Diversity and Evolution Flashcards
natural selection
- heritable variation for a particular trait (morphology, behaviour) exists in a population
- individuals with the trait that is suited for the particular environmental conditions will be more likely to survive and reproduce, and thus the frequency of that trait will increase
(differential reproduction of inherited traits)
adaptation
match of form and function to the environment
ex. no giant horns in dense forest environments (because they are not advantageous)
stabilizing selection
Type of natural selection in which the population mean stabilizes on a particular non-extreme trait value.
directional selection
A mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.
disruptive selection
Describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups.
coevolution
the evolutionary change in one species is responded to by a change in a second species and so on
-i.e. a cheetah evolves to run faster, the monkey evolves to run faster
diffuse coevolution
- coevolution between one species and a suite of other species
- ex. dung beetle moving many species of seeds in DUNG
What are strategies/adaptations for coevolution not occurring?
in DUNG beetle:
Make seed bigger - cost, more energy and attractive to mice on forest floor
Change shape of seed - dung beetle wouldn’t want to have that in their ball
group selection
-groups differ in attributes and these differences relate to differences in group survival
sexual selection
-a component of individual selection that is created by the pressures that males and females exert on conspecifics as they compete for mates
- male-male competition
- female choice
kin selection
- selection operating between closely related individuals to produce altruistic behaviours
- helps your genetic success bc your kin have some of your genes
inclusive fitness
-a measure of total genetic success via personal reproduction (direct fitness) and effect on reproduction of non-descendant kin (indirect selection
anagenesis
- a single species that evolves into another species over time
- aka chronospecies
cladogenesis
- a single species evolving into two or more species over time
- increases diversity
allopatric speciation
-speciation with a physical barrier (e.g. a river) that prevents gene flow and allows two populations to diverge