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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1answer
68 views

Expected number of SNPs in a sample of size `k`

Consider a Wright-Fisher population of constant size N. We sample k haplotypes in this population. What is the expected number ...
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1answer
374 views

Why are fatty acids synthesized in two carbon units?

Why does long-chain fatty acid synthesis involve the two-carbon precursor, malonyl CoA, rather than the one-carbon acetyl CoA (or even a three-carbon precursor). Is this because fatty acids with an ...
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2answers
82 views

Why do the two sexes have different reproductive costs and capabilities?

Is there an evolutionary explanation that shows why the reproductive costs are mostly on the female sex? And therefore, why do males can potentially have more offspring? Does that happen to create ...
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39 views

What is the evolution metaphor about water flowing downhill?

As part of my biology undergrad degree, I took a course on the Origin of Species, where we read Darwin's book and also several other readings about the origins of evolution. I recall that during this ...
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3answers
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Role of epigenetics in evolution and transmission of defects caused by drugs

In a documentary, they were saying that epigenetics changes caused by the environment in an individual can be transferred to the following generations. I have some questions on that: How many ...
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1answer
523 views

Why don't the female lions in a pride help their male lion to protect their children from other males?

I watched a dozen of videos taping the fights between male lions; none of them involve female lions assisting in the fight. It is also known that the male lion who take-over the pride will kill all ...
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1answer
100 views

Why humans didn't evolve to safely consume rotten food? [duplicate]

I'm not a biology person at all so please forgive me if my question is silly. I was just wondering that why didn't evolution cause us to digest, without issues decomposed food?
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1answer
82 views

Why do mammals rarely have eyespots?

An eyespot is a marking to mimic the eyes. Many examples of eyespots can be found in fish, reptiles (including birds), and insects. Recently Radford 2020 has shown that artificial eyespots can reduce ...
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The Proofreading Function of Coronavirus Polymerases

I have heard that the Coronavirus family have a proofreading and editing function in their polymerase enzymes which can recognize and excise mutations. This is obviously disastrous for the population ...
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Shrinking size of Y chromosomes

I read on the web that the size of Y chromosomes decreased in earlier period of time and the picture below tells that it is still occurring. So basically I want to know what caused this shrinking and ...
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2answers
98 views

Evolution: what were we doing for 100.000 years? [closed]

I'm not a biologist/anthropologist but there is a question that comes up again and again and which I couldn't find any deeper thought, even not a speculation. As far as I understand it, according to ...
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1answer
96 views

If coral didn't exist, would jellyfish not exist either? (Or vice versa)

Is the evolution of corals, sea anenomes and jellyfish intrinsically linked to the point where if say corals did not evolve, neither would jellyfish? Or vice versa.
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1answer
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Is there a metric for “evolutionary agility”?

By "evolutionary agility" I mean how fast an organism can adapt to changes in the environment. I’d imagine that a population with more offspring and a shorter time between generations would ...
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1answer
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Did humans evolve the ability to swim? Or is it just luck that we are able to swim?

Many animals like ducks have evolved features to be able to swim. Even not so aquatic animals like a tiger evolved so that its feet can act as paddles. In humans I don't see any direct feature that ...
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Why does the sandalwood tree produce a fragrant oil?

Why do sandal trees produce fragrant oil? Is there any purpose for it? Is it to make it unpalatable for other herbivorous animals? If so, why do humans find the fragrance pleasing?
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651 views

Evolution: Can the genotype frequencies change, but the allele frequencies remain constant?

If a population isn't evolving because it's in Hardy-Weinberg (HW) equilibrium, then I know that both genotype and allele frequencies must stay constant. My question is, can evolution still not occur ...
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1answer
78 views

The significance of haplotype blocks

I looked up haplotype blocks in Google Scholar, and the results returned seemed to show that almost all the relevant articles were published between 2001 and 2009, with almost nothing since 2010. Why ...
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1answer
65 views

What factors have led to selection for intelligence in crows and rooks?

The Corvidae family could include some of the smartest species after primates. What could be the factors that differentiate them from other species of birds that have determined their potential for ...
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1answer
59 views

When life first formed in earth's ocean, was it salty yet?

Do we have any tangible proof, e.g. by studying fossils of primitive life forms, that during their time the ocean was already salty, and at roughly similar levels to today's, or on the contrary, that ...
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1answer
49 views

The fraction of the genome that is evolutionarily conserved through purifying selection is less than 10%?

I would appreciate help in understanding the meaning, logic, and, in particular, how to interpret the phrase: The fraction of the genome that is evolutionarily conserved through purifying selection ...
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163 views

Is natural selection actually random?

In the Theory of Evolution, two main factors take place: One is random, which are the different mutations that organisms' DNA suffer. This process adds genetic variability to a given population. The ...
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Tree-pest coevolution

Many trees first reproduce decades after germination. Many pests of trees reproduce in under a year. It would seem that the pests have an advantage in the evolutionary arms-race, as they can evolve ...
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How is knowledge about farming transfered between generations in farming ants

There are some varieties of ants capable of "agriculture", e.g. dairing ants farming aphids and leaf-cutting ants farming fungus. How is the knowledge about the techniques involved passed ...
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2answers
73 views

How do microbes spread from a small place to a very large place?

Bacteria are very small, so they cannot move very far on their own. Viruses cannot move themselves at all. So how does a specific type of bacteria or virus spread from a small place to a very large ...
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0answers
63 views

How does sleep prevent our eyes from drying out?

If we don't sleep for about 16 hours, our eyes start to get dry, and no amount of eye drops helps. You use eye drops and then you're dry 10 minutes later. However, after you've slept for 8 hours, your ...
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67 views

Examples of species whose extinct common ancestor is well documented?

If we follow the ascendence line of two closely related species we can build a "Theoretical" common ancestor, whose characteristics were inherited with few differences by the offspring. <...
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Why largest cats so much larger than canids?

It is striking to me that there is no dog-like creature larger than a wolf while there are at least two species, tigers and lions, many (at least twice and probably 3 or 4) times the size of the ...
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Why do we anthromorphize evolution and genes and nature?

Books sometimes says things "Our genes want us to have as many children as possible", or "Evolution wants the fittest to survive". But genes are not conscious entities who can want ...
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Are there real world examples of one way isolation between two populations?

I know that for two populations A and B, there are situations in which there is a two way exchange of individuals between the populations, and there are situations in which there is no exchange of ...
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1answer
65 views

Is it possible for a invertebrate to evolve features like that of a vertebrate or BECOME a being similar to that of a vertebrate? [closed]

Could a invertebrate, for this lets say, a centipede/millipede, evolve into something like that of Pikaia? or something similar? Just an invertebrate turning into something similar or what would look ...
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Is evolution the reason why water is colourless for our eyes?

Liquid water is transparent to most of the visible spectra, whereas it absorbs infrared. Similarly, the air is almost transparent to the visible spectra too. Could these be the reasons why our eyes ...
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1answer
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Do viruses pickup new genetic sequences from the host cell?

Virus replication does not involve meiosis so the virus genome does not gain diversity from having two parents , so other than from mutation, do viruses obtain new genetic sequences from the host cell ...
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Are there animals that have evolved a resistance to human activity or encroachment?

There are countless sources, both peer-reviewed and popular, explaining how overuse and misuse of antibiotics is breeding a new generation of antibiotic-resistant "superbugs" such as MRSA (Methicillin-...
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Does epigenetics suggest there is at least some element of truth to Lamarckism?

I am not a biologist. But googling "epigenetics lamarck", I find many different opinions: For: Lamarck rises from his grave, Epigenetics: Lamarck’s Revenge?, Darwin’s theory ... is incomplete without ...
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1answer
85 views

Why is cannibalism not an evolutionary stable situation?

In the 'the selfish gene' Dawkins writes (page 109): "The reason lions do not hunt lions is that it would not be an ESS (evolutionary stable situation) for them to do so. A cannibal strategy would be ...
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1answer
141 views

Why is selection less effective in small populations than in larger?

I can understand that the genetic drift has a higher impact on smaller populations, but what does it mean for the selection to be less effective in small populations than higher?
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About what percent of mutations are not adaptive?

Many popular texts that discuss evolution and natural selection often mention that many (or most) mutations are bad (not adaptive). Have there been any studies on what the rough percentages are? (E.g....
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Are there known chains of beneficial mutations?

Are there known examples of chains of beneficial mutations? What I mean by that is a mutation that leads to a series of mutations occurring after each other over a relatively short period of time ...
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50 views

Century old trees and evolution

We always think of natural selection as occurring at the level of populations not individuals. how about century old trees where germline is being produced from constantly dividing cells. Are all ...
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71 views

Question regarding the number of alleles

Why is it that in biology we often say that a gene has two alleles? When we analyze allele frequencies (e.g. using Hardy-Weinberg Equilibrium), formulas are often generalized for two alleles of a gene....
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Is there any evidence that discards the possibility of an organism-aided evolution?

The theory of evolution of Darwin is mostly accepted nowadays, while Lamark theory has been abandoned. There are many experiments that show that experiences do not alter the genes or are passed to ...
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In what ways does the number of legs affect an animal's functioning?

After much research, I've only been able to find specific examples of leg-number's impact on locomotion and dexterity (and/or object manipulation). I feel as though there must be other ways it has a ...
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1answer
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First neurotransmitter?

Cnidaria are considered to be the first phyla to develop a nervous system. Nervous systems having 1, 2 and three neurons are considered to have appeared first in Cnidaria, with 2-neuron nervous ...
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Why did we lose our fourth type of cone cell (in the eye)?

Most species of birds, reptiles and fish have four types of cone cells in their retina, thus they have four independent channels for conveying color information. They are: short-wave (S) cones: ...
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Why do humans have flat faces, as compared to chimps?

Apparently adult, particularly older human faces resemble infantile chimps more tham they resemble any other adult hominid. And adult humans even have as many body hair follicles as infantile chimps. ...
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Recommended books and articles on the origin and evolution of sexual reproduction? [closed]

I'm interested in learning about the origin and evolution of life on Earth. In particular, one topic that puzzles me a lot as a layman is the evolution of sexual reproduction, since the DNA mutations ...
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Are there computational models verifying the feasibility that complex biological systems can emerge by random mutations plus natural selection?

I am interested in studying the theoretical feasibility that very complex systems such as the vascular system, the respiratory system, the nervous system, the digestive system, among others, could ...
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1answer
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Can DNA be used directly to determine the age of a mutation?

I've studied that proteins found in a sample as biochemical evidences for evolution. Its variation in structure and configuration can be used to date the age when that mutation occured, effectively ...
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Is there a bacterium that became a virus?

Is it possible for a virus to be a descendant of a bacterium that was not through horizontal gene transfer? How I think this could happen: Suppose a species of bacteria lives in an environment where ...
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Why animals haven’t yet evolve in 2020? [closed]

In past when I was born like 1990s I notice most animals haven’t evolved in 30yrs. Example cats haven’t gain more muscular body as to be strong to defend themselves from predators like well many ...

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