Evolution refers to the observed changes in successive generations of biological organisms due to heritable components (genes and DNA). Charles Darwin proposed a major mechanism of evolution: natural selection.
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Why 20 amino acids instead of 64?
This question got me thinking about amino acids and the ambiguity in the genetic code. With 4 nucleotides in RNA and 3 per codon, there are 64 codons. However, these 64 codons only code for 20 amino ...
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How does “be altruist to those who are similar to you” evolve?
There are many cases when people commit altruism. One is relationship. I am willing to die for 2 of my children or 8 nieces, say an evolutionary psychologist. Another is reciprocal altruism, which is ...
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What is the evolutionary advantage of death?
I know death and cancer doesn't hurt humans' reproductive success. It's not helping either.
Why do we die? Why dying humans (all of us) are common? What's the point of dying?
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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 ...
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Short-term Lamarckism in asexual single cell organisms
I was reading through the Karr et al. (2012) whole-cell computational model. One of the things they did was to induce single-gene disruptions in their model. They observed several to be fatal, but:
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Why do plants have green leaves and not red?
I know plants are green due to chlorophyll.
Surely it would be more beneficial for plants to be red than green as by being green they reflect green light and do not absorb it even though green light ...
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How did the first self replicating organism come into existence?
When people try to explain evolution, they tell me that evolution is a cumulative result of mutations & natural section of the more superior individuals of a particular species. I think I'm fairly ...
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Do large animals often evolve into smaller animals?
There are several examples where the largest animals were killed off preferentially due to a major ecological shift:
The KT extinction event
The Holocene extinction, as well as the major megafauna ...
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Why have humans evolved conciousness?
Why did humans/animals evolve to become self-aware of their own thoughts. That is, why don't humans act and compute like a machine, or walking zombie. In my mind, such creatures would still be as ...
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Can two humans with 44 chromosomes produce viable offspring?
It is known that there are very few individuals having 44 chromosomes, not the usual 46 chromosomes.
One example is a male in China: the first article, the second article.
The other is a female in ...
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650 views
Why do we grow so much hair on our heads compared to our bodies?
I've been wondering about head hair, facial hair in particular. Human males can grow very extensive beards should they choose to not shave - however you do not really see this in our chimpanzee ...
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Human evolution: Where *exactly* did the first human come from, whose parents were not?
Layman here. So I have never really quite understood this facet of human evolution, (or any other for that matter), in that, I understand the evolutionary process, but I get lost on the 'border' ...
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Why did the process of sleep evolve in many animals? What is its evolutionary advantage?
The process of sleep seems to be very disadvantageous to an organism as it is extremely vulnerable to predation for several hours at a time. Why is sleep necessary in so many animals? What advantage ...
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Why is polyploidy lethal for some organisms while for others is not?
Polyploidy is the multiplication of number of chromosomal sets from 2n to 3n (triploidy), 4n (tetraploidy) and so on. It is quite common in plants, for example many crops like wheat or Brassica forms. ...
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Mathematical Modelling of Natural Selection
I'm a math undergrad looking for some papers on modelling the process of natural selection. The only paper I've been able to find is by the pre-eminent mathematician Herbert Wilf from 2010,
There's ...
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Evolutionary origin and exogenous cues of ~28 day infradian rhythm?
The most obvious example of an approximately monthly biological cycle is the human menstrual cycle. My questions are the following:
Is it known when and where this cycle or one like it arose?
What ...
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What is the most difficult feature to explain evolutionarily? [closed]
I wonder what are examples of organs/structures/behaviours/cooperation that evolutionary biologists themselves find most difficult to explain -- to explain how they could appear evolutionarily -- ...
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How many times did endosymbiosis occur?
According to the endosymbiont theory, mitochondria and chloroplasts originated as bacteria which were engulfed by larger cells. How many times is it estimated that this occurred in the past? Are there ...
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876 views
Why is glucose our primary source of energy?
Is there any evolutionary reason for glucose being the "main" molecule used as a source of energy, beginning with glycolysis and subsequently cellular respiration (after being converted to two ...
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677 views
When has an organism evolved enough to be called a new species?
Imagine that we take a population of horses, split them in half and place them in completely different environments. The two species will evolve separate from each other and because the environment is ...
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Why are not all species hermaphrodites?
If a hermaphrodite animal (like slug, snail, etc) finds a partner they can mate immediately.
If another animal with "normal" reproduction (lets say a mouse) finds a partner they can only mate if they ...
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Good source that explains the evolution of single-celled organisms “from scratch”
Are there any books or sites that detail, step-by-step, the evolution of the first single-celled organisms (bacteria, archaea) from a Miller-Urey-like beginning? That is, assumes only amino acids, ...
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Why Is Most Life Symmetrical Externally But Not Internally?
Mammals, reptiles, arachnids, insects, etc are all as far as I am aware symmetrical in appearance.
Take a human for instance, make a line from the top of our head right down the middle. However, ...
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What is the difference between orthologs, paralogs and homologs?
These three terms are often misused in the literature. Many researchers seem to use them as synonymous. So, what is the definition of each of these terms and how do they differ from one another?
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Height and natural selection in humans?
I watched the documentary "Evolve" recently and in the segment on "size" Scott V. Edwards, Harvard evolutionary biologist mentioned the idea that humans might evolve to be 7' tall in 'hundreds of ...
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Are there genes in humans from the common ancestor of all organisms?
How long ago can human genes be traced? Are there any genes that go back unchanged to the beginning of life on Earth? And if so, how many?
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Does becoming martyr have an evolutionary advantage?
This is related to
How does "be altruist to those who are similar to you" evolve?
Altruism that is
Not reciprocal
Not familiar
has little explanation. One possible explanation is that ...
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145 views
Computational/mathematical models for predicting phenotype from genotype
Karr, Sanghvi, et al. (2012) propose a whole-cell computational model for predicting phenotype from genotype in Mycoplasma genitalium. Their model simulates myriad cell processes such as DNA ...
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Extraretinal photoreception in mammals? [duplicate]
A Finnish firm Valkee sells light-ear-plugs against thing such as jetlag. I asked a researcher in Aalto university how do they really work and he responded ...
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Why do eukaryotic organisms have introns in their DNA?
We touched on introns and exons in my bio class, but unfortunately we didn't really talk about why Eukaryotes have introns. It would seem they would have to have some purpose since prokaryotes do not ...
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Why do men have nipples?
I'd be tempted to call nipples in men vestigial, but that suggests they have no modern function. They do have a function, of course, but only in women. So why do men (and all male mammals) have them?
...
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Why are there exactly four nucleobases in DNA?
Does someone know why DNA is composed of four nucleobases? In particular, is there an explanation for the number? Why four and not two, or eight?
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Why is 'Grudger' an evolutionary stable strategy?
I am currently reading 'The Selfish Gene' by Richard Dawkins, which I am sure many here have read. The topic are evolutionary stable strategies (ESS) regarding cooperation.
I apologise for the long ...
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Is there an advantage to linear chromosomes?
The DNA copying enzymes have a hard time working to the end of a chromosome. For circular chromosomes this is not a problem, since there is not a sharp 'end'. However, for a linear chromosome, without ...
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Abiogenesis: Beyond the research journals as a lead in to discussions on evolution
I just came across this abstract:
Aminoacyl-tRNA synthetases (aaRSs) are responsible for creating the pool of correctly charged aminoacyl-tRNAs that are
necessary for the translation of genetic ...
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335 views
Is there an evolutionary advantage to crying when sad?
It seems as though the act of crying when sad does nothing to relieve that sadness. Is there an advantage to crying from an evolutionary perspective, or is it the end result of a different process? ...
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What was the reason for some plant and animals to become giant in course of evolution?
The dinosaurs, mammoths, giant plants etc are known to be bigger than modern animals. I wonder why they had been lived and why they are not living now? I really don't know much but is it something ...
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Why can't humans drink sea water?
Why can't humans drink sea water?
It would seem to be a huge evolutionary advantage for an animal to be able to drink sea water rather than have to rely on fresh water, and it's provably not ...
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How did butterflies evolve to have eyes on their wings?
Some butterflies, such as the UK native Peacock butterfly (Google Image Search) have markings on their wings that look just like eyes, complete with a white fleck to imitate a convex, transparency ...
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Why does so much variation exist within species?
My last phrasing of this question did not go down well, so I will try again.
The genotype of species is not always the same. If you ask yourself why not all of these possible expressions except one ...
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Since Darwinian times, has there been any striking/notable effects of evolution on humans?
I understand that evolution is constant process that acts on a population in successive generations. Thus, it is obvious that evolution is happening. However, I'm curious as to the stricking examples ...
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Is the theory of evolution being disproved by bats?
For some species the Darwin's theory evolution makes perfect sense. I can easily imagine how, for example, the giraffe has evolved to its current appearance: the natural selection was favoring ...
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Why would deers keep crossing a river full of crocodiles while some of them have been killed?
I recently watched a clip on Discovery Channel, where I saw deers crossing a river full of crocodiles, ignoring the fact that some of them would have been killed doing so.
What could be an ...
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What is the evolutionary rationale for palm sweating?
Sweaty palms seems to be a reaction to stress, anxiety, etc. For our forest-inhabiting primate ancestors sweaty palms could cause unwanted side-effects such as slipping off tree branches under ...
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How can homosexuality evolve despite natural selection?
I would imagine that the answer to this question would be population control, especially since even if one sibling is homosexual this does not necessarily mean that the other siblings will be too.
