Topic 2 - Continuity of life on Earth Flashcards
Evolution
Change in the genetic composition of a population during successive generations, which may result in the development of new species
What is evolutionary radiation?
A time of increased diversity/morphological disparity
What are mass extinction events?
Rapid and widespread extinction events
What is molecular homology?
The study of similarities in the amino acids of common proteins across animal species that suggests evolution from a common ancestor
What is microevolution?
Small-scale variation of allele frequencies within a species or population, in which the descendant is of the same taxonomic group as the ancestor
What is macroevolution?
The variation of allele frequencies at or above the level of species over geological time, resulting in the divergence of taxonomic groups, in which the descendent is in a different taxonomic group to the ancestor
What is a gene pool?
The set of all the alleles in all the organisms in a population
What is natural selection?
A species will evolve to to better suit their environment through the probability of selection of favourable alleles
What is directional selection?
When an extreme phenotype is favoured over other phenotypes, causing the allele frequencies in a population to shift over time in the direction of that phenotype
What is disruptive selection?
When extreme phenotypes of a trait are favoured over intermediate phenotypes
What is stabilising selection?
When genetic diversity decreases and the population mean stabilises on a particular non-extreme trait value
What is genetic drift?
When random mutation affects the frequency of a certain allele in the population
What is the bottleneck effect?
A severe reduction in genetic diversity due to a catastrophe that can change allele frequency
What is gene flow?
The mixing of genes from separate groups of the same species over time
What is divergent evolution?
When two closely related species become more phenotypically dissimilar over time
What is convergent evolution?
When two distantly related species become more phenotypically similar over time
What is parallel evolution?
When two closely related species have the same phenotypic traits as distant ancestors
What is coevolution?
When two species who interact with each other evolve based on those interactions
