Speciation: Patterns of Evolution Flashcards
What are the 4 Evidences for Evolution?
- Fossils
- Biogeography
- Comparative Anatomy
- Molecular Biology
What are Fossils? How are they evidence for evolution?
Fossils are the preserved remains of organisms in layers of strata. Fossil records show the change in organisms over time how extinct ancestral species evolved into modern species.
What is “Biogeography”?
Biogeography is the natural geographical distribution of related species.
What are 3 evidences of convergent/divergent evolution?
- Homologous structure
- Analogous structure
- Vestigial structure
What is a Homologous structure?
Ancestral structures inherited by a variety of species for different uses (same structure, different use)
What is an Analogous structure?
A structure/trait unrelated species develop due to exposure to similar selection pressures.
What is a Vestigial structure?
Remanants of features that once served an important function for their ancestors but are now organs/tissues that serve no function.
How is molecular biology evidence for evolution?
Compare nuclear DNA (number of similar amino acids) to see who is most closely related (random mutations/crossing over)
Mitocondrial DNA, passed down the maternal line, mutations occur at a similar rate (clearer record of ancestry)
What are the two types of evolution?
Divergent and Convergent evolution
What is Divergent and Convergent evolution?
Divergent: The process where closely related populations of an ancestral species accumulate genetic differences due to being exposed to different selection pressures. This leads to the formation of distinct species, as mutations and favorable alleles spread within each group, allowing them to adapt/become best suited to their specific ecological niches.
Convergent: The independent evolution of two or more unrelated species who evolve to resemble one another due to being exposed to similar selection pressures.
What is Co-evolution?
When two species form an interspecific relationship where they have exerted selection pressures on one another over time. Changes in one species will result in a reciprocal change in the other species.
What is a mutualistic relationship?
When two species both experience increased survival/reproductive success as a result of their interaction. (Can become disadvantageous as they can become completely reliant on one another acting as a selection pressure)
What is Adaptive Radiation?
A process by which a large number of new species evolve over a relatively short period of time after major events that significantly reduce populations all over the ecosystem opening up new niches for species to fill.
What is Gradualism?
The accumulation of changes step-by-step until the organisms are so different from one another that they are considered another species. (occuring over millions of years)
What is Punctuated Equilibrium?
Long periods of relative stability followed by short periods of rapid evolution followed by more stasis (sudden appearance of a new species in fossil record)
