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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Evolution of healing for burn injuries in mammals?

I recently got second degree burns on my hand and it got me thinking. Our body had very specialized processes for healing burn injuries. Namely the process of blistering. My question is how this ...
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15 views

Seeing through the rain

This question leads me to wonder about seeing in and through rain. From visual point of view, rain is light-bending droplets moving downwards, unformly in steady rain, less uniformly if there's ...
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3answers
107 views

Why does all life use the same macromolecules in their genetic code?

There is no biochemical constraint of any sort, so why doesn't some other code work? Why is it specifically RNA/DNA?
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20 views

What is the distribution of the number of heterozygotes in finite populations?

Consider a bi-allelic locus with alleles A and a. We denote the frequency of the A allele by ...
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32 views

Evolution of a Population

Scientists observe a newly established population of sexually reproducing plants growing on the shore of a small island. An observable trait of the plant has two possible phenotypes. It is determined ...
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130 views

Hardy-Weinberg Equilibrium Question

I have four questions concerning H-W Equilibrium: (i) In a population of mice, the presence of black spots is the result of a homozygous recessive condition. If the frequency of the allele for this ...
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Why is polyploidy lethal for some organisms while for others is not?

Polyploidy is the multiplication of number of chromosomal sets from 2n to 3n (triploidy), 4n (tetraploidy) and so on. It is quite common in plants, for example many crops like wheat or Brassica forms. ...
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49 views

Junk DNA and “random” mutations [on hold]

I'm somewhat irritated by "mutation" generally being described as a fully random factor in evolution: pure randomness does not seem like something that can survive in a long evolutionary process. And ...
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269 views

Parasitism and mimicry

I was reading this article which states this: Classical Batesian mimicry, in which an undefended mimic evolves to look like a toxic model, is a parasitic relationship in which the mimic gains ...
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32 views

Why not frozen evolution? [on hold]

I'm not sure if you have heard of it. It is a theory proposed by the best Czech evolutionary biologist (even though it disproves the selfish gene and darwinism for sexual species :), but it is not ...
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26 views

If humans are 10cm taller than 200 years ago, then how can it be that we are “not much different” from humans 70000 years ago? [on hold]

According to Yuval Noah Harari in his book "Sapiens: A Brief History of Humankind" we today are not much different from the post-cognitive-revolution Homo Sapiens which lived 70000 years ago. But then ...
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14 views

Why is 2 sexes in an organism so common? [duplicate]

Sorry if this is a super simple question, but why do a lot of species have only 2 sexes? Some species just have 1 sex, but I've never heard of an organism having 3 sexes, for example. 3 sexes seems ...
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31 views

How octopus develops its imitation skill?

I've watched one documentary about a Mimic octopus which they can imitate another animals in several form e.g. a Lion fish, a Sea snake, a Flatfish, etc. My question is how these octopuses can have ...
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2answers
155 views

What are the theories behind zootoxin evolution?

I've always wondered how toxins secreted or emitted by certain organisms has evolved. Particularly, organisms that produce toxins as a deterrent to predators as opposed to organisms that use it to ...
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2answers
36 views

Is it possible there were multiple origins of life? And, if so, why did the one which became the common ancestor between all organisms prevail?

I have learned that all currently-living organisms come from a common ancestor, which I theoretically understand. However, my professor in a class mentioned that there is a chance that there were ...
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9 views

How did the double circulatory system evolve from the single circulatory system

I already learned how the mammal circulatory system (double circulatory system) evolved from the reptilian circulatory system. How did natural selection evolve the reptilian circulatory system and the ...
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40 views

Why do we turn darker in the sun?

I tried the all powerful google to answer this question - but I am not getting the answer I seek. I know we turn darker because the skin produces melanin. The question remains - why darker? I am a ...
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3answers
113 views

How is genetic speciation defined?

What determines speciation at a molecular level? At what point does a scientist determine two lineages are different enough to be considered separate species? Does it have a margin of error?
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3answers
74 views

Why didn't humans evolve to reproduce identical twins all the time?

According to the selfish gene theory, it seems like because identical twins sometimes get produced, a mutation to a gene that says, "if you have an identical twin, be fully altruistic towards them" ...
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35 views

why didn't natives of south america evolve darker skin?

I understand that darker skin tone is caused by melanin which helps to protect against the extra UV radiation that comes from more direct sunlight. It evolved in Africa before we migrated away from ...
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30 views

How did the tendency to perform death rituals evolve?

Both elephants and humans perform rituals when deaths occur. However, I do not see any evolutionary benefit of this. The rituals take time, which apparently could be better spent hunting, foraging, ...
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37 views

Is there a correlation between mutation rate and recombination rate?

I have in mind that homologous recombination (HR) can cause mutations (indels and substitutions). I am wondering if this is true and if it is, then I am wondering whether this effect is really ...
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1answer
365 views

Why do genetic drift generates negative linkage disequilibrium?

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

How did people's liking of ceremonies evolve? [closed]

Habitual group activities are prevalent across many animal species, particularly in mammals, especially in primates. However, I do not see any evolutionary benefit of this. 'Ceremonies' take time, ...
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1answer
40 views

History: Do evolutionary and ecological processes occur at the same timescales?

Classically, it was thought that evolutionary processes occurred at a much slower pace than demographic/ecological processes. Nobody, ever thought about incorporating both processes into the same ...
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2answers
120 views

Within and Between Allelic Class Diversity

I am reading Charlesworth et al. 1997. They talk about diversity within and between allelic classes. Nucleotide diversities ($π$) at each neutral site were estimated from the mean of $2 \sum z_t ...
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2answers
145 views

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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66 views

How many traits can a multivariate breeders equation handle?

The multivariate breeders equation (MBE) by Lande predicts the change in a trait $\Delta \bar z$ (response) as $\Delta \bar z = G \beta$ where $G$ is a genetic variance-covariance matrix and ...
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36 views

Variance in Fst in the infinite island model

The most famous result in the study of structured populations come from Sewall Wright. He showed that in an island model, where each subpopulation is of size $N$ and the migration rate is $m$, then ...
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33 views

Extinction of species with extant descendants

From what I've seen, species such as Homo heidelbergensis which have extant descendants are classified as extinct, which makes sense as far as it goes. However, given that species exhibit a continuum ...
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3answers
229 views

Is our genome decaying (see “Genetic Entropy”), and, if so, is this evidence for our genome being “young”?

In the book Genetic Entropy & the Mystery of the Genome the author says that the genome cannot be old because the genome is "decaying". Decay is a very subjective term, but in this case he means ...
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7 views

Endothermy in different species

Birds and mammals are both endothermic, meaning they metabolically generate the heat they need to keep their body within a certain temperature ranger. But birds are closer relatives to reptiles than ...
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1answer
310 views

Why cannot there be multiple sources for same species origins?

We often associate Africa as the geographical location of the origin of humans. Why cannot there exist multiple geographic locations of origin (given same environmental conditions)? The same ...
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4answers
6k views

Why would a plant evolve to produce an addictive chemical?

It seems kind of anti-productive in terms of survival for a plant to produce an addictive chemical as that plant will constantly be sought after by animals that ingest it. In this instance, I'm ...
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1answer
58 views

Is it “easier” for researchers to detect evolutionary ancestry than distance in the evolutionary tree?

I'm a researcher in another field who has wandered into a problem with applications to biology. I hope to sell my results by making the following statement: Given two species X and Y, it is ...
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1answer
46 views

What was the evolutionary reason for cross lateralization of the brain?

In the human brain the right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body. What led to this development? Why doesn't the left side of the ...
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1answer
613 views

Cell evolution: immortality vs reproduction

Many sci fi movies produce interesting ideas and technologies that we seem to be able to realize in real life at some point. "Lucy" was not one of those movies. But Morgan Freeman's speech in the ...
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1answer
106 views

Why is the pituitary gland located in the brain?

Why is the pituitary gland located in the brain in humans, instead of elsewhere in the body? Why would this be an evolutionary beneficial adaptation?
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1answer
60 views

What are the units of Phylogenetic Independent Contrasts (PICs)

PICs are a popular phylogenetic comparative method and I was wondering what units the actual contrasts are in. I want to say they are unitless but I am not entirely sure.
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23 views

Why does our body exhibit bilateral symmetry? [duplicate]

Externally, we (humans) look symmetrical. However, internal organs don't show the same patterns of symmetry (heart being on the left side while the liver is on the right side, etc.). It is a bit ...
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2answers
91 views

The selective pressure of contraceptives

Does it seem probable that the existence of contraceptives (which has reduced human reproduction to below survival-level in many populations) will be a completely new selective pressure on human ...
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2answers
76 views

Evolution of protein and protein efficiency

Suppose we have a bacterial protein that performs a function and let's say we can measure the efficiency of the protein. Let's say we have two species, species A and B, both of which have this ...
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37 views

Did modern alligators and caimans come from prehistoric crocodiles?

I know that crocodilians have been here since the time of the dinosaurs. I also know that crocodiles came first. But alligators have been here for a good 37 million years. Did alligators come from ...
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2answers
537 views

Are there any multicellular forms of life which exist without consuming other forms of life in some manner?

The title is the question. If additional specificity is needed I will add clarification here. Are there any multicellular forms of life which exist without requiring the consumption (destruction) of ...
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2answers
1k views

Is Mutation Theory still “valid” for complex organisms?

I'm afraid like most people I suffer from having learned "A History of Evolution" in school, rather than cutting to the chase and learning the actual "up to date" version of the subject. (Imagine if ...
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2answers
81 views

What are the evidence that all life today descended from a common ancestor (LUCA), and which organisms (if any) challenge the concept?

If I understand correctly, the concept of the LUCA (last universal common ancestor) is based on the hypothesis that archaea and bacteria share common ancestry. In the realm of mathematics, the same ...
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8answers
2k views

Is there a biological mechanism for evolution encoded into our DNA?

Throughout high school, I remember learning about Darwin's theory of evolution as if it were near-fact. But something always seemed wrong about the ideas presented. Survival of the fittest Random ...
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1answer
48 views

How did evolution support sports, fun, entertainment etc [duplicate]

We know that many animals entertain themselves by playing games. But sports actually increases risks of death,or at least accidents. So why did evolution choose it? And why did evolution decide to ...
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2answers
99 views

Driving force for speciation for millions of species today

I would like to know if speciation really occurs (trans-speciation). Have we had enough time for millions of species? A creationist argument is that the slow changes in traits in organisms, taking ...
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1answer
67 views

Why does the number of mutations per individuals follow a Poisson distribution?

I was reading this review. On page 11, left column, first paragraph, one can read: [..] there is a Poisson distribution of the equilibrium number of mutations per individual, if fitness effects ...