Questions tagged [evolution]

Changes in the heritable attributes of populations of organisms over time. The mechanisms of evolution are mutation, migration, drift, and selection.

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Why aren't green eyes more prevalent?

Why aren't green eyes more prevalent, given that the green allele is dominant over the blue one? My understanding is that human eye colour is determined by two genes: 1) HERC2, with alleles Bx, BB ...
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Why are the fertility rates of large predators kept low?

Predators at the top of a food chain, like lions, seem to have a relatively low fertility rate, which fits well to the ecosystem and avoids overpredation. But what is the mechanism that keeps the ...
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How does Natural Selection shape Genetic Variation?

Background Importance of the additive genetic variance As stated here, the fundamental theorem of Natural Selection (NS) by Fisher says: The rate of increase in the mean fitness of any organism ...
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Why would deer continue to cross a river full of crocodiles even though some of them have been killed?

I recently watched a clip on Discovery Channel, where I saw deer crossing a river full of crocodiles, ignoring the fact that some of them would have been killed doing so. Is there a possible ...
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Cat's tail movement as an indicative of tension

It appears to me that tail's twitching in the cats indicates how much tension the individual is under. During a hunt, when a cat tries to stay invisible, while approaching a target it is almost ...
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What is the definition of a mutation?

There are two alleles that determine the sensitivity of a person to Coumadin (a medicine for blood thinners used to treat a stroke etc). Sometimes you encounter the terminology that one has a mutation ...
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What preceded ATP synthase?

ATP Synthase is ubiquitous throughout life on earth and so most probably evolved within the last universal common ancestor (LUCA) before that lineage diversified into the various kingdoms of life. ...
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Does pheomelanin have a useful biological function?

Melanin is a natural pigment that is categorized into two main forms, eumelanin and pheomelanin. It's well documented in the science literature that increased eumelanin levels reduces the risk of ...
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Genetic Diversity and Adaptation

I am somewhat new to evolutionary biology, having studied it on my free time as a computer science student. There is one particular thing that has always bothered me for which I have not seen a good ...
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What are the atmospheric requirements for large dinosaurs?

What are the atmospheric requirements for large dinosaurs? and are the atmospheric constituents for supporting large dinosaurs any different from the atmosphere today?
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What is the Edward O. Wilson fuss about?

I have just read this article on E. O. Wilson and I don't understand what the difference is between what he is arguing and "standard" natural selection. I read "the extended phenotype" some years ago ...
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What advantage would the initial 'donor' in horizontal gene transfer by conjugation have received?

I am struggling to think why horizontal gene transfer between bacteria would have persisted during the course of evolution as surely it puts the 'donor' at a disadvantage? For example, consider a ...
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Is there are evolutionary explanation for why humans and primates are ticklish? How might it have evolved?

Tickling is a rather interesting phenomenon: When humans or apes are touched in certain areas like the armpits or sides, we respond with laughter AND frantic attempts to stop the assault. Obviously ...
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Why don't we see life form again and over again?

If life formed on earth by natural laws, why can't we observe the formation of life from matter today? Is it because this is a rare phenomenon? It seems just after formation of earth life formed on ...
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How and when did a dedicated immune system evolve?

I have recently been doing a lot of research into the interplay between the innate and adaptive immune systems in humans, and mammalian laboratory models. This has led to my reading some interesting ...
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How did dolphins acquire their dorsal fin?

I had been thinking bout atavism when I saw a picture of a dolphin. I had seen it before, but suddenly the dorsal fin startled me. How did this dorsal fin evolve? Is it some atavism from eons ago, a ...
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How does population stability evolve?

The number of individuals constituting a population is called population size. Over time population size does not remain constant, it fluctuates to different extent over generations because of ...
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Gender and age-specific mutation rate in plants

Background General concept According to Cochran and Harpending (2013), mothers transmits on average a number $x$ of new mutations to their offspring. This number $x$ is independent of the age of the ...
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Genetic Drift: Models, assumptions and empirical observations

There two main mathematical models to describe the process of genetic drift are Moran model and Wright-Fisher model. My questions concern the assumptions of these models, the existence of other ...
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Evolution of spider webs?

Web making seems like a fairly complex behavior built from a pretty strong material. So how exactly did it evolve? Do we have any clues about what kind of features/behaviors preceded web making and ...
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Expected time for a neutral allele to reach a frequency of $p_1$ when starting at frequency $p_0$

Kimura and Ohta (1968) showed that the expected time for a neutral allele to reach fixation (given that it will reach fixation) is $$\bar t(p_0)=-4N\left(\frac{1-p_0}{p_0}\right)\ln(1-p_0),$$ where ...
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When does weak selection produce qualitatively different results from strong selection?

In evolutionary game theory, it is typical to model organisms as having a base fitness that is modified slightly by the game interaction. The ratio of the game effect versus the base fitness ...
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What evolutionary advantages are provided by ovoviviparity?

I read that some sharks are ovoviviparous. What advantages and disadvantages are provided by this type of reproduction as opposed to egg laying and live birth?
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Evolutionary reasons why you cannot tickle yourself but masturbate

There are obviously good reasons that explain why you cannot tickle yourself (see e.g. here). This got me thinking why it is possible to masturbate... Wouldn't it make more sense to not being able to ...
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What is the closest species to humans in animal kingdom?

I presumed chimpanzees were the closest relatives of us. However, after watching this TED Talk, it seems bonobos are closer to us both in skeleton and behavioral similarity than chimpanzees. I once ...
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How does “be altruist to those who are similar to you” evolve?

There are many cases when people commit altruism. One is relationship. I am willing to die for 2 of my children or 8 nieces, say an evolutionary psychologist. Another is reciprocal altruism, which is ...
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Why haven't land animals evolved beyond urination?

It occurred to me (while urinating) that this would seem to be selected against because water is a scarce resource. Why are we constantly losing water we don't need to through urination? What is ...
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Where did Neanderthals and Denisovan Man come from?

Neanderthals, Denisovans and our species (Homo sapiens) are commonly cited as closely related subspecies, even interbreeding with each other. Yet our species theoretically didn't migrate out of Africa ...
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Why is the Kakapo more attracted to humans than its own kind?

The Kakapo can be seen in this video by BBC. It is said that the species is strongly sexually attracted to humans. Why could this be the case?
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Are fishes evolving?

As far as I know, Fishing has been one of the important occupation since early ages, and infinite number of fishes have already been captured. As the time passes, they must've developed some sort of ...
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Why are lions the only social cats?

We know that almost all cats are solitary. How did the Lions (Panthera leo) end up social animals? Do we have an explanatory evolutionary path describing how the Lions became social while the rest of ...
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What is the evolutionary explanation for bat's echolocation [closed]

The bat's ability for echolocation is amazing (so are other the abilities of other animals). I was wondering how all of it came to be.
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Human genetic diversity in Africa in comparison with the rest of the world

Background The claim ... Most of the genetic diversity in humans is in Africa ... is quite common. On Biology.SE, it is easy to find posts that make this claim. Consider for example: Do humans ...
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Why do Mangoes have a single large seed, and not multiple small ones?

I was just thinking about this, wouldn't it make more sense for a mango to have multiple seeds, as it would allow more seed propagation?
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How exactly are game theoretical evolutionary models described during implementation for computer simulations?

When a biologist or a layman tries to reason the evolutionary explanation for something, they would simply use English with some math thrown in (for a random example, pick any explanation out of "The ...
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Is there a dominant gene for right-handedness?

Has there been any definitive research about handedness being genetic? Also, why is right-handedness clearly dominant in humans? I'm interested in evolutionary theories, as well as any molecular ...
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What evolutionary pressures pushed Galápagos tortoises to mature so slowly and live so long?

I read that they take up to 40 years (in the wild) to reach the age of reproduction and are thought to live over 100 years, with one in captivity reaching over 170 years. Can someone explain in ...
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How and why did mouth and nasal cavity evolve separate?

My initial objection is that nose filters air, mouth is for eating but is used for breathing also, plus they both are used to create sounds. What is the cause and reason in this case, why do we need ...
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Why is selfishness the 'obvious' strategy?

Thinking of behaviours an organism can adapt, at the very base an action can always be either selfish or altruistic (cooperative). Usually, selfish behaviour is assumed to be the preferred choice and ...
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Did human hairs actually evolve from scales?

What is the evolution of hairs? Did they evolve from scales?
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Like other animals, why humans don't have species & breeds?

Like other animals, why don't humans have species & breeds ? Even my pet dog is one type of breed, but we (humans) lack breeds & species? What is the main reason?
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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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Why is it thought that silicon based lifeforms never flourished on Earth?

Reading the recent ScienceAlert article "For the first time, living cells have formed carbon-silicon bonds", it is stated that despite the relative abundance of silicon in the surface of the Earth, ...
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Why are certain baby (water)fowl yellow?

Why are e.g. ducklings, goslings, turkey and chicken chicks (partly) yellow? What is the chemistry background to this? What compounds from the egg cause this to happen? What is the evolutionary ...
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What do we know about the Last Universal Common Ancestor (LUCA)?

All life on Earth (bacteria, archaea, eukarya) is thought to have evolved from a common ancestor, or last universal common ancestor (LUCA). What do we know about the characteristics of LUCA based upon ...
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Are there any known mutual symbiotic relationships that has more than two agents?

We are all familiar with the examples of symbiotic relationships in nature consisting of two agents, like lichen or the co-evolvement between certain birds and flowering plants. Do we know of any ...
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Why do most mammals have long snouts?

It seems like most mammals, e.g. dogs, have long snouts. My pet dog's snout would seem to me like an evolutionary disadvantage, since her canine teeth are way out at the end of her jaw, which acts as ...
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why has evolution favored sexual reproduction using two mates over sexual reproduction using three mates?

Many animals species require two members — a male and a female — to sexually reproduce. Why has nature (or the process of evolution) chosen to favor the form of sexual reproduction which requires two ...
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Do other animals suffer from myopia or hypermetropia?

Mammals have eyes similar to humas and many other animals like octopuses have a lens in the eye. So do they have such eye defects? If yes, how do they overcome it? Do they feel selection pressure ...
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What are we missing about the real workings of the evolutionary process? [closed]

As a scientist (and a computer scientist at that) my view is that if we cannot simulate a process we have not understood it properly. I have been following the interesting field of Artificial Life for ...

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