Overview
Evolution explains how modern organisms descended from ancient ancestors. It is driven by mechanisms like natural selection, genetic drift, and mutation, acting on genetic variation within populations.
Core Idea
Natural Selection: Individuals with traits better suited to their environment are more likely to survive and reproduce, passing those traits to the next generation. Over time, this leads to adaptation.
Formal Definition (if applicable)
Hardy-Weinberg Principle: A null model stating that allele frequencies in a population will remain constant in the absence of evolutionary influences (selection, mutation, migration, drift).
Intuition
Imagine a population of beetles, some green and some brown. Birds eat the green ones because they stand out against the brown bark. Over time, brown beetles survive and reproduce more, so the population becomes mostly brown. That’s evolution.
Examples
- Antibiotic Resistance: Bacteria evolving to survive drugs.
- Darwin’s Finches: Beak shapes adapting to different food sources on the Galapagos Islands.
- Human Evolution: The development of bipedalism and large brains in hominins.
Common Misconceptions
- “Evolution is ‘just’ a theory.” (In science, a theory is a well-substantiated explanation, not a guess.)
- “Humans evolved from monkeys.” (We share a common ancestor with them.)
- “Evolution creates perfection.” (It only creates “good enough” for survival.)
Related Concepts
- Speciation: The formation of new and distinct species.
- Phylogeny: The evolutionary history of a group of organisms.
- Convergent Evolution: Unrelated organisms evolving similar traits (e.g., wings in bats and birds).
Applications
- Medicine: Understanding pathogen evolution (e.g., flu shots).
- Conservation: Managing genetic diversity in endangered species.
- Computer Science: Genetic algorithms inspired by evolution.
Criticism / Limitations
While the fact of evolution is undisputed in science, debates continue over the specific mechanisms (e.g., gradualism vs. punctuated equilibrium) and the role of group selection.
Further Reading
- Darwin, On the Origin of Species
- Gould, The Structure of Evolutionary Theory
- Mayr, What Evolution Is