Linked Questions

8 votes
3 answers
3k views

why has evolution favored sexual reproduction using two mates over sexual reproduction using three mates?

Many animals species require two members — a male and a female — to sexually reproduce. Why has nature (or the process of evolution) chosen to favor the form of sexual reproduction which requires two ...
Yashas's user avatar
  • 261
3 votes
1 answer
5k views

Why do nerve cells convert electric signals to chemical signals?

One would assume that a faster response time in the nervous system would be beneficial. However, nerve cells have to convert electrical impulses to chemical signals and cross a synapse. Why didn't ...
rainwaffles's user avatar
3 votes
1 answer
8k views

What is the point of a runny nose during a cold?

What is the biological purpose of having a runny nose during a cold? Note, this is a different question than "What causes a runny nose" and other similar questions. Those question are about the cause,...
gman's user avatar
  • 149
7 votes
2 answers
1k views

Why do fruit flies go so close to large reservoirs of liquid when they are likely to fall in due to surface tension?

I had accidentally left out half a glass of red wine by the windowsill when I went to sleep. As anyone knows, if you do this with a window cracked you will get quite a few fruit flies near it in that ...
hisairnessag3's user avatar
5 votes
2 answers
494 views

Do Traits Have to be Adaptive in Order to Survive?

I'm reading Michael Pollan's book 'How to Change Your Mind', which is largely about psychedelic mushrooms. In discussing the biology of the mushrooms, he writes: 'Even if psilocybin in mushrooms ...
nothingIsMere's user avatar
2 votes
2 answers
918 views

Recycling and storage of nitrogen from breakdown of macromolecules?

If nitrogen is so important (it's a constituent of both proteins and nucleic acids), why are animals still throwing them out, and needing to eat it again? Is it true that in almost a billion years of ...
Rodrigo's user avatar
  • 1,300
4 votes
2 answers
822 views

Why was not RNA completely replaced by DNA when the RNA world evolved into a DNA and protein world?

If DNA just has a slightly different chemical composition from RNA, why can't DNA act as a catalyst and why hasn't it replaced RNA? Here, I am talking in terms of evolution, shouldn't evolution just ...
James Moriarty's user avatar
5 votes
3 answers
1k views

Why did the face of human species changed so much during the course of its evolution?

I recently watched this video which showed the evolution of facial features of the modern man https://youtu.be/-69K7E0UlBI I'm wondering what evolutionary advantage did we get by having our face ...
Serotonin's user avatar
  • 512
8 votes
1 answer
3k views

Why does Citric Acid occur in Citrus fruits?

Why is there so much citric acid in citrus fruits? And how did it evolve i.e. what did it come from? Is it a by-product of the ripening process? Why have citrus fruit evolved a particularly high ...
Phototroph's user avatar
6 votes
2 answers
781 views

How significant is the genetic component of homosexual behaviour?

From some basic googling, I found that nobody has ever proven that people are born gay and that environment plays a great part in homosexuality. I wish to know if there is a genetic component to ...
Luca's user avatar
  • 77
8 votes
2 answers
604 views

Why doesn't life produce diamond, graphene, nanotubes, etc? Could it?

It seems that life is really good at assembling carbon into extremely complicated molecules (e.g. DNA). Graphene is stronger than any materials currently used by biology. Diamond is harder than any ...
hexagon's user avatar
  • 196
2 votes
1 answer
980 views

why is cellulase not found in animals? [closed]

As it is really beneficial for all organisms, why are animals, especially mammals (I don't know about other vertebrates) unable to synthesize cellulase enzyme in their body? Is it linked to some DNA ...
another 'Homo sapien''s user avatar
1 vote
2 answers
669 views

Why even if all requirements for natural selection are met, it may not happen?

In the book written by John Endler Natural Selection in the Wild p. 4 it says that even if condition a, b and c are met, evolution by natural selection might occur, [...] , but not necessarily, [...
M. Beausoleil's user avatar
1 vote
2 answers
409 views

Why isn't the ovum reabsorbed into the body (like sperms) if it is not fertilised?

I have read that when sperms are not ejaculated out of the body, they are broken down and reabsorbed. Why can't the ovum be reabsorbed into the body instead of shedding it out during menstruation.
ADR's user avatar
  • 41
1 vote
3 answers
228 views

Is evolution a means to an end?

In "The Red Queen", Matt Ridley frequently argues that evolution is a means to an end, without providing much explanation for such a big statement. Is this a fact in biology? Do species mutate their ...
Paul Razvan Berg's user avatar

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