Evolution Flashcards
Evolutionary convergence
desenvolvem características semelhantes de origens diferentes
Shared vs derived characters
shared - common between two lineages
derived - evolved in the leaneage that sets them appart from others
homologous vs analogous
homologous - inherited from an ancestor
analogous- evolved independently (convergent evolution)
cryptic colouration
helps camouflage
principle of variation
there’s variation between members of a species regarding morphological, physiological and behavioral traits
principle of heredity
variation is in par heritable so offspring resembles more their parents than non related
principle of differential fitness
different variants leave different number of offspring either in imediate or remote generations
3 conditions for evolution by natural selection
- phenotipic variation
- heritability
- associated differences in fitness
Which mutations are really important in evolution
germline cell mutations- can be passed down to offspring
phenotypic plasticity
ability of individuals to alter its physiology morphology and or behaviour in response to change in the enviromental conditions
selection differential vs gradient
differential - change in the mean phenotype before and after a selection episode, response to selection
gradient- relationship between the phenotype and the fitnes, how selection acts on a trait
explanations for a presence of a trait besides selection
- it’s ancestral, retained because it was favored by selection/lack of genetic variability/genetic or functional constraints
- its derived, by a stochastic process (mutation by genetic drift, ld or pleiotropy) or adaptation (driven by selection)
pleiotropy
related or controled by genes that have other importat functions and are dificult to modify without negative effects - one trait is influenced bt many genes
adaptation from pleiotropy by…
gene duplication :
- unequal crossing over
- retroposition
- partial or total genome duplication
ring species
two populations which do not interbreed are living in the same region and connected by a geographic ring of populations that can interbreed.
batesian mimicry
eddible animal resembles animal that’s avoided by predators
why can mimicry be imperfect?
Proved theory- relaxed selection
Disproven:
- eye of the beholder, similar enough
- constraints that limit the evoution of a more perfect one
- multiple predators
- satyric mimicry, on porpouse to confuse and make time
effects of different types of selection on a population
- Stabilizing : mean is constant, variance decreases
- Directional: Mean changes, variance decreases
- Disruptive :mean changes, variance increases, dimorphisms, speciation
Haldane’s rule
early stage speciation : if in a specia hybrid only one sex is inviable or sterile, that sex is more likelly to be the heterogameti sex
