7

Good question. And good analysis. I have little to add! I'll simply provide my own list of thoughts to complement your ideas, which are not mutually exclusive. The fact that it wasn't discarded during the course of the species' evolution suggests it must have offered some benefit. This statement is speculative. The key word here is suggests. i can ...


4

S Pr lists a number of reasons that might allow non-adaptive traits to spread. One other that's probably important in some populations is "allelic surfing". If you imagine a smallish population that suddenly expands (say, starlings in the Americas, or humans in the past few thousand years), the original genes are going to expand no matter what - even ...


4

Yes and no. According to this paper, great apes and our ancestors had a life expectancy at birth of about 13 years (chimpanzees). Over a few million years of evolution, human life expectancy rose to >30 years in the 18th century. Industrialization and improved nutrition, hygiene and medicine resulted in a jump to >60 and now around 80 years in developed ...


3

I just want to report the finding of one paper here. I don't know much about the rest of the literature and can't comment on it. Otto et al. (2015) investigate this question in sexually reproducing organisms. As I understand it, they assume that the amount of time spent in on phase of the life cycle is proportional to the amount of selection happening in ...


2

The simple answer is that the evolution of large, slowly reproducing organisms is not preferred: it is simply not selected against. The key mistake in your thinking is this statement: One of the main goals of living organisms is to reproduce Most living organisms have no such goal, they simply take actions that have, historically, led to the ...


2

Short answer: Many of the evolutionary developments in plants developed in the sporophyte life stage. Because increased fitness of these increasingly sporophyte-"dominant" plants would result in a greater survival and reproductive success, these plants became more dominant than the more-limited gametophyte-dominant early plants. In other words, natural ...


1

I assume by asking why, you are asking about the distal evolutionary causes, and not the molecular mechanisms that account for these things. (Important disclaimer: these causes are difficult to be certain about; they require a fair amount of informed speculation.) With that said: it is widely agreed upon in evolutionary biology that human males, as in ...


1

Adjustment = a small alteration or movement made to achieve a desired fit, appearance, or result; the process of adapting or becoming used to a new situation (Google Dictionary). Adjustment is a very general term; it doesn't mean anything specific in biology or other sciences and it can cover all the terms you've mentioned: adaptation, acclimatization and ...


1

Yes, in virtually every way. In terms of pairwise distances, measured in percentages, humans and coelacanth are closer to one-another than coelacanth would be to any ray-finned fish. In terms of individual genes, there would be genes that humans and coelacanth share with their common ancestor, but are not found in any ray-finned fish. Remember, humans are ...


1

This is for an animal, not a plant. But, when I was in school, the Peppered moth was used as an example of rapid evolution from the 19th century. Its white coat made it very noticeable against soot-stained surfaces so it had a rapid selection pressure to become black. If you can organise a trip with your kid to a natural history museum, you might be able to ...


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