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Fishers Geometric Model (FGM) is a theoretical prediction about the adaptation process in traits. There are a number of things to establish before attempting comprehend FGM. Firstly, shifts in an adaptive landscape, in natural scenarios, are generally quite small. Because populations have been evolving for such a long time and the small shifts in adaptive ...


1

No it isn't necessary that the parents should be of the same species. Mules (male donkey X female horse) have been found to be fertile (reference). The wikipedia page on hybrids lists many inter-species hybrids that are fertile including Beefalo (Domestic male cattle X american bison). There are also many canine hybrids which are fertile. Wholphins have been ...


1

How many more weeks in utero does Karp think would be ideal? I don't know Karp at all, but a quick search indicates he's known for soothing babies by swaddling. Great. My mother swaddled all her infants many decades ago. If he is comparing human neonates to primate neonates, he's correct. Baby primates are born pretty much knowing how to cling onto the ...


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Is it conceivable to influence the course of their evolution so that it becomes more likely they gain the intelligence to support a civilization in the distant future? No, I don't think so, based on what is known about evolution. Your idea is in keeping with the opening of Kubrick's 2001: A Space Odessey, where the monolith inspires one of the ...


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Short version The paper has nothing to do with punctuated equilibrum vs. gradualism (see also here), which was published a few years earlier. This debate is much different (but equally important, I think). The authors of the Spandrels paper criticized evolutionary biologists of taking a very narrow view of the evolutionary process. They claiming (wrongly) ...


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Basically, Giarda is a an Excavates while Trichomonas is a Cercozoa meaning a Rhizaria (Chromealveolates in the broad sense as noticed by @har-wradim in the comments (now deleted) because Cercozoa are neither Chromista nor alveolata). Because the very basis of the tree of eukaryotes is still unresolved (eukaryotes), the most recent common ancestor of these ...


2

Short answer your grand-grand-grand...-sons will never fly because you've teach your kids (grand-kids, grand-grand....-kids) to flap their hands. Longer answer If you manage to create a tradition of hand flapping in your family, then everybody may flap their hands in the following 1000 generations but nobody will ever gain the ability to fly, they will ...


5

New Answer, following discussion in comments below. Spiders are capable of choosing habitats based on the specific requirements of the species (reviewed by Riechert and Gillepsie 1986). Spiders move within and among suitable habitat for a number of reasons, including damage to existing webs, and life history changes that require new habitat types. They ...


7

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 ...


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 ...


6

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 ...


3

There are two good papers on this that I like a lot: Noise in Gene Expression: Origins, Consequences, and Control Cellular decision making and biological noise: from microbes to mammals. I think they can tell you better than I can, but the major other source of noise is extrinsic noise. Extrinsic noise typically is taken to means two things (both of ...


1

If by "consistent" you mean homogenous, the answer is no. Regions conserved among individuals (and/or species) tend to accumulate less mutations (specially avoiding deleterious mutations). Even within a gene sequence, there are conserved regions which accumulate low number of changes, whereas non-conserved regions accumulate many mutations.


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Well, for start, there are "mutational hot spots", regions that are more prone to mutation than others. As for immune system genes, first of all, lung cells and heart cells and retina cells don't need to mutate those genes, because they don't use them. But you are right that in immune cells there is a lot of DNA futzing in the sequences for the heavy and ...


0

Intelligence can have an impact on selection, but keep in mind that flexible intelligence (like the kind humans possess) is a high-cost/high-reward kind of adaptation. Brains consume a lot of energy, so the resulting intelligent behavior needs to 'pay for itself' (in terms of survivability and ability to reliably gather the necessary food) if it's going to ...


2

First Comment The questions in the OP's post (and his/her comments below the post) are very poorly phrased and let the reader think that the OP has few knowledge about evolution (no offense). This is a reason why I don't directly address my below answer in the terms of the question as it seems that the OP uses a unusual definition of the term "evolution". ...


0

Seems safe to assume that intelligence CAN influence fitness, depending on the selection pressures. As Hav0k mentioned, this won't necessarily be favorable, i.e. lead to more progeny. In the case of modern humans, even if a person got more mating opportunities by being, or just appearing to be very intelligent in some areas, it might not do much to affect ...


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In Pigliucci (2004) (repeated in Hansen (2006)) the mutational variance is defined as being the new additive genetic variance entering in the population each generation due to mutations. In consequence the mutational variance is not define at the level of the mutation in the sense that we do not care about how many mutations yield to this new genetic ...


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After reading your question, I had a vague memory that this subject was indirectly touched upon in "On the Origin of Species", so I did some text searches (in this pdf version I found online). From what I can see, Darwin never used the technical term 'variance' (don't know how old this use of the word is), but 'variability' is often used, both with regard to ...


4

What do you call an "evolved trait"? To my knowledge, the concept of "evolved trait" does not exist in evolutionary biology. Here are various definitions I can think of that could apply to the expression "evolved traits". Heritable Traits Does evolved traits mean heritable traits? A trait may be heritable or not. See for example my answer to this post to ...


1

I think Darwin just stuck to the empirical observation that variation exists. Without knowing about genetics and mutations, he didn't know the mechanism that generates variation, and he knew that he was lacking that, but he knew variation was being generated.


0

I guess it is. I am no expert on the field but whatever trait that affects organisms fitness (likelihood to survive and reproduce) affects the destiny of the underlying genes. Thus it is obious to think that greed might be advantageous sometimes. Nevertheless society could evolve genes to abolish those kind of behaviours so it may be disadvantegeous too. But ...


1

To add to the previous answers that treat specifically of the biological Darwinism, there is also Universal Darwinism which postulates that evolution is a natural phenomenon that appears when a set of conditions and constraints are present. And indeed, it has succesfully been applied to a number of fields (see below the quote), which seems to imply that ...


3

The answer provided by Mike Taylor is just perfect and complete. However, I'd like to add some thoughts of my own in a more colloquial style: Survival of the fittest is not always true. There is also "survival of the luckiest" (e.g. the fittest is showing off in the beach with the other turtles and is struck by lightning). Reproduction is not that ...


1

I have not been able to find any studies that look specifically at the genetic mechanism for nose development. I certainly do not know but I'll offer up two hypotheses. My first hypothesis is that the elongated nose is a remnant of the elongated lower face of our ancestral species, as you note in your answer. Take a look at this brief YouTube video (1:17 ...


5

Any time a species has needed the development of a specific feature to survive, it has developed that feature, and that feature precisely. This statement is clearly false. The dinosaurs didn't develop what they needed, did they? It turned out that on this occasion, the mammals happened to be best adapted to the conditions at the time, just as ...


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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 ...


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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 ...


29

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" ...


3

Schweitzer et al. (2007) studied soft tissue preservation in a number of specimens, including an 800-1000 year old moas, 300,000 year old mammoth and mastodon, and 65 million year old *T. rex. and Triceratops. The oldest specimen was a 78 million year old Brachylophosaurus. Their goal was to try to find common environmental conditions that favor soft tissues ...


0

When asking why a particular group of organisms, such as mammals, has a particular feature, such as a long snout, you must be careful about the hypothesized reasons. While the other answers here propose various adaptive reasons, they do not actually explain the presence of the long snout in the majority of mammals. Instead, you have to look at the ...


0

Long snouts may have an advantage in long noses. A longer nostril could give more room for olfactory neurons and allow for a more sensitive sense of smell. Animals would rely on smell to find prey or avoid predators, so better smell would give better advantage. The only predators I can think of off the top of my head that would have short snouts would be big ...


0

I'm not a scientist, so this is my best guess: Since humans are an uncommon exception among mammals for lacking snouts, we should find the benefits of a snout by looking at other ways that humans are unique among animals, enabling us to not have snouts. I think the answer is the opposable thumb; animals need snouts because it does for them what thumbs do ...


1

Sexual dimorphism evolves, as you suspect, via natural selection, specifically sexual selection (which I view as a form of natural selection). Genetic drift, by definition, is random. Random changes of allele frequencies are extremely unlikely to lead to the consistent evolution of phenotypic differences between males and females. Sexual selection on the ...


1

Blue color alone does not guarantee survival. Blue color provides camouflage only when background is blue. Ocean floor is not blue therefore lobster color advantage is limited. Nature has its own checks and balances. When a lobster molts it is vulnerable to attacks from predators. A chain is as strong as its weakest link. Nature ensures weakness to prevent ...



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