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

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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 ...
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0answers
29 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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1answer
486 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?
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125 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 - ...
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1answer
167 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 ...
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46 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 ...
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239 views

Opposite results between Blomberg's K and phylogenetic signal in Phylocom (AOT)

I've been trying to test for significant phylogenetic conservatism in some plant traits. So far I used R-package picante (Blomberg's K) and AOT in Phylocom. So far these two methods yield completely ...
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1answer
36 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 ...
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93 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 ...
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196 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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459 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 ...
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2answers
92 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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246 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 ...
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437 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 ...
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3answers
240 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 ...
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1answer
65 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 + ...
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1answer
100 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 ...
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66 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 ...
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1answer
1k 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 ...
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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 ...
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1answer
84 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 ...
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1answer
87 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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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 ...
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1answer
103 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 + ...
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1answer
264 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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340 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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79 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 ...
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95 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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240 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 ...
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38 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 ...
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1answer
60 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 ...
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1answer
112 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 ...
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8answers
595 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. ...
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2answers
85 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 ...
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134 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'.
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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 ...
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Why doesn't recombination occur in male Drosophila?

"Males do not show meiotic recombination, facilitating genetic studies." For a while I have known that this phenomenon occurs, this quote comes from the Wikipedia page on Drosophila melanogaster, ...
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2answers
73 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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2answers
448 views

How did the first sexual animal come to exist? [closed]

I am more or less familiar with the evolution theory based on mutations. Now, starting with a nonsexual being, how did the first organism that reproduces sexually come to exist.
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81 views

Chromosome 2 alternate explanation - apes gaining a set of chromosomes?

I'm preparing for a debate (just between friends) on evolution (I'm in support), and one of the points I plan to bring up is the Chromosome 2 evidence. I'm now trying to predict their potential ...
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25 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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28 views

How do beneficial features evolve in species without progressing through detrimental stages?

I'm thinking in particular of wings on birds that would - I'm guessing - have to progress through stages during which they confer no particular advantage. Or is it that all evolved features must have ...
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439 views

Why does sexual selection evolve beautiful features?

First question here. I have a very raw understanding of sexual selection: Say a group of females of a certain species "likes" some feature of a certain groups of males; by "like" I mean some ...
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46 views

How did the roar evolve from snort?

When Lions roar, or Dogs show aggression, they do that snort-roar thing. They're producing sound while inhaling. How did that come to be when all (?) other forms of sound involve exhaling? Humans do ...
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358 views

What is needed for a G-matrix?

I have been doing a lot of reading on quantitative genetics and the G- (and B-) matrix lately. I get the principle behind performing the analysis now but I am still not sure how to do it. I'd like to ...
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3answers
161 views

Evolution (Reductionism)

My recent post was tagged as unclear so I wanted to re frame my question. Though I am a layman, I would love to read books and find the stuff, if I get an overall picture of intelligence factor. My ...
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2answers
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Is there an advantage to linear chromosomes?

The DNA copying enzymes have a hard time working to the end of a chromosome. For circular chromosomes this is not a problem, since there is not a sharp 'end'. However, for a linear chromosome, without ...
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1answer
60 views

Effective population size when the population sizes varies from season to season

Let's think of a species which has four generations per year and which population size changes from season to season so that the population size is 100 in summer, 200 in spring, 50 in autumn and 20 in ...
2
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1answer
128 views

Evolution of Homo Erectus to Homo Sapiens

I just read an article on Wikipedia and noticed that some similarities between Homo Erectus and Homo Sapiens in the "Comparative table of Homo species". My question is; Is it possible to say that ...
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138 views

What is the evolutionary purpose of the topology of the human ear?

What is the evolutionary purpose of the topology of human ears? I understand why the ears may have a funnel-like shape but if the various "hills and valleys" do not amplify incoming sound, what ...