Natural Selection Drives Evolutionary Change
Definition
Natural selection
Natural selection is the process where individuals with traits better suited to their environment have higher reproductive success, passing these traits to the next generation.
- Over time, this leads to changes in the population, driving evolution.
- Don't confuse natural selection with evolution.
- Natural selection is a mechanism of evolution, not the entire process.
Key Principles of Natural Selection
- Overproduction of Offspring:
- Most species produce more offspring than the environment can support.
- This leads to competition for resources like food, water, and shelter.
- Variation Among Individuals:
- Within a population, individuals vary in traits such as size, color, or speed.
- This variation is often due to genetic differences.
- Struggle for Survival:
- Not all individuals survive to reproduce.
- Those with traits that give them an advantage (e.g., camouflage or faster speed) are more likely to survive.
- Differential Reproduction:
- Individuals with advantageous traits are more likely to reproduce and pass these traits to the next generation.
- Change in Population Over Time:
- Over many generations, the population evolves as advantageous traits become more common.
Green Sea Turtles
- Female turtles lay hundreds of eggs, but only a few hatchlings survive predators and environmental challenges.
- Those with traits like stronger shells or better swimming abilities are more likely to reach adulthood and reproduce.
- In species that reproduce asexually, mutation is the primary source of variation.
- This limits their ability to adapt quickly to changing environments.
