___________ Provide evidence that living things involved from earlier species
1. Fossil evidence: The fossil record provides a timeline of increasingly complex life forms, showing a progression from simpler organisms to more complex organisms over time. Fossils of transitional forms, such as Archaeopteryx (a transitional form between dinosaurs and birds) and Tiktaalik (a transitional form between fish and tetrapods), provide direct evidence of evolution.
2. Comparative anatomy: Comparative anatomy shows similarities in the structures of different organisms, indicating common ancestry. For example, the pentadactyl limb structure (five digits) is found in many vertebrates, suggesting a common ancestor with this characteristic. Vestigial structures, such as the human appendix or tailbone, are also evidence of evolution as they are remnants of structures that were once functional in earlier species.
3. Molecular evidence: DNA analysis and molecular genetics have provided strong evidence for evolution. By comparing the DNA sequences of different species, scientists can determine the degree of relatedness between organisms. Genetic similarities between organisms that are not closely related morphologically provide evidence of common ancestry.
4. Biogeography: The distribution of species around the world provides evidence for evolution. The presence of similar species in geographically isolated locations can be explained by evolution from a common ancestor. For example, the presence of closely related marsupials in Australia and South America is evidence of evolution from a common ancestor that existed when these continents were connected.
5. Observational evidence: Observational studies of evolutionary processes, such as natural selection, genetic drift, and speciation, provide further evidence for evolution. Examples of natural selection in action, such as the evolution of antibiotic resistance in bacteria or the coloration of peppered moths in response to pollution, demonstrate how populations can change over time in response to their environment.