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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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5
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1answer
62 views

How related are trees?

I was surprised to see how far apart macadamia and hazelnuts are from each other. I always thought all trees had a common ancestor that was also a tree. But that doesn't seem to be the case? Did wood ...
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4answers
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Why are there no wheeled animals?

In physics, "almost everything is already discovered, and all that remains is to fill a few unimportant holes." (See Jolly.) Therefore, on Physics SE, people are veering off into different directions: ...
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"Why" did the naked molerat lose its fur? [closed]

Or any other small, furless mammals? This question asks the same for humans, but circumstances are markedly different (at least naively) between humans and rodents; for one, smaller animals have less ...
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1answer
88 views

Did Dinosaurs have a neocortex?

Did dinosaurs have a neocortex in their brains? If not, when did it come into existence?
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On the origin and evolution of vaccinia virus

I was browsing Wikipedia and learned that vaccinia virus, the basis of the smallpox (variola virus) vaccine, was originally thought to be derived from cowpox but was later discovered to be a separate ...
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10answers
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Why are there no organisms with metal body parts, like weapons, bones, and armour? (Or are there?)

Reading this question, Why are there no wheeled animals?, I wondered why no organisms seem to make use of the tensile and other strengths of metal, as we do in metal tools and constructions. I am ...
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0answers
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How can more vegetation can result in more species diversity?

I am a high school student and I am a little confused. In my textbook, while discussing the longitudinal pattern of biodiversity they say one of the reasons is that "tropical areas have more ...
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0answers
52 views

Do bacteria select for "soap resistance"?

When people wash their hands with soap, this limits the spread of bacterial infections. That much, I am pretty convinced of. Duh. What I don't get is how this doesn't lead to evolutionary pressure on ...
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5answers
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Why did abiogenesis only happen once?

If the "primordial soup" theory of abiogenesis is to be believed, self-reproducing organisms spontaneously arose on Earth at least 3.5 billion years ago, surprisingly soon after the Earth cooled down ...
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2answers
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What is the highest concentration of sodium chloride for the oceans to be able to sustain life?

What is the maximum concentration of NaCl for life in the oceans to be possible? Was it fortuitous that the concentration was originally no higher, in which case the evolution of life on Earth would ...
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3answers
363 views

Is designing alien life still just science fiction?

As we continue to search for life in very different environments than the earth, it would make sense to me to think about and design lifeforms (theoretical) that could work in these environments. I ...
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2answers
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Are there life forms that freely fly in the atmosphere?

Are there (unicellular) Earth lifeforms that most of their life fly high in the atmosphere without contact with surface? For instance, in clouds, etc? If so, at what max altitude have they been ...
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Does surface to volume ratio matter for cold-blooded species with regards to temperature?

While surface grows quadratically with scale, volume growth is cubic. Temperature exchange (gain and loss) of animals is mostly dependant on surface area (the more area, the faster) whereas heat ...
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1answer
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Evolution of Aging according to Weismann

Several authors agree to the fact that August Weismann was the first to propose an explanation to biological aging (Kirkwood and Cremer, 1982; Gems and Partridge, 2013). A lot of hallmarks (and some ...
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1answer
93 views

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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0answers
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Difference between heritability on the scale of liability versus the scale of observation

I was reading a paper on disease heritability ("Estimating Missing Heritability for Disease from Genome-wide Association Studies") and it struck me that I don't have a great understanding of ...
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0answers
72 views

Why are mosquito bites and other histamine-triggering events itchy?

When a mosquito bites a human, it injects some saliva containing compounds that dilate the blood vessels and prevent blood clotting. The human body's response to this is to create an extremely itchy ...
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79 views

How do evolutionary forces influence the number of copies of the p53 gene?

p53 is an important tumor suppressor gene. Around 50% of cancers are associated with loss of function in p53. Humans have only two copies of p53 in their genome (one on each homologous chromosome). ...
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58 views

Evolutionary reason green bottle flies are shiny

Just noticed some green bottle flies in my backyard. They are shiny. A shine like that attracts attention (of potential predators) and probably takes some work to maintain. This made me wonder why ...
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0answers
57 views

What determines the complexity of phenomenology of humans senses with respect to evolutionary development?

My question is a bit hard to phrase as I'm not sure what is cause and effect of evolution of human or animal senses. But in general I need a pointer where to start reading concerning why for instance ...
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1answer
38 views

How old is the Pogona genus?

What it says on the title, how old is the genus Pogona, which includes all bearded dragons? I tried looking online, and all I got was the useless answer of “bearded dragons are descended from their ...
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27 views

Explanation for lack of wing-leg-fin transformations in arthropod evolution?

I don't know much about evolutionary biology so I may be missing something obvious. It seems that vertebrate evolution somewhat frequently re-invents the fin out of the leg or wing and the wing out of ...
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1answer
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Fluctuations in disease burden of respiratory viruses (especially influenza/coronaviruses)

Compared to peaks in terms of disease burden (morbidity and mortality, or incidence of severely symptomatic cases and deaths caused by a viral strain within a population), is the relatively light ...
202
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4answers
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Why are so few foods blue?

Although blue foods exist, they're rare enough compared to other foods for food preparers to use blue plasters as a convention. The natural colour of a given food is due to pigments that have some ...
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1answer
882 views

Were there any vertebrates with 6 or more limbs?

My question is actually a bit more broad than what's in the title, but I don't know how to put it succinctly. When I was trying to find the answer to that question, I found that all known terrestrial ...
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1answer
49 views

Cell Theory- does the first cell not contradict cell theory [closed]

In cell theory, we have cells arise from other existing cell. But the first cell did not arise from existing cell, and that means there are some other condition which allows cell to be formed. I ...
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4answers
172 views

Is existence of different alleles for a gene a result of mutation?

I would like to understand evolution. Here are a few questions Why are there different alleles for a gene? Is the different alleles of a gene are mutated versions of a gene? Why selection pressure ...
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1answer
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From an evolutionary standpoint, why don’t couples attempt to have as many kids as possible?

Many couples have 4 or 5 kids, but it is unusual for a couple to have 10 or 15. Shouldn’t humans have evolved to want as many kids as possible to maximize the chances that their genes are passed down?
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Darwinism and the idea of being too successful

Is there an example of any animals or insects that have evolved too efficiently and went extinct due to upsetting the homeostasis of their environment? Outside humans. I was thinking about venomous ...
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2answers
212 views

Any species returning to the land twice throughout their evolution?

Here's a question from my son I've found interesting enough to ask here. There are plenty examples of species returning back to the water environment, like dolphins, sea lions, walruses, some snakes, ...
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How it happened that in cactuses the difference between the fruit, the leaf and the stem so much blurred if they were normal plants in the past?

Looking at a cactus may make impression that they evolved separately from other plants, which usually have stem, leaf and fruit. But the fruit in cactuses has the same structure and surface as the ...
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1answer
457 views

How has the theory of evolution changed over time?

I learned at school and in the documentaries like everybody that (to summarize) molluscs evolved into fishes then reptiles then mammals then humans. Does the theory still make the same claim ? or ...
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1answer
58 views

On the Origin of Homo Sapiens

Paleoanthropologists are certain Homo sapiens originate from Africa. However where in Africa is still contested. Could you give the reasons why it is thought that Homo sapiens evolved in Eastern ...
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1answer
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Where in Africa did Homo sapiens evolve from? [closed]

I’m aware that the possible oldest homo sapiens fossil was found in Morocco. The vast majority of our fossils however is found in Eastern Africa. In recent years,a controversial study on mitochondrial ...
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2answers
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What’s the largest animal in the evolutionary history of birds?

I know that birds evolved from dinosaurs (or a related clade). However, some dinosaurs are large and others are small. Did birds evolve only from a line of dinosaurs that stayed small throughout ...
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3answers
340 views

Is there a name for this phenomenon described in "Phylogenies and the Comparative Method"?

The figures below are from Felsenstein's paper "Phylogenies and the Comparative Method". I was wondering if there was a specific name for this effect where there is an apparant correlation that is ...
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0answers
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Is the principle of "the least energy" a fundamental principle of evolution? How does it stand with the rule "the one who replicate the most"? [closed]

The principle of "least energy" seems to be a fundamental law of the universe (is it?). I probably use the wrong word. I'm just talking about the reason why electrons are filling first the ...
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1answer
59 views

can a cell evolve into a different species in the lab?

A friend of mine does not believe in evolution. He claimed that we can not as humans observe a single cell evolving into a different cell. Is that possible to be observed in the lab? Thanks in advance....
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2answers
152 views

When is it better for a gene to cause a biased sex ratio?

Because genes are selfish and want to maximise their transmission from generation to generation, if they can distort a population's sex ratio, isn't it always in their interest to cause a biased sex ...
4
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2answers
256 views

From where did the selfish gene get its selfishness?

This is in reference to the book The Selfish Gene by Richard Dawkins. Further, Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is ...
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1answer
123 views

Can vaccines drive viruses to evolve? If so, how?

Obviously, destroying vaccine-vulnerable strains of a virus will leave the vaccine-resistant ones to represent an increased fraction of the overall viral population. I'm asking, though, whether/how ...
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80 views

Kleiber's law and Bergmann's rule

I was researching that deep-sea animals are much larger than their close relatives in the upper ocean (gigantism), and from what I've seen, this is due to two rules: Kleiber's law and Bergmann's rule. ...
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1answer
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Are there mammalian species in which the male makes no contribution after coitus?

It seems that live bearing is very high cost relative to egg laying. Therefore, I would expect that in a live bearing species the male would always have a post coital role. Is this the case?
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1answer
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When does a virus become a different species?

Related: When does one decide to refer to a virus as a new variant? I've been thinking about all the news related to "variants" of the SARS-CoV-2 virus, including the infamous "Delta ...
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7answers
349 views

Resource recommendation: a good book explaining and evaluating the evidence for evolution?

I take a great interest in the intersection between science and religion and evolution is therefore something I often read about. Many of the critics of evolution like to poke "scientific" ...
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1answer
1k views

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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2answers
37k views

Why do these 2 dots frequently occur in dogs' eyebrows? Does it serve/served any advantage?

I have been wondering why, in spite of the variation in color-patterning in dogs, these 2 dots (1 on each eyebrow) seems to be frequently occurring. Dog-1: This one has a white dot. Photographed from ...
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1answer
220 views

Are there some natural instances of thermosensitizer?

Let's define thermosensitizer as any chemical or biological agent that can sensitize the cells to heat. In lab setting, thermosensitization seems to be achievable, such as by inhibiting chaperone ...
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1answer
58 views

Do mutations that cause the loss of a complex trait occur more often than mutations causing gain of a complex traits?

The Wiki entry on the evolution of biological complexity states that "[m]utations causing loss of a complex trait occur more often than mutations causing gain of a complex trait". There is ...
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0answers
77 views

At what point in evolution is a new species identified? [duplicate]

As we know, a change in allelic frequency leads to evolution, and as these changes accumulate a new species is created. My question has two parts - A classical definition of species which is now not ...

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