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Genus sizes are usually measured in number of species, since a particular species under a single taxonomic authority shouldn't be found in more than one genus. Check out Strand and Panova, 2014 for some numbers on number of species found in each genus on average across several thousand genera from eight major taxonomic groups.


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How about the Italian wall lizards that evolved new muscles around their intestines after being introduced to an island? (other article, actual paper)


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As a bioinformatician, one of my tasks is quite often to get information from databases or find the correct database to compare to. There are several big databases around, but even those are way too many for any single person to know. There are databases specialising on genetic data, some specialising on taxonomic information, some on ecological information ...


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First: My opinion on why the question has received that many down votes There were many down votes to this question, not because the question is no of interest. The question actually makes sense and is interesting. The post attracted those down votes because the post and the comments of the OP shows little understanding of evolutionary processes. Here are ...


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Explaining phenotypic variance You may want to make sure you have a good understanding of the concepts of the underlying variance of phenotypic variance (discussion linked to the concept of heritability) before reading this answer. In this post, I linked several sources of information on the subject. Culture (environmental variance) Variance in food ...


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In my humble opinion the right question to ask is: Why those animals (the male ones) who do not feed their offsprings with milk do have nipples. Because, from the evolutionary and biological point, it is very logical that males would not have nipples at all (as well as mammary glands). I'm afraid that your question is a little bit hypothetical, just because ...


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Bearing in mind that the information is bound to be incomplete (as is the list of existing species), you could use the NCBI taxonomy database. For example, checking the page for the Drosophila genus will give you an idea of its size. For more precise numbers, you can download the taxdump.tar.gz file from NCBI's FTP server (link), extract it and run the ...


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As far as I know, speciation in sexually-reproducing organisms is primarily identified as the inability to produce viable offspring. In other words, it is not so much determined at the molecular level, but at the organismal level. As @Augurar rightfully asked - the mating procedure does not work in asexually reproducing species. In this case molecular ...


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This is a very fundamental, and in my opinion, interesting question. You might not find many sources that directly cover this question because it is hard to test. If speciation did happen in two separate locations and the resulting species were so similar that they could breed with one another and not the original species, how would we be able to tell if the ...


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Yes, absolutely. That's what a phenotype is (definition from the biology online dictionary): noun, plural: phenotypes (1) The physical appearance or biochemical characteristic of an organism as a result of the interaction of its genotype and the environment. (2) The expression of a particular trait, for example, skin color, height, ...


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Queens do not generally breed with their brothers, but with males from other nests. In the life cycle of bees (and other social Hymenoptera), new queens are born late in the season along with haploid male drones. These all leave the nest and disperse in the landscape to find mates to reproduce with. After mating, all males die and the queens overwinter to ...


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Answering the question what is needed for a human brain to evolve starting from a cephalopod brain is hard. However, I can expand on what is thought to have been the driving forces behind the evolution of the humanoid brain (Hawks, 2013): The species of the famous Lucy fossil, Australopithecus afarensis (~3-4 mln yrs ago), had skulls with internal volumes ...


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I wouldn't go so far as to say that they are entirely unrelated -- our understanding of selective processes can certainly inform our study of the origin of life -- but I would say that they are quite different projects. One important reason is that evolutionary biologists can use phylogenetic information to reconstruct much of the history of life. For ...


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Masked allele is a term that is sometimes used for recessive alleles, and it should be suitable to the situation you describe. A common phrasing could be; "The wild type allele is masking the expression of the deleterious allele X.". For your particular example you could use: Deleterious mutations on the Y chromosome are more easily purged since they ...


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This phenomenon is described as regressive evolution (the loss of a phenotypic trait). There are several reasons why this occurs: Neutral mutations which become fixed through genetic drift. Positive selection of regressive mutations that are beneficial. Pleiotropic antagonism: positive selection for one trait may have the consequence of disrupting ...


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So-called "vestigial" features are defined in a post-hoc fashion as features which do not have a positive correlation with a population's fitness under its current living conditions. There are no special names for the evolutionary processes that lead to their loss, since they are exactly the same evolutionary processes that act upon any feature that has a ...


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I think recessive refuge is the term you are looking for (this is the best link I could find, sorry: https://quizlet.com/4176029/bio-experiment-1-and-2-flash-cards/)


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Frequency-dependent selection is the term you are looking for, I believe. Positive frequency-dependent selection encompasses traits that become more advantageous as they become more common. Negative frequency-dependent selection encompasses traits that become more advantageous as they become rarer.


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I think it's a mistake to assume that there is such a point. All plausible seeming models of abiogenesis currently under consideration involve evolutionary processes long before they reach the stage we'd consider alive. Evolution will occur whenever there is (a) replication-with-error and (b) selection (simplifying slightly). This is the case with a ...


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Ive found that the study of this feature, the nose is far from complete.Although we see the evolution of other mammals and their faces has a great deal to do with there ability to survive different enviornments I believe it , our snozz is a genetic mutation in which allows us the ability to go from nonaquatic to aquatic with out needing a snorkel. ?.by ...


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Found the following on wikipedia. Seems pretty self explanatory: The Golgi, ER, and lysosomes are likely to have evolved as a result of the plasma membrane going through invagination. An increase in the overall volume of a cell would require the plasma membrane to fold in order to maintain a constant surface area to volume ratio. These folds may ...


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You can try http://timetree.org/ to get the divergence time if you already have the names of the taxa.


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Could not fit in a comment... There are several issues with your question. The correct question is not why such species need something but rather why it occurs in this species. In other words, why did a hierarchy evolved in a given species? It is unclear to me why your are interest in cows (or other grazing animals) rather than any other species that has ...


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Maybe you could get some information from the Angiosperm Phylogeny Group: http://www.mobot.org/MOBOT/research/APweb/ They even have a tree where model organisms are highlighted: http://www.mobot.org/MOBOT/research/APweb/trees/modeltreemap.html


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If you know the species name, you can search TreeBase to find previously published phylogenetic trees which will point you towards close relatives to your species. Depending on how obscure your taxon is, though, you might not find much.


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@MadScientist: Certain functions require every single one of these 20 amino acids. However, in isolated cases a selected subset of amino acids might very well lead to an active protein.


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Extremely briefly, we do not evolve shorter lifespans because natural selection does not act for the good of the species. As an interesting historical aside, August Weismann proposed essentially the idea you are suggesting in 1889, in his Essays upon heredity and kindred biological problems. Within a few years, however, he backed away from this hypothesis. ...


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At least online, I think the single best introductory evolution resource is the Evolution 101 tutorial at UC Berkeley's Understanding Evolution project. The site has been designed by some of the top evolutionary biologists and evolution educators in the country, and does a very good job presenting a basic overview of how evolution works.


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Welcome to Biology.SE! There are a many misunderstanding of what evolutionary processes are in your post and it is therefore quick hard to answer (hence the current two close votes I guess). You might want to read some introductory textbook on evolutionary biology or other online resources such as the understanding evolution project. The most obvious ...


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Natural selection selects for individuals who can leave the most progeny in the next generation. Traits such as longer lifespan do not typically affect fecundity/fertility. So males and females who have the largest families as quickly as possible are providing the raw material for natural selection.


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Maybe not exactly what you are searching for, but you should look at the evolutionary biology version of Academic tree. This provides family-tree type relationships between researchers, but mostly (only?) of supervisor-student relationships. As an example, the tree for Joe Felsenstein includes links to e.g. Dobzhansky, Lewontin and Sewell Wright. You should ...


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Here is my mistake, I think. $w_i$ can be written in terms of $p_i$ in the following way (note that $p_i$ can only assume two values, 0 and 1): $w_i (0) = w_0 + kb$ $w_i (1) = w_0 -c + (k-1)b$ where $w_0$ is the baseline fitness and $k$ is the number of altruists in the group (so, $k$ can be 0, 1, or 2). When we are calculating $\beta (w_i, p_i)$ the ...


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I am not sure I understood the question. Let me know if this helps. Case: N=2, freq=0.5 Let's assume that the frequency of those who cooperate is 0.5. The slope of the regression line (which R.squared is equal to 1 as we have as many data point than degrees of freedom) is by definition $\frac{\Delta w}{\Delta p}$. You defined $\Delta p = 1$. What is ...


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Hypothesis testing in evolutionary biology Pretty much any paper of empirical evolutionary biology tests hypothesis. If you go on google scholar and look for any empirical paper in the field of evolutionary biology such as "does sexual selection has antagonist effect to natural selection", "evolution of range limits", "evolution of mutational robustness" or ...


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I see one possible advantage to round pupils. A slit pupil gives higher visual acuity vertically than horizontally because of diffraction and when a slit pupil is very nearly shut, there's high diffraction in the horizontal direction giving poor horizontal visual acuity. A round pupil on the other hand gives a creature the highest visual acuity in all ...


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To achieve whole genome alignment between a genome as large as a human, and as small as an archea organism, is possible, but in the end, you'll have to strain your eyes to see patterns. The archea genome is about 1-5 million bp long, whereas the human genome is about 3.3 billion bp long (that's a thousand times too large). In practice what this means is ...


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Welcome to Biology.SE! I am not aware of any book that talks extensively about the evolution of dominance. It is a very interesting field of research. You can probably search for papers on the subject that will go much further than my below answer. For example, you may want to read Mayo and Burger (1996), Bourguet (1999) and Billiard and Castric (2011) I ...


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Researchers have puzzled over the selective explanation for the ABO polymorphism at least back to the 1950s. Multiple lines of more recent evidence, including the very old age of the ABO polymorphism and (perhaps) multiple convergent evolution events, suggest that the ABO polymorphism is maintained by balancing selection (E.g. Saitou and Yamamoto 1997, ...


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Genetic view of adaptation: Do note that this is looking at the view from the POV of a gene. Please read the comments below this answer, for a small discussion on the kin selection hypothesis. Do note that I do not study evolutionary psychology, or work on the level of the population. This is a bit of a misconception, as nature really doesn't work like ...



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