Genetic Diversity and Adaptations

• Population: All the organisms of a particular species that live in the same place.
• Allele: Different forms of a particular gene, found at the same locus (position) on a chromosome.
• Genetic diversity: The total number of different alleles in a population.
• High genetic diversity provides the ability to adapt to a change in environment, allowing natural selection to occur.
• Natural selection results in the development of new characteristics due to random mutations and the advantage of certain alleles.
• Directional selection occurs when environmental conditions change.
• Stabilising selection occurs when environmental conditions stay the same, favouring individuals closest to the mean and selecting against any new characteristics, resulting in low diversity.
• Over time the mean of the population will move towards these characteristics.
• Birth weight is a phenotype that affects survival, with babies that weigh around 3kg more likely to survive than those at lower or higher weights.
• Individuals with phenotypes suited to the new conditions will survive and pass on their genes.
• Antibiotic resistance occurs when bacteria with a mutation allowing them to survive in the presence of antibiotics reproduce, increasing the frequency of this allele and shifting the population to have greater antibiotic resistance.
• The role of a species within its environment is known as its niche, and species sharing the same niche will compete with each other.
• The three types of adaptation are anatomical (changes to body structure), physiological (changes to bodily processes), and behavioural (changes to actions), with examples including oily fur, venom production, and hibernation.