Natural Selection Flashcards
What is natural selection?
The process by which heritable variation between individuals leads to differential survival
= [in genetic terms] differential survival of alternative alleles.
What is adaptive radiation?
The diversification of a group of organisms into forms filling different ecological niches
What is a species?
The largest group of animals that can interbreed and produce fertile offspring
What is an allele?
Each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome
What is a polygenic characteristic?
A characteristic which is controlled by two or more genes at different loci on different chromosomes
What are two examples of species which provide evidence of how genes can influence behaviour?
Drosophila (fruit flies)
• use of mutagens
• studying natural variation in population
Warblers (song birds)
• migratory behaviour
What are 3 examples of group selection behaviours?
- Threat displays (vs dangerous fighting)
- Population control
- Dominance hierarchies
Give an example of animals exhibiting threat displays behaviour
Rival red deer, front each other at a distance rather than fighting
Give an example of an animal exhibiting population control behaviour
Birds fecundity adjustments (laying less eggs than they can successfully incubate) so that the species does not over-exploit available resources
Give an example of an animal displaying dominance hierachy behaviour?
Elephant seals
dominant vs submissive
Submissive accept status for benefits of population control.
Name 3 issues with group selection
- Many traits evolve which are not to group’s advantage
- Cheats will always prosper
- Groups do not go extinct fast enough
What year was Darwin’s ‘On the Origin of Species’ released?
1859
