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Flowering plants evolved before bees, so clearly in the ~100 million years, they must have been pollinated by other methods. Some plants still retain this ancestral characteristic. This paper shows a species Magnolia tamaulipana (Magnoliaceae) which is pollinated by beetles.


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The concept that you hint at, has been studied at the example of the island of Australia, where marsupials often look quite similar as their counterparts in the same ecological niche, which live outside Australia and have a placenta, and are less related on the DNA level (e.g.: squirrel-like animals, wolf-like, and the now everywhere extinct saber-toothed ...


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Fay and Wu test is a test that compare expected sequences under a standard coalescent theory model, that is a single panmictic population with non-overlapping generation of constant size $N$ and effective population $Ne=N$, that is the variance in allele frequency at any following generation is $\frac{p(1-p)}{2N}$, where $p$ is the frequency of a given ...


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Before you consider the development of bilatteral symmetry (which is what you are talking about), you need to look at the overall changes relating to animal body plans. To begin with, sponges (Porifera) completely lack symmetry and came very early in the evolution of animals. Basically, it's a large cluster of growing cells with some differentiation (ie: ...


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The issue of IBD and IBS can indeed be confusing. The identity by state definition refers to the fact that at some point two individuals, even if they are not related to each other, present the same allele at a specific locus. Because of their un-relatedness this similarity probably arose from a similar mutational event. On the other side, with IBD two ...


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As I understand the main purpose of the gallbladder is to ensure the full digestion fatty or otherwise difficult or complex foods to digest in support of the liver. Both rats and mice breastfeed for about the same amount of time 4-5 weeks. Rats typically have a longer life cycle than mice. But there are more specific reasons why some mammals don't have or ...


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Temperature affect pretty much all metabolic pathways. There are incentive in fishes as well to control their internal temperature. Control of Body temperature can be categorize along two axes, one concerning the source of heat and the other the magnitude of temperature variation. Please have a look at this post to understand the terms endo-, exo-, poikilo-,...


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1) Reproduction is metabolically costly, so a high reproduction rate, such as that seen in fishes that lay thousands of eggs at a pop, is generally a strategy to compensate for a high mortality rate. On the other hand, bacteria, that can in some cases double every 20 minutes, have the advantage of rapidly evolving resistance to antimicrobial agents. 2) ...


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The first part of the question is interesting. Does an increased reproduction/mortality rate provide an evolutionary advantage? The concept of evolutionary advantage for a species needs to be used with much cautious as different definition of evolutionary advantage may exist. You should typically have a look at game theory beforehand to understand the ...


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A large part of the body of your question seems relatively unrelated to the main question which is a little confusing. I will focus on the question Is it possible for there to be a random un-mutation of genes? Yes, these are usually called reversed mutation. It is quite common though that a second mutation at a distinct locus may reverse the phenotypic ...


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The estimated diversity, in this case species richness, is higher on land than in the ocean. To resume the state of knowledge of biodiversity, here's an excerpt from an open-access paper by Mora et al. (2011) How Many Species Are There on Earth and in the Ocean? "...(our analysis) predicts ∼8.7 million (±1.3 million SE) eukaryotic species globally, of which ...


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As anongoodnurse has mentioned in the comments, an incomplete course can allow weakly resistant stains to expand their population. As you mentioned, the antibiotic does not cause the bacteria to mutate but it kills all strains that do not carry the mutation that provides the resistance. This mutation arises randomly (in certain cases it can be acquired by ...


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I am a bit wobbly on the subject, but I think the most important bit of information is that they are re-parametrising Wright's (1951) hierarchical analysis of variation, "F-statistics," "hierarchical partitioning of variation," or "population parameters," depending on whom you ask. The parameters correspond as follows (on the bottom of p.1358): Fit=F, Fis=f, ...


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"According to Darwin, eventually, the fittest will survive" Darwin never said this. Fitness and survival are two separate concepts. In a simplistic version, fitness is measured by reproductive output. Survival is, well, survival. You can have higher output than your brother, but have a lower chance survival. In fact, the very act of producing offspring ...


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The main area-specific factors I can think of: Disease resistance. Local diseases put a lot of evolutionary pressure. So if your area is prone to some illness, you can expect higher immunity to it amongst the locals. For example, here on Earth most Africans are malaria-resistant (duffy negative), while most non-Africans are not. Food/water specific. If ...


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Many consider pubic hair to be a sort of protection or warmth, however this can only hold true for the vagina, since pubic hair doesn't offer any additional protective advantages to the male urethra. The most prevailing theory is that simply it is one of the odor producing parts of the body and humans (like most life forms in general) are simply aroused by ...


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(Not an evolutionary biologist, but I couldn't resist :) I don't think your premise is correct. In (symmetric) cell division, we should consider that the old cell "disappears" and two new cells appear; neither of the two daughter cells is the parent cell, they are both descendants of it (hence the term "daughter cells"). The parent cell is gone. Therefore, ...


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From the abstract of MacLarnon & Hewitt, "The evolution of human speech: the role of enhanced breathing control", Am J Phys Anthropol. 1999 Jul;109(3):341-63: Evidence presented herein shows that modern humans and Neanderthals have an expanded thoracic vertebral canal compared with australopithecines and Homo ergaster, who had canals of the same ...


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First, the setting for this question is almost always related to explaining some aspect of broadly defined trait differences in extant (currently-living) species. The specific problem at hand is one in which someone is trying to explain what may drive the observed differences among competitors. It is unclear whether such differences are relatively recent (...


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If they find it pleasurable it can be because physically the anus has a lot nerves in it so stimulating could cause pleasure. Phychologically it is also a matter of penetrating a person which could feel very intimite. And last but perhaps not at least it is something 'dirty' and 'uncommon' which could give the action a little bit more excitement. On the ...


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Topograhpy refers to earth's physical features and a topographic barrier refers to physical features that prevent free movement from one position to another. As GForce pointed out, whether or not something is a barrier can depend heavily on the animal in question. A long, wide canyon can be a barrier for squirrels, but not for birds. Think of topographic ...


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Whether something is considered a topographic barrier for an organism depends on the species being considered and its ability to traverse the terrain from one side of the barrier to the other. There's no blanket classification of what is considered a topographic barrier and what isn't. For example, a certain mountain range may be a topographic gradient to ...


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This is in between an extended comment and an answer. What do you mean by "Natural"? The question makes no sense as the term "natural" isn't properly defined. (I am voting to close as unclear). For example, if you go to an area where there is "naturally" a high radioactivity, this will increase your mutation rate. Is this a natural way to change your ...



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