atomfullerene

atomfullerene t1_j254hhe wrote

It's very tricky to find a natural reservoir of a coronavirus like this. You might want to compare with SARS 1, where a very similar virus was found in palm civets being sold for food at the time of the outbreak. But that was a combination of luck and extensive testing. The civets are likely to have been an intermediate step, hosting the virus after it left bats and before it entered humans. But remember, viruses are constantly mutating, so the virus in the civets wouldn't necessarily be the same as the virus in the bats or the people.

Anyway, why can't we do this with SARS 2? Because when the outbreak happened, China locked down their wet markets and killed most of the animals, which means there was very little sampling done. This probably means we'll never know exactly what path the virus took to get from bats to people.

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atomfullerene t1_j20ynjt wrote

You should provide the context where you found them if you can, I or someone else might be able to help out more in that case.

"Darwinism" and "Darwinian" aren't really something I would think of as technical terms but are usually used to refer to some form of evolution involving natural selection....so if I were to hazard a guess, I would say that probably what they are talking about is something like a genetic algorithm, so maybe searching for information on that will help.

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atomfullerene t1_j20wn41 wrote

Huh, I'd never really noticed before how heavily non-metric distance measurements in space are.

I think the reason is that the benefits of metric come from convertibility. Metric's really handy if you need to estimate the mass of a cubic volume of something, or move between mm and km, or get the amount of energy needed to move some mass some distance.

But in space, your distance measurements are all just distance. You aren't using them with other units, typically, so there's no real drive to make them metric. Instead they stick to the older method of using measurements that are convenient for the particular specific context they are being used in.

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atomfullerene t1_j1shetb wrote

I think the structural value of proteins comes from the diversity of amino acids (although possibly causality went the other way there). Lets consider all our possible structural elements. They need to be something that's big....basically, they need to be a chain of repeating units that's arbitrarily long. Fats don't really do this.

That leaves sugars, nucleic acid, and protein. Long sugar chains are sometimes structural (see cellulose and chitin) but there are only a few kinds of sugars used in these structures and they don't have a lot of complexity in chemical nature. So the number of things you can make from them is limited. Nucleic acid has more options, with four bases it can and does bind to itself to form special molecules that use special structures that have catalytic function. A lot of people think this used to be what life originally used, before proteins really got going (the RNA-world hypothesis).

And finally we have proteins. Proteins have 20 types of amino acids to work with, which allows for a ton of variety in chemistry of each individual part. Which in turn means proteins can do all sorts of things, because the different arrangement of parts let proteins fold in all sorts of ways and interact with their environment and each other in all sorts of ways. With so many different amino acids, you can make a ton of different proteins that do a ton of different things...including structural proteins.

To make an analogy, building with sugars is like if you have one kind of lego block, building with nucleic acid is like if you had 4 kinds, and building with protein is like having a 20 different widely varying lego pieces to work with. It's just more versatile.

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atomfullerene t1_j0ohaj8 wrote

Worth noting that the answer isn't quite as straightforward as simply replacing teeth with baleen, because we have fossils of whales that appear to have had both teeth and baleen

https://www.sciencedaily.com/releases/2021/05/210524091939.htm

Although other whale fossils that may be in the line seem to have had neither teeth nor baleen

https://evolution.berkeley.edu/evo-news/whales-lose-teeth-gain-baleen/

No surprise that something as weird as baleen is a bit mysterious

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atomfullerene t1_j07nflq wrote

Quite right. And ground sloths weren't really unusually large...they filled the same sort of large-mammal ecosystem niches that rhinos and elephants fill today. Really they were just standard-sized big mammals, the unusual part isn't that land mammals were large in the past, it's that large land mammals are so scarce in the modern world.

It's really only the giant insects that grew large due to high oxygen (and lack of competition from flying vertebrates)

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atomfullerene t1_j07lj2h wrote

To answer a part nobody else has answered yet, there aren't humans that can produce their own vitamin C. The mutation that disabled C production is millions of years old and shared not only by all humans, but all monkeys and apes. So there aren't any populations of humans hanging around that still have the ability.

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atomfullerene t1_izembsl wrote

Diseases are hugely important in the ocean, you just dont hear about it as much. Just to start off with, viruses are constantly infecting and destroying a significan fraction of planktonic algae. A disease very nearly wiped out sea urchins in the carribbean, another did the same to many starfish on the west coast. Canine distemper outbreaks have big effects on seals and sea lions where they occur. Seagrass wasting disease wiped out north atlantic seagrass ecosystems in the 30's. White spot syndrome had a huge effect on the shrimp industry in the 90s.

Theres a lot going on below the surface

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atomfullerene t1_iyamezc wrote

>Also isn’t it curious that humans are the only species to drink another species milk?

It's not that surprising. If you want to drink another species' milk, you have to be able to domesticate that animal. Sure, you get ants doing something vaguely similar with aphids, but when talking about mammals no other species has the capability to manage it, so they just don't have the option. At least, unless they have humans around to provide it for them. If you had a dozen intelligent mammals with civilizations similar to humans, I bet many of them would be milk drinkers. It's incredibly useful if you are a pastoralist, since it means you can get calories out of your cattle or goats without having to kill them. Useful enough that the descendants of most pastoralists still bear the genetic stamp of heavy selection in favor of milk drinking (aka, lactose tolerance into adulthood).

> And why not dog milk- or rat milk?

Obviously you are joking, but it's all about diet and volume. The whole point of dairy, from a premodern perspective, is turning grass into useful calories. Dogs don't produce a lot of milk and you can't graze them, while rats are far too small to produce usable volumes of milk.

That said, Simpsons did it

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atomfullerene t1_iy616rj wrote

It's really a case of birds, fish, reptiles, and various invertebrates vs mammals. Mammals are the odd ones out. The main reason is that bright colors are usually used for sexual selection or species identification. Most mammals lack full color vision and rely more heavily on scent and sound for sexual selection and species identification. So mammals lack a lot of the really bright coloration. Primates are the oddballs of the group that rely more on sight and less on smell.

Mammals do come in some pretty varied shapes though, not many equivalent groups contain species as diverse in body shape as bumblebee bats and blue whales. But in terms of decorative frilly bits, again, those are often about sight based signalling.

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atomfullerene t1_iy60q10 wrote

>It's also worth noting that fish in particular may be so widely varied because they're miscategorized; there's a push among some biologists to split up "fish" into several differently groups because there's so much more variation among "fish" than among equivalent groups.

While this is true, the splits would be jawless fish, sharks and rays, lungfish and kin, and everything else. So a huge chunk of the diversity of fish, and especially the colorful fish, is actually in one group of fish.

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atomfullerene t1_ixusr28 wrote

They are both formed by skin cells laying down protein in precise patterns. The dna comes from the living cells at the root of the hair. For feathers, i suspect it similarly comes from cells or the remains of cells at the root and/or pulp of the feather

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atomfullerene t1_ixtzgm4 wrote

Feathers are not alive, they are nonliving keratin structures, like hair. Because of this, they have to keep their color when not alive in order to continue to function...a bird with feathers that faded in color would rapidly fade in color itself. As a result of this, birds need to use stable pigments and structural colors to maintain their color during the ordinary course of living. And what works when the feather is still attached to the bird works just as well when it has come off, because to the feather itself, it's all the same.

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atomfullerene t1_iwqmid5 wrote

Epigenetics isn't really the inheritance of acquired characteristics, though. It's more the ability to alter what traits your offspring express in response to your environment. There's no requirement that those traits be the same as the ones you have. For example, you could imagine a situation where high food availability causes parents to lay down epigenetic markers that cause their offspring to also have a high tendency to gain weight. Or you could imagine a situation where high food availability causes parents to lay down epigenetic markers that cause their offspring to avoid gaining weight. Or a situation where high food availability cause parents to lay down epigenetic markers to suppress melanin production and produce lighter fur (although I have no idea why such a system would ever evolve). The point is, there's no necessary connection between the parent trait and the offspring trait. There can be a similarity, but there doesn't have to be. It just depends on what sort of adaptations the organism has.

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atomfullerene t1_iwnoyu1 wrote

First of all, what is a "bird hip" vs a "lizard hip"? It's a reference to whether the pubis bone points forward (as in lizard hips) or backwards (as in bird hips). Think of this as a general description of shape, like "square" vs "triangle"

Ancestrally, dinosaurs had lizard-like hips.

Early on dinosaurs split into two groups, "Bird hipped dinosaurs" and "lizard hipped dinosaurs". The "bird hipped dinosaurs" had birdlike hips, with the pubis pointing backwards. The "Lizard hipped dinosaurs" kept the original arrangement with the pubis bone pointing forward.

Later, a branch of the "lizard hipped dinosaurs" (the maniraptorians) independently transitioned from "lizard like hips" to "bird like hips". They were still in the "lizard hipped dinosaur" group because that is the ancestry they descended from. But they no longer had lizard like hips. One branch of this group went on to become birds.

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atomfullerene t1_iwm3z3r wrote

No, math like this explicitly cannot be copyrighted, at least in most countries (I don't know about every single one).

>what will happen IF something like the Pythagorean theorem is being copyrighted?

It would just be a huge mess and not really be enforcable, and if it was enforced would cause all sorts of problems, which is why math isn't copyrightable in the first place

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