Atellus

I would suggest that the phenotype is only present today because people with smaller, weaker jaws are better able to survive on the softer, more palatable modern diet that is now available, with relatively little variation, all year round. There are also numerous dietary supplements available as well. In times past, even in relatively recent history, strong teeth and jaw muscles were needed to masticate a variety of less palatable substances. Even today, in many parts of the world you will find people eating types of plant matter and animal parts which western humans would find very difficult to chew, and if it's not well chewed it doesn't digest as easily or quickly, and the immedicate nutritional benefit is reduced as a result. So, in the past people with weak jaws tended to suffer more from malnourishment related ailments, particularly in winter, and died off in greater numbers which prevented them breeding in the same numbers or as frequently as their square jawed compatriots.

I have three dogs, all of whom eat and regurgitate plant material from time to time. They're fed on a mixed diet of one third fruit and vegetables to approximately two thirds meat by mass, plus some essential dietary supplements like iodine salt and bone meal. I often flavour it by adding my own leftovers from the previous evening. I've seen one of them eat everything from home baking to slices of cucumber and banana! This sort of diet can be very flexible and useful as you can finely control a dogs weight. During periods of relative lack of activity I often increase the fruit and vegetable fraction to bulk the meal up, which satisfies them quite well without filling them full of calories they don't need and piling on the fat as a result. I was thinking of logging incidences of "grazing" and whether or not the plant matter was regurgitated, and correlating these with the worming schedule to see if intestinal parasites might be a factor. I thought that this behaviour might be a good indicator for parasites if the two are related.

Thanks for the link! Answered my questions.

So the green colouration is not necessarily indicative of the presence of copper? Why is the blue blood colourless when deoxygenated, when the blood of most other species is not? Which is providing the inspiration for a valid and interesting question about the constituents, structure and function of the blood of different species. A function which science fiction has performed for over a century.

In my humble opinion, I think this is essentially correct. There is a single phrase which aptly expresses the astounding level of technological advancement that took place in a very short time during the second world war. "Necessity is the mother of invention" A world population at peace is, in the absence of an outside competitor, not only impossible but deeply undersirable as we will have seen the end of invention and will witness the stagnation of culture. Granted, there will be a slow, steady slog to improve in areas such as health care, but even that will be difficult in the absence of the motivation provided by commercial concerns in the pharmaceuticals industry.* The best example we have from history is probably the Cold War, in which the Eastern and Western blocs faced off on the brink of self inspired armaggedon, followed by WWII again, in which the Allies came together in a common cause to win a global conflict and ensure their own continued survival as autonomous states. In both instances, despite the over-whelming pressure of competing with a powerful outside force, and despite the very great efforts of co-operation at all levels, at all levels there was well documented intrigue, political manoeuvring and scandal revovling around each member of these alliances seeking advantage, power and influence over his fellow allies. So, even if we did encounter a powerful alien competitor, around the threat of which we were able to unify the planets population, we would still compete with each other behind closed doors for the simple goal of being the biggest fish in this very small pond. It's a problem which plagues European Union decision making at the state level: everyone is anxious to remain the big fish in their individual small ponds, and is terrified of becoming a normal sized fish in an even bigger pond. *(I am making the assumption that in order to be happy and at peace, we will need to find a different economic model, because empiral observations suggest that the free market economy is a source of unhappiness for most of the population most of the time. Additionally, in the case of pharmaceuticals, you will never make Africa a happy continent until they can all afford the drugs, which means either giving them away or revoking patent rights.)

As McCoy was apt to say. I was watching an episode of Star Trek which featured a Vulcan who bled a lot. This got me thinking about the colour of blood and why it is the colour it is. In particular, I pondered why a Vulcan should have green blood. The official explanation according to Trek Lore appears to be that a Vulcan's blood is copper based, but if that were so, then surely they are not metabolising oxygen as oxygen would not bind to the iron-containing haem group? Apparently there are some species of lizard which have green blood. I have also heard that horseshoe crabs have blue blood which is blue when oxygenated and colourless when deoxygenated. Discounting the copper based theory, what explanations are there for the green appearance of blood and why might this be an advantage in an oxygen environment?

Need more specifics on the form these plant based minerals take. Are they present in minute amounts or are these things basically metal crystalline organisms of some kind. If you burn one in a hot enough fire, how much metal would be left behind after any organic components were combusted? One thing that is obvious from the history of our species is that humanity is an extremely resourceful and imaginative survivor. If metals were available in this form in useful quantities, at some point someone would notice and divine a way to exploit them. Perhaps another and more cogent question would be to ask exactly what proportion of your present day population that are beamed to this world would actually possess any such knowledge? We live in a world of comfort where, in many places, scholars heavily outnumber craftsmen and tradesmen. How many media consultants does it take to smelt copper?

The responses so far seem to be suggesting something along these lines: Essentially, agricultural technology is key. This technology is perhaps the simplest to develop as initially it would be based on observation and folklore. Basic agriculture can be carried out with very basic tools that you pick up off the ground. When you get good at it you generate a surplus of food so that some people can be scholars instead of working to harvest their dinner all day. Then over time you develop a culture based on an ever growing body of accurately recorded knowledge and observations upon which each successive generation can build. This, perhaps, stimulates the imagination and creativity of the populace at large who have the precedent of their antecedents ability to divine new techniques in agriculture and textiles, which proves to them that it's possible to make such advances, as opposed to assigning all currently existing arts and crafts to the generosity of the gods/spirits/earth mother who bestowed them on man, intact. With all this in place, you have merely to wait for the most important factor: Serendipity!

Ah! I never thought of that, despite banging on about reproductive activity! Very interesting answer. Thank you.

As I get older, I'm becoming hairier. This is not a complaint, you understand. I don't look forward to the possibility that conspicuous parts of it may one day fall out. However, at the same time, it occurs to me that this aspect of maturation does not deserve to be taken for granted. Why not? Well, for one thing, it doesn't seem to make sense. I'm more hairy now than I was 10, or even 5, years ago. I refer specifically to body hair. Torso hair is what doesn't make sense. Obviously, it's all a left over from our primitive past but what we do have still contributes something on those chilly nights, and for our arguably slightly hairier immediate ancestors, every little advantage is worth the effort. Scenario: a group of hunter gather homo sapien's a few thousand years ago. Climate is moderate, varying between warm but tolerable summers and cold but bearable winters. Individuals become sexually active quite early by modern standards (at least legally speaking). A young male of 18 years is considered well into his early adulthood, is hunting with the other adult males and is a fully fledged member of this social group. And yet, his body does not appear to have kept pace. An individual 10 years his senior, who shares the same habitat, whose lineage has experienced the same selective pressures, who endures the same seasonal cycle year in, year out, has at least twice the quantity of body hair. Question: if this fully matured elder male is equipped with this quantity of hair than presumably this is because he needs it. Why is the apparently fully matured younger male not also so equipped at his early age? He is reproductively active, therefore, in natures view, he is fully matured. Why doesn't he grow the hair that natural selection says he needs faster? If you think this is a silly question, well, you've just gained an insight into my thought processes whilst staring into the bathroom mirror every morning. Lucky you.

Indeed. Interesting idea though, to dilineate time by human development.

For lack of a better suited forum (and not wishing to couch this discussion in religious terms only) I posted this here instead. I have just read this very interesting discussion about dating systems. http://studentsfriend.com/feed/topic11.html For myself, if we are to abandon the traditional designations of Before Christ and Anno Domini, then I would favour the use of the same letters (BC and AD) to mean Before Commong Dating and After Common Dating, perhaps going so far as to use BCD and ACD. Failing that, the use of + and - dates seems overall to be a simple and elegant solution, but perhaps only as a form of shorthand. What's your take?

Hello. I recently purchased a couple of plastic water jugs but discovered that the inside had a very powerful and distasteful odour, as do many plastic products. I was advised to fill both jugs with bicarbonate of soda and leave them standing for a few hours. I did this and found that the odour had gone completely! Can anyone explain this? Thanks

Thanks!

Hello. I wonder if someone could answer a question on a particular aspect of lightning? Why do positive streamers appear purple in colour? Thank you