to be more populated by individuals who have inherited traits that are competitive(better suited to their habitat).

10. Individuals with variations that are less successful are less likely to breed and pass on their variety to the next generation. This removes unsuccessful variants from the breeding pool.

11. How does this connect to the definition of Evolution? The individual variation is based on the alleles inherited in the genes. A gene can have more than one version, called an allele. The different alleles can sometimes cause different phenotypes, or variations between individuals. If one phenotype is more competitive at getting resources than another it is said to be more successful. This means the successful phenotype will have more offspring and have more of its type in the next generation. When more of one sort of allele appears in the next generation, the frequency of that allele in the gene pool has changed.

12. Group 3 Individuals with the best suited characteristics are able to breed more. This is important because then the favourable traits are passed on to the next generation, which means the next generation is more likely to survive.

13. The suitability depends on the habitat. 3 different species with suitable Characteristics for their habitats.

14. How does this connect to the definition of Evolution? The best suited characteristics are controlled by the alleles inherited by the individual. These individuals pass these alleles on to their offspring. These offspring are more competitive for resources in the habitat so they will survive (and reproduce). The most favourable alleles become more frequent in the gene pool over generations.

15. It is important that not all young survive when the resources are limited. It puts individuals in the group under pressure to survive. A population can respond by having some individuals migrate to a new area, which reduces the pressure on resources. This allows the population remaining to continue without pressure. Group 4 Organisms produce more young than are able to survive.

16. Individuals that are under pressure for resources have to compete. The majority of the offspring that survive will have the most suitable characteristics to compete.

17. How does this connect to the definition of Evolution? Those successful offspring have inherited the successful alleles from their parents. If the unsuccessful variations in the offspring die and are not passed on those alleles are less and less likely to appear in the population in the future. The frequency of the successful alleles and unsuccessful alleles is changed over time.

18. Group 4 Organisms produce more young than are able to survive. Another way of looking at it is that This is important because if the offspring could all survive, the only way a gene pool could change is by chance. This could mean that the gene pool didn’t fit the environment.

19. The significance of Evolution is that the whole population becomes more suited to the habitat they live in, by the process of Natural Selection, over time. If the environment doesn’t change, the same selection pressures continue to operate on the gene pool and the same variations are successful. When the environment does change, new selection pressures cause different variations in the population to become more successful.