Evidence and Mechanisms of Evolution
Evolution is change in inherited population characteristics across generations. This lesson combines independent evidence from fossils, anatomy, development, geography, and molecules with mechanisms that can change allele frequencies.
Learning goals
- define the central terms precisely
- connect molecular, organismal and population evidence
- apply the ideas to unfamiliar biological cases
Core concepts
Biological evolution is a change in inherited characteristics or allele frequencies of a population across generations.
The fossil record preserves ordered evidence of past organisms and documents appearance, change, and extinction through geological time.
Homologous structures share an underlying anatomical plan inherited from a common ancestor even when present functions differ.
Natural selection occurs when heritable differences cause unequal survival or reproduction in a particular environment.
Genetic drift is random change in allele frequencies caused by chance sampling, with stronger effects in small populations.
Similarities and differences in DNA or protein sequences can be compared to infer degrees of evolutionary relatedness.
Concept map
Why these ideas matter
These concepts help scientists interpret evidence, design fair tests, communicate uncertainty, and make responsible decisions in research, health, agriculture, and environmental management.