Unit 7: Topic 6 - Evidence of Evolution Flashcards
What types of scientific evidence can be used to support evolution?
Fossils (geological/physical), Homologies (morphological), DNA sequences (genetic), molecular and cellular processes (molecular/biochemical), and structural evidence (biochemical).
How can geological evidence (fossils) be used to support evolution, and how can they be dated?
Fossils in strata show the newest at the top (closer to the surface), with older fossils in lower strata. They can be compared to others in locations around the world to see if any match, revealing more information about the species and the state of the world around that time. Fossils ultimately show change over time in many species. Scientists date fossils through radiometric dating, using a radioactive isotope such as carbon-14 and its half-life, the age of the surrounding rock, or the geographical position of the fossil.
What are morphological homologies and how do they help show common ancestry?
Homologies can be evaluated to find common ancestry through similar features. They include homologous features, and vestigial features, with analogous features being the exception. A homologous feature is a shared physical feature in multiple species. Embryology is a common method of evaluating homologous features. A vestigial structure is a lost homologous feature due to its not being advantageous to the organism. Both show a feature that a common ancestor had which got passed down through many generations and species. An analogous feature is one that is shared among multiple species but was brought up from convergent evolution, which does not show common ancestry and is why it is an exception.
How can DNA/amino acid sequences provide evidence of common ancestry?
Shared genetic information, gene expressions, amino acids, and genetic codes in all organisms show common ancestry. Homologous genes also show common ancestry of multiple species, similar to a homologous feature.
What molecular/cellular processes are conserved across all organisms?
Metabolic pathways such as glycolysis. DNA/RNA as the universal genetic information.
