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 doesn't evolution converge on perfection?

I got to know about an organism called "Tardigrade(water bear)" which is an extremely hardy organism and can survive in most conditions. My question is that if the aim of life in general is to ...
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Does natural selection still increase biological complexity?

I recently read The Selfish Gene by Richard Dawkins, which I found very interesting. In one of the last chapters, he gives multiple possible explanations to the question "Why did natural selection ...
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Is the frequency at which a species mutate affected by natural selection? [duplicate]

As per natural selection, is it safe to assume that some species will have it genetically encoded so that they produce a certain 'perfect' rate of mutation so that they can adapt to an environment ...
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Why are ducks more cautious than pigeons?

In my city park there are mostly two types of bird: Mallard ducks Rock doves (pigeons) When I feed pigeons, they approach me very closely. Sometimes they peck the food that fell on my feet. If I ...
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How many generations are required for a specific neutral mutation to reach fixation?

In population genetics, the term “time to fixation” is defined as the time it takes for a specific mutation to appear in a population, plus the time required for this mutation to spread throughout ...
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What advantage does lactose have as the main sugar in milk?

Most organisms have lactose as their main sugar in their milk. What advantage does lactose give have over sucrose (Which is a common sugar in the plants, so it makes sense for it to be present in ...
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Why do men have nipples?

I'd be tempted to call nipples in men vestigial, but that suggests they have no modern function. They do have a function, of course, but only in women. So why do men (and all male mammals) have them?
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What might earlier versions of caddisfly shelter-building behavior have looked like?

The caddisfly has an amazing ability to build armor for itself by using a self-produced underwater glue to hold together pebbles: https://www.youtube.com/watch?v=Z3BHrzDHoYo. How could this behavior ...
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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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How many generations between the first lifeform and humans are there?

I expect very large error bars, but what's the number of generations between the very first lifeform (that can be described as evolving in generations) and humans? Is it closer to a quadrillion or a ...
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What is the oval shaped bone in the heads of some fishes?

I had a dish of fish and found 2 oval shaped nearly 1cm long bones in its head.What help does it do to the fish? what is its name? I have clicked the picture myself .
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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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Evolution of the unique mating system of the scorpion Androctonus australis

Sperm transfer in the scorpion Androctonus australis involves a sclerotized spermatophore, which is formed in the paraxial organs of the male reproductive system. The right paraxial organ produces the ...
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How could viruses evolve?

I know that Viruses are really complex generally, but what makes me wonder is, how they evolved. As an example, I first use a giraffe. The neck got really long so she could reach the leafes on the ...
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Is there any program or website that allows me to create phylogenetic trees without having to insert an already created dataset?

I asked a similar question on Quora before, but did not get any useful answers as the program the one answerer suggested turned out to have the exact same problems as all others I have found so far. ...
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What are the disadvantages of myelin

The myelination of axons has plenty of advantages. It increases signal speed in axons, and thereby reduces reaction times. This is, of course, very good for the survival of the animal in question. ...
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How did interspecies reciprocity involving cleaner wrasses originate?

The small bluestreak cleaner wrasse (Labroides dimidiatus) will approach a much larger fish (for example a grouper such as Cephalopholis miniata), enter its mouth, and spends several minutes cleaning ...
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Why don't all ants have wings?

Since the new queens-to-be have wings, it means that ants either evolved from insects that can fly, or insects that can fly evolved from ants, or that we have a case of parallel evolution (which is ...
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Genetic variance for a behavioural trait among human populations

From this article from The Guardian: We instinctively assume that differences in behaviour that are in fact due to culture must be linked to – even caused by – characteristics of appearance. That ...
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In asexually reproduced species, is HGT the only thing that enables existence of species there?

If some single celled organism which reproduces asexually, and without horizontal gene transfer, I guess after some number of generations, ALL descendants of some individual will be different enough ...
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Why is one phase of a plant dominant (Alternation of generation)?

In plants, there is the alternation of generation. In nearly all land plants, one phase of the two possible phases is dominant--namely the sporophyte. The "dominance" over the other phase can be ...
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A theory about the possible connection between protists and first animalia

I learnt that organisms within Kingdom Animalia can be either microanimals or (nonmicro)animals. a microanimal is any Kingdom Animalia organism that in general cannot be seen by a human eye without ...
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Is evolution a fact? [closed]

Richard Dawkins in one of his videos says that Evolution is a fact and not just a theory. He goes on to say that man and chimpanzees both evolve from apes. Is this correct (Is evolution a fact and ...
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What evolutionary advantages does a longer muzzle have against a shorter muzzle and vice versa

Basically I'm curious as to why when it comes to mammalian predators that some like say bears and canines tend to have longer muzzles than those like big cats. aside from their ancestors/evolutionary ...
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What does the 4DTv (four-fold synonymous) mean?

I saw this sentence "4DTv is the transversion rate at fourfold synonymous codon positions, and ranged from zero (for recently duplicated paralogs) to ~0.5 (for paralogs derived from an ancient ...
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What's the evolutionary benefit of stress and cortisol? [closed]

Stress and cortisol lower immunity and increase hard disease. But why is it that way? If that's true then we shouldn't be stressful at all. What's the benefit of stress then? Why do we (and most ...
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Evolution of recurrent laryngeal nerve in a giraffe [closed]

Do natural selection and survival of the fittest explain the divergent length of the recurrent laryngeal nerve...centimeters in the human, 15 feet in the giraffe?
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Evolution of hunting behavior of parasitoid wasps

Wasps in the genus Pepsis lay their eggs in a specific region on a species of tarantula and their larvae eat the tarantula organs in a specific sequence to keep it alive as long as possible. How ...
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Can any animals photosynthesize?

Plants and animals have the following distinct properties: Plants live from solar energy by photosynthesis, they use solar energy to make sugar and oxygen out of carbon dioxide, which gives them ...
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lifespan of Nautilus compared to other cephalopods

Most cephalopods live uncharacteristically short lifes compared to other creatures of their size and intelligence. The octopuses with the longest lifespan for example, the giant pacific octopus, only ...
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Is Urea excretion a shared ancestral trait of amphibians and mammals relative to synapomorphic Uric Acid excretion in living reptiles?

Is the ancestral condition of prehistoric amphibians and early amniotes urea excretion? Would it follow then that the lineage leading to living reptiles went on to evolve uric acid excretion as a ...
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Can convergent evolution be used to explain similarity of genome of low and high Species e g. gorilla and human?

Example: 1) molecule Rhodopsin in halobacteria for producing energy from light. 2) molecule Rhodopsin for vision in human. These are said to be of different lineages and their high similarity are due ...
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Is evolution always unidirectional?

Is it possible, at least in theory, for a species to evolve into another species and then evolve back into the first species?
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Are there any known plesiomorphies of all living mammals relative to a newer trait state in all living reptiles?

If I understand how a "trait" is defined, a turtle's shell is a synapomorphy relative to mammals and the common ancestor of living amniotes. The same would go for a snake's limblessness, etc. But are ...
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What are the implications/predictions of the selfish gene theory?

Are there any testable predictions or implications of the selfish gene theory? Or it is just interesting interpretation of the observations/experimental data? If this theory is not falsifiable and ...
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Has any flying creature evolved into a sea creature?

I am talking about a creature that has evolved true flight. Has any such creature evolved into a sea creature, that permanently dwells on water (like fully aquatic fish) and doesn't come out? ...
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What is indirect vs direction selection of genes?

As the title suggests, what is the direct and indirect selection of genes. Couldn't find a straightforward answer. Is it the same as direct and indirect fitness?
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Examples of animals who 'forget' their offspring

Occasionally on the news I read about young children dying in hot cars on a sunny day. Usually the article reports that the parent(s) 'forgot' about their children still being in the car. Obviously ...
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A question about the clarity of certain terms

In the Red Queen's depiction, a population must evolve just to be able to survive its ever-evolving natural enemies. I'm trying to refer to a state in which many natural enemies have evolved adaptive ...
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In what does Genetic clustering and Cline sharpness differ?

They are both ways to measure divergence in species but I'm not understanding in what exactly the differ if both use hybrid zones and gene frequencies in the study.
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Evolution of multicellular eggs

Which animals where the first in which ova were not simply released, but instead provided with some additional nutrition and/or protection in the form of a larger egg?
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Can I make an population genetic analysis from incomplete protein?

I have an dataset of fasta sequences. This proteins are not complete (My sequences have 700 nucleotides,while complete sequences have 1725 nucleotides)I would like to know if i can make an population ...
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Who were the first authors to talk about local adaptation?

I was curious to read about what Darwin had to say about the existance of locally adapted subpopulations. I discovered to my surprise that the expressions and terms "local adaptation", "spatial ...
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Thermophilic plants which are also halophilic?

I know that in botany there is a wide classification for plants that can survive in hot deserts (semi-arid or arid) and harsh climates such as 4-season countries with a tendency to droughts each year (...
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Is the suicide of a moribund individual to be considered group selection?

When a moribund individual commits suicide (e.g., Refardt, Bergmiller & Kummerli, 2013; http://rspb.royalsocietypublishing.org/content/royprsb/280/1759/20123035.full.pdf), is this to be considered ...
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What is the difference between phyletic and phenotypic gradualism?

As I understand it, Phenotypic gradualism describes the development of new traits as a series of incremental steps. How is Phyletic gradualism different?
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Can we make a rough estimate of the number of generations since the origin of life?

According to what we've learnt : we can approximate the number of generations since the first human pretty much like us (depending what / who we talk about). we have an idea of the series of life ...
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Modern understanding Darwin's “correlation of variation”

In Variation under Domestication, Darwin makes several references to the concept of "correlation of variation": I will here only allude to what may be called correlated variation. Important changes ...
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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 birds?)...
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life based on different elements [duplicate]

It is commonly proposed to look for life based on silicon, based on it's relative abundance and similarity to carbon. However, carbon and silicon are not completely interchangeable. The bond strength ...