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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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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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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Did we first have swimming birds or flying birds?
Looking at the swimming birds building nests just across my garden, I suddenly wondered how evolution came to swimming birds and whether flying birds started swimming or whether swimming bird like ...
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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 ...
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How do we know that dinosaurs were related to lizards and/or birds?
Do we clearly know what the living closest relative of the dinosaurs are? And connected to the first question, in scientific manner how do we know these relationship between extinct species and living ...
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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 ...
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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 ...
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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 ...
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Did researchers evolve multicellular yeast or did they just turn on multicellularity?
In this new paper "Experimental evolution of multicellularity" found via Ars Technica the researchers describe having developed multicellularity and apoptosis within 60 days from a unicellular yeast ...
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In which order did the cells of the immune system evolve?
Thinking about how complex the interactions between different types of immune system cells (T-helpers, T-Killers, Phagocytes, B-Cells etc.) are, it's fascinating how they all combine to get the ...
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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 ...
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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 ...
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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 ...
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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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What is meant in biology by the term “evolved”?
A student asked me this the other day and I thought that I would ask it again here. If one organism is said to be "more evolved" than another, what exactly does this mean?
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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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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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How did the human brain evolve?
A common question posed is, "how did the eye evolve?", because the eye is so complex. However, this has been answered rather clearly and there are several examples around the world of animals in ...
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Is there an “evolutionary species similarity calculator”?
Is there a website where I can input pairs of species and get an "evolutionary similarity score"?
E.g. (numbers are completely made up)
Input: Chimp and Human, Output: 97%
Input: Cat and Human, ...
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Are there differences in DNA between humans of today and humans from 2000 years ago?
Are there any significant differences in our genome compared to the genes of our ancestors from 1000-2000 years ago?
And if there are significant differences, do they result in significant ...
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What are the evolutionary niches differentiating an apple from a pear?
So, as far as I understand (basic) evolutionary theories, diversity is generated by "niching." That is, if there is an environmental factor that hasn't been fully used by any species to "profit" off, ...
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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 ...
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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 ...
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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 ...
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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 ...
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Predators faking to be not hungry?
I believe that there are predator/prey combinations where the prey can easily spot that the predator is not hungry and will not try to flee from it. I’m thinking, for example, of gazelles who will ...
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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 ...
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Why would stablising selection ever happen?
If the aim of evolution is to allow an organism to better compete against rivals, why would stabilizing selection ever happen? If you're not selecting the most highly adapted competitors at either end ...
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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 ...
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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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Why is the Kakapo more attracted to humans than its own kind?
The Kakapo can be seen in this video by BBC. It is said that the species is strongly sexually attracted to humans. Why could this be the case?
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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?
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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 ...
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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, ...
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What preceded ATP synthase?
ATP Synthase is ubiquitous throughout life on earth and so most probably evolved within the last universal common ancestor (LUCA) before that lineage diversified into the various kingdoms of life.
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Did human hairs actually evolve from scales?
What is the evolution of hairs? Did they evolve from scales?
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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 ...
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Disadvantages of unihemispheric sleep
Is is well known fact that marine mammals and some birds can sleep with one brain hemisphere at a time, since it's essential for their survival.
However, at least in my opinion, such mechanism would ...
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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 ...
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Why *don't* all ants have wings?
Since the new queens-to-be have wings, it means that ants either evolved from insects that can fly, or insects that can fly evolved from ants, or that we have a case of parallel evolution (which is ...
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Genetic Models for Natural Selection?
My question is simple:
Given that evolution is described by random genetic mutations allowing certain members of a species to gain a reproductive advantage over others that coexist in the particular ...
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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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Do men have more extreme variations than women?
This question was considered unsuitable for Skeptics and I think it is more suited to BIology than Cognitive Sciences
I was reading this article which I found interesting. It is not supported with ...
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The evolution of dogs through domestication and artificial selection
I am currently reading Richard Dawkins's book 'The Greatest Show On Earth: The proof for evolution' and in the second chapter he talks very much about the evolution of dogs.
He says centuries ago ...
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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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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 ...
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Is it possible to increase lifespan through controlled evolution?
A few years back when I was reading The Selfish Gene by Richard Dawkins, there's this short passage where he theorizes about a way to achieve an increased lifespan through controlled evolution.
The ...
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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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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 ...
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What measures are commonly used for the complexity of an organism?
I'm aware of measures like number of distinct cell types being used as a measurement of complexity in biology, for example in the G-value paradox. But this doesn't really help for unicellular ...
