Recent comments in /f/askscience

notenoughroomtofitmy t1_j9ikpld wrote

Reply to comment by qwertyuiiop145 in Why do we all have different voices? by LegitVirusSN-2

Also,

We have different everything. Voices (like faces) are noticeable because we use them as a primary means for communication within our group, and our brains have evolved to zone in on the differences nonchalantly because it was a matter of life and death back then. Nothing about two people is exactly the same, things may be very similar. Most of these things go unnoticed, since they didn’t play as significant a role in our evolutionary history.

I imagine a dog asking on doggedit: “why do humans all have different smell?”

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Treadwheel t1_j9ik046 wrote

Reply to comment by urbanek2525 in What are more accepted hypotheses that similarly explain the aspects of hominid evolution that the "pseudoscientific" aquatic ape theory does? by KEVLAR60442

That's not quite what's going on there. The drug in question worked by inhibiting aldehyde dehydrogenase, which is an enzyme which handles the direct metabolites of alcohol, but which isn't specific to just ethanol metabolism. All sorts of aldehydes are produced and consumed by the human body and need to be dealt with.

ALDH is involved in the conversion of retinol to retinoic acid, which is necessary to produce sperm, but the relationship is more of a general purpose tool having many applications than a bizarre coincidence of evolution.

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KJ6BWB t1_j9iip77 wrote

Reply to comment by Marsdreamer in What are more accepted hypotheses that similarly explain the aspects of hominid evolution that the "pseudoscientific" aquatic ape theory does? by KEVLAR60442

> Even deleterious mutations and traits can rise to fixation in a population

To be fair, it requires a lot for a new mutation to spread through a population. For instance polydactylism, or having more than 5 fingers on a hand, is a dominant trait but despite its advantages most of still only have 5 fingers on a hand because it's really hard for a new trait to spread unless it confers a real evolutionary advantage, meaning those who lack it die and most of the survivors have that trait.

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Virtual-Study-Campus t1_j9ihjo2 wrote

Reply to Why can’t mules reproduce? by Imaginary_Camel4213

They have trouble making sperm or eggs because their chromosomes don't match up well. And, to a lesser extent, because of their chromosome number. A horse has 64 chromosomes and a donkey has 62. A mule inherits 32 horse chromosomes from mom and 31 donkey chromosomes from dad, for a total of 63 chromosomes.

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urbanek2525 t1_j9if8nu wrote

Reply to comment by PJHFortyTwo in What are more accepted hypotheses that similarly explain the aspects of hominid evolution that the "pseudoscientific" aquatic ape theory does? by KEVLAR60442

Also, there are many ways that things in our biology are interconnected and entantangled for no discernable reason. There are a lot of adaptations that have some good and some bad impacts. As long as the good outweighs the bad, it tends to stay.

For example, there is a drug that suppresses a man's body's ability to produce a particular protein. While that protein is suppressed, the man produces very little sperm. A near perfect male contaceptive. The thing is, in addition to enabling sperm production that protein also contributes to alcohol metabolism. So, alcohol makes the user very ill. There's no rhyme or reason that these two operations would be using the same darn protein, but they are. There are thousands of these overlaps that have developed over the millenia.

This is because there's no plan behind evolution. It's too complex to draw straight lines. It's a random mess.

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cookerg t1_j9ie7o8 wrote

Reply to comment by alien_clown_ninja in What are more accepted hypotheses that similarly explain the aspects of hominid evolution that the "pseudoscientific" aquatic ape theory does? by KEVLAR60442

So how did we get that endurance and running gait? However it evolved, humans are capable of covering longer distances in a day than most mammals, and do it voluntarily. And sled dogs might only be capable of keeping up, or beating us, because we selected them for it

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codyish t1_j9idhaz wrote

Reply to comment by Marsdreamer in What are more accepted hypotheses that similarly explain the aspects of hominid evolution that the "pseudoscientific" aquatic ape theory does? by KEVLAR60442

So much this. I can't believe how many highly educated and smart people, some in biological sciences, can't accept that many traits appear for no reason and don't disappear because they have no reason to. My advisor used to say, "evolution doesn't have to help you to happen; it just can't kill you or make others not want to fuck you".

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