Adaptation Flashcards
what is adaptation?
species adapting to an environment
leads to major structural and physiological changes
better adapted individuals are selected for
what is an adaptive landscape?
dynamic
graph
constantly changing
promoted by mutation
counteracted by drift
always trying to reach out of valleys to the optimum
what is mullers ratchet?
an accumulation of deleterious mutation
removed by sexual reproduction
gets stuck in adaptive valleys
when does adaptation occur?
when an organism displays traits that allow it to live in a particular environment
biological factors limit the niche organism can live in
what is a fundamental niche?
total range of environmental conditions suitable for existence without the influence of interspecific competition or predation from other species
what promotes adaptation?
- Moderate mutation rates
- A small amount of gene flow
- Directional selection
- Developmental competence (related to ancestry)
what prevents adaptation?
- Inbreeding
- Genetic drift
- Large amounts of gene flow
- Stabilising selection
how is local adaptation and role of natural selection linked?
different environmental conditions within a species
will then consist of small number of sub populations that differ slightly
all species then adapted for their envirnments
what is macroevolution?
major evolutionary change, especially with regard to the evolution of whole taxonomic groups over long periods of time
what is microevolution?
evolutionary change within a species or small group of organisms, especially over a short period
what are co-opted traits and exemption?
new uses for existing traits
exempt from natural selection
what is genetic hitchhiking?
traits selected for as they are linked to something else
not because itself is under natural selection, but near another gene undergoing natural selection
what is dollo’s law?
evolution is not reversible
what are maladaptations?
if in one setting the trait is advantageous, in another it is deleterious and maladaptive
