Changes in the heritable attributes of populations of organisms over time. Major mechanisms include drift, natural selection, mutation, and gene flow (migration).

learn more… | top users | synonyms

10
votes
3answers
150 views

Is there a fundamental reason that plants cannot fix their own nitrogen?

Plants must have nitrogen to grow. According to the answer to this question, there are no plants can fix their own nitrogen (without the help of bacteria). Plants get their nitrogen in the form of ...
10
votes
3answers
187 views

Formation of Life

Originally, life evolved from non-living matter. Why is life only generated from other life nowadays, and why doesn't it evolve from inanimate matter, like it did originally billions of years ago, ...
10
votes
2answers
246 views

Why is venom more common in fish and snakes than other vertebrates?

Reading this question, I wondered why is it that we associate vertebrate venoms so often with snakes and fish, and more rarely with lizards, amphibians, mammals, and birds (apparently never, in ...
10
votes
4answers
2k views

Does pheomelanin have a useful biological function?

Melanin is a natural pigment that is categorized into two main forms, eumelanin and pheomelanin. It's well documented in the science literature that increased eumelanin levels reduces the risk of ...
10
votes
2answers
385 views

Is there any evidence that a virus can modify human evolution

I was just reading Evolution of lactose tolerance, and in it one line says "But there was a time in human history when our diet and environment conspired to create conditions that mimicked those of a ...
10
votes
2answers
170 views

What is the Edward O. Wilson fuss about?

I have just read this article on E. O. Wilson and I don't understand what the difference is between what he is arguing and "standard" natural selection. I read "the extended phenotype" some years ago ...
10
votes
1answer
193 views

What advantage would the initial 'donor' in horizontal gene transfer by conjugation have received?

I am struggling to think why horizontal gene transfer between bacteria would have persisted during the course of evolution as surely it puts the 'donor' at a disadvantage? For example, consider a ...
10
votes
1answer
632 views

Is there are evolutionary explanation for why humans and primates are ticklish? How might it have evolved?

Tickling is a rather interesting phenomenon: When humans or apes are touched in certain areas like the armpits or sides, we respond with laughter AND frantic attempts to stop the assault. Obviously ...
10
votes
2answers
213 views

Did Darwin ever reach the conclusion that selection will remove variation?

According to simple models of selection the genetic variance in a population should be reduced by selection. (Fisher's fundamental theorem states that the rate at which a population can evolve is ...
10
votes
1answer
135 views

Do babies resemble their father?

An often heard theory is that newborns and babies resemble the father more than the mother, a theory apparently ignited by a Nature paper by Christenfeld and Hill (1995). Figure 1 shows one of the ...
10
votes
2answers
2k views

What is the evolutionary reason behind the fragility of teeth?

Almost all organs in the human body have a rather large threshold within which the organ or tissue is capable of repairing itself using materials supplied by the body, whether it's made from organic ...
9
votes
3answers
2k views

Why does the butterfly have a cocoon stage in its life cycle?

Why does the butterfly have a cocoon stage in its life cycle? It could have simply grown up within the egg/cocoon, and emerged as a butterfly. Instead it is first an egg, then a worm, then a ...
9
votes
2answers
6k views

Did animals evolve from plants?

Did animals evolve from plants? Did animals' ancestors have chloroplasts in their cells?
9
votes
4answers
4k views

What is the closest species to humans in animal kingdom?

I presumed chimpanzees were the closest relatives of us. However, after watching this TED Talk, it seems bonobos are closer to us both in skeleton and behavioral similarity than chimpanzees. I once ...
9
votes
2answers
853 views

What is the evolutionary explanation for bat's echolocation [closed]

The bat's ability for echolocation is amazing (so are other the abilities of other animals). I was wondering how all of it came to be.
9
votes
1answer
456 views

What is the modern state of the theory of evolution?

When I studied biology at my medical school we used to learn things about a century old: the famous Darwin's voyage on "Beagle" to the Galapagos Islands, the classical triad of his Theory of ...
9
votes
1answer
2k views

Why are some berries poisonous?

In my understanding, the evolutional function of berries is to be eaten and pood out somewhere else, so that the seeds of the plant spread. Is this so? Then why are some berries poisonous?
9
votes
3answers
2k views

Why did abiogenesis only happen once?

If the "primordial soup" theory of abiogenesis is to be believed, self-reproducing organisms spontaneously arose on Earth at least 3.5 billion years ago, surprisingly soon after the Earth cooled down ...
9
votes
1answer
762 views

Why are there nail growth differences between humans and other mammals?

When a cat is growing, his nails are growing with him to some extent. A grown cat has a fixed nail length that is not extending. By contrast, human finger nails just keep on growing, so we have to ...
9
votes
2answers
1k views

Which sex has higher variance of reproductive rate in modern societies - male or females?

Who has a more varied reproduction rate in modern western societies - men or women? The average rate is the same of course, but I wonder which sex have higher variance - higher variance means that ...
9
votes
2answers
7k views

Why does human facial and head hair continue to grow?

Many people can grow extremely long head hair and facial hair. Are there evolutionary theories as to why this is the case? It seems like having long hair could be a disadvantage, and extremely long ...
9
votes
2answers
164 views

Why is selfishness the 'obvious' strategy?

Thinking of behaviours an organism can adapt, at the very base an action can always be either selfish or altruistic (cooperative). Usually, selfish behaviour is assumed to be the preferred choice and ...
9
votes
1answer
788 views

Could humans and chimpanzees hybridize?

In some cases two species can hybridize. For example, Tigers and lions can hybridize to produce "Ligers". Would it also be possible for humans and chimpanzees (or any other species) to hybridize ? ...
9
votes
1answer
1k views

Why do some plant species have lobed leaves, while similar species in the same habitat don't?

Some plants have lobed leaves, like the English oak (Quercus robur), while other plants growing the same deciduous woodland habitats, and very often growing alongside oaks, such as the European beech ...
9
votes
3answers
294 views

Why did humans become bipedal?

Somewhere in evolutionary history homo started walking upright and became bipedal. You hear these hypotheses that, by walking upright, they could see better across the grassy savannas to escape ...
9
votes
1answer
356 views

Structure of fitness landscapes in the NK model

The NK model of rugged fitness landscapes consists of $N$ sites where fitness contribution of each site depends on its state $\{0,1\}$ and is epistatically affected by $K$ other sites. When defining ...
9
votes
2answers
174 views

Are there any structures in mammals that are used only by males?

There are examples of structures which only serve a purpose in females, but it seems like the opposite could also be true. Are there any structures which exist in both mammalian sexes and only serve a ...
9
votes
1answer
871 views

How does population stability evolve?

The number of individuals constituting a population is called population size. Over time population size does not remain constant, it fluctuates to different extent over generations because of ...
9
votes
1answer
202 views

Are there specific features of birds that cats/small predators are attracted to?

I've recently heard a podcast, in which a professor describes one of the theories as to why we like abstract art. In his talk, he mentions an experiment with seagull chicks, in which the seagull ...
9
votes
1answer
610 views

How and when did a dedicated immune system evolve?

I have recently been doing a lot of research into the interplay between the innate and adaptive immune systems in humans, and mammalian laboratory models. This has led to my reading some interesting ...
9
votes
2answers
420 views

Is there any recent evidence for the aquatic ape theory of human evolution?

aquatic ape theory suggests that many features that distinguish humans from their nearest evolutionary relatives emerged because the ancestors of humans underwent a period when they were adapting to ...
9
votes
2answers
103 views

Why is iodine used for metabolic hormones?

Iodine and related biological iodine-carrying hormones are phylogenetically very old, at least according to Wikipedia. Humans use iodine as a metabolic indicator, as do axolotls and apparently most ...
9
votes
1answer
124 views

What are the costs associated with carrying lots of genetic material

What are the costs (if any) associated with carrying lots of genetic material (Big genome size)? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and ...
9
votes
1answer
400 views

When does weak selection produce qualitatively different results from strong selection?

In evolutionary game theory, it is typical to model organisms as having a base fitness that is modified slightly by the game interaction. The ratio of the game effect versus the base fitness ...
8
votes
3answers
619 views

What exactly does adaptive mean?

This is a quote from Dey et al 2014: Hatching asynchrony is thought to be adaptive because... What exactly does adaptive mean here? Does it mean hatching asynchrony has fitness benefits? Or does ...
8
votes
3answers
4k views

Why is Galapagos island so special?

I am not a biologist so the question may be very stupid. I have no idea. Why did Darwin formulate his theory of evolution just after his visit to the Galapagos island? Why is it so special from the ...
8
votes
5answers
277 views

Theoretically, is domestication of (virtually) any animal possible?

Looking at ones that manage well alongside us human animals, such as dogs and cats, we see that this is possible for evolved, distant animals to have heritable, preferable traits around people. ...
8
votes
2answers
210 views

Is there a dominant gene for right-handedness?

Has there been any definitive research about handedness being genetic? Also, why is right-handedness clearly dominant in humans? I'm interested in evolutionary theories, as well as any molecular ...
8
votes
3answers
5k views

Why doesn't recombination occur in male Drosophila?

"Males do not show meiotic recombination, facilitating genetic studies." For a while I have known that this phenomenon occurs, this quote comes from the Wikipedia page on Drosophila melanogaster, ...
8
votes
2answers
858 views

Did human hairs actually evolve from scales?

What is the evolution of hairs? Did they evolve from scales?
8
votes
1answer
224 views

Why aren't green eyes more prevalent?

Why aren't green eyes more prevalent, given that the green allele is dominant over the blue one? My understanding is that human eye colour is determined by two genes: 1) HERC2, with alleles Bx, BB ...
8
votes
2answers
3k views

why is AUG the initiation codon?

Is there any reason why AUG is the initiation codon ? Why is there a need for an initiation codon ? Can't translation start with different codons?
8
votes
4answers
2k views

What is the difference between a circular and a cat's-eye pupil?

I've been to local zoo the other day and one lizard caught my attention: its pupils are circular, which, I thought, is not usual for reptiles. Turns out it is, but now I can't find any explanation on ...
8
votes
1answer
163 views

What do we know about LUCA?

All life on Earth (bacteria, archaea, eukarya) is thought to have evolved from a common ancestor, or last universal common ancestor (LUCA). What do we know about the characteristics of LUCA based upon ...
8
votes
4answers
467 views

Why people like to see pornographic scenes, but do not feel the same about eating scenes? [closed]

This question may seem funny, but I think biology must have good answers. I think no more explanation is needed. I really thought about this and searched for an answer, but there is nothing yet. If ...
8
votes
3answers
132 views

Evolution: One big population vs. many small populations

Let's say I want to evolve a bacterium that is resistant to an antibiotic. I want to do this by growing initially clonal populations of bacteria in presence of this antibiotic for a long time. I have ...
8
votes
2answers
157 views

How can a three-base codon evolve from a two-base codon?

Inspired by this question among others. It's widely suggested that the current 3-base codon system of encoding protein sequences in DNA evolved from an earlier 2-base codon system. This makes sense ...
8
votes
1answer
146 views

Model for fluctuating selection

Is there any mathematical model to predict the behaviour and long-term consequence of counter-acting selection at different time scale? For example, let's consider the bi-allelic gene A, with alleles ...
8
votes
2answers
411 views

What does fitness really mean?

Fitness is certainly the most important concept in the theory of evolution. My question does not have to do with practical measures of fitness but with the theoretical definition of it. I am a bit ...
8
votes
1answer
196 views

Genetic Drift: Models, assumptions and empirical observations

There two main mathematical models to describe the process of genetic drift are Moran model and Wright-Fisher model. My questions concern the assumptions of these models, the existence of other ...