Sometimes it is. Parthenogenesis isn't always forming a perfect copy of the parent, but can also involve eggs fusing back together or duplication of the chromosomes during various stages of meiosis. Depending upon which stage this happens at, it can be equivalent to selfing, or equivalent to clonal reproduction (sort of).

Generally no, but sometimes yes.

We actually know of a fairly high number animals and plants with fully duplicated genomes (tetraploidy), and most are nearly identical to their diploid ancestors. One big difference in cell size, which seems to increase with whole genome duplicates. This has few consequences, but oddly enough it affects the call frequency in tree frogs, and fruit size (and overall size) in plants. The latter has lead to deliberate selection for and creation of whole genome duplicates in crop plants, often repeatedly- strawberries are octoploid.

However, such duplications can provide "raw material" for evolution. Now you have 4 copies of a gene to work with, so you can keep the original set and let the new copies evolve. Gene duplication is more common than many people think and an important part of evolution. Whole genome duplication is less common, but has occured several times, most notably at the origin of vertebrates and the origin of teleost fishes.

The link is broken. But that rationale sounds weak - why would a separate nerve improve either response time or control? Is there actual evidence that the lateral rectus response faster or with greater precision than the rest of the oculomotor nerves, either in humans or other species?

Short answer: we don't know.

Longer answer: the layout of the cranial nerves only makes any kind of sense once you realize all vertebrates are just modified fish. It seems like the cranial nerves used to just be like the spinal nerves, with a dorsal and ventral branch, with the ventral branch mostly innervating the gill arches. This is still the case, with 5, 7, 9, and 10 innervating structures derived from the first, second, third, and posterior gill arches, and their dorsal partners spreading elsewhere.

The problem is that we know the locations of the nerves and their targets can and do shift over evolutionary time, and many of the species which could help us resolve which is connected to what and how and why they've shifted are either highly modified due to diverging from us 500+ million years ago (e.g. lampreys, hagfish) or just plain extinct and rarely fossilized with enough skull detail to help (e.g. ostracoderms, conodonts, acanthodians).

There's an exceptionally detailed look here: https://academic.oup.com/book/37442/chapter/331583157

"Autopsy notes: subject showed signs of nasal congestion, hives, disemboweling, and itchy eyes."

One part of it comes from recent fossils. Some older species are actually present in the fossil record, and in sufficient numbers that we can compare size distribution. We have Nile croc fossils from >5 million years ago (exact same species), and more recent fossils of other taxa, and all seem to be around the same size.

Another is from complete fossils, like those magnificent Archaeopteryx fossils. If they shrunk after burial, either the bones would separate from each other as each bone shrank, or some unknown force would have to pull them all together as they shrank in a strikingly uniform way, despite the tremendous pressure from the surrounding dirt/rock holding them in place.

The fundamental understanding is hard to find, but simple: our metabolism is broken, badly, as a baseline, and we make it worse to have a fever.

It doesn't cost anything near what we pay to run a body of our size. We know this because everything with "cold blood" does so for literally 10% of the cost (normalized for body weight and temperature).

Where do the other 90% of our baseline calories go? Heat. Specifically, we poke holes in the membranes of our mitochondria (via uncoupling proteins) to make them less efficient. This means we burn more energy to get the same ATP (cellular energy molecule), the rest of which is heat. This, in turn, heats our body and lets us be "warm blooded", at tremendous metabolic cost. To get warmer, we simply increase the number of these proteins. There's also diet drugs that do this, but they're incredibly dangerous because you can't plug the holes once they're made, you just have to wait for the proteins to break down.

Incidentally "cold blooded" species can get fevers too - pyrogens prompt them to bask more and get to hotter temperatures, a sort of "behavioral fever".

For pendants, note the quotes around "warm blooded" and "cold blooded".

>The size doesn’t matter. Birds evolved much better vision than humans but their eyes much smaller in many cases

Incorrect. A larger eye will simply have more photoreceptors per degree of optic field, allowing a higher-resolution image, all other things being equal. If you are small (e.g. most birds), you can compensate by packing them more tightly, but this comes at an energy cost (photoreceptors are expensive).

>Note that people genuinely at high risk - veterinarians, mainly - do in fact get vaccinated, because that changes the risk calculation.

I know a lot of bat biologists, and all of them get vaccinated for rabies. "Let's deliberately catch the most common vector for this disease" is a pretty big shift in risk, after all.

Incorrect. The term "respiration" is used for both; they're simply different enough that nobody gets confused when talking about cells vs multicellular animals exchanging gasses.

This is correct. Plus, it's possible to mineralize exoskeletons as well. Crustaceans do this for most larger species, but some insects can as well.

Somewhat related, my university has motion-activated light switches so the lights turn out if someone stops moving. Except in the labs and lab-animal housing, because apparently the motion sensor uses ultrasounds that's within the hearing range of mice, and they get stressed out by it.

Some of it is probably just natural variation - slight differences of 1% that are utterly inconsequential to most of us become tremendously important when enduring very high loads, especially repeatedly. My ACL could be 1% weaker than usual and I'd never know, because I don't do anything to puts extreme loads on it the way tackle football does. But if I was a pro athlete getting tackled constantly in practice and games, that tiny difference might be what ends my career.

Another possibility is steroids. Steroids increase your muscle size and force very fast, but tendons and ligaments take much longer to accommodate those forces because they have very few cells (they're mostly just collagen molecules), so can't remodel easily (they also take much longer to heal from injury for the same reason). Consequently, steroid use is a risk factor for many tendon and ligament injuries. But of course, they're never going to say "well, Smith got injured a lot this season because he's juicing", so he's just "injury prone".

Not so far as I know. Collagen isn't so much adhesive as it's physically linking things together, like a billion tiny, molecular ropes. Collagen is also present in bones and dentin in teeth, so it's basically tying on to the "rope ends" on each surface.

Without going into too much detail, the odds of something bad go down exponentially, specifically with 1/2 for every extra link in the family tree away from a shared ancestor. 1/8, 1/16, and 1/32 odds per gene (3,4, & 5 links, respectively) are pretty bad across >20,000 genes, but it doesn't take a lot of distance (14 links) before your risk drops to 1/16384, at which point it's basically trivial. By the time you're 3rd or 4th cousins, you're basically genetically unrelated.

Collagenous connective tissue. Basically, each tooth's roots sit in corresponding sockets, and there a thin but very strong layer of fibrous connective tissue connecting the tooth root to the surrounding bone.

This is why teeth can sometimes, but not always, fall out of long-dead skulls. Collagen is really tough stuff, and pretty decay resistant once it dries up, so if the skull is dry, the dried tissue keeps the teeth in. But if the collagen rots, gets wet, or is eaten by something, the teeth just fall out. Bone collecting subreddits are full of laments by people who put a skull in water and Dawn to degrease and all the teeth fell out.

Laplace's Law - the greater the radius of a cylinder, the greater the wall stress. More formally, stress = Pressure × radius / thickness as long as thickness is less than 10% of radius.

To generate a very high force, you would need very high pressure and radius, which in turn means you either need very thick walls or very strong material to prevent failure. Neither is impossible but both are expensive.