Questions tagged [evolution]

Changes in the heritable attributes of populations of organisms over time. The mechanisms of evolution are mutation, migration, drift, and selection.

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Like other animals, why humans don't have species & breeds?

Like other animals, why don't humans have species & breeds ? Even my pet dog is one type of breed, but we (humans) lack breeds & species? What is the main reason?
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Parasitism and mimicry

I was reading this article which states this: Classical Batesian mimicry, in which an undefended mimic evolves to look like a toxic model, is a parasitic relationship in which the mimic gains ...
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Birds and Dinosaurs

This came up in an argument with some friends. I know that birds are direct descendants of dinosaurs, shown pretty clearly through the fossil record. However, is it proper to say that birds are ...
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Drake's Law. What is the genome-wide mutation rate and what are the estimates?

Drake's rule Drake's rule states that the genome-wide mutation rate is more or less constant across all species — from E.coli to the house sparrow. Data From what I think being Drake's original ...
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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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Is designing alien life still just science fiction?

As we continue to search for life in very different environments than the earth, it would make sense to me to think about and design lifeforms (theoretical) that could work in these environments. I ...
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Why do human females have periods?

Why do human women have periods when most animals don't? It is known that the unfertilized egg needs to be shed from the uterus. But why shed the whole endometrium? Why didn't evolution put ...
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Why are there species instead of a continuum of various animals?

As I understand it, various animal traits have to evolve gradually, but what happens to the species that are "neither here nor there"? To put it differently, if a species evolved from another, it did ...
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Why have humans evolved much more quickly than other animals?

Humans have, in a relatively short amount of time, evolved from apes on the African plains to upright brainiacs with nukes, computers, and space travel. Meanwhile, a lion is still a lion and a ...
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Why and how does complexity usually tend to increase through time?

The question of complexity is classic in the very first lectures of evolutionary biology where the teacher usually tries to tell the students that complexity does not necessarily increase and that ...
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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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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 ...
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How did the genetic code evolve?

The genetic code is redundant, there are 20 amino acids for 64 possible nucleotide combinations (triplet codons). Therefore some amino acid are coded by several different codons. While leucine is ...
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Fisher's Geometric Model for Dummies

Fisher's geometric model is still today one of the most important and fundamental model in evolutionary biology but it seems to me that most student in evolutionary biology don't really understand it (...
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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 ...
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Book recommendations for algorithms used in evolutionary biology

Do you have recommendations for a book that presents the different algorithm used in theoretical evolutionary biology? I don't mean evolutionary or genetic algorithms (otherwise this question would ...
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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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How many humans have been in my lineage? Is it almost the same for every human currently living?

If I were to count my father, my grandfather, my great-grandfather, and so on up till, say chimps, or the most common ancestor, or whatever that suits the more accurate answer, how many humans would ...
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Why does sexual selection evolve beautiful features?

I have a very raw understanding of sexual selection: Say a group of females of a certain species "like" some feature of a certain groups of males; by "like" I mean some behaviour that makes this ...
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Why, specifically, does each generation, on average, improve upon the design of the species rather than degrade it?

In every non-life example I can envision, a copy of a copy is always a degraded or less pure version of the original unless some outside influence acts to correct the copy back toward the ideal ...
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Can any species be bred selectively/engineered to become as diverse looking as dogs?

I've done some research and it appears that dogs are the most diverse looking single species of mammals. The questions that interest me is - are dogs special in respect to genes/gene activation ...
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Why is it thought that silicon based lifeforms never flourished on Earth?

Reading the recent ScienceAlert article "For the first time, living cells have formed carbon-silicon bonds", it is stated that despite the relative abundance of silicon in the surface of the Earth, ...
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Is local equilibrium a reasonable assumption for evolutionary processes?

Whenever I look at discussions of fitness landscapes (in particular, Kauffman's NK model) the questions tend to resemble: The population is at a local equilibrium, but another equilibrium of higher ...
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How is “selection” best defined?

There is natural selection but there is also sexual selection which some regard as a category of natural selection. There is also artificial selection (by humans). The question is, what is a most ...
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How does evolution produce complex organs

I've been wondering lately how evolution manages to produce complex organs. It is pretty obvious to me how evolution would select some minor traits like size, resistnce to illness or climate. There is ...
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The Origin of Mitochondria

For a long time I've just accepted, because it is just what everyone told me, that mitochondria became organelles in the cell when they were "engulfed" by another cell which acted like it's host. This ...
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How did the huge dinosaurs cope with gravity and loads on bones, etc.?

It's very costly to be a huge animal. Your mass grows in cube when you scale up, but you still only have two/four legs to support the same weight. This increases the pressure that your body needs to ...
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Is there a name for the evolutionary loss of vestigial structures?

Consider a biological structure which no longer benefits an organism, such as the eyes of an organism whose population now lives in total darkness. I can think of three reasons why such a structure ...
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Reasons why living fossils exist?

A living fossil is a living species (or clade) that appears to be similar to another species otherwise known only from fossils, typically with no close living relatives. A living fossil is ...
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Effects of selection on effective population size

Background The effective population size ($N_e$) is a central concept of evolutionary biology and is influenced by several parameters. For example: sex ratio bias affects $N_e$ $\left(N_e = \frac{...
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Empirical evidence for Group Selection?

A controversial concept in Biology "Group Selection", has caused confusion and conflict amongst scientists since the since the mid 1990s. The more general realm of study is termed the "unit of ...
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Viruses: Adaptation to a new host through repeated host jumps

A friend told me, during a 3 minute discussion, that viruses that are endemic in host $A$ and make repeated jumps to host $B$ but can't be transmitted between individuals of species $B$, may slowly ...
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Extinction of species

I barely know anything about biology and realize that this might be a stupid question, but I'll ask anyway! I know that species "transform" into other species through the process of evolution. Many ...
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Variation in MHC in humans

What evolutionary process lead to so much variation in MHC? What is the advantage of having such variation?
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Chromosome 2 fusion?

I read this article by Jeffrey Tomkins and Jerry Bergman claiming to debunk chromosome 2 fusion. Is there anything wrong with these conclusions? " 1.The reputed fusion site is located in a peri-...
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Fisher's Fundamental Theorem of Natural Selection

Ronald Fisher discovered what he, with humility, called the Fundamental Theorem of Natural Selection. This theorem says (in its modern terminology): The rate of increase in the mean fitness of any ...
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Why does the apex of the human heart usually point to the left?

In the majority of human beings, the apex of the heart (left ventricle) points towards the left side of the body. Sometimes however (approx. 1/12000 births), a person is born with a condition known ...
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Book recommendations for evolutionary models

I was recently working on getting a statistical model of a DNA sequence. To do this I found that understanding evolution quantitatively seems to be quite important. I would really appreciate any book ...
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Why does the number of mutations per individuals follow a Poisson distribution?

I was reading this review. On page 11, left column, first paragraph, one can read: [..] there is a Poisson distribution of the equilibrium number of mutations per individual, if fitness effects are ...
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building intelligent structure with random evolution requires series of non useful steps

In order to build an intelligent design such as a bridge or a mechanical watch, you need a series of non useful steps. As far as I understand, in random evolution theory, the "intelligence" involved ...
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What is the minimum eye?

What is the minimum eye which confers some evolutionary advantage? By minimum I mean anything less than this has no advantage whatsoever and therefore is not favored by natural selection. By eye, I ...
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The falsifiability of natural selection [closed]

I was wondering if we could think about experiments to falsify natural selection . According to this wiki : we could invalidate natural selection “...if it could be shown that selection or ...
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Additive genetic variance with $n$ alleles

The genetic variance of a quantitative trait (the quantitative trait in question is fitness) can be express as the sum of two components, the dominance and additive variance: $$\sigma_D^2 + \sigma_A^...
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Additive genetic variance with $n$ loci

The genetic variance of a quantitative trait (the quantitative trait in question is fitness) can be express as the sum of two components, the dominance and additive variance: $$\sigma_D^2 + \sigma_A^...
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Is evolution a predictive theory? [closed]

My feeling is that almost any observation can be explained by current evolutionary theory. Is there any example of someone developing a rigorous framework or mathematical model of how evolution works?
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Which was the last significant event in human evolution? What's next?

At 10.000 BC (12 ka), we became the last of the Homo species on Earth. In evolutionary terms this is a very little time range to something happen, but I'm wondering anyway, in this meantime which are ...
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Is there any evolutionary/physiological advantage to multi-lateral symmetry?

Just wondering ; I get the impression a large number of multicellular organisms are multi-lateral in their physical structure. Why would evolution/mutation have retained multi-lateral symmetry in an ...
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Approaches towards a theory of innovation in evolution

Evolutionary biologist Andreas Wagner writes in his book "The Origins of Evolutionary Innovations: A Theory of Transformative Change in Living Systems" (Oxford University Press, 2011): We are ...
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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 that can fix their own nitrogen (without the help of bacteria). Plants get their nitrogen in the form ...
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Why Did 6 Great Ape Species Survive But Only 1 Hominid Species?

My dad asked this question when I explained some circumstances surrounding Homo sapiens survival against all odds. We know there is only one hominid species left in the world, Homo sapiens. We also ...

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