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1500 questions
307
votes
3 answers
Why do I only breathe out of one nostril?
I was just sitting with my hand next to my nose and I realized that air was only coming out of the right nostril. Why is that? I would think I would use both, it seems much more efficient. Have I always only been breathing out of my right nostril?
David says Reinstate Monica
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207
votes
4 answers
Why are so few foods blue?
Although blue foods exist, they're rare enough compared to other foods for food preparers to use blue plasters as a convention. The natural colour of a given food is due to pigments that have some biological origin. Is there any evolutionary reason…
J.G.
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202
votes
7 answers
Does DNA have the equivalent of IF-statements, WHILE loops, or function calls? How about GOTO?
Does DNA have anything like IF-statements, GOTO-jumps, or WHILE loops?
In software development, these constructs have the following functions:
IF-statements: An IF statement executes the code in a subsequent code block if some specific condition is…
user12939
153
votes
2 answers
How many times did terrestrial life emerge from the ocean?
Evolution is often mistakenly depicted as linear in popular culture. One main feature of this depiction in popular culture, but even in science popularisation, is that some ocean-dwelling animal sheds its scales and fins and crawls onto land.
Of…
Konrad Rudolph
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139
votes
1 answer
Do bacteria die of old age?
I know that the cells of mammals at least stop dividing when they are old, and then die a programmed cell death. Then other cells have to replace them.
But in a bacterial colony, each cell replicates for itself. Obviously, if a division of a…
rumtscho
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124
votes
4 answers
Is there a reason why human eyesight and plants make use of the same wavelength of light?
The accepted range for the wavelengths of light that the human eye can detect is roughly between 400nm and 700nm. Is it a co-incidence that these wavelengths are identical to those in the Photosynthetically Active Radiation (PAR) range (the…
Rory M
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118
votes
3 answers
Why is thymine rather than uracil used in DNA?
What is the advantage gained by the substitution of thymine for uracil in DNA? I have read previously that it is due to thymine being "better protected" and therefore more suited to the storage role of DNA, which seems fine in theory, but why does…
Rory M
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112
votes
3 answers
Are male and female brains physically different from birth?
Male and female brains are wired differently according to this article:
Maps of neural circuitry showed that on average women's brains were highly connected across the left and right hemispheres, in contrast to men's brains, where the connections…
Pablo
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111
votes
4 answers
What is the effect of non-vaccinated people on vaccinated people?
Many times have I heard that anti-vaccine people are dangerous even to the vaccinated population. Is that true? If so, how can it be? People say that germs will attack them, and soon they would eventually grow and spread even toward general…
leo
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111
votes
9 answers
Why do plants have green leaves and not red?
I know plants are green due to chlorophyll.
Surely it would be more beneficial for plants to be red than green as by being green they reflect green light and do not absorb it even though green light has more energy than red light.
Is there no…
Joe Clarke
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102
votes
2 answers
Can HIV be transmitted via mosquitos?
It is known that HIV is usually transmitted by direct blood or body fluid contact between an infected individual and a healthy person (like blood transfusion or needle sharing):
Suppose a mosquito bites an individual suffering from AIDS and in the…
rishab bairagi
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101
votes
3 answers
What's the evidence against SARS-CoV-2 being engineered by humans?
A couple of colleagues suggested in a discussion that the virus that causes COVID-19 appears to be made by humans, since nature could not have produced such an efficient virus — that spreads so fast and whose patients are contagious quite some time…
Alexei
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101
votes
6 answers
Do beneficial viruses exist? If so, what examples are there?
Typically, people call viruses some kind of organic compounds that cannot reproduce autonomously and which lower the fitness of their hosts. Even the word "virus" means "venom" in Latin.
But from the perspective of natural selection, one would…
rus9384
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100
votes
4 answers
Does the string "...CATCAT..." appear in the DNA of Felis catus?
In Hofstadter's Gödel, Escher, Bach: An Eternal Golden Braid (GEB), the following claim appears:
...in the species Felis catus, deep probing has revealed that it is indeed possible to read the phenotype directly off the genotype. The reader will…
skytreader
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93
votes
8 answers
Why do some bad traits evolve, and good ones don't?
If a trait would be advantageous to an organism then why hasn't it evolved yet?
Conversely, if a trait is not advantageous or mildly disadvantageous, why does it exist?
In other words why does evolution not make the organism more "perfect"?
This is…
WYSIWYG
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