Concepts 2.1-2.6 (Evolution) Flashcards
What Darwin’s 3 points “on the origin of species”?
1) Phenotypic variation exists among individuals of a population
2) There is a differential survival (selection) attributable to that variation
3) There is a hereditary component to the variation
What are some different types of mutations?
Substitution, insertion/deletion, frameshift
What is a germline mutation?
Mutation transmitted via sexual reproduction that create new variation (alleles) and can be heritable.
What is somatic mutation?
Affects all daughter cells of a single cell (not heritable)
What are the main consequences of mutations?
No phenotypic effect (neutral)
Deleterious (negative)
Advantageous (positive)
What are the 6 agents of evolutionary change?
Mutation, genetic drift, natural selection, recombination, non-random mating, gene flow
What is genetic drift?
The process by which allele frequencies fluctuate and change between generations due to random chance events
What is a population (in terms of genetic drift)?
A group of individuals that share genetic information
What is a gene pool?
The sum of genetic information (genetic composition) that is carried in the population
What is macroevolution?
Evolution among species spanning long periods of time
What is microevolution?
Evolution within species that can be observed directly acting upon natural populations
How does an adaptive trait arise?
Advantageous mutation
What is non-random mating?
(Generally) when individuals don’t choose mate at random
What can non-random mating effect?
Allele frequencies of a population
What is gene flow?
The spread of genetic variation across geographical area due to migration, hybridisation or gamete dispersal.
What does gene flow lead to overtime?
Increasing genetic variation within populations and can homogenise allele frequencies across the landscape or between connected subpopulations
What is needed for gene flow to occur?
Individuals must be able to disperse, interbreed and produce viable offspring
What does the impact of gene flow on the gene pool depend on?
- The genetic difference between populations
- The level of migration, movement or hybridisation
What is recombination?
During meiosis, chromosomal pairs align and undergo crossing-over of chromosomal regions to create new genetic combinations
How does meiosis result in independent assortment?
Each gamete only carries half of the chromosomes
What is assortive mating?
When individuals with similar or dissimilar phenotypes mate more frequently than expected by chance.
What is an example of assortive mating?
Plants favouring certain flower colours to attract different pollinators
What is meant by the founder effect?
Small populations have higher genetic drift so can evolve faster
