Study Notes
Natural selection is a process where individuals with beneficial adaptations are more likely to survive and reproduce, leading to changes in allele frequencies over generations. Variation — differences among individuals in a population. Example: Human populations vary in height and skin color. Mutation — original source of genetic variation. Example: New alleles are produced by gene mutation. Adaptations — characteristics that make an individual suited to its environment. Example: Giraffes have long necks to reach high leaves. Overproduction of Offspring — species produce more offspring than the environment can support. Example: Southern ground hornbill raises one fledgling every three years. Differential Survival and Reproduction — individuals better adapted to their environment tend to survive and reproduce more. Example: Antibiotic-resistant bacteria survive and reproduce in the presence of antibiotics.
Exam Tips
Key Definitions to Remember
- Variation
- Mutation
- Adaptations
- Overproduction of Offspring
- Differential Survival and Reproduction
Common Confusions
- Confusing genetic variation with acquired characteristics
- Misunderstanding the role of mutations in natural selection
Typical Exam Questions
- What is natural selection? Natural selection is the process where individuals with beneficial traits are more likely to survive and reproduce.
- How does variation occur in a population? Variation occurs through mutation, meiosis, and sexual reproduction.
- Why is overproduction of offspring important in natural selection? It leads to competition for resources, allowing only the best adapted to survive.
What Examiners Usually Test
- Understanding of how natural selection leads to evolution
- Examples of adaptations and their significance
- The role of genetic variation in natural selection