Easy Questions?

[Pachyderm]

They do. They also have a whole raft of other problems to deal with, and it's usually one of them that does them in, predation, starvation, getting smacked with a big stick for looking unappealing, that sort of thing. Rats, those most excellent of opportunists, will only nibble a new and unknown foodstuff, then, if there are no unfortunate side effects, take a bigger bite etc. They do the same with water, just drink a little. then a bit more.

[Aggie]

The long-term exposure get 'em too...  long-livved beasties bioaccumulate all sorts of nasties and probably get cancer as much as similarly-exposed humans do. Actually, we may be more resistant to certain toxins (benzo(a)pyrene and other PAHs ) due to our long-standing association with fire.

[Sibling Zono (anon1mat0)]

In that sense long term nasties are possibly worse for smart long lived creatures as matriarchs and patriarchs that otherwise would lived long to teach their clan what to and what not to do die earlier than they would have otherwise.

But the great majority of creatures die well before that. An informal way to tell the average in the wild for any species is to take the age at which they can procreate successfully plus the time for the infant to learn how to survive on his/her own; a simpler way is to multiply the age at which they usually reproduce by two. In our case that number is between 22 and 30 which is what our ancestors used to live*. Everything outside are the nice exceptions that confirm the rule.

*or when our warranty expires

[Aggie]

Ayuh, the main reason you don't see sick animals in the wild is because they already died.

[Griffin NoName]

Do wild animals instinctively drink upstream from where the crocodiles shit?

[Aggie]

There is no upstream from where the crocodiles shit, unless you are upstream of all crocodiles!

I've heard rumours to the effect that many European cities are required to place their sewage-treatment outfall pipes upstream of their drinking water intake pipes, to ensure that adequate treatment is being conducted (because there is always someone else downstream). Is this true?

[Griffin NoName]

I've heard rumours to the effect that many European cities are required to place their sewage-treatment outfall pipes upstream of their drinking water intake pipes, to ensure that adequate treatment is being conducted (because there is always someone else downstream). Is this true?

You mean they'd rather the citizens died than have their quality assurance suffer?

[Aggie]

No, more that they'd rather drink their own sh*t than their upstream neighbours (assumes everyone on the river follows same policy).  Better the dookie you know...

[Griffin NoName]

Just watched a documentary on research dealing with issues of cousin marriages in Pakistani communities - health related - high risk of children with (quite dreadful) disabilities/diseases.

Then watched a program on Gorillas in the wild.

Made me wonder if animals know not to mate with their cousins? Or are there huge numbers of offspring that die from genetic malfunctions? Is there a difference in way congenital disease is passed on for humans and animals? If not, which one would assume, then how do endangered species ever produce healthy offspring? It's all very puzzling.

will this worry keep me awake tonight? Should not watch TV at bedtimes

[Sibling Zono (anon1mat0)]

I imagine there is a link between a higher mortality rate and a smaller genetic pool, although what makes our 'experiment' different from other animals is that we allow children with defects to survive and in many cases to procreate, plus the fact that we outlive our expiration date and keep procreating after that (as a rule of thumb humans rarely lived beyond 30 as hunters-gatherers). If the genetic disorder manifest itself after that age it doesn't preclude procreation.

Also is worth considering that genetic disorders usually show up in small portions of the population (significantly smaller than 1%) and that our large numbers (plus the media) amplify that signal. In wild species the only thing that matters is that procreation is capable of replacing the current population and frequently many young compensate for those who will die in the process before they're able to procreate.

[Aggie]

I've been taught of studies (in Japanese quail, IIRC) that indicate animals tend to find their cousins most attractive as mates, since they are not as genetically similar as siblings, but do tend to be adapted to the local environment.  Mating too far outside your genetic heritage leads to maladaption, for animals.  The risk of genetic disorders might be worth the adaptive advantage, and populations with too many genes for said disorders might quietly weed themselves off over time.  Some disorders are also potentially adaptive, if one gets only one copy of a recessive gene, such as sickle-cell anaemia.

Humans have escaped the need to be perfectly camouflaged/temperature-adapted/right-beak-for-food-type and the rest of the smallish details that can be critical to animal competitiveness, so it's probably less of a concern, and therefore taboos against marrying cousins are far from universal (legal in Canada, iirc).

I think Zono's on to something as well - recessive genetic disorders (the types that show up in inbred populations) only manifest in a small portion of the population, and while lack of genetic diversity leads to lots of carriers of a single recessive gene for these disorders, in the past (i.e. before modern medicine) child mortality from genetic disorders was probably a small thing beside child mortality from pathogen-based disease, and therefore not a strong enough factor to bring about widespread taboos.

[Swatopluk]

Many species have systems in place that encouruage out-breeding, e.g. young males are driven from the group by the older, dominant ones and have to find a mate outside the group.
It also partially depnds on the healthiness of the original pool. A historical example would be Jews in Central Europe. During the ghetto period there was inevitably a lot of inbreeding but since the 'stock' was good to start with, the negative effects were comparatively low. In a way inbreeding can keep out defects that are not part of the original pool. The Romans in classical time had a highly organized but simple system that prevented too much inbreeding. the ruling families/clans formed a cycle. Males of one family married females of the family next in line. For the females the direction was the other way around.

[Griffin NoName]

A historical example would be Jews in Central Europe. During the ghetto period there was inevitably a lot of inbreeding but since the 'stock' was good to start with, the negative effects were comparatively low. In a way inbreeding can keep out defects that are not part of the original pool.

Actually Jews do marry cousins quite a lot, not just in restricted gettos. There's quite a few cases in my ancestors.

(one of my mother's distant cousins was married to a distant cousin of my father, so I am related to myself by marriage, but I think that doesn't count )

[Swatopluk]

I guess this was just upkeeping of tradition. In the 19th century it was also heavily discouraged from both sides for Jews to marry outside the 'race'. The non-Jews feared the pollution of their precious bodily fluids and the Jews the slow loss of identity. In Israel today the racism seems to be more on the Jewish side. Some right wing organisations have been founded with the main purpose to destroy relationships between Jews (esp. females) and non-Jews (esp. Palestinian males, religion secondary).

[Swatopluk]

Here is a math question that defeats me.
The random number generator available in your standard programming language software produces a uniform distribution (usually in [0;1]).
I need a formula how to turn this distribution into a normal distribution with a preset standard deviation.
Or better a normal distribution that contains as it main variable the probability of an event to fall within a given distance from the center.
E.g. p = 10%  d = 5 m => formula with a random input [0;1] yields a distribution where 10% of hits fall within 5 m of the target and the rest fall according to the bell curve.