EVO Flashcards
What is a gene pool?
A gene pool comprises all the genetic information in an interbreeding population.
What are the four sources of genetic variation
mutation
random fertilization
independent assortment (miosis)
crossing over (miosis)
describe how natural selection leads to speciation
The population is separated due to a barrier (e.g. geographical). That means no gene flow between populations. The populations experience different selection pressures. Increase the frequency in favourable alleles. This leads to specialization because the populations are unable to interbreed to produce fertile offspring
What is allopatric speciation
Geographical barrier separates a population and stops the gene flow, leading to speciation.
What is sympatric speciation
Sympatric speciation occurs when there is no geographical isolation but gene flow is still prevented leading to reproductive isolation.
How do you define a species
The members of the species can interbreed to produce fertile offspring.
What are the three methods of defining a species.
· morphological similarity
· biochemical similarity
· sharing a common gene pool.
What is morphological similarity?
Comparing physical structures or homologous features.
What is DNA hybridization
- DNA of different species are extracted and heated (together), breaking
- The mixture is combined to allow DNA to recombine with that of the other species
- The hybrid DNA is reheated. The higher the melting point, the closer the relation of the species
How is DNA sequencing used to determine if individuals are from the same species
The closer the sequence of bases (A, T, C, G), the closer related the species
What is divergent evolution
Where species come from a common a ancestor but evolved to become different
What is convergent evolution
Where species developed similar features due to facing similar selection pressures without having a common ancestor.
What is adaptive radiation
Organisms diversify rapidly from ancestral species into new forms due to selection pressures. (bird example)
Describe temporal isolation as a pre-zygotic factor of reproductive isolation
The breeding cycle doesn’t overlap due to factors such as time
Describe behavioral isolation as a pre-zygotic factor of reproductive isolation.
Differences in mating calls or rituals/ not attracted to each other. Their behavior is not compatible.