Evidence for Evolution Flashcards
fossil record
Similarities between fossils (structural homology)
They show evidence of change over time
Evolution has not occurred gradually but in spurts as small populations adapted quickly to change
comparative embryology
Compares the early developmental stages of organisms. In early development stages, all vertebrates share gill slits and arches.
geographical distribution
Biogeography is the study of where organisms live now and where they and their ancestors lived in the past. Abiotic factors impact distribution.
what is Darwin’s biogeographical theory
Organisms will evolve and adapt to fit their environment. This creates variation so we don’t go extinct.
Biogeography of the Galapagos species suggest that populations on the island had evolved from mainland species.
Over time, natural selection on the islands produces variations among populations that resulted in different, but closely related island species eg. Different beak shapes.
comparative protein sequence
A ubiquitous protein is one which performs basic but essential tasks for all organisms to live. They carry the same task in different organisms.
By comparing the type and sequence of amino acides in similar proteins from different species, the degree of similarity can be established.
Longer time period = greater number of amino acids that are different.
comparative DNA
The comparison is based on DNA hybridization. The more similar sequencing of bases, the closer the relation of the animals, and the evidence of a common ancestor.
Despite the common ancestor, the code in the DNA will be different for different species. New genes would be gained by mutation; others would be lost by natural selection, genetic drift or some other process.
All living things use the same DNA code = all living things are related.
