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Go to: Disappearing species

arstood's Avatar Jump to comment 5 by arstood

To prevent the short term effects of inbreeding, like amplification of deleterious recessive alleles, a genetically effective population size of about 50 is needed. To prevent the long term loss of genetic diversity due to drift, a population of about 500 is needed. Genetic diversity allows for rapid evolution as response to a changing environment, and loss of this diversity makes the species unable to adapt quickly. Most mutations are deleterious, and the rare beneficial mutation is not very likely to become fixed in the population simply due to the effects of drift, so relying on mutation, rather than diversity, to increase the ability to adapt is not practical. With random mating, the 34 individuals (which still probably have a genetically effective population size of about 100 or so) would probably become extremely inbred very quickly, but with careful manipulation of mating behavior by humans, it may be possible to keep the genetic diversity at a reasonable level. (genetically effective population size refers to the minimum size of a population that is needed to maintain the same level of diversity. When a population is in rapid decline, the effective population remains higher than the actual population, and when a population rapidly increases, the effective size remains very low.)

Mon, 10 Oct 2011 03:42:50 UTC | #879298

Go to: Biodiversity - who needs it?

arstood's Avatar Jump to comment 35 by arstood

Why save species? I read somewhere that over half of our pharmaceutical products were derived from naturally occurring substances, and even if they weren't, they were probably at least inspired by them. If we didn't have nearly as much biodiversity, we wouldn't be able to know what is possible. “Turritopsis nutricula, the potentially immortal jellyfish, is a hydrozoan whose medusa, or jellyfish, form can revert to the polyp stage after becoming sexually mature. It is the only known case of a metazoan capable of reverting completely to a sexually immature, colonial stage after having reached sexual maturity as a solitary stage.” Also, I heard that some chemicals in the skin of some red eye treefrogs has the potential to kill the aids virus. If either of these species had died off, we would never even think these effects were possible, but now that we know, we can try to copy them, to our benefit. This goes for countless thousands of species, many of which have not been described yet, let alone studied. Think of species as “the answers in the back of the book” that we can use to solve the problems that face us. Also, besides medical applications, think of velcro, “gecko tape,” those new, more efficient windmill blades modeled after humpback whale fins, and thousands of other nature-inspired inventions. Species also offer us a unique opportunity to study how we got here and why we are the way we are. If we are interested in why we are monogamous, we can look at other species that are and look for similar selective pressures across many taxa. If there are pressures that monogamous reptiles, mammals, and even insects share, then we can say with near certainty that our ancestors probably evolved under the same pressures. If those species were gone, we might never know. Also, having many closely related species around allows us to view the results of a naturally occurring experiment. Take fruit flies. If we only had one species, they wouldn't be a very good model organism. But since we have thousands, nearly every possible mutation of any gene can probably be found already existing somewhere in nature, so we can discover the effects without having to run an experiment ourselves. Again, we find that biodiversity is the “answer key”

As for the giant panda, that particular species is very specialized, and there is no other species like it, so who knows what insights we can gain about selective pressures from it. It's an experiment where the knobs have been tweaked in unique and novel ways, so it would be a tragedy to lose it before we even come up with some good hypothesis to test on it. Same goes for the platypus, elephants, whales, and most other large mammals. To a lesser extent, to all species. Each one represents a uniquely evolved, uniquely specialized organism, the result of thousands or millions of years of living in a certain niche. Each one is a data point. The more data points gathered, the more sure you can be of any conclusions derived from them. Imagine how much more we would know about human psychology if neanderthals were still around. Right now, we only have a single data point for sentient species. Now imagine if we were to lose the great apes, our closest relatives, and how much less we would know about ourselves.

This is only what we've discovered so far, and it's just scratching the surface. All of these are just SOME of the “selfish” reasons of why we should save species, off the top of my head, they don't even address the aesthetic or ethical issues.

As for the idea of humans going extinct due to ecosystem collapse, that sounds like rubbish. Humans are way too adaptable. We can survive in ice fields and deserts and even temporarily on the moon. Any amount of ecosystem collapse doesn't threaten the human species one bit. Maybe it would lower the population a bit, but our species would survive.

Sun, 19 Dec 2010 02:03:12 UTC | #565365

Go to: Our world as a simulated reality...

arstood's Avatar Jump to comment 18 by arstood

If we ever are able to simulate/create a universe that is a mirror of our own,I presume that it would take less than all the matter in the universe to do so. We could probably just program a few simple initial conditions in a kilogram or so of "computronium (a theoretical arrangement of matter that is the most optimal possible form of computing device for that amount of matter.)" and then hit the start button. If it were a true simulation of our universe, that would mean that any intelligent beings that eventually evolve in it would then be able to do the same thing, with one of their countless kilograms of simulated computronium. Does this imply that there is no limit to the computational power of reality? If not, does it mean that we would never truly be able to simulate our universe?

Mon, 13 Dec 2010 07:23:05 UTC | #562374

Go to: Some thoughts on the origin of religion

arstood's Avatar Jump to comment 25 by arstood

Our brains suck at logic and percentages. They evolved to to be "good enough," not perfect. I recently researched "sex selection" techniques for parents who want their baby to be a certain gender and was surprised to find how popular some of them were. It makes sense though if you realize that ANY technique has about a 50% chance of success, so fully half of the people that try it for the first time will come to view it as a successful technique and tell all their friends that it worked. Similarly, if you put a random assemblage of herbs together and tell your friend to take them to get better, and then your friend actually does get better(which would have happened anyway), there's another "convert" to superstition. If your tribe is experiencing a drought, you could sacrifice a goat to the rain gods to end it, and it would work 100% of the time, though sometimes it just might take a while. If any of these superstitions fail, the proponents can always claim that "it just didn't work THIS time, for some reason or another," but then when they happen to work, they claim full responsibility. This system (confirmation bias) worked "good enough," in that it got our species to civilization. Our brains are still wired for it. When we try to reason, to think logically and numerically, Our brains are like fish out of water, gasping for air and flopping around. We're not very good at it yet, and it takes a lot of training and re-wiring our brain from it's default state to be even moderately good at science. It's not just religion that results from our "default state" of superstition, but all the pseudosciences, homeopathy, belief in ghosts, astrology, santa claus, etc.

Mon, 29 Nov 2010 20:11:58 UTC | #555519

Go to: How best to promote atheism/naturalism/secularism

arstood's Avatar Jump to comment 10 by arstood

I recently got my first "conversion" of a theist. It's really satisfying to know that there is one more person whose worldview is now shaped by rationality.

I was able to do it over the course of about a week, discussing various topics for 3 or 4 hours each day. At some times I was frank and brutal, but I was also openly willing to admit it when he made a good point. I also tried to at all times maintain the "home field advantage" by insisting that before we debate the implications of god's existence, first lets establish that a god likely exists. I used the santa claus and tooth fairy analogies a lot. I think the main thing that worked was genuine honesty. I was careful to address every one of his points in depth. After our discussions, he didn't talk to me for a few weeks, but later he thanked me for opening his eyes.

I think the best way to promote our worldview is to be persistent in planting the seed of doubt, to be extremely honest, and to show them that an Atheist can be a moral, loving, compassionate being even without the fear of hell or of punishment in an afterlife.

There is room for both the "confrontationalist" and "accomodationist" strategies, depending upon your own personality and that of your adversary. . I tend to be more of a confrontationalist, but sometimes I find myself in the other camp. The November 24 Skeptics guide has a great segment on this very topic, starting at about 42 minutes in. I highly recommend listening to it.

Mon, 29 Nov 2010 08:14:27 UTC | #555176

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