SkepticLance

The reason I suggested accident might be a factor was not really as a serious suggestion - just pointing out that we do not know, and do not have the data that might permit us to know. We simply do not have any idea why the dinosaurs died out while leaving so many other animal groups to survive, and later evolve by adaptive radiation into so many successful species. Though the chance factor is unlikely, with our level of ignorance, why should we reject it? Another possible, but unlikely factor might be geography. Perhaps a small part of the world managed to get 'hit' a lot less than the rest by the after effects of the asteroid impact, and that part was made up only of islands that had life, but no dinosaurs. Hey, it is unlikely, but all we got is wild speculation.

If Mars has caves, they might be able to be modified into habitats. If not, we could dig trenches, and roof them over with air tight structures, plus thick foam for thermal insulation, and then spray liquid water on top. It would set as ice immediately. A sufficient thickness would be enough for radiation protection. There is some evidence that Mars may have sufficient water.

It's a bit hard to know what Flynn was actually talking about with his concept of making women infertile early, and reversing the infertility only when a baby is wanted. This is because such a technology does not yet exist. Until it does, anything we say is hypothetical. I think he envisaged something like the pill, taken only in a single treatment, and reversed by another pill. However, the final solution, if we ever get one, could be surgical, immunological, or otherwise. I do not think anything based on coertion would be acceptable in our society. However, if a treatment rendered young women infertile at, say, 13 years of age, and was reversed on demand, it would still have the desired effect. I would guess that, even with this treatment, women of lower soceo-economic class would still have more babies, but the difference would be less.

Obviously I cannot draw firm scientific conclusions on the basis of something seen on TV. However, I think the point is made. Australopithecus was one metre tall, had inoffensive teeth, and a relatively fragile body. To suggest that a tribe of them could fend off attack by big cats (and Smilodon was very big) without some form of weapon is not really very likely. There is no direct way of knowing what weapons they would use, short of finding them with fossils. If they were of wood, or of unmodified stone, bone or antler, we would not get a clue in the fossil record. Personally, I think the idea of a wooden branch with a sharp point is the most likely, since a whole lot of them wielded by the able bodied members of the tribe would have the most effect, but I could be wrong. The descendents of Australopithecus are possibly Homo erectus and its relatives, and there is some evidence to suggest they were the first to make shaped stone tools. I do not think it is too big a leap of the imagination to suggest the Australopithecines might have made good use of tools of a different, and less sophisticated type.

Sayonara said : The sources I have read state that the bulk of the damage done by the solar radiation takes place in the upper atmosphere, and that explorers on the surface would be exposed to high levels of radiation only during solar eruptions (from several a day to perhaps one a week). If you have different data it would be helpful if I could see it. It has been a while since I read up on this. There was a Scientific American article on the effects of radiation on the health of astronauts etc. I recall that the radiation was dangerously high even on a day to day basis, though there are times when it is much worse. As I understand it, though, it makes no difference whether the radiation hits over a period of time, or only when a solar storm is in progress. If a person is exposed for a long period - say a couple of years - then they can expect to die of cancer while still young. If the exposure is only for a couple of months, they have an increased lifetime risk of cancer, but not a sure death sentence. Certainly, if we are talking about a permanent Mars colony, that means radiation protection is essential. And the best way is to go underground. A dome would need a layer of something like ice or cement perhaps ten metres thick to screen out most of the radiation.

To the Cap'n. This is not my field of expertise, but my general reading would suggest that intelligence, and hence IQ, are probably a blend of genetics and learning.

I doubt that the essential difference, permitting birds and mammals to survive, was as simple as size. What we often forget is that there were a lot of small dinosaurs. It may be that there were a lot more species of small dinosaurs than big. Many were chicken size or smaller. New species appear to paleontologists searching for fossils every year. All of the arguments about the advantages of small size apply equally to small dinosaurs - yet they all died out. It cannot be warm vs cold blood since lots of fully cold blooded reptiles survived. It cannot be insulation, since lots of dinosaurs had feathers. It cannot be ability to swim or fly, since lots of dinosaurs could do one or the other. For all we know, it could be purest accident that led to enough birds, mammals, lizards, crocodiles etc surviving long enough to breed, while dinaosaurs did not.

An interesting item in our local newspaper. Dr. Jim Flynn is emeritus professor at Otago University, and an expert on the interaction of class, race and IQ. While he argues vigorously that race is not a determinant of IQ, he says that class can be. He feels that, in a society that is socially mobile (meaning anyone with ability can rise into higher socio-economic levels), those of lower IQ remain in the 'lower' classes, while those of high IQ rise into higher socio-economic classes. He notes that women in the lower classes produce more babies than those in higher. The following figues relate to New Zealand, but are probably similar for other western countries. Women with Ph.D.s have, on average 1.4 babies. Women with basic tertiary degress have, on average, 1.85 babies Women with no higher education have, on average, 2.57 babies. Jim Flynn says that, at age 73, he is too old to worry about offending anyone. He claims that, on current performance, the children of New Zealand will get measurably dumber over 3 to 4 generations. He points out that the babies of educated women are generally wanted, while those of women with no higher education are often accidents. He suggests that the solution is to develop a new form of contraception - one in which all women are essentially rendered infertile, but can take a treatment to become fertile. Thus, all babies will be wanted. He also says that this system would result in a smaller proportion of new babies being to lower IQ parents, and result in the average IQ over the next few generations remaining reasonably high. Flynn was asked if this was a form of eugenics. He says no, and points out that the current situation is a form of negative eugenics. I would be interested in other people's opinions.

CDarwin said : Uhm... if being in large groups doesn't help with predation unless you're wielding pikes, why do herders do it? Or monkeys? Or chimpanzees? I saw on a TV documentary the reaction of a tribe of baboons to a single leopard. In spite of having lethal canine teeth, the baboons turned and ran. Australopithecus was much more poorly equipped with natural weaponry than baboons, and had to face much more lethal predators than leopards. There is no way they could have survived by making loud noises and throwing stones.

Sayonara said : Why are you obsessed with settlers living underground on Mars? It's not "almost certain" at all, it's unnecessary and economically stupid and therefore remarkably unlikely. Currently, due to the very thin atmosphere, and , compared to Earth, minimal magnetic field, there is a high radiation flux reaching the surface of Mars. Settlers will need to be protected from this, and will only be able to stand a certain amount of time on the surface. The easiest form of protection is to build dwellings underground. A few metres of rock above our heads would be enough to cut the radiation to acceptable levels.

There is no need to increase the gravity on Mars, even if we had such a method. Mars is fully capable of holding a much denser atmosphere, even with its current small gravity. It will not hold it forever, of course, but the 'short' period it can hold an Earth density atmosphere is measured in many millions of years - quite enough for humans to live there. The problem is to get the atmospheric gases to Mars. The easiest way would be to tap material already on Mars. We cannot really know how practical this would be unless we go there to carry out a proper inspection. If the right materials are present, we could produce the atmospheric gases in situ. Some people have suggested that we might set up 'space tugs' and tow ice satellites, probably from orbit around Jupiter or Saturn, and crash them into Mars. This would add heat to Mars, vaporise some of the ice to add atmosphere, and add liquid water to Mars. Obviously all this crashing would have to be done before people settled there. This consideration alone makes it unlikely. Moving material from Earth to Mars in large quantities will almost certainly remain impractical. The costs, both financial and environmental, are simply too great. There is also no need. There is plenty of CO2 on Mars. There is probably plenty of water also. We will need to sequester CO2 right here on Earth to reduce the excess in the air. Various suggestions have been made for how to warm Mars, ranging from adding lots of greenhouse gases to its atmosphere, to putting giant mirrors into orbit, to reflect extra heat down. I doubt if anyone really has a solution to this problem, but one may develop in the future. However, all this is for the reasonably distant future. If humans get to live on Mars, the first 50 odd generations will almost certainly live in domes or underground habitats, sealed off from contact with the cold and toxic air of Mars.

Do you remember the 'Walking with Cavemen' television series? They had this ridiculous bit about Australopithecus afarensis. The one metre high upright ape apparently lived in the African plains. As such, it would be prone to predation by big cats. The TV series said that it resisted this predation through social grouping. Togetherness to drive off the sabre tooth giant cats. Yeah right! I immediately visualised a bunch of, say 100 Australopithecus being stalked by a Smilodon. The big cat would simply walk up to the bunch - grab an individual - and return again every time it was hungry. Within a few months the apes would be gone. However, if we alter the picture a wee bit, everything changes. Imagine that our ancestors instead are carrying long wooden branches, with points on the end. Smilodon walks up and is confronted by a porcupine of sharp spears. The Australopithecus wielding these spears stab viciously at the cat, and drive it off. Survival through the use of tools and weapons.

lucaspa said : Also consider: the elephant is already in a warm climate! What happens if you plunk that elephant down in a blizzard? The large area + no insulation means freezing to death. Not a good example, since modern elephants are adapted to living in the tropics. That's why they got big ears! However, we have the example of the woolly mammoth, adapted to very cold conditions. Even more dramatic, though, are mammals adapted to living in the sea. Heat loss, for a specific thermal gradient, is about 30 times as rapid for an animal immersed in water compared to one in air. Thus, animals in cold Arctic or Antarctic waters need to have a means of conserving heat. While this can be achieved by fur or feathers that retain a film of air underwater, or a thick layer of blubber, the best method of conserving heat in frigid aquatic environments is simply size. Seals and penguins often have to get out of the water to warm up. Very large marine mammals (whales and sea elephants) can stay in water at minus 2 Celsius for months or years at a time. When they move into warmer waters, their big problem is over-heating. Humpback whales have enormous pectorals, into which they can pump lots of blood to provide a cooling surface, when in warm waters. Other whales have alternative cooling methods, such as pumping more blood into skin in the tail flukes.

I suspect that feathers first evolved for insulation. After all, they came from scales, and an object half way evolved between scale and feather has no value for flight, but may be better than scales alone for insulation. Of course, once evolved, they may have developed all sorts of uses, in addition to insulation and flight. Sexual signals, bright colours, fluffing out as threat displays, shock absorbers etc.

Here is a very recent and very pertinent reference for this topic. http://www.newscientist.com/channel/life/mg19526114.000?DCMP=NLC-nletter&nsref=mg19526114.000 Quote : So when are we likely to see unequivocally synthetic life, with the entire cell built from scratch? "It could be five months or 10 years," says Church. "These things aren't so much a question of timescales as the amount of money available."

lucaspa said : If you are smaller, the amount of heat lost is smaller, therefore the less you have to replace by metabolism Actually the reverse is correct. Proportional to body mass, the larger an animal is, the less the heat loss. That is why an elephant has almost no hair and has developed those massive ears, which it flaps around to lose heat. Whales have no hair either, and maintain body heat without external insulation in the Earth's coldest oceans. Admittedly, they have blubber layers, but these are less efficient insulators than air held under hair or feathers. Small animals have to eat enormous amounts of food to replace the energy lost as heat. A shrew will eat half its body mass each day.

I followed up with a google search for Australopithecus and tool use. I found two references. The first denied Australopithecus used stone tools, instead claiming that chipped stone tools found with Australopithecus fossils were actually made later by Homo erectus. The other reference claimed to have studied animal bones found with Australopithecus fossils and found wear marks consistent with them being used to dig out termites. Either way, Australopithecus apparently used tools, but may not have fabricated them.

The short answer is that we do not know. We can speculate all we like, but more data is needed. In the last 10 years, we have discovered an amazing amount of information about dinosaurs. It is predictable that we will discover a heap more in the next 20 years about all forms of life before and after the big disaster. Watch this space....

The ideal communist state is shown by a termite nest. Of course, it helps that termites got no brains! We don't even need to speculate on this subject. Enough places have actually tried to set up such a society. It failes every time.

Interesting about erectus boating to Indonesia. I looked on google and found two references to this. One reference looked highly suspicious, and my anti-virus told me - "do not touch." The other is less complete, but confirms the facts. http://www.highbeam.com/doc/1G1-53501818.html I have thought for a long time that our pre-human ancestors were smarter and more technological than we normally give them credit for. Some years ago, I read of crudely chipped stone tools being found with fossil Australopithecus about 2.5 million years old. Could be that Homo erectus was a pretty smart cookie.

The truth is that we are discussing a problem with democracy. Any democratic election on a national scale is essentially 'trial by television'. We look at how the candidates perform in TV interviews, and at what TV journalists report about them. Generally, the candidate with the most television charisma wins. The truth is that the vast majority of voters have no way of judging how good one politician or another might be. Some people, like those who contribute to this forum, are careful thinkers and examine the issues. But most people vote for whoever gives them the best 'warm fuzzies.' This is something that all politicians understand, and they all have spin doctors who work on warm fuzziness. At the end of the day, we get the leaders we deserve, and that does not say much.

Sayonara You are correct. We do not seem to be getting very far. We are all aware of the distinction between habitat loss and other extinction causes. If nothing else, it is well covered in popular literature. I thought my offered definition had some possibilities, but it looks as if my debate partners would rather destroy a possible definition than try to construct one. If we cannot try for a more constructive approach, then we probably should end the thread.

OK. Can we agree that the key part of 'loss of habitat' is the word loss. In other words, loss of habitat occurs when one or more vital ecological supports are removed. For example : if a bird species suffers loss of the trees that supply fruit for food, and goes extinct - that is loss of habitat. Of course, it could be other vital factors that are lost - not just food. The alternative drivers of species extinction, by contrast, come from adding an inimical element, such as an extra predator.

To lucaspa Here is a web site on tool use by the crow. http://language.psy.auckland.ac.nz/crows/our-research.htm I have not been able to locate my reference to observations of kea using tools, and it is apparently rare. However, the kea (mountain parrot) is unique in being the world's only alpine parrot, the world's only meat eating parrot, and one of the most intelligent birds in the world. Here is a Wiki reference. http://en.wikipedia.org/wiki/Kea

To fattyjwoods What has changed in the interim is that whaling has become non economic. The older generation that bought whale meat is dying off and the new generation is less interested. Whale meat is not selling, and whaling is losing money.