The theory by which mutations in the genetic code lead to differences from the previous phenotype that, should they be advantageous to an organism's survival to reproductive age, may be passed on to offspring.

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How did the horned lizard evolve?

It's a lizard that has the ability to burst blood vessels in it's eyes and shoot blood as self defense. How can this behavior be explained evolutionary? Wouldn't it mean that there had to be some ...
3
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0answers
42 views

Intuitive explanation for Kin- and Group- selection

It is known from theoretician in the field of kin selection that kin selection (inclusive fitness theory) and group selection are actually two sides of the same coin. In other words, these two ...
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3answers
162 views

Where are the evolutionary “inbetweeners”? [closed]

The problem I've always had with evolution is the actual lack of variation between animals. More specifically, the lack of observable gradual change between species. Take for example the hammerhead ...
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4answers
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Why are there species instead of a continuum of various animals?

As I understand it, various animal traits have to evolve gradually, but what happens to the species that are "neither here nor there"? To put it differently, if a species evolved from another, it did ...
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17 views

coevolution by physical interaction between RNA sequences

There are several items that relate to the concerted evolution between pairs of sencuencias (especially structural) rRNA as a consequence of physical interaction in tertiary, or even quaternary ...
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16 views

detection of primary origin (natural selection or genetic drift) on alterations in sequences

I recently had a question about how to distinguish the origin of variations in the sequences of rRNA as to whether alterations are generated by genetic drift or natural selection. For me it has not ...
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1answer
67 views

What is the outcome of a human population starting with only 2 individuals? [closed]

Starting with a human population N = 2, is there any way the genetic variability seen today could have come about? I don't know that much about meiosis, but isn't there a very limited number of ...
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19 views

Soft and Hard selection

Seems to me that these two sources (M. Whitlock, B. Wallace) use different definitions of soft and hard selection. M. Whitlock: Soft selection occurs when the relative fitness of an individual is ...
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2answers
110 views

On evolution statistics [closed]

This basic evolution theory question has been haunting me since childhood and I'm kind of embarrassed that I can't explain it yet: Consider a butterfly. It's wings have evolved to look like the eyes ...
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2answers
435 views

Is there evidence that some non-human species perform sexual selection based primarily on intelligence? How do they do this?

I'm a biology amateur, but it seems like sexual selection is almost always performed based on physical characteristics, the outcome of physical contests, or some sort elaborate courtship. But do any ...
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37 views

$F_{ST}$ 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 $F_{ST}$: $$V_{Among Pop} = 2 F_{ST}V_G$$ ...
2
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3answers
720 views

What evolutionary adaptations cause trees to grow tall?

I think there are some obvious costs for trees to grow tall. Carbon and other nutrients costs, maintenance cost, energy cost (for growing, to bring water (and nutrients) up to the higher leaves, ...
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1answer
33 views

Distribution of fitness in wild populations

If I get out in the wild observe wild populations and measure the distribution of fitness $f(w)$ in a given population. What will I find out? Will I observe a Gaussian distribution, a Poisson ...
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30 views

Definition of Sexual Selection?

How do you define Sexual Selection (SS)? (One might want to subdivide SS into intra- and inter- SS to answer) Is SS clearly different from Natural Selection (NS)? Is SS nested within NS or are NS ...
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25 views

What is a sex-biased gene?

How do you define a male-biased gene and a female-biased gene as they are found in the abstract of this article.
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2answers
76 views

problem with natural selection [duplicate]

I fail to see how natural selection can build any kind of new functionality. New functionality in a design requires sacrificing a complex series of meanwhile useless steps before the new ...
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1answer
34 views

Two-fold cost of sex and r/K selection theory

This article cites a bunch of articles (I haven't been through them) that the effect of the two-fold cost of sex is "reduced" in stable environment or in K-selected environment. It says: [..] the ...
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1answer
154 views

Evolution and the levels of selection

Reading Okasha's "Evolution and the levels of selection" he talks about "the levels of selection problem." There is a bit of a problem with this opening chapter because, while he talks about why the ...
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3answers
119 views

Has it been enough time for evolution through simple natural selection?

Let first state that I understand natural selection. I am not asking if evolution happened. I see evolution as a fact, but I do not assume the current theory of natural selection as fact. I wonder if ...
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49 views

Is there an evolutionary explanation for depression?

Evolutionarily speaking, depression (both clinical depression and temporary sadness) is a curious phenomenon. Since being depressed is likely to increase the chance of a person with it to commit ...
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2answers
221 views

Correlation between genome size and mutation rate?

Martin Nowak in his book "Evolutionary Dynamics" talks about a given correlation between genome size and mutation rate. What correlation does exactly exist between these two concepts? Is it a ...
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4answers
169 views

Does evolution take place universally?

Why does evolution (namely the evolution of primates into humans) take place both uniformly and universally on the earth? Why aren't there any creatures who have not taken the same evolutionary steps ...
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0answers
33 views

Effects of Genetic Drift on Linkage Disequilibrium

From what I understood of @Canadianer's answer here... Genetic drift randomly causes negative or positive linkage disequilibria, by changing allele frequencies through random sampling. Natural ...
2
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1answer
120 views

Why do genetic drift generates negative linkage disequilibrium?

The very first sentence of the abstract of this article are: "In finite populations subject to selection, genetic drift generates negative linkage disequilibrium, on average, even if selection ...
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1answer
25 views

Definition of Linkage Desiquilibrium (LD)

According to [wiki][2], linkage disequilibrium $D$ equals $$D = x_{11} - p_1\cdot q_1$$ where: $$ \begin{matrix} \text{Haplotype} & \text{Frequency}\\ A_1B_1 & ...
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0answers
19 views

Source of information on the evolution of aging/senescence

Do you know a good review (published peer-reviewed or an online course or whatever) that offers a good overview of all hypothesis explaining the various patterns linked with aging? I'd like this ...
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74 views

Model for fluctuating selection

Is there any mathematical model to predict the behaviour and long-term consequence of counter-acting selection at different time scale? For example, let's consider the bi-allelic gene $A$, with ...
3
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0answers
49 views

Effective population size and overlapping generations

From this book; If generations overlap, then the effective population size $N_e$ does not equal the population size $N$. I know mathematical formulations in order to find the effective population ...
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49 views

Effect of natural selection on phenotypic variance

Short background Theoretically speaking, natural selection causes a decrease in genetic variance and because the environmental variance should remain unchanged, natural selection causes a decrease of ...
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2answers
68 views

Can I force evolution in a group of cells by removing all the smaller cells?

I actually have algae growing in water in a container. I was thinking if it was possible to filter the water so that all the small cells will be filtered out and only the bigger ones will remain to ...
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1answer
57 views

Does recombination increase the additive genetic variance for fitness?

On this article, first column, eighth line of the introduction: By bringing together favourable alleles from different chromosomes, sex and recombination increase the additive genetic variance for ...
3
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1answer
68 views

How does GC-content evolve?

Background GC-content refers to the frequency of base pairs that are either C or G in the genome, or in other words the number of GC base pairs divided by the addition of the number of GC base pairs ...
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2answers
86 views

Heterozygosity under genetic drift

The wright-Fisher model of genetic drift is: $$p_{ij} = \binom{2N}{j}\left(\frac{i}{2N}\right)^j \left(1- \frac{i}{2N}\right)^{2N-j} $$ ,where $\binom{2N}{j}$ is a binomial coefficient. From this ...
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1answer
49 views

Additive genetic variance with $n$ loci

The genetic variance of a quantitative trait (the quantitative trait in question is fitness) can be express as the sum of two components, the dominance and additive variance: $$\sigma_D^2 + ...
0
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1answer
34 views

List of the biggest companies that work in selective breeding

Looking at this question, I've been wondering, What are the biggest private companies which work in both animal and non-animal selective breeding? Let me know if Biology.SE is not appropriate for ...
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1answer
81 views

Additive genetic variance with $n$ alleles

The genetic variance of a quantitative trait (the quantitative trait in question is fitness) can be express as the sum of two components, the dominance and additive variance: $$\sigma_D^2 + ...
4
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1answer
171 views

Why does the slope of parent-offspring regression equals the heritability in the narrow sense?

Background ---- Notations and assumptions ---- let $W_{ij}$ be the fitness associated to the genotype $AiAj$. $x$ is the frequency of the allele $A1$ in the population. The frequency of the allele ...
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3answers
139 views

Fisher's Fundamental Theorem of Natural Selection

Ronald Fisher discovered what he, with humility, called the Fundamental Theorem of Natural Selection. This theorem says (in its modern terminology): The rate of increase in the mean fitness of any ...
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2answers
83 views

Effect on fitness of mutations

What is the distribution/probability density function (PDF) of impacts on fitness of new mutations? I very welcome any partial answer that does not give the whole PDF but just some information ...
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1answer
35 views

Dominance/recessivity of new mutations

What is the distribution/probability density function (PDF) of recessivity/dominance of new mutations? I very welcome any partial answer that does not give the whole PDF but just some information ...
3
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1answer
207 views

How do I calculate the change in allele frequency in a haploid population under selection?

From this book For simplicity, let us consider a haploid organism and assume that the frequencies of alleles $A_1$ and $A_2$ are given by $x$ and $y=1-x$, respectively. We also assume that the ...
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2answers
55 views

DNA adaptation in human life

Does our DNA adapt by human lifetime? Or do we have the same genetic information from birth to death? I mean: What is usually called "evolution" means "natural selection" like this: ...
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27 views

Linkage disequilibrium with $n_l$ loci $n_a$ alleles

Linkage disequilibrium $\left(D\right)$ for two bi-allelic loci is defined as: $$D=X_{11}X_{22} - X_{12}X_{21}$$ , where $X_{11}$, $X_{12}$, $X_{21}$, X$_{22}$ are the frequencies of the haplotypes ...
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1answer
23 views

Could mating/recombination be responsible for evolution of entirely novel features?

The diploid chromosomal architecture is rather interesting. For example, because of diploidy we Humans have to mate. Of course in that sense, because diploid organisms often have mate, this has led to ...
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1answer
89 views

Is Natural Selection like a Copy Editor?

I am stuck on a Homework Question. It says: Evaluate the following statement: “Natural selection works like a copy editor; it works only with what is already present in a population.” (Note: ...
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1answer
79 views

Assumptions of Hamilton's rule

Which elements of the following list are assumptions of the Hamilton's rule? Population structure (non-panmictic population) Additivity = Fitness of the heterozygote equals the mean of the ...
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1answer
25 views

What indices can we use to describe fitness landscapes?

We usually talk of smooth or rugged fitness landscape. Are there any (standard) indices to measure the "structure" of fitness landscapes? For example, one might consider the mean epistatic ...
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1answer
103 views

question about directional selection

Cattle breeders have improved the quality of meat over the years by which process? A) artificial selection B) directional selection C) stabilizing selection D) A and B E) A and C I know the answer is ...
3
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1answer
346 views

Ka/Ks (dN/dS) analysis module for Python?

From this wiki article: In genetics, the Ka/Ks ratio (or ω, dN/dS), is the ratio of the number of Nonsynonymous substitutions per non-synonymous site (Ka) to the number of synonymous ...
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0answers
109 views

Empirical evidence for Group Selection?

A controversial concept in Biology "Group Selection", has caused confusion and conflict amongst scientists since the since the mid 1990s. The more general realm of study is termed the "unit of ...