SkepticLance

Blackhole. Your touching faith in scripture is not borne out by the facts. It is well recognised that the various bits of the bible were written by mere humans. While Christians believe these writing were 'under the inspiration of God', they still passed through imperfect human brains, which distort everything that passes. If you do not believe me, read the accounts of the death of Judas Iscariot in Matthew 27; verses 3 to 10, and compare to the description of the exact same event in Acts 1 chapter 1; verse 18 to 20. Judas dies by hanging himself, and also by falling over and dashing out his guts in the potters field. A direct contradiction. You cannot have it both ways. Why not just accept that scriptures were written by imperfect human and were thus, also imperfect?

Talk about complicated questions! There are ten million factors in determining how big we are. Some is sexual selection. The lady prefers a big guy as mate. The kids end up big. In equatorial Africa, some tribes grow tall and thin. High surface area to volume ration means good cooling through sweat. In high Arctic regions, some tribes grow short and wide. Small surface area to volume ratio means good heat conservation. Evolution works through all these factors and more, to end up with a compromise average size.

This question is extraordinarily badly worded. The examiner should have his/her arse kicked very solidly. If the question is taken as worded, then yes. it is density dependent.

Taking the question at face value, my interpretation is : Higher larval density means longer time to pupation. Since mortality is constant (numbers of deaths per day), a longer time to pupation must been a higher percentage of larvae die before pupation.

A nice dating system is the decay of Potassium 40 to Argon 40. This is nice since Potassium is solid and Argon is a gas. This means that when rock turns liquid, all the Argon bubbles out. It is like resetting a clock. Thus, if we want to date a rock stratum, we look for rock that was once liquid - volcanic - magma or lava. At the time it was hot and liquid, all the Argon disappeared. This means that when we analyse the rock today, the Argon 40 in it is all from the decay of Potassium 40. By measuring the ratio between remaining Potassium 40 and Argon 40 we get a date, to when the rock was liquid. This method is good for many hundreds of millions of years.

The human ancestral line split off from the ancestral line leading to our closest cousins (chimps and bonobos) about 6 million years ago. It has been estimated that the average lifetime of a species is one million years. After, either the species has evolved into one or more new species, or has gone extinct. In fact, it is estimated from the fossil record that over 99% of all species that have ever lived are now extinct. Add to the 6 million years, with an extinction or change every million, and you will see that the line leading to humans has a lot of intermediate species - not truly ape, but not truly human.

j_p I think you may have missed my point. Humans moved into all continents without evolving. We are adaptable precisely because we do not need to evolve in the biological sense to adapt to an environmental change. Changes in culture and technology serve us in a way that is far superior than simple biological changes. It is much quicker for a start.

Webgecko. Scientists are already hard at work devising ways to use viruses. Gene therapy usually uses viruses as vectors to carry genes. Not a good technology yet, but wait for Mark II! Scientists in Georgia (the Georgia that used to be part of the USSR) are working on bacteriophages (viruses that attack bacteria) in the hopes of using them as antibiotic substitutes. etc.

Webgecko said : Why couldn't this agent actually be an immune agent ? Which brings me to another question. Are virusses at all like lymphocytes ? Lymphocytes are immune agents. Virusses can infect and destroy other organisms which have at least one (or more ) cell wall. So they could make good immune agents for some organisms. A virus is not an immune agent. The general life cycle of a wide range of viruses is known. Their actions are that of infecting agents, not immune agents. Are they like lymphocytes? No. Lymphocytes are complex cells with nuclei. A virus is entirely orders of magnitude smaller and simpler.

Quote from New Scientist 6 May 2006 page 14. "HIV had been living quite happily in chimps without making them ill, but when it crossed the species barrier to humans ...." "...most scientists believe happened when blood from butchered chimps got into the human bloodstream." Not a very good quote, I know. I have seen a more definitive one recently, but I cannot seem to locate it right now.

daneeka. How harsh my comments are seen to be will depend on what we are talking about. This thread began discussing reincarnation. If the question is : Is it true? Then I have to say, speaking as someone who thinks scientifically and looks for proper empirical evidence all the time, it is a load of horse manure. Obviously if your interest is something to give you emotional satisfaction, such as art, culture, literature, romance, or even religion, then that is fine. You will not advance the course of human knowledge through those routes, but you should gain that emotional satisfaction, and good luck to you.

To The V. Am I to assume that you consider yourself to be non scientific? My view is based on history, and says that non scientific modes of thought are useless, because they have achieved nothing. There is traditional wisdom, which lead to ultra slow progress by trial and error, and there is science that leads to massively rapid progress, since it is right! And there is all the rest, which basically amounts to a load of horse manure.

HIV has now been found in chimpanzees. It is almost certain that it jumped into the human population when someone killed a chimp for food, and got some chimp blood in contact with an open wound. The origin of viruses is still an open question. The most frequent theory is that it was a more complex life form that evolved into a parasitic life style and devolved - losing unnecessary characteristics. This may, or may not be correct.

If you want to totally alarm the neighbours (especially in this era of Sept 11 paranoia), here is something you can do. 1. Make a fuse. Take old fashioned cotton thread and soak in Potassium nitrate solution. Dry it. When you light the end, it will fizz beautifully. Try this and get the feel of the speed. 2. Fill a balloon with hydrogen gas. This is easy. Mix some caustic soda with water, say one part to 20. Let it cool and put it in a glass bottle. Add some aluminium (say, kitchen foil). Fit the balloon mouth over the mouth of the bottle. The aluminium will slowly dissolve in the solution releasing hydrogen gas, which will blow up the balloon. You may have to try it a couple of times to get it right. 3. Fit the balloon with the cotton fuse, and tie it off. Wait till night, and release the balloon with LOTS of fuse trailing. Light the fuse and let the balloon go. It will drift through the night sky and go off with a real bang.

bascule. Whether the universe is finite depends on your definition of 'the universe'. If current ideas are correct (Big Bang followed by expansion) then the universe is indeed finite. On the other hand, some physicists accept the possibility that our piece of reality may be just one of many in a 'multiverse'. if so, then we are in speculation-land about finite vs infinite.

Agrobacterium as a vector for transferring genes may work. But you should not underestimate the complexity of the task. you would need the target plant in tissue culture times about 10,000. Each and every one of that 10,000 has to be tested to see if the gene has been transferred.

Actually, H2SO4, the fact that the universe's expansion is accelerating makes contraction unlikely. Still, who the hell knows for sure.

j_p I seriously doubt the vulnerability of the human species. If anything is vulnerable, it is currently endangered (non-human) plants and animals. Humans are, in my opinion, the most adaptable mammals. We are the only species, to my knowledge, that has colonised, unassisted, every continent without changing into a range of different new species to permit adaptation. Our cultural and technological flexibility is such that we can adapt in those ways to environmental change.

Both questions, as the two earlier postings say, are enormously variable in possible answers. Generally though, without caloric input, death will come in about 25 to 60 days. Without water or similar fluidic input, death will take 2 to 5 days.

Since the universe, no matter how big it gets from expansion, will always be finite, and since energy cannot be destroyed, there will always be some energy. However, the energy density will inevitably drop till it is too low to support life, of any kind. There was an article in Scientific American about this a few years back. The authors concluded that it would take about a trillion years to get to this point.

Sorry to disappoint you. This has been followed by New Scientist magazine, and the latest shows it to be of definite terrestrial origin. Something picked by meteorological phenomena and re-deposited. The spread was over too small an area to be remotely possibly of extra-terrestrial origin.

bascule. As you know, you and I do not always agree on global warming issues, since I am a skeptic and you tend to agree with the 'humans are causing catastrophic warming' hypothesis. However, I commend you on your posting. I think you are one whose feet are pretty much on the ground, and you see through a lot of the nonsense. Your points 1 and 2 are correct. Your point 3 is, as you say, speculation. To predict catastrophic loss of life is premature at the least. Point 4 is also unproven. This is not the first time in history that there have been more than the normal lot of serious hurricances. Point 5 - past the tipping point. Well, how the hell can anyone say that? The tipping point itself is a purely speculative construct. The world has warmed and cooled more times than I can count. It always rebalances. I am pleased that you have expressed the facts accurately, even if your interpretive bias is a little different to the way I interpret these facts.

Silkworm. Ethics are a wonderfully malleable construct. In the 1960's, the idea of human artificial insemination was seen as quite unethical. 40 years later ....... In the same way, any ethical standard you currently construct will be a quaint thing of the past in 50 years.

I seriously doubt you can do this at home! GM is a sophisticated process. Incidentally, the main gene for glowing organisms is not taken from fireflies, but from a jellyfish.

Psycho. You are undoubtedly correct. However, I am not sure it matters. If regulations exist to prevent any harmful modifications, does it matter whether babies are born brown or blonde?