Changes in the heritable attributes of populations of organisms over time. Major mechanisms include drift, natural selection, mutation, and gene flow (migration).

learn more… | top users | synonyms

31
votes
7answers
5k views

Why does evolution not make our life longer?

Why does evolution not make life longer for humans or any other species?
-1
votes
4answers
318 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 ...
2
votes
1answer
59 views

Coefficient of relationship and path of coefficient

A path of coefficient of relationship is defined as $$\rho_{AO} = \left( \frac{1}{2}\right)^n \sqrt { \frac{1+f_A}{1+f_O}}$$ This SE post discusses this definition From this, the coefficient of ...
10
votes
2answers
244 views

Why is venom more common in fish and snakes than other vertebrates?

Reading this question, I wondered why is it that we associate vertebrate venoms so often with snakes and fish, and more rarely with lizards, amphibians, mammals, and birds (apparently never, in ...
0
votes
1answer
38 views

evolution and mutation of microrganisms against medicines?

I presume microorganisms would have very short life span and they would multiply more creating millions of their kind. Is it really a threat to consider when we use anibiotics and other stuff more ...
5
votes
2answers
156 views

Viruses: Adaptation to a new host through repeated host jumps

A friend told me, during a 3 minute discussion, that viruses that are endemic in host $A$ and make repeated jumps to host $B$ but can't be transmitted between individuals of species $B$, may slowly ...
0
votes
1answer
87 views

Defining: Evolutionary (quantitative) Genetics and Population Genetics

How do we define the fields that are Evolutionary (quantitative) genetics and population genetics. What set these two fields apart? Can you try to provide definitions? To my intuitive understanding, ...
5
votes
2answers
266 views

How Sex Evolved ? and when?

As I know evolution comes bit by bit mutation by mutation How sex evolved which requires a major change in at least two individuals one to become male and one to become female ? When that happened ...
3
votes
2answers
307 views

How are two species with similar phenotypes identified as different?

How are two species with similar phenotypes identified as different? Have two different individuals that were thought to be different species ever been determined to be from the same species ( or ...
1
vote
2answers
128 views

Which was the last significant event in human evolution? What's next?

At 10.000 BC (12 ka), we became the last of the Homo species on Earth. In evolutionary terms this is a very little time range to something happen, but I'm wondering anyway, in this meantime which are ...
1
vote
0answers
150 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
votes
3answers
212 views

Many spermatozoa, but just one ovum

Why do men produce so much spermatozoa, that will get discarded, but women, just ovulum, but it's a good one. Couldn't men produce good spermatozoa as a limited edition? Where is the evolutionary ...
2
votes
1answer
332 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 ...
1
vote
1answer
143 views

Heterozygosity and overdominance

Consider $m$ loci with heterozygote advantage (overdominance) such that the fitness of the two homozygotes is $1-\frac{s}{2}$ and the fitness of the heterozygotes is $1+\frac{s}{2}$, where $s>0$. ...
3
votes
1answer
137 views

Are people genetically predisposed to being interested in specific fields/ideas? How does specialization occur?

I'm not sure if I formulated my question well, but I'm curious about a couple statements made by Steven Pinker and and James Heckman. In this interview: ...
1
vote
1answer
204 views

definition of tempo and mode in evolution

I am reading Punctuated Equilibria: The Tempo and Mode of Evolution Reconsidered, which mentions the "tempo" and "mode" of evolution. I'm not familiar with the related literature and when I google the ...
2
votes
0answers
34 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 ...
1
vote
1answer
783 views

Advantage of being deuterostome

We know that most of the so called "Advanced" organisms are deuterostomes (i.e., development of gut starts from anus). Is there any evolutionary advantage of that? If not, why and how did it evolve?
1
vote
1answer
130 views

Population genetics and the fitness probability distribution. Why is the arithmetic mean all we need?

When recording change in allele frequency in diploid, bi-allelic, infinite and panmixic population we usually use this kind of equation: $\delta_p = \frac{p * q *( p (w11 - w12) + q * (w12 - ...
2
votes
1answer
211 views

List of heritability estimates in humans?

Many people on this site ask questions that directly or indirectly have to do with heritability in human. Do you know a list of estimates of heritability of various traits in humans? Or could you try ...
2
votes
1answer
47 views

How are new chromosomes replicated into the next generation via sexual reproduction?

If an individual has a new chromosome, which is very unlikely to happen, he will not have any luck in finding a sexual partner with this same trait. How will the offspring inherit this trait. And ...
1
vote
1answer
39 views

Coalescent Theory - Probability for $k$ alleles that of one coalescence event occured $t+1$ generations ago

From this textbook Under the wright-Fisher model of genetic drift and under the assumption that all alleles are neutral, the probability that $k$ alleles had $k$ distinct parent alleles the previous ...
2
votes
1answer
112 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
votes
1answer
324 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 ...
5
votes
3answers
499 views

Evolution: How could all useful traits evolve simultaneously?

I have a basic question about evolution, for which I never found an answer. I understand how evolution works if we focus on one specific organ or trait. With each generation, some organism is more ...
3
votes
2answers
95 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 ...
3
votes
1answer
349 views

What is the beneficial function of IgE antibody?

Dont tell me the "function" of IgE is to cause allergy ! In whatever texts I have seen it is written that IgE is important to cause allergies but what is the beneficial function of IgE ? Why was it ...
10
votes
2answers
480 views

How does the genetic code evolve?

After looking at this question, some other questions poped in my mind. The DNA code is redundant, there are 20 amino acids for 64 possible nucleotide combinations. Therefore some amino acid are coded ...
12
votes
2answers
255 views

How do we know that dinosaurs were related to lizards and/or birds?

Do we clearly know what the living closest relative of the dinosaurs are? And connected to the first question, in scientific manner how do we know these relationship between extinct species and living ...
1
vote
1answer
69 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 + ...
2
votes
1answer
102 views

Earliest ancestor of humans who could integrate into modern society

Assuming the current model of human evolution to be correct, approximately when did the earliest ancestor of humans live, who was intelligent enough, that if raised from a young enough age, could ...
3
votes
1answer
81 views

Evolution from Mating types to different sexes

Imagine a lineage of multicellular organisms that had mating types and evolved their mating types into sexes. What are the possible mechanisms that might have brought this lineage to evolve sexes from ...
1
vote
1answer
2k views

Why do different humans look different?

Although farmers appear to be able to tell their cows apart, cows look very much alike to me. And this similarity in appearance seems to be a general trail across the animal kingdom: one individual of ...
1
vote
0answers
19 views

Propagation of tool use in primates?

There are several famous cases of great apes demonstrating a surprising degree of wherewithal in communication and tool use - even monkeys can learn some tool use from each other observationally, even ...
2
votes
1answer
109 views

Why do the neuron pathways decussate?

I learn about the brain right now, and there are crossing of neuron pathways everywhere; in the thalamus, the medulla oblongata, the pyramidal tract... And I don't understand why? What is the reason ...
1
vote
1answer
130 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 ...
1
vote
0answers
25 views

Triune brain model

I have heard about the triune brain model in biology class, but my teacher does not know much about it. What I'm curious about, is this model accepted by most of the neuroscientists, or is it just a ...
1
vote
1answer
108 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
votes
1answer
335 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 ...
4
votes
3answers
443 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 ...
2
votes
1answer
89 views

Life on other planets [duplicate]

first of all I'm not sure if I should post this here or in the astronomy stack. I think biologist are more likely to answer my question. To make it short: Why when looking for any sort of life on ...
1
vote
2answers
97 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 ...
1
vote
1answer
289 views

Cyanobacterial photosynthetic oxygen yield

I am somehow not convinced that biotic factors are solely responsible for creating 21% of atmosphere (around 40 million moles of oxygen). There may be additional issues here. Since cyanobacteria ...
1
vote
1answer
39 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 ...
0
votes
1answer
67 views

How can a recessive allele propagate until they manifest?

Suppose a specific gene has two possible alleles. In a given population all members have only the dominant one. By a mutation on member receives the first recessive allele of that population. Is it ...
1
vote
1answer
126 views

building intelligent structure with random evolution requires series of non useful steps

In order to build an intelligent design such as a bridge or a mechanical watch, you need a series of non useful steps. As far as I understand, in random evolution theory, the "intelligence" involved ...
1
vote
8answers
639 views

How does the creative process of Biological Evolution work?

In order for nature to go from microbes to man, there needs to be new information. Where does this new information come from? It is understood that Evolution basically involves three elements. ...
2
votes
2answers
98 views

Evolution of bee hives

How do the instinct to create a hive appeared in bees? Is there some evidence of "intermediate" hives? With this questions i mean all the factors necessary to build a hive, including the social ...
1
vote
2answers
154 views

Why do we find nature 'beautiful', from an evolutionary perspective?

Most people I know find nature beautiful and holidays generally involve a place that has 'natural beauty'.
16
votes
5answers
5k views

Why are not all species hermaphrodites?

If a hermaphrodite animal (like slug, snail, etc) finds a partner they can mate immediately. If another animal with "normal" reproduction (lets say a mouse) finds a partner they can only mate if they ...