Evolution SJ 2 Flashcards
define adaptation
the way each organism ‘fits’ its environment
what are the 3 steps in developing a scientific method?
1) look for patterns: diversity/unity/adaptation
2) produce a testable theory for that pattern
3) test the theory(s) using repeatable methods that produce evidence that can disprove the idea
what is the definition of evolution?
any change in gene frequency
describe weismanns principle
- information transmitted from one organism to the next is in the germ cells (gametes)
- soma cells make up rest of organisms body
- any changes in the soma cannot be transmitted back into the germ line (arrows only in 1 direction)
what is the modern equivalent to weismanns principle and what is the difference?
the central dogma where instead of soma and germ cells the example of DNA and protein is used
what is genetic drift and why does it occur?
variation in the relative frequency of different genotypes in a population owing to the disappearance of particular genes are individuals die or don’t reproduce because mendelian inheritance is not exact
what is meiotic drive?
genes distort segregation so that gametes that don’t carry the gene die during gametogenesis favouring the transmission of one or more alleles over another
what is molecular drive?
molecular drive genes are able to convert slightly different genes into identical copies of themselves
what are 3 ways to recognise an adaptation?
1) optimality approach - working out optimal to understand evolutionary characters in behaviours
2) comparative studies - similar lifestyles = similar traits?
3) experimentation - if a trait is adaptive, then changing the trait will change its adaptive value
what are 3 ways to recognise an adaptation?
1) optimality approach
2) comparative studies
3) experimentation
what is the difference between adaptation and mutation/genetic drift?
adaptation is directional the other 2 cause evolutionary change but are random
what are 2 ways of detecting selection?
1) Look for correlations between characters and spatial or temporal variation in the environment
2) look directly for differences in fitness
what are 2 ways of detecting selection?
1) Look for correlations between characters and spatial or temporal variation in the environment
2) look directly for differences in fitness
what is an example of runaway sexual selection?
selection for long tails in peacocks is attractive so offspring have long tails and it carries on in a positive feedback loop until natural selection kicks in at optimal tail length
what is an example of runaway sexual selection?
selection for long tails in peacocks is attractive so offspring have long tails and it carries on in a positive feedback loop until natural selection kicks in at optimal tail length
what is a punctuated equilibrium in fossil records?
dramatic changes in differences in species due to gaps in fossil records
what 2 things could also explain gaps in the fossil record?
1) rapid change
2) periods of stasis caused by stabilising selection
what is orthogenesis?
evolution in which variations follow a particular direction and are not merely sporadic and fortuitous
what was the permian extinction driven by?
environmental change - shallow marine habitats disappear and so do invertebrates in them
what is kin selection?
altruistic behaviour to look after kin - if relatedness to target and benefit to target are bigger than cost to individual the altruistic act will be carried out
4 causes of rapid evolutionary change
1) competition - between 2 species
2) exploitation - by humans
3) climate change - lack of resources
4) parasites - selection pressure
2 uses of phylodynamic data?
1) tells us which lineages have gone extinct and when and which survived
2) can map on other data and look at phylodynamics
2 uses of phylodynamic data?
1) tells us which lineages have gone extinct and when and which survived
2) can map on other data and look at phylodynamics
3 reasons why evolution is important?
1) explains the history of life on Earth
2) helps us understand extinction and speciation
3) evolutionary principles help us decide which species and areas we should spend our limited resources conserving
what are 3 consequences of phylogenetic niche conservatism?
1) closely related species share similar levels of threat
2) conservatism is a consequence of low rates of adaptability and evolution
3) improved knowledge of extinction risks
