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31

Very intresting question. The problem is that animal intelligence is hard to measure not only for scientists, but probably also for the potential mate. Paradoxically, that is why selection for intelligence, if it occurred, may be very strong. One has to be smart in order to recognise smart behaviour, so preference and preferred feature are strongly ...


31

This entire answer will be long, so read the short part first, then read the rest if you (or anyone else) is curious. Citations are included in the long section. I can include additional citations in the short section if needed. Long Story Short You're question touches on some common misconceptions about how the evolutionary process. Organisms don't "want" ...


16

I am not sure I'll answer your question so let me know if I miss your point or if I help! What factors determine whether some species "stick"? Natural selection is nothing but differential fitness (fitness is a measure of both reproductive success and survival) among individuals within a population. Individuals having greater fitness will leave more ...


16

Mathematician/computer programmer's answer here: There is a continuum of different animals — in fact it's pretty fair to say that every animal occupies a different place on this continuum. They're just not uniformly distributed over the continuum; they're clustered around forms that are most likely to survive and reproduce, and the lowest-energy paths ...


12

I looked up winglets so I had context for this answer. I'm interpreting winglets as the vertical tips at the end of airplane wings. If so, then you are correct. The spread primary feathers of soaring birds like eagles function as winglets (Tucker 1993). Airbus has a biomimicry web page devoted to some of the biological designs, including winglets, they ...


11

He formulated his theory after travelling the world aboard the Beagle, here's the route! He found the Galapagos Islands particularly inspiring, 'The natural history of this archipelago is very remarkable: it seems to be a little world within itself.' This is a more detailed account of his relationship with the Galapagos islands, and there is also a ...


11

Nothing happens to them. Organisms exist. They breed with other organisms who are genetically compatible. We humans might try to categorize them according to certain traits, but our labels are just labels, biology isn't governed by them. Over time, we might see that a population used to have one trait, and its descendants no longer have it, they look ...


11

About your question This kind of very basic question has the drawback to need a very long answer. In consequence your question might get some close vote. I'll do my best to help but you might want to look at some source of information as an introduction to evolutionary biology. A book eventually or Khan academy maybe. Darwin's evolution theory The ...


10

To get a non-circular answer to why humans and other mammals have only two sexes, it's helpful to take a look at our evolutionary history. While mammals possess several adaptations to a terrestrial life cycle, including internal fertilization and gestation, which require substantial anatomic specialization between males and females, these are all secondary ...


9

Typically when both new and old species still exist it is because evolution pushed the new one into a different habitat or role. As a hypothetical example reef fish vs deep water fish and their relative size. Lets say deep water fish evolved into reef fish, but we still have deep water fish. So there were deep water fish that were a little smaller than ...


8

I just wanted to add that although we are pretty confident that domestication of wolves created domestic dogs in pretty short order. In addition to the fact that they can still interbreed and the taxonomical resemblence of dogs to wolves and finally the genome sequence, probably the most awesome evidence is the domestication of the silver fox. Russian ...


8

The idea that we only love our family according to biology is not true, but its also not clear what people mean by the word 'love'. There are many ways to interpret that word! Hope this doesn't totally suck any romantic ideas out of you, but metaphysical concepts of love and romantic ideas of love are not always relevant when you talk about biology. A ...


8

Definitions of adaptation Unfortunately, there is not such thing as a single, standard definition of adaptation. But for most cases the accurate definition the author is using is not of much importance as all of the usual definitions totally fit in the sentence without changing the meaning of the concept they want to express. In you case however, the ...


8

The logical assertion "winglets have not happened in a long time, therefore they are not advantageous" is incorrect. It is possible for an advantageous trait not to evolve even when advantageous, if there is no "path" to it. The trait only occurs gradually, in small incremental steps. If intermediary steps are harmful, the trait will not occur, even if the ...


7

Its pretty much impossible to predict what will happen in the evolution of species. Evolution is a parallel search with millions (or in the case of humans 8+ billion) of threads. Our adaptive capacities have never been fully understood and will always surprise us I think. Of course that doesn't stop people from trying! The prediction you mention is ...


7

According to Serpell, 1995 (http://books.google.co.uk/books?id=I8HU_3ycrrEC, page 8), wolf bones in association with human bones have been found from as early as the middle pleistocene (126,000–781,000 years ago). I think we're talking about more than a few centuries here :) It's still relatively little in comparison to naturally selected evolution, but ...


7

Short answer version: It seems plausible to me that we (advanced life) could have a biological mechanism to "write" needed alterations into either our own DNA or our reproductive DNA over time, triggering the very specific evolutionary developments necessary to our survival without relying on random mutation. No, it's not. Despite what your ...


7

There are two possibilites with evolutionary processes: The development either never went into this direction or it brought no advantages. Besides this two possibilities the claims from the other forum are wrong. Birds (not all of them though) do have winglet-like structures. If you look at big birds, you can see feathers on the end of the wings looking like ...


6

Well first of all I don't know if natural selection favors larger animals - most of the living things in the world are single celled. Still there are advantages to being larger. I don't know if I can list them all! In no particular order: 1) Living things that are large are more metabolically efficient. The amount of food required goes as a 3/4 power ...


6

Do you know about BioPython? Here, on another website, someone already asked this question and a pretty nice answer was provided by Brad Chapman. He gives already written functions to perform this kind of analysis (I personally haven't tried the codes). In Perl there is Bio::Align::DNAStatistics. You might adapt it to Python. This might be useful as well. ...


6

More specifically, the lack of observable gradual change between species. Most significant phenotype differences occur over several thousand generations, which means several thousand years on up. While we certainly can create experiments where a controlled form of evolution occurs within a very small time-frame, I'm going to assume that you're not ...


6

Presumably this means that at least some grey haired humans have noticeable reproductive advantage, or maybe they had it in the recent past. No it doesn't. Natural selection is not that strong, it doesn't optimize every single possible physical trait towards maximum reproducing. And as others have mentioned, having lots of grey hair usually ...


5

Very little is known about the structure of fitness landscapes. H.A. Orr (2005; also Whitlock et al., 1995; Kryazhimskiy et al., 2009) explains that most experimental results do not actually attempt to measure the fitness landscape, but instead report just the average fitness versus time and average number of acquired adaptations versus time. This can't be ...


5

I know nothing about biology however I did watch an amazing PBS documentary on cuttlefish that I think is fairly relevent. From http://www.pbs.org/wgbh/nova/nature/kings-of-camouflage.html NARRATOR: During mating, males outnumber the females, sometimes 10 to one. And they're all looking for the chance to pass on their genes. While a female lays eggs ...


5

Galápagos islands are one of few islands with a unique fauna and flora. This can only happen when the distance to other land is great enough, and when the island exists long enough that flora and fauna could grow (volcano islands are sterile for a long time). Now Galápagos is even more unique because it is comprised of several islands that are distant ...


5

My question was why does evolution take place at the same rate with the same results to every member of the species all around the world? It doesn't. Evolution acts on populations, not individuals. I will never evolve, you will never evolve, but humans are evolving, and sure, certain pockets evolve at different rates. Here's a long but ...


5

A commonly used empirical example of species selection (a.k.a clade selection, lineage selection) is pelagic larvae in sessile ocean species. See Maliska et al (2013) for a recent paper discussing this in Tunicata and Jablonski & Hunt (2006) for larval modes in gastropods. The idea is to some extent really intuitive - pelagic larvae means higher ...


5

Well, I think I found the very simple mistake I made… Looking again in my equations, I realize that (for some reason) $cor = 2 \cdot \frac{\sigma_A^2}{\sigma}$ And looking at this website, I see that the slope of the parent-offspring regression is $\frac{h_N^2}{2} = slope$ Here was my mistake!


5

Here is my full derivation to the book example you gave, hopefully it'll help you clear up what went wrong: You need to remember that after there is selection acting on the population, you no longer have a total of 1 after selection. Think of selection as "killing" individuals, which means the total is now 1 minus what has been "selected out". s*y is what ...


5

Your questions mean basically the same. Birdcare.com says: The situation in which all the eggs in a clutch do not hatch at (more or less) the same time, as is more usual among birds, but have their hatching spread over several days. It is well seen in the various types of raptor, and is an adaptation to a type of food supply which may fluctuate. During ...



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