Topic 6: Evidence for Evolution Flashcards
what is meant by the term macroevolution?
evolutionary change above the species level (specie level changes can sometimes be placed at this level)
what are categories of evidence for evolution?
- direct observations
- homologous traits
- fossil evidence
- biogeography
what is meant by the term “direct observations”?
evolutionary changes are documented by overwhelming amounts of biological studies, especially from studies on organisms with short life spans
what is meant by the term “homologous traits”?
character traits that evolved from a common ancestral structure, these traits are similar due to share ancestry among taxa
what is meant by the term “morphological morphology”?
looking at phenotypic traits
what is meant by the term “comparative embryology”?
- demonstrates homologous features visible during embryonic development
- general features showing up earlier, can be used as supporting evidence for shared ancestry
what is meant by the term “comparative anatomy”?
- demonstrate homologous features visible in individuals after birth
- homology of limbs in vertebrates
what is meant by the term “vestigial structures”?
evolutionary remnant of ancestors, modifications during decent remove the original functions in the ancestors
what is meant by the term “molecular homology”?
- homologies demonstrated by similarities in genetic make-up inherited from a common ancestor
- degrees of similarity among species is determined by how long ago they diverged from common ancestor
what is meant by the term “fossil evidence”? give some key characteristics.
- indisputable evidence that ancestral species existed on earth
- often document the “in-between” stages of evolution
what are fossils?
remains of species in Earth’s history (many are extinct but are related to extant species)
what does fossil evidence offer? give five examples.
- biology of extinct species
- origin and diversification of some clades
- relative branching order among clades
- tracking evolution over a long, long time
- calibration of geological time for molecular study
what is meant by the term “biogeography”?
- the study of the past and present geographic distribution of species
what are biogeographic studies used for? give three examples.
- assist in reconstruction of historical paths that animals travelled
- document distribution of phenotypic and genotypic variations
- monitor interactions between extant species that may lead to evolutionary changes
what is meant by the term “endemic species”?
biological taxa that are native to a specific geographic area, and are not found in other regions
what are key concepts of endemic species?
- remote locations such as islands
- populations would experience selection pressure different from that experienced by populations with wider distribution (which means over time they may accumulate sets of genotypic and phenotypic variations that lead to speciation events)
