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

6
votes
4answers
506 views

If Evolution Is In Progress, Why Fight Extinction?

Natural selection is a central tenet of evolution. However, most biologists seem determined to prevent the extinction of the species that have been selected against. Why is this? Preservation of ...
10
votes
2answers
1k 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 ...
4
votes
1answer
466 views

Why do sloths come down from the trees to defecate?

I'm under the impression that most sloths exhibit this behavior, but why? They are slow moving and so have no way of escaping from predators when on the ground. Not to mention the energy they expire ...
3
votes
1answer
220 views

Macroevolution vs. microevolution

Where is the line usually drawn between macroevolution and microevolution? I thought that, although similar processes govern both, the line was at the species level, with macroevolution being changes ...
35
votes
3answers
2k views

Why are there no wheeled animals?

In physics, "almost everything is already discovered, and all that remains is to fill a few unimportant holes." (See Jolly.) Therefore, on Physics SE, people are veering off into different directions: ...
1
vote
1answer
115 views

Lineage selection in plasmid evolution

I've been reading through Paulsson (2002) and I am not sure what he means by "lineage selection" in the second to last section. The paper deals with plasmid replication, and mostly concentrates on the ...
9
votes
1answer
290 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 ...
3
votes
1answer
189 views

Are there natural selection experiments that quantitatively agree with theoretical modeling?

Has anyone ever conducted an evolution experiment and quantitatively compared it to theory? For example, has anyone ever put bacteria in a million petri dishes filled with antibiotics and calculated ...
6
votes
2answers
216 views

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 ...
2
votes
1answer
90 views

The oldest common ancesstor of all human beings

Do all human beings have a single oldest ancestor (a man and a woman), or were there were many ancestors at the same time at different places on earth? This article sheds some light. Is there another ...
1
vote
1answer
89 views

Reproductive isolation causing evolution

My course book says about reproductive isolation that it does not allow the interbreeding among the individuals of different species. It also says that it is a cause of evolution. How is this cause ...
0
votes
1answer
185 views

Why does the PR form of phytochrome exist?

I know how it gets converted because PR is more stable and when there is neither red or far red light PFR naturally converts to PR. But what is the point of it? If PFR is the biologically active one ...
1
vote
1answer
145 views

What's the Evolutionary Purpose of Religion? [closed]

I would imagine the answer to this question would be that religion tends to cause greater compliance of individuals within society, so it is pro-society. Plus these religions tend to incorporate some ...
3
votes
3answers
270 views

Is it possible to make bacteria vulnerable to antibiotics it's resistant to?

Since bacteria becomes resistant to antibiotics after an unfinished course, is it possible to do anything to be able to get treatment with the same antibiotic again, and reverse the resistance in the ...
1
vote
1answer
206 views

Cyanobacterial photosynthetic oxygen yield

I am somehow not convinced that biotic factors are solely responsible for creating 21% of atmosphere (around 40 million moles of oxygen). There may be additional issues here. Since cyanobacteria ...
2
votes
3answers
1k views

How did this spider evolve to mimic exactly a human face and arms?

So I came across something terribly amazing today, that is, a video showing this species of peacock-spider, that literally, transforms into a human face waving his arms about. What could have ...
3
votes
1answer
225 views

How might gene clusters like the lac operon evolve?

The obvious answer for a gene cluster is gene duplication and mutation of one or both genes. But the genes in the lac operon seem not be so functionally/structurally similar (as compared to the Hox ...
1
vote
2answers
156 views

Effect of zero selection (pressure) on the population health

Evolution naturally produces better features: stronger muscles, teeth and minds. Killing the weakest, evolution wipes defective genes out of populations. The mutations are necessary for advance. ...
3
votes
3answers
1k views

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.
2
votes
5answers
173 views

Why do some people find vegetables so repellent when evolutionarily they should find them an attractive and thus tasty food?

Why do certain people (especially kids) find vegetables so "repellent" when evolutionarily they should find them an attractive and thus tasty food? I ask this question because if Darwin's theory of ...
6
votes
2answers
404 views

Why does sexual selection evolve beautiful features?

First question here. I have a very raw understanding of sexual selection: Say a group of females of a certain species "likes" some feature of a certain groups of males; by "like" I mean some ...
2
votes
1answer
61 views

Indestructible Super Shrimp

How are shrimp and other animals able to not be crushed by the 1000x greater pressure at the bottom on the Mariana trench? Wiki says the trench is home to "large living creatures such as a sole or ...
1
vote
1answer
107 views

Agony, Hydrophobia and viruses in the light of evolutionary principles

I'm undergraduate physics student, but I've always been interested in biology. So I have a couple of questions about an application of the evolutionary principles to practice. Agony as the last ...
1
vote
0answers
98 views

Why aren't antheridia and archegonia touching?

Antheridia and archegonia are the two male and female gametangia, respectively, and they are found in bryophytes. To cause fertilization, usually a thin film of water must be present for the sperm ...
9
votes
1answer
310 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 ...
7
votes
3answers
972 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 ...
0
votes
2answers
114 views

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 ...
1
vote
2answers
126 views

Plants without bacteria? is it theoretically possible?

I know from school, that all live on the Earth need bacteria as low-level "machines" that break down/extract/convert/produce chemical elements and combinations, other high-level organisms needed. But ...
5
votes
2answers
591 views

Why did the urinary bladder evolve?

Sure it's convenient to decide when to urinate but not essential for survival or reproduction, as I understand. But just convenience is not a drive for evolution. Does the bladder serve any essential ...
0
votes
3answers
216 views

Can this theory on the evolution of human appearance be flawed?

This is what a friend of mine said: When there's human offspring, it will look a rough 'medium' between the two parents, with it sharing features from the two. well if the offspring of one set ...
11
votes
2answers
545 views

Do plant-animal cross races exist?

Plants and animals have the following distinct properties: Plants live from solar energy by photosynthesis, they use solar energy to make sugar and oxygen out of carbon dioxide, which gives them ...
8
votes
3answers
3k 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, ...
4
votes
3answers
189 views

How does natural selection favour large body mass and size (or so it seems)

I was walking through a park this afternoon and observed a few birds having fun flying around and it got me thinking why would natural selection favour birds with flesh at all if it hinders their ...
2
votes
1answer
206 views

Is there an “Adam and Eve” for each new trait during (not just human) evolution? [duplicate]

Do new beneficial mutation evolve simultaneously and independently with several individuals of the same specie or only with one specimen who then transfers it to all of the specie? In other words, ...
-1
votes
3answers
151 views

A question regarding evolution

I'm not a biologist so bear with me. I know that the DNA molecule carries extremely large amounts of information. If the process of evolution is driven by completely random process .I think about it ...
1
vote
0answers
57 views

Why did animals evolve genders? [duplicate]

The majority of animals have two genders, and both are needed in reproduction. It seems like it would be more advantageous for creatures to be hermaphrodites, since they could mate with any member of ...
9
votes
2answers
636 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 ...
8
votes
2answers
145 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 ...
3
votes
2answers
956 views

Why do some animals have 8 Limbs (e.g. Spiders, Octopuses)?

Octopuses have 8 tentacles, spiders have 8 legs. Is there something special about 8? It seems like an animal that needs 360° mobility has 8 legs.
10
votes
3answers
695 views

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 ...
4
votes
2answers
312 views

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 ...
6
votes
3answers
381 views

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

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 ...
1
vote
4answers
786 views

Refutation of Darwin's Random Evolution Theory [closed]

I saw this refutation online of Darwin's Random Evolution Theory and cannot see any holes with the logic. Can anyone crack this simple refutation? Refutation of the Theory of Random Evolution ...
2
votes
2answers
101 views

Are humans still competing in the same way now that the first life forms did?

I'm not sure if this is actually a philosophical question, but I was reading a timeline of life on earth and I came to this: 4500-3500 Ma The earliest life appears, possibly at Alkaline vents ...
0
votes
2answers
663 views

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 ...
3
votes
4answers
861 views

What evolutionary reason is there for having the urinary duct and reproductive organs so close together?

As the old joke goes, "God must have been a civil engineer. Who else would put a waste facility straight through a recreational area?" But maybe it wasn't God. Is there any evolutionary reason (or ...
4
votes
1answer
307 views

Why are eggs “egg” shaped?

Is there a reason as to why chickens lay "egg" shaped eggs, as opposed to spherically shaped eggs (or a random shape)? <--- Main Question For extra points (actually just to add more words in ...
9
votes
3answers
3k 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 ...
4
votes
1answer
160 views

Evolutionary explanation to why we have such large memory capacities?

The scientific consensus is that no one ever fills up their memory capacity by learning facts and so on, even in the information age. My question is therefore, is there an evolutionary reason as to ...
2
votes
1answer
65 views

Historical recovery from mass extinction events

Is there a way to generally characterize how species "regrew" after the various mass extinction events happening periodically from 450 Ma to 65 Ma. Would the surviving species just start back where ...