evolution by natural selection exemplar answer format 1

• A population has naturally-occurring genetic variation due to mutations
• Members of a species reproduce at a rate that creates more offspring than the environment can support, leading to selection pressures such as predation, disease, and competition creating a struggle for survival
• A change in the environment causes a change in the selection pressures acting on the population
• Well-adapted individuals, with advantageous inherited alleles for characteristics like the ability to avoid predators, compete strongly for food and resources, or be less susceptible and more resistant to disease, have a selective advantage
• Well-adapted organisms are more likely to survive, reproduce, and pass on their advantageous adaptations to their offspring through natural selection
• Over time, the number of individuals with advantageous alleles increases, leading to evolution as favorable adaptations become more common in the population over many generations