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1

I assume that the figure comes from a section on genetic drift (since this seems likely), and it shows how the allele frequency will change over time under drift in a diploid population. So in short, each line represents the distribution of allele frequencies in different hypothetical populations, that all started with the allele frequencey p=0.5. As for ...


0

This is not a proper answer. Bear with me. I'm in a hurry; will edit the answer to a decent form when I find time. From the abstract of this paper: Of the 80% of oxygen consumption coupled to ATP synthesis, approximately 25-30% is used by protein synthesis, 19-28% by the Na+-K+-ATPase, 4-8% by the Ca2+-ATPase, 2-8% by the actinomyosin ATPase, ...


5

If you with 'humans' refer to our genus Homo (which is often the case), we do have multiple species, see wikipedia for an overview. The difference to many other organism groups is just that all species except Homo sapiens are extinct. Also, taxonomic ranks below the species level - such as breed, subspecies, population and race - are very poorly definined ...


0

Humans are a species and within our species we, arguably, have races. Although the term 'race' is highly controversial and ill-defined, as pointed out by @fileunderwater in his elegant answer, I just want to express that races can be, in a way, compared to breeds and hence that the human species does have some of the species-subdivisions you are addressing. ...


0

If you have the budget for it, I highly recommend Geneious for topology work. It was a real saver for me on an epi paper last year. Anyway, they allow for testing per-log likelihood without adjusting edge length. If you want to throw up some dummy data somewhere I can throw up an example. I have no connection or stake with the company, just happy with ...


1

Fruit being eaten is a very useful attribute for a plant, just like pollenisation through provision of nectar is often better than wind dispersal. Seeds contain startch and sugar, so seeds are always attractive to animals, so plants with fruit actually dissuade animals from eating the seeds, and encourage the fruit to be eaten in such a way as to be ...


0

From the statistical point of view, this question is rather vague. One would need a mathematical definition for the term "genetic variance". In one extreme, if the "genetic variance" merely means the categorial variations of nucleotides (i.e. ACTG) in the pooled genomes of interest, then the distribution of total "genetic variance" vs. loci variation is ...


2

There are plenty of animals with brief procreative periods, as you suggest. In chimps, sex takes 10 to 15 seconds - much less time than humans. So the question is really why have humans evolved to be different? I don't think any of the answers based on fitness are particularly compelling. It's not like sex feels like running a marathon or less physically ...


1

I can think of an example for the 3rd picture in your image "Common Agent With Multiple Symbiotic Relationships." We have: 1.) a species of parasitoid wasp 2.) a species of plant and 3.) a species of moth. The moth provides pollination activity for the plant. The plant provides a place for the moth to lay its eggs, and a food source for caterpillars once ...


3

I think what you are asking for is "Multiple Mutualism". Normally, Most of the known cases of multiple mutualism involve relationships in which two of the partners are at the same organizational level—usually two bacteria that might be interacting directly—but are both essential for the survival of the host — Entente cordiale: Multiple ...


0

LD describes the associations among alleles at different loci. For anything more than two bi-allelic loci, you need more than just one number to fully describe the associations. For instance, if we have three bi-allelic loci 1-3, we need the three pairwise LD coefficients, plus one extra three-way coefficient. In general, if we have $K$ loci, and the ...


3

Interesting question (+1) but not that easy to answer. I'll give a try! First, the rate of evolution and rate of adaptation are two different things. There are two main thing processes that quantitatively differ in populations of different sizes. 1) population-wide mutation rate and 2) genetic drift. 1. Population-wide mutation rate Large populations ...


2

The human body contains a few billion microbes (more than human cells), so we live in symbiosis with many different species. Some of them protect us from infections, some of them help in the digestion, and so on... So I think the human body fulfills your requirements. wikipedia - human microbiome Normally we don't live in sterile environment. So we ...


3

The habit of burying food in modern dogs is an instinct that came from the grey wolf (Canis lupus) long ago, and originates from a phenomenon called surplus killing, where a carnivore would kill more than it could eat, and often use it at a later time. Many, if not all, carnivores possess behaviour patterns which allow utilization of a kill at a later ...


0

The problem with Bateman is that he was only looking at zygote production. There are many more factors influencing reproductive variance aside from number of sperm vs. number of eggs. If I were you, I'd read the book titled "Dr. Tatiana's Sex Advice to All Creation: The Definitive Guide to the Evolutionary Biology of Sex." The author is Olivia Judson (by the ...


12

Seeds are spread by many mechanisms Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory. Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory. Water: Similarly to wind ...


1

Being a typical molecular biologist, I am a little uncomfortable with classical genetics terms. I might redefine some symbols (perhaps to mean the same) [It is like talking to oneself while thinking]. There are four DNA-blocks : A1, B1, A2 and B2. Ak and Bk are adjacent blocks. [Perhaps this is same as what you defined the symbols as]. A and B are ...


5

Drift is a random element of evolution from one generation to the next, it is equally likely to spread a deleterious mutation as a beneficial one. The reason the answer is D is because selection should remove a deleterious allele, while drift makes no distinction, and is therefore the only scenario where drift is expected to be a reasonable answer. However, ...


1

There is an interesting relationship between the length of an animals femur, the thickness and the mass of the thickness. A point that should be taken into account is that bones can different densities and so might be able to support varying amounts. The muscle in you leg also does nothing for the support of you weight it is (basically) all in the bone. ...


2

I think part of the confusion is that these terms are very loosely defined. Also this discusses evolution in terms of taxanomic radiation, e.g. macroevolution at large spatial and temporal scales. Problem 1 is that you haven't been clear about what kind of competition, inter or intraspecific competition? These will have opposing effects generally which ...


1

All cases of same species grooming I know of involve animals with a certain amount of dexterity. For example (images from wikipedia): Macaw beaks:                              Primate fingers: ...


1

Perhaps it has something to do with fish slime coats. Fish are covered in a thin layer of mucus which helps with immune system function, etc. According to these guys at least, who admittedly are not exactly a scientific authority. Perhaps grooming as a social behavior would disturb the slime coat more often than it would help remove parasites? Or it's ...


1

Something from my imagination: Probably the first fishes were of small size with some of them evolving to be big. The variation in the sizes of the fishes is larger compared to the variation in the sizes of mammals(picture elephants and rats with whales and tiny fish). That being said, if you'd have bank of small fish staying in one place and all grooming ...


2

There are so many things that are implied in this paper, not explicitly said. The mutation rate here detected seems to be the emergence of chain-terminating (CT) mutations, which truncate protein coding genes, usually just one gene in a bacterium or phage, which would be possible to observe from inspecting a plate to see which colonies die or survive. ...


7

This is an interesting question, and there are a number hypotheses available to explain this phenomenon. The short answer (as far as I can say this after my literature search) is that we don't know the answer for sure. The long version follows below. The main problem with all these hypothesis is that they have some valid point, but a definitive hasn't been ...


3

This study of the recently sequenced pine species states that 82% of genome is repetitive. This is characteristic of any complex genome, including humans. Such sequences have often been considered "junk DNA", though any scientist will tell you that just because we don't know its purpose doesn't mean it doesn't have one. That said, a good portion of repeats ...


0

Two reasonably close relatives of the most recent chimpanzee-human ancestor (CHA) are Sahelanthropus tchadensis and Orrorin tugenensis, but both are poorly attested. One better candidate is Ardipithecus ramidus, which has a fairly-complete skeleton ("Ardi") among other fossils. It's a bit young (4.4 Ma), perhaps, to be a CHA but should be a close relative. ...


2

I'm going to give a tentative answer full of speculation and guesswork, but it's too long to fit in a comment so here goes. Sex duration is possibly a sort of human reproductive handicap. Sexual arousal can soften the cervix, increasing fertility during lengthy sex sessions. Lengthy sex exposes them couple to predators and takes time and energy, so if you ...


1

I'm going to hazard that primordial sociality by this definition and this question proceeded primordal motility in cells. Algae started to form physically attached groups like these filaments, giving them some of the advantages of higher organization. Its easy to see how this is a relatively simple adaptation - just have proteins or carbohydrates on ...


-3

Easy. Look at human baby development in mother belly. While newborn develop in egg they need less care so parent can go around caring themselves and don't need to carry a burden much. Also if the parent die the child will continue to grow separately Laying egg has many benefit even more than I said so most animal do it this way would have more chance to ...


1

The honest answer to this and many other similar evolutionary questions is that we don't know the answer. We can sample information from many different points along an organism's developmental timeline using the fossil record, genetics, etc. and reconstruct various states of said organism's development. The overwhelming evidence is that evolution is the ...


0

Simply put, evolution through natural selection is a process which occurs naturally. It will occur to any self-duplicating organism with variations, hereditary traits and threats to propagation (e.g. all life forms we are familiar with). Evolutionary biologists study this, the same way astrophysicists study space, and studying black holes or life forms ...


0

Developing anything by the body takes energy so generally only useful products are conserved. If some sort of mutation caused an organism to produce some sort of by-product that also happened to be toxic to its predators, then that organism is more favored to survive. No species ever starts producing something with the intention of toxicity in a ...


3

Organisms on Earth did not evolve in a homogenous environment. A critical part of speciation (when you go from a single species into two or more) is a reproductive barrier. This can be a literal, physical barrier - mountain range appears between two populations, valley in the middle of habitat floods and isolates the two halves of the population, a small ...


0

Interesting question. I will dissect your question into its assumptions before giving my view on the overall question. 1) ..that nerves became larger.. : Why should there be a general tendency for nerves to increase in size during the course of evolution when there is no need to? 2) ...that nerves became more myelinated...: A general tendency towards ...


6

No, fish scales are dermal (= formed in derma) bones like skull roof bones. Scales in reptiles are formed by epidermis and are made primarily of protein (from keratinocytes), being similar in derivation to hair, feather and nails. On the other hand, in reptiles one must differentiate between scales and osteoderms (= scutes). Scutes are widespread among ...



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