Natural selection is the process by which organisms with traits better suited to their environment are more likely to survive, reproduce, and pass on those traits to the next generation. Over time, this leads to evolutionary change, shaping species and increasing their fitness in specific environments. In IB Biology, natural selection is a core topic that explains how diversity and adaptation arise in the natural world.
Quick Start Checklist for IB Biology Students
- Understand Charles Darwin’s theory of evolution by natural selection
- Learn key terms: variation, adaptation, fitness, and survival
- Be able to describe examples of evolution in real species
- Practice data-based questions involving allele frequency changes
- Strengthen your understanding with RevisionDojo IB Biology study guides
How Natural Selection Works
Natural selection operates on genetic variation within populations. These variations arise through mutations, meiosis, and sexual reproduction, providing the raw material for evolution.
The process follows several key steps:
- Variation exists among individuals in a population.
- Competition occurs for limited resources such as food and space.
- Individuals with advantageous traits are more likely to survive and reproduce.
- Favorable traits are inherited by offspring and become more common in the population over time.
This continuous process results in populations that are better adapted to their environment — a principle central to the IB Biology Evolution and Biodiversity unit.
