Questions tagged [natural-selection]

A mechanism of evolution that leads to non-random spread of genes due to the effect that genes have on reproductive success.

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Games with non-uniform interaction rates

Background: Many models in evolutionary game theory assume uniform interaction rates. For instance, consider the $2\times 2$ game: \begin{array}{l c c} & A & B \\ A & a & b \\ ...
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How does the population fitness change after a change in mutation rate?

The mean population fitness as given by mutation load theory depends only on the genome-wide mutation rate ($U$). My question is: How many generations is needed to reach a new mutation load ...
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effect of background selection on promoter regions compared to distant enhancers?

Has anyone looked at the effect of background selection on the levels of conservation of promoter regions compared to distant enhancers? Do promoter regions have a higher conservation due to ...
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Why are fairyflies so small?

The Mymaridae are the smallest insects. This video explains their numerous adaptations to being as small as 140 microns yet still complex, such as smaller cells with as little cytoplasm as possible, ...
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Why might the chirality of gastopods be dominantly dextral?

This wikipedia page on gastropods provides a definition of chirality, and briefly describes the genetic mechanisms behind why a shell is wound left (sinistral) or right (dextral) handed. It also ...
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Niche differentiation in birds of prey

I'm not much of an ornithologist but I know enough to distinguish most Central European birds of prey. To me it is amazing that there are so many species that seem to occupy the same niche. Especially ...
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$F_{ST}$ and the genetic variance in metapopulations

From this video (21'15''), the speaker gives the following formulae in order to calculate the between and among populations genetic variance from the $F_{ST}$: $$V_{Among Pop} = 2 F_{ST}V_G$$ $$V_{...
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What is the difference between effective and efficient selection?

I always thought of the efficiency of natural selection in the context of molecular evolution. I.e. that linked selection and smaller population size cause less efficient selection. It took me a while ...
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What model of epistasis best fit the reality?

In theoretical population genetics, it is very common to have to assume a model of epistatic interaction. The two most common models are the additive model and the multiplicative model. Additive ...
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Replicator equation for mixed strategies?

The the replicator equation is usually defined for pure strategies. More specifically, the replicator eqn for $n$ strategies is given by: \begin{equation} \dot x_{i} = x_{i} \left( \sum_{j=1}^{n} a_{...
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Variance in reproductive success and effective population size

Background The effective population size $N_e$ is the size of the Wright-Fisher population that experience the same amount of drift than the population under consideration. The higher the variance ...
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What is the probability of fixation for a mutant under fluctuating selection?

Here is an answer which explains how one can model the frequency of an allele that is under fluctuating selection (the selection that varies through time). Not, thinking about fluctuating selection, ...
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Ancestral states of sex determination system

Most (maybe all?) species that reproduce sexually have either genders (anisogamy) or mating types (isogamy). There exist today many different type of sexual determination system. There is a whole ...
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Who were the first authors to talk about local adaptation?

I was curious to read about what Darwin had to say about the existance of locally adapted subpopulations. I discovered to my surprise that the expressions and terms "local adaptation", "spatial ...
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Sharks, alligators and Gould's “random walk” theory

I was thinking about Stephen Jay Gould's view on evolution as pure "random walk" / Drunkard's Walk, increasing or decreasing complexity in basically random fashion, just limited by death if an ...
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Are there any evolutionary reasons for the different tree shapes? If so, What are they?

So we know there are a thousand types of trees with different shapes. We have Columnar shaped trees: Pyramidal or Conical shaped trees: Weeping shaped trees: And we also have Round, Vased, Open-...
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Does natural selection select for randomness in development?

In a podcast with Sean Carroll and Liv Boeree they discuss a result from game theory that the optimal strategy in the face of incomplete information can require random decision making. For example, ...
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Finding intensity of selection against dominant homozygotes

I was looking at some Olympiad questions and came across the following: If the frequency of a completely recessive allele is $0.2$ and it remains unchanged from generation to generation due to ...
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Balancing selection vs introgression?

Balancing selection can maintain polymorphisms in natural populations for extended periods of evolutionary time. However, in this paper, Dannemann et al. 2016 identify three archaic haplotypes in the ...
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Does consistency in minor allele frequency of a SNP across populations imply selection?

If a particular SNP has very similar MAF value across multiple largely non-overlapping populations, with the assumption of no gene flow between the populations over many generations, would that then ...
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Is it possible to calculate the evolutionary response to nonlinear selection gradient as a change in variance of phenotypes?

I often see the breeders equation written like this: $R = h^2s = \frac{V_a}{V_z}s = V_a\beta$ or $\Delta \bar z = G\beta$ But is it possible to get something like this: $\Delta \sigma_z = G\...
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Selective pressure for reduced rates of growth and maturity in primates

Humans are somewhat notable for the slow rate at which they grow and reach physical maturity. Some related primates also take over a decade to reach sexual maturity. However, many mammals – ...
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Can the value of heritability be greater than 1?

Heritability defined as genetic variance divided by total variance seems to be bounded between 0 and 1. However, I see a way of calculating heritability on this page (http://www.radford.edu/~rsheehy/...
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Ecological specialization and relative abundance

I am reading Evolution in Changing Environments by R. Levin but have a hard time. Claim At page 25, Levin says as a conclusion The more efficient a caste at meeting the contingency for which it ...
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Do scouting bees get to pass their genes to offspring?

Let's say the food-scouting behavior of scouting bees are enhanced when some particular alleles are expressed. By natural selection, the allele frequency for that "good" allele should increase because ...
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How did the double circulatory system evolve from the single circulatory system

I already learned how the mammal circulatory system (double circulatory system) evolved from the reptilian circulatory system. How did natural selection evolve the reptilian circulatory system and the ...
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Name/Examples of Traits whose benefit is non-obvious and/or which evolve despite apparent mal-adaptivness?

I'm a graduate student in cognitive science doing work on people's explanations and learning, particularly having to do with natural selection. Often, students misunderstand natural selection as a "...
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How can normalizing selection (stabilizing selection) be involved in speciation?

In Mayr's book What Evolution Is, he discusses about normalizing selection in rapidly evolving lineages. "However, normalizing selection is equally active in rapidly evolving lineages." ...
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How did migrations evolve?

Disclaimer: I know nearly nothing about biology. I was wondering how did the migratory behaviour of birds evolve. Assuming that evolution/natural selection works slowly and gradually (at least most of ...
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Does epigenetics suggest there is at least some element of truth to Lamarckism?

I am not a biologist. But googling "epigenetics lamarck", I find many different opinions: For: Lamarck rises from his grave, Epigenetics: Lamarck’s Revenge?, Darwin’s theory ... is incomplete without ...
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Examples of animals who 'forget' their offspring

Occasionally on the news I read about young children dying in hot cars on a sunny day. Usually the article reports that the parent(s) 'forgot' about their children still being in the car. Obviously ...
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Why can't geese regurgitate food?

I saw this harrowing video on how barnacle goslings have to jump off very high cliffs because the parent's can't feed them. The death rate seems high. Why did natural selection come to favor jumping ...
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Can Females Songbirds Have Male Plumage?

Male birds are colorful for courtship displays, females are dull for camouflage. But, is written in a website somewhere that sometimes, when females birds are sterile, they grow male plumage due to ...
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What is the relationship between r/K strategy and filial infanticides?

In other words, is the frequency of killing one's own offspring among species dependent on their location on the r/K strategy spectrum?
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Is social anxiety a part of human gene pool and caused by natural selection?

I'm reading a book called 'Why Buddhism Is True' and I'm not sure I understand author's point regarding social anxiety and natural selection: Our ancestral environment didn’t feature cocktail parties,...