15
votes
2answers
3k views

How and why did mammals go back to the oceans?

If I understand evolutionary biology correctly, mammals first evolved on land as small, rodent-like creatures, in a time when reptiles were dominant on land. Eventually, they diversified into the ...
15
votes
4answers
3k views

Height and natural selection in humans?

I watched the documentary "Evolve" recently and in the segment on "size" Scott V. Edwards, Harvard evolutionary biologist mentioned the idea that humans might evolve to be 7' tall in 'hundreds of ...
15
votes
4answers
2k views

Why would a single celled organism evolve to be multi-celled?

I read a story this week on Richard Lenski who has been 'evolving' E. coli for more than 50,000 generations now. One comment I read was from someone who doesn't accept Evolution who pointed out that ...
15
votes
3answers
584 views

What is the most difficult feature to explain evolutionarily? [closed]

I wonder what are examples of organs/structures/behaviours/cooperation that evolutionary biologists themselves find most difficult to explain -- to explain how they could appear evolutionarily -- ...
15
votes
2answers
2k views

Is it known how the first viruses formed?

The oldest known virus is known to have infected prehistoric insects 300 million years ago. A virus is basically a parasitic strand if DNA or RNA encapsulated in a protein coat. It enters cells by ...
15
votes
3answers
2k views

Transmission of epigenetic regulation through surrogate mother

I know the basics of epigenetics, but I do not know how epigenetic mechanisms are transmitted from parents to children (or if there is even enough literature to derive a consensus). My question is ...
15
votes
2answers
1k views

What's the difference between male and female?

As long as we only look at humans the differences are clear: males have chromosomes XY, produce sperm and don't get pregnant. Females have chromosomes XX, produce egg cells and bear babies. But when ...
15
votes
2answers
1k views

Why do we get runny noses in the cold?

The most annoying thing for me about being cold is a runny nose. Is there an advantage to having a runny nose when cold? What does having a runny nose achieve?
15
votes
4answers
5k views

Why we have no enzyme to digest cellulose?

As we know, cellulose is the most abundant polysaccharide in nature. Why don't we have any enzyme to digest cellulose?
15
votes
3answers
2k views

What causes a 'stuffy' or 'runny' nose when you have a cold?

When humans get the common cold, a common symptom is a stuffy or runny nose. Is that the body's immune response or is that the virus's doing?
15
votes
1answer
1k views

Why does looking at bright light trigger sneezing in some people?

Why does looking at bright light trigger sneezing in some people? Are there any recent studies that have found a cause for this Photic sneeze reflex? The Wikipedia article only references studies ...
15
votes
3answers
2k views

What is this fish?! Is it even real?

According to a guy in a Facebook group I belong to, this fish was caught in the Missouri River near Omaha, NE, US. I have never seen one like it in my life, not in person or photo or anywhere. What on ...
15
votes
1answer
906 views

How Do White Blood Cells Learn? Or Do They?

So I get the concept that a vaccine is a weakened form of a virus so that the body can "learn" to fight it and make a person immune to that disease, but how exactly does this learning take place? What ...
15
votes
1answer
528 views

How fast does the rotor in ATP synthase spin?

I'm sure the exact frequency varies, but does anyone know roughly how many revolutions per minute / second the rotating center part makes?
15
votes
1answer
144 views

Why does mint oil feel cold on the skin?

When putting (japanese) mintoil on the skin it produces a cool feeling. You can experience this, when adding it to your bath or using a spray with mint oil on your skin. The cool feeling occures ...
15
votes
3answers
406 views

Can plants get cancer?

I can't think of any reason why plants wouldn't be able to get cancer, but I've never heard of a plant growing a tumor. I've also never seen a plant with a noticeable abnormal growth. Can plants get ...
15
votes
1answer
22k views

Can a person really die quickly from biting their tongue?

A common trope in certain circles (like Eastern martial fiction), is someone committing quick suicide by biting his or her tongue. But is this really possible? The internet turns up millions of ...
15
votes
4answers
372 views

Machine learning for light microscopy — problems to solve?

I would like solve some biological problems that would improve the state-of-the-art of biology or bioinformatics. In particular, I want to apply machine learning on light microscopic images. The ...
15
votes
1answer
565 views

How do porcupines keep from pricking each other while mating?

How do porcupines keep from pricking each other while mating? It seems like they would constantly be scratching each other.
15
votes
3answers
273 views

Defining paper(s) in epigenetics

For someone who is interested in learning about the discovery of epigenetics, which are the foundational defining papers in the area?
15
votes
2answers
266 views

Can methylation from DNA get copied to RNA during transcription?

Methylation on gene-body and 3'UTRs if copied to mRNA can potentially regulate post-transcription modifications or expression regulation. But I'm not sure if they are maintained after transcription or ...
15
votes
2answers
5k views

Why is glucose our primary source of energy?

Is there any evolutionary reason for glucose being the "main" molecule used as a source of energy, beginning with glycolysis and subsequently cellular respiration (after being converted to two ...
15
votes
2answers
942 views

Impact of Alan Turing's approach to morphogenesis

Shortly before his untimely passing, the computing pioneer Alan Turing published his most cited paper The Chemical Basis of Morphogenesis (1952). The central question for Turing was: how does a ...
15
votes
1answer
4k views

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 ...
15
votes
2answers
415 views

Can parts of a human brain be asleep independently of each other, or vary in the times required for them to fall asleep?

I know that some birds and marine animals can continue complicated activity (swimming, flying?) while one hemisphere of their brain is asleep. I'm interested if human brain has some parts of it that ...
15
votes
1answer
173 views

Haidinger's brush: Is this a by-product of the eye's physics, or are there any evolutionary grounds for it?

The human eye is, very subtly, sensitive to the polarization of light. This is an effect known as Haidinger's brush (see Wikipedia article of this name). What, if anything, is known or at least ...
15
votes
1answer
510 views

Is it correct that the body only responds to the most painful stimulus?

I'm rather ashamed to say that this question is partly based on an episode of House. I have previously heard that, if there are multiple simultaneous painful stimuli, the mind will only feel the ...
15
votes
2answers
1k views

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 ...
15
votes
3answers
835 views

Why do some trees have a life span, while some don't?

I have heard that there is no limit on the growth of trees, but then why do some trees, such as boxelders and poplars, tend to live shorter than redwoods, for example? Some advertisements for improved ...
15
votes
1answer
488 views

Additive genetic variance components from LMER in R

I've set up some dummy data in R which makes 40 genetically related lines, they are all siblings within a line so are genetically related by a factor of ½ thus additive genetic variance should be ...
15
votes
0answers
168 views

Was the recent “conservation hunt” of a black rhino supported by science?

CNN recently covered a sanctioned black rhino hunt in Namibia by Texan Corey Knowlton, who bid US$350,000 for the license. In the story, he claims that the hunt was actually supporting conservation of ...
14
votes
8answers
2k views

Is there a biological mechanism for evolution encoded into our DNA?

Throughout high school, I remember learning about Darwin's theory of evolution as if it were near-fact. But something always seemed wrong about the ideas presented. Survival of the fittest Random ...
14
votes
8answers
10k views

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 ...
14
votes
3answers
5k views

Why isn't vomit corrosive?

Vomit comes from gastric acid, right? And in gastric acid there is HCl and HCl is corrosive (strong), how come when I vomit, it doesn't destroy things that it (as the vomit) hits (such as floor, ...
14
votes
3answers
4k views

What causes the development of antibiotic-resistant strains of bacteria?

I understand bacteria have become resistant to antibiotics due to selection pressures, but how do resistant bacteria process antibiotics when exposed to it, compared to non-resistant bacteria. Also, ...
14
votes
4answers
75k views

Why is DNA replication performed in the 5' to 3' direction?

DNA replication goes in the 5' to 3' direction because DNA polymerase acts on the 3'-OH of the existing strand for adding free nucleotides. Is there any biochemical reason why all organisms evolved to ...
14
votes
3answers
47k views

What is a coupled reaction and why do cells couple reactions?

I was wondering what exactly a coupled reaction is and why cells couple them. I read the wikipedia article as well as several others, such as life.illinois.edu but I still don't get it. Could ...
14
votes
3answers
1k views

What evolutionary explanations are there for 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?
14
votes
3answers
1k views

Is the size of the genome across species roughly the same?

Chromosome number differs across species. Is the amount of DNA comparable between organisms, just being split into smaller chunks in those species with more chromosomes? Or do species have different ...
14
votes
4answers
979 views

How many human proteins have a solved 3D structure?

I was wondering how many human proteins have a solved 3D structure. Is there a database with only human proteins? I looked at pdb but couldn't find a filter.
14
votes
2answers
364 views

Why was it so hard to decode the corn genome?

My teachers growing up told me it was impossible to decode the maize genome. But yet its been done. Why was decoding the genome so significant, and what made it so difficult?
14
votes
2answers
1k views

How to make a fake auditory signal?

My question is about making fake auditory signals. The ear collects sounds from the environment, which are transformed into a neural signal by the hair cells in the inner ear. This signal is sent ...
14
votes
6answers
2k views

Online Molecular and Cellular Biology Video Lectures?

I am looking for video lectures to go through to guide my reading in intro molecular and cellular biology. I've had intro bio and I study evolutionary theory, but my molecule- and cell-level knowledge ...
14
votes
3answers
6k views

Supercomputer Vs Human Brain

With supercomputers doing calculation in petaflops ($10^{15}$ Calculations per Second), have we crossed the speed of Human Brain?
14
votes
5answers
2k views

Why are some genes dominant over others? What is the mechanism behind it?

If I have a brown eye gene which encodes the protein that is responsible for the brown color and have a blue eye gene as well, what is the reason that my eye color is brown? How does one gene maintain ...
14
votes
2answers
5k views

How will rising carbon dioxide levels in the troposphere affect photosynthetic producers?

Much discussion has been had about the affects of climate change on plantlife, but how will rising carbon dioxide concentrations affect the photosynthetic process itself? Since CO₂ is a reagent in ...
14
votes
4answers
3k views

Why do parasites sometimes kill their hosts?

It's bothered me for a while now. I understand why a parasitoid would do this, as it only temporarily requires the host, and that not all parasites kill their hosts. There seems to be no evolutionary ...
14
votes
2answers
1k views

Why do we like salt?

A few friends of mine told me that salt provides zero nutritional value to us, and in fact can harm our bodies. Now, these guys are medical students, and being an engineering student myself, I decided ...
14
votes
4answers
2k views

Can two humans with 44 chromosomes produce viable offspring?

It is known that there are very few individuals having 44 chromosomes, not the usual 46 chromosomes. One example is a male in China: the first article, the second article. The other is a female in ...
14
votes
3answers
2k views

What implications has the missing 2'-OH on the capability of DNA to form 3D structures?

The chemical difference between RNA and DNA is the missing 2'-hydroxyl group in the nucleotides that build DNA. The major effect of that change that I know of is the higher stability of DNA compared ...

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