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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How does sleep prevent our eyes from drying out?

If we don't sleep for about 16 hours, our eyes start to get dry, and no amount of eye drops helps. You use eye drops and then you're dry 10 minutes later. However, after you've slept for 8 hours, your ...
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Why largest cats so much larger than canids?

It is striking to me that there is no dog-like creature larger than a wolf while there are at least two species, tigers and lions, many (at least twice and probably 3 or 4) times the size of the ...
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Does epigenetics suggest there is at least some element of truth to Lamarckism?

I am not a biologist. But googling "epigenetics lamarck", I find many different opinions: For: Lamarck rises from his grave, Epigenetics: Lamarck’s Revenge?, Darwin’s theory ... is incomplete without ...
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In what ways does the number of legs affect an animal's functioning?

After much research, I've only been able to find specific examples of leg-number's impact on locomotion and dexterity (and/or object manipulation). I feel as though there must be other ways it has a ...
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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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114 views

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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44 views

Has anyone confirmed Darwin's theory that nectar began as something “injurious” to sap?

In "Origin of Species", Darwin says (I have added bold for emphasis): Certain plants excrete sweet juice, apparently for the sake of eliminating something injurious from the sap: this is effected,...
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67 views

What are haplotype blocks and what is the effect of hybridization on these?

In this PDF, there is a quick definition of haplotype blocks. A haplotype block is a set of closely linked alleles/markers on a chromosome that, over evolutionary time, tend to be inherited ...
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When we talk of functional macromolecules (e.g. proteins as enzymes, hormones, receptors, antibodies etc), towards what are they evolving?�

Actually this is a question which is given in a book and to be honest,it has baffled me.I'm not so much well versed with molecular evolution so my guess would be,say some sort of enzyme which could ...
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79 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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Is evolution of gametangia in land plants and charophyceae convergent?

Is the presence of gametangia in both land plants and charophyceae a result of convergent evolution or are they of the same origin (and have been lost in other types of algea)?
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How would inserting a nonfunctional protein impact fitness of an organism?

Producing proteins costs energy, and producing longer proteins costs more energy than shorter proteins. Producing proteins which have no function, would therefore presumably negatively impact the ...
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53 views

What function will survive evolution?

I wrote the following phrase in my scientific text: X is ubiquitous in life of Y. On some occasions X might be detrimental, resulting, for example, in so so phenomena. But is it plausible that a ...
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87 views

What is the closest relative to odd-toed ungulate?

I have seen about 3 variation of phylogenetic tree about odd-toed ungulate and I don't know which one is really updated or outdated or which one have more backed up theory First is odd-toed ungulate ...
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38 views

Are cloned spieces significantly more vulnereble to deseases than sexually reproducing species?

I would like to be able to compare the risk for species to go extinct implied by their reproduction mechanism in the very short term. Imagine we choose some species A that can reproduce both sexually ...
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What is the evolutionary or biological origin of apathy and indifference. Is it uniquely a human thing?

I believe that social apathy is one of the main reasons why changes cannot easily be brought about in contemporary society due to the general lack of interest of the public, and this has ties with ...
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175 views

Difference in multicellularity between prokaryotic and eukaryotic organisms

As most prokaryotic organisms are single-celled, and in eukaryotic organisms this is the reverse, is there some evolutionary advantage that led to these features evolving? Or is it purely the fact ...
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Is there any evolutionary significance of downward facing nostrils in human beings?

The nostrils in apes and monkeys are almost at the front, but in humans nostrils (external nares) face downwards. Also a lot of non-primate mammals like goats have nostrils at the front. Is it the ...
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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 necessary criterion for the maintenance of signaling honesty?

Zahavi's (1975, Journal of Theoretical Biology) handicap principle held that the cost associated with a signal is integral to ensuring that signal is accurate, since dishonest signals would be too ...
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416 views

How did Portuguese man-of-war evolve?

In particular, how did the close cooperation of its many component species evolve? My hypothesis is that it began with a few, probably no more than two zooids cooperating in symbiosis, and overtime, ...
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Is there a defined non-trivial chromosome number distribution for a given kingdom?

I'm pretty aware of the mechanisms for chromosome number evolution in specific groups (e.g. inside a given genus). Nevertheless, looking at a broader scale (e.g. in the Metazoa kingdom), is there a ...
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Origin of melatonin: oxidative stress defense OR circadian rhythm?

Question Which functional role of melatonin came first? Regulation of the circadian rhythm Defense against oxidative stress Other Background I was well aware of the important role melatonin plays ...
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Source for an upper bound in the number of genes based on mutation rates

So I've found myself referring in an answer once again to the idea that complexity (insofar as it's a quantity for which "number of genes" is a proxy) has an upper bound, limited by Muller's ratchet-...
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psbA-trnH intergeneteic spacer inversion

What kind of software tool would you recommend as best suited to detect psbA-trnH inverisons? I have 1x coverage Sanger .fasta files and >2000 sequences, with 1 sequence per species. Most tools I have ...
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Why do most fish move fins orthogonally with their axis of symmetry?

So recently I read the question why are most fishes vertical (in the sense of distribution of their body mass) and it got me thinking what is the reason behind the direction they move their fins. My ...
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Has any animal ever had a rotating part?

Outside of microscopic structures (I'm thinking of a flagellum, which I think is a true motor) has any animal evolved a part that continually rotates compared to the rest of its body?
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Why is sex pleasure giving activity but not childbirth?

Asking from an evolutionary viewpoint. Sex is a pleasure giving activity so that it encourages reproduction and spreading of genes. But childbirth ,the most crucial part of the reproductive process, ...
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204 views

Have people in Africa already started evolving resistance to AIDS?

Are people living in areas where AIDS is rampant (for e.g. Africa), less likely to die from it than they once were because some of the people without genes/mutations that give them resistance already ...
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What model of epistasis best fit the reality?

In theoretical population genetics, it is very common to have to assume a model of epistatic interaction. The two most common models are the additive model and the multiplicative model. Additive ...
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Effective population size of a metapopulation structured on a grid

Scenario Consider a rectangular metapopulation consisting of $x \cdot y$ demes, where $x$ is the number of deme horizontally and $y$ is the number of demes vertically. The population size per deme is ...
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Why does the Vas Deferens detour over the pubic bone?

I was surprised to learn that the vas deferens detours over the pubic bone instead of taking the obviously more direct path. https://human.biodigital.com/widget?be=u1P&uaid=1ly5V Because I would ...
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Replicator equation for mixed strategies?

The the replicator equation is usually defined for pure strategies. More specifically, the replicator eqn for $n$ strategies is given by: \begin{equation} \dot x_{i} = x_{i} \left( \sum_{j=1}^{n} a_{...
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550 views

What are constrained genetic elements?

I am somewhat of a newbie in evolutionary biology currently taking my first steps in bioinformatics. I was reading a paper when I came across the term "constrained genetic elements", referring to ...
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321 views

Variance in reproductive success and effective population size

Background The effective population size $N_e$ is the size of the Wright-Fisher population that experience the same amount of drift than the population under consideration. The higher the variance ...
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179 views

What is the probability of fixation for a mutant under fluctuating selection?

Here is an answer which explains how one can model the frequency of an allele that is under fluctuating selection (the selection that varies through time). Not, thinking about fluctuating selection, ...
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How likely is it that through dog breeding, tail-wagging has been disassociated with happiness?

I am not a biologist, so sorry to anybody for misinformation in this post. If I understand correctly, dogs evolved the ability to show emotions through various sounds and tail-wagging in order to ...
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Odds of Fusion of Chromosome #2

There is strong evidence that chromosome 2 in humans is a fusion of two chimp chromosomes (i.e. common ancestor of chimps and humans) as explained at wikipedia here The question is what are the odds ...
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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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3answers
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Which fish did modern tetrapods descend from?

Did modern tetrapods descend from Tiktaalik or Ichthyostega? While I understand that in terms of all tetrapods, the lineages of Tiktaalik and Ichthyostega both would be included, but I want to know if ...
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What is the meaning of 'primary' and 'secondary' sympatric speciation in this paper?

Sympatric Speciation in the Genomic Era. Both terms are used throughout the paper. I'm not able to make sense of these terms in the contexts used. I've also heard the terms 'primary' and 'secondary' ...
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Does the radula sac in any mollusc serve a purpose other than sheathing the radula?

According to Barne Gat Shellfish: When not feeding the radula is retracted into this chamber which protects the mouth from the sharp teeth of the radula. Does the radula sac serve any other purpose?
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What terrestrial Gastropod (specifically snails) has the fastest reproductive rate?

I am looking to do a series of experiments to test the adaptation of snails to different environments (Controlled environments in a lab setting. No organisms would be released into the wild under any ...
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75 views

What is the evolutionary advantage of breathing and heart beats syncing between partners?

I recently read that partners who are close to one another usually when touching have their heart beats and breathing in sync. Why does this occur? What is the benefit of it occurring? How does this ...
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What is the common ancestor of humans and trilobites?

I have always been immensely fascinated by trilobites. What is the single common ancestor of humans and trilobites? Do we know? Do we have a name for it? Have we identified it?
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Why are some organisms able to regenerate?

Why can sponges, cnidarian polyps and planaria regenerate if broken up, but other animals e.g. humans and phylum chordata cannot?
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Why does the sandalwood tree produce a fragrant oil?

Why do sandal trees produce fragrant oil? Is there any purpose for it? Is it to make it unpalatable for other herbivorous animals? If so, why do humans find the fragrance pleasing?
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Tree-pest coevolution

Many trees first reproduce decades after germination. Many pests of trees reproduce in under a year. It would seem that the pests have an advantage in the evolutionary arms-race, as they can evolve ...
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How is knowledge about farming transfered between generations in farming ants

There are some varieties of ants capable of "agriculture", e.g. dairing ants farming aphids and leaf-cutting ants farming fungus. How is the knowledge about the techniques involved passed ...
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Is evolution the reason why water is colourless for our eyes?

Liquid water is transparent to most of the visible spectra, whereas it absorbs infrared. Similarly, the air is almost transparent to the visible spectra too. Could these be the reasons why our eyes ...