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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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Where does Darwin state his “principle of multiple utility”?

I have never heard of Darwin's 'principle of multiple utility', but several papers refer to it. For example, from Darwin at the molecular scale: selection and variance in electron tunnelling proteins ...
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Do ring species exist?

In trying to understand evolution better, I have been looking at examples of speciation, and have thus come across the topic of ring species. I have tried to find concrete examples of how these work, ...
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Evolution of scratching

Is scratching (aka the scratching reflex) thought to be inherited from a single vertebrate ancestor or is it something that evolved several times e.g. in birds, mammals etc., i.e. is it a case of ...
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Polyploidy, or why plants of different species can produce fertile offspring hybrids more frequently than animals?

This site says: Plants hybridize much more frequently and successfully than animals do. [...] Chromosomal doubling (polyploidy) occurs more frequently in plants and facilitates the fertility of the ...
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How frequent are selective sweeps?

Introduction Selective sweep is the most famous genetic signature of selection. We know of a number of classical examples of selective sweeps, some of them in humans. See the classical example of the ...
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Evolutionary explanation of the bicuspid on the left and tricuspid on the right

The left heart handles more pressure and logically it would make sens to have a valve with three leafs on the left (If I had got to choose, I'd have put three on both sides). Other than being more ...
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Escaping resource limitations during tumor evolution

In their discussion of the importance of r- and K-selection on tumors, Aktipis et al. (2013; figure 3) provide the following illustration of a hypothetical cancer growth curve: In it, you can see ...
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Games with non-uniform interaction rates

Background: Many models in evolutionary game theory assume uniform interaction rates. For instance, consider the $2\times 2$ game: \begin{array}{l c c} & A & B \\ A & a & b \\ ...
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Why do naked mole rats live in colonies with a queen?

What was the evolutionary advantage in having queens? Is it because the ones that had queen like tendencies in the new environment had kids that cooperated better giving higher chance of survival of ...
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How does the population fitness change after a change in mutation rate?

The mean population fitness as given by mutation load theory depends only on the genome-wide mutation rate ($U$). My question is: How many generations is needed to reach a new mutation load ...
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At what rate do chromosomal rearrangements occur?

How often do chromosomal rearrangements occur? I am interested about these kind of chromosomal rearrangements that are passed on to the descendants, i.e. germ line chromosomal rearrangements. The ...
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For which taxonomic levels are xylotomical, embryological, and palynological evidence each most useful in determining species relationships?

From the 2010 USABO Semi: In plant systematics, three lines of evidence may be useful in determining relationships; xylotomical (wood anatomy), embryological and palynological. Match these ...
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Mutation-Selection-Drift Equilibrium

mutation-selection-drift equilibrium is one of the most important concept of population genetics. I could easily find the calculations for mutation-secltion equilibrium and for mutation-drift ...
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Were there any terrestrial species in the ancestry of all crustaceans?

To the exception of woodlice, Crustaceans live in aquatic (marine or freshwater) environments. Crustaceans are arthropods which is an immensely diverse taxon. Many arthropods live in terrestrial ...
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How old is the action of sneezing?

Is there an estimate for when the ability of sneezing evolved? A little bit of research, and some critical review of my memories tell me that: Many, if not maybe all mammals sneeze. Some reptiles ...
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Is there recent info about the hypothetical ancient two-codon genetic code?

Here is the latest I have found. link This is the basic idea: Evolution does not look ahead and make plans. It would not create a system of mRNA with giant ribosomes to create proteins, until ...
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Mammalian scales

Many small mammals have scaly skin on their tails and sometimes limbs. The examples can be found among rodents (rats, degu, scaly-tailed squirrels), insectivores (shrews, desmans), oppossums, musky ...
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Why are animal mitochondrial genomes so conserved and small in comparison to those of plants?

Background Levings and Brown (1989): Higher plant mitochondrial genomes are much larger and more complex than those of other organisms. They vary in size from about 200 kb in Brassica species ...
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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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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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First infection of malaria

As I know Plasmodium falciperum survive in either a host animal, human or mosquitoes. But how does malaria come to infect either of them initially? I am interested in knowing evolution of malaria. ...
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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 might the chirality of gastopods be dominantly dextral?

This wikipedia page on gastropods provides a definition of chirality, and briefly describes the genetic mechanisms behind why a shell is wound left (sinistral) or right (dextral) handed. It also ...
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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 does a broad-leaved evergreen (Mahonia aquifolium) has red leaves?

To my knowledge, oregon grape (Mahonia aquifolium) is purportedly an evergreen shrub? Deciduous broadleaf plants lose their leaves in autumn usually and before that as the leaves die they oxidize and ...
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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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Derivation of discrete replicator dynamics

Related: Discrete vs Continuous Replicator Dynamics I am trying to perform a derivation of the discrete time replicator dynamics, but I am unable to get through Cressman's derivation in "Evolutionary ...
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Were Neandertals as Hairy as We Are?

What I mean to say regards facial and androgenic hairs. There are many theories as to why some people have both kinds of hairs, while others have one or the same and others still have neither. The ...
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What is the effective population size of a simple two deme metapopulation?

I am confused as to how to compute the effective population size $N_e$ of a theoretical structured population. Let's consider here a simple case study. Imagine a 2-deme metapopulation. Each deme is ...
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Is $F_{ST}$ a probability and a correlation coefficient?

$F_{ST}$ is one of the most famous and most important statistics of all of evolutionary biology. Yet, many people misunderstand it or misuse the classical results from the literature on $F_{ST}$ (...
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What form of reproduction did the first land animals use?

What form of reproduction did the first animals on land use*? Were they hermaphrodites, or did they have male and female sexes? [Is there a proper term for sexual separation in a species?] Were any ...
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Why does bacillus thuringiensis produce bt toxin?

Background : B.thuringiensis produces an inactive crystalline toxin during sporulation which when ingested by an insect, gets activated and causes pore formation in gut , subsequently leading to death ...
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How to understand relatedness in an infinite island model?

My understanding is that the relatedness coefficient in kin selection models measures positive assortment. That is, altruism is more likely to evolve if altruists tend to interact with other altruists....
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What are the common methods to estimate additive genetic variance?

Additive genetic variance can be estimated in a number of ways, and is a key concept in evolutionary biology and quantitative genetics. What are the typical methods (experimental designs) used to ...
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Understanding the meaning of $s$ and $t$ in a population genetics equation

Sewall Wright in this article (1937) at the end of page 313 gives the equation: $$\Delta q = (s+tq)q(1-q) \space\space\space\space\space\space\space\space\space(1)$$ This equation is an ...
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Does the Jungian notion of collective unconsciousness have any legitimacy in the light of modern neurobiology and epigenetics?

Carl Jung has long ago proposed a rather controversial notion of collective unconsciousness [1, 2, 3], a form of the unconscious (that part of the mind containing memories and impulses of which ...
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Evolutionary motivation behind number of neurons in DCMMP

I'm studying neuro-anatomy right now and I was surprised to learn that there are only three neurons along the Dorsal Column Medial Lemniscal Pathway (DMLP) which relays mechanical sensations from the ...
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$F_{ST}$ and the genetic variance in metapopulations

From this video (21'15''), the speaker gives the following formulae in order to calculate the between and among populations genetic variance from the $F_{ST}$: $$V_{Among Pop} = 2 F_{ST}V_G$$ $$V_{...
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Inbreeding Coefficient and Coefficient of Relationship

Wikipedia gives the following formula to calculate a "path of coefficient of relationship" between an ancestor $A$ and an offspring $O$: $$\rho_{AO} = 2^{-n} \left( \frac{1+f_A}{1+f_O} \right)^{1/2} =...
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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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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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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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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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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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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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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 ...