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About tantalus

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    Ecology, Evolutionary Biology, Agricultural Science
  1. It's a strange angle your taking on it Fabian imo. Conservatives aren't blocking nuclear energy, I suppose their apathy towards political action on climate change would reduce their motivation to give the industry new life moving forward, if such funding stemmed from a motivation to tackle carbon emissions, nevertheless, that would be a poor account of the state of the industry. The reasons Nuclear failed to materalise on its early promise (1960s onwards) has nothing to do with climate change and the blame doesn't rest with the right which never has possessed a strong inclination to environmental protection or regulation. Nuclear has been weakened by several factors over the last 3 decades, and those historical reasons give a reasonable account for the present scenario. Several disasters didnt help with the perception towards the industry and ever changing regulations damaged the industry and led to very expensive and drawn out construction phases. A company might commit hundreds of millions to a reactor , and halfway through, regulations change in response to an accident, or court cases, and it takes a decade longer and millions more to complete, this was not good business and eventually the life got sucked out of the industry. At times it has seemed like nuclear might make a return, but then the cycle returns and fossil fuels get very cheap again for a period, undermining nuclear investment which takes a lot of time to get to market from the outset, and the market is often very different by the time you get there. Nuclear requires huge capital investment from the outset, has been historically unpopular and challenged in court and by mutating safety regulations, and undermined by variable fossil fuel prices. To get it off the ground today public perception and capital are key. Just look at what happened recently in Japan, very difficult to convince private companies to risk that kind of investment, when it seems clear cheap fossil fuel has a some battery life in it yet, especially with the development of the fracking industry and the re-emergence of Iran into the global market. I think nuclear has missed its day, and not sure at this point climate change can bring it back. That said public perception might shift if people could be convinced that the new generation reactors are infinitely safer than in the past, but naturally nobody wants one in their own backyard. Ultimately we burned more coal over nuclear in the 80s and 90s, and that was far more damaging to the environment and human health.
  2. I think ice age and tropical as word choices are misleading. The theories for the wave of extinction during your stated period are climate change, human arrival and hunting, disease (linked to human arrival), comet impact, or some combination. Also discussed is ecosystem shift due to key singular extinctions that also may have altered fire regimes. Interesting over the last couple of years, the clovis first theory (that the clovis people first settled the americas) has finally been put to bed. That theory dominated the field for decades and nobody has a wining theory to replace in at the moment. We know now that there were people pre-clovis, from where, when, how many, where they big game hunters?, is yet to be established. This has potential to significantly alter conclusions on the megafaunal extinctions. Personally, I favour human arrival as the significant factor. Maybe I just have a bias for correlation. The timing is very good, and the existence of pre-clovis, on first thought, seems to strengthen the case, and weaken the argument human populations couldnt have grown fast enough, with the clovis first theory. However, it has been argued (through mathematical modelling) that the clovis people could have hunted at the necessary levels to bring about the extinction wave in the time period required. There were not too late or too few to do the deed. Also, Interesting new paper. http://www.pnas.org/content/113/4/886.full.pdf?sid=78082c56-76a7-46a1-8248-a0c6d1760c4e However this focuses on the clovis people, despite the fact we know of pre-clovis (the paper mentions this). But it can't be ignored that clovis arrival, migration and technology may still be the key cause, even with the presence of pre-clovis humans. The paper attempts to establish a geographical pattern of extinction through time that could only fit the clovis theory. It is suggestive, although I would question the idea that extinctions will neatly occur in space and time to fit any theory. If such kind of evidence is found, great, but its absence doesn't necessarily destroy a theory imo. I also like human hunting as a cause when you look at megafaunal extinctions globally over last 100,000 years, where they were occurred rapidly, they seems to coincide with human arrival (with previous isolation), Americas, Australia, New Zealand , Madagascar, less so and further back in history for the Old World. To expect perfect fits and neat patterns of extinction doesn't fit with reality, so I feel some of the criticism are unreasonable when one finally needs to draw conclusions, or hedge bets, whatever of the process. Other suggestive evidence is large species surviving on islands when extinctions where occurring on the americas. The eventual extinctions correlated with the later arrival of humans. Of course the clear pattern of extinctions of large species over small ones is suggestive of hunting as a major factor.
  3. I would recommend A brief History of Time by Stephen Hawking ad Leonard Mlodinow. It is actually very short and concise and and provides an overview of many of the key issues studied and discussed by physicists over the last century. It is remarkably accessible given the difficulty of the subject matter.
  4. The language we use when we discuss evolution, and the way we conceptualise and find meaning in events and processes is where the difficulties begin here. I think choosing the word direction is not preferable, blind might be better, or vision, or the idea of forward planning. The neat trick is that you can still get biological machines of high complexity from such a process. Personifying evolution as an entity is a useful trick in furthering understanding, but it's also a double edge sword that can lead to confusion. In the sense you are using evolution, it seems reasonable to define it under the terms of natural selection as the differential survival and reproduction of individuals. If we could leave the argument of what is the unit of selection in evolution to the side for the moment. All this really means is that some individuals survive, others die, some reproduce, others fail. Then you have the next generation, who have inherited the genes of their parents. It all happens again. But those who die and those who reproduce is not random when we consider their genes and when we consider their environment. Yet, a very large number of small events influence who dies and who reproduces. For the sake of this discussion, it is meaningful to consider those events as largely separate and independent of each other. It follows that we are not inclined to give all the events that influences who dies and who reproduces a single name or describe them as a single process when we start to thing literally, step by step, what is actually happening in the real world. In this way evolution is not a thing, and it can't have a direction, it's a name that you re trying to give to a very large number of events that combine to produce the differential survival and reproduction of replicating entities. But someone doesn't die of pneumonia to direct evolution, or get caught by a lion to insure faster generations, yet these events happening alters the composition of the next generation. There may very well be an inevitability as you state, but it doesnt stem from design or direction. The counter-intuitive element is that you can get complexity, design without a designer. But without a designer you may have some difficulty achieving perfection. This ignores the difficulty of achieving perfection when your competitors, enemies and environment are in constant flux, the criteria for perfection changing rapidly. The difficulty of the absence of a designer is that that what produces change from one generation to the next, who dies and who reproduces is influenced by the now, the very large number of small independent events...The large number of small mutation events required to get to a better design, towards perfection are likely to get you killed on route. It's what happens now that matters. So you could say that evolution has no direction, there can be no perfection, yet that doesn't mean prevent intricate design and it doesn't mean there aren't events that are more likely, highly probable, even inevitable compared to other alternatives.
  5. Your right, I am not sure now that you point it out. Although viviparity is mostly associated with placental mammals in which their particular form of viviparity has a common evolutionary origin.
  6. Ovoviviparity is a mode where the egg is retained longer in the body (your intermediate of sorts), one obvious benefit is to protect the egg(s) from predation, not just thermoregulation. The process would have probably been gradual, as the amount of retention time increased over the genrations. Eventually species would have evolved that retained the egg the entire reproduction period. This would have provided the opportunity, or perhaps it co-evolved with increased retention time, of the evolution of the substitution of some and then more and then most of the nutrients in the egg for those directly from the mother. Marsupials have a different lineage than placental mammals having diverged in the cretaceous
  7. Just look at twin studies on religiosity, they are consistently finding significant genetic effects on the likelihood of being religious, upwards and over 50% of the variance. This speaks to the influence on genes, whatever of the adaptive or non-adaptive history in evolutionary terms. There is also research indicating the increased influence of genes on religiosity into adulthood, probably as people leave their parents homes and their influence dwindles, the most powerful environmental factor.
  8. You misunderstand me, HADDs may possibly explain why religion is a spandrel, by postulating the adaptive evolution of mental machinery that inadvertently favoured the cultural evolution of religion. God of the moral gaps goes further than that however, tying the idea to God to our clearly adaptive moral tendencies , and discusses the possible evolution of a belief in God with the evolution of our morality as discussed by Gray and Wenger. Some may prefer to separate such a belief from religion. under such a framework as they outline in may be difficult to separate the adaptive evolution of morality from a belief in god. [mp][/mp] I want to summarise an excellent article which I consider informative http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4345965/ Part of the difficulty is defining religion and morality, and separating evolutinary/biological elemets from cultural ones which have developed later in shaping religion and its function. This leads people to suggest a simplistic, singular cause, where multiple are required Separating the evolved underlying mental mechanism that facilitate religious thinking, from cultural effects that have influenced the development of religion as a social phenomenon. First the article attempts to the define the question and how to handle the question, when handling the diversity of religion and separately moral behaviour. If true this would be an example of the futility of trying to find a single explantion of the evolution of religion, as opposed to the idea if breaking religion up into separate components of religious behaviour, each potentially having a different cause or combination, evolutionary or culturally, adaptive or by-product... This is important because I think we have seen some discussion on the thread about various possible advantages of religion in terms of group selection and tribal benefits etc. Now there may be merit here evolutionary, and there may not be (I favour the latter), but that's not to deny these functions are not real, and not useful, and not realised consciously by individuals, groups, tribes, religions, it's to say they might not be the adaptive reasons for their emergence, an ultimate explanation. We should seek to find an adaptive reason that finds its selective pressure lower than that of the group,at the individual, or gene, which may favour group benefits in practice, culturally, Second is Theory of Mind (ToM). I skipped over HADDs as I previously discussed them. If we embrace the earlier of point of breaking religion up into different elements, the theory of mind has potential with dealing with one element in particular, the afterlife. Given humans ability to process the world, consciousness and reflect on their existence, difficulties potentially emerge for an biological individual that can realise its own death, and such a realisation could prove destruction to that individual for achieving maximum evolutionary fitness. Could certain modules be adaptive in proving religious explanations of an afterlife to provide innate coping mechanisms to such a self-ware biological machine??? Third is teleofunctional Explanations Fourth Rituals Its important to not evoke group selection, you can have gene and individual level selection that favours group co-operation behaviour. Fifth- Kin selection The paper offers a summary in the section :The Religion–Morality Relationship in Biological Evolution which discusses their preferences in regard to different ideas they summarise from the literature. They state Note the choice of the word initially, leaving open the door to the idea that adaptive functions of various religious behaviour may have followed in time... I would love to know what Dennett thinks of this creative speculation... The paper conitunes on the back of such a speculation to discuss empirical evidence of religiosity and increased “moral” behaviour. (we could call this a sixth avenue of exploration) As an atheist, as an anti-theist, this subject makes for fascinating reading for me. Note. They also discuss methodological and bias challenges to some of this research. See article for discussion on limitations of such games such as conflicting moral motivations in game design. They also briefly discuss religiosity with negative moral traits, but morally good or bad, is of course not informative against something being evolutionary adaptive. Although they provide caveats, see article. Important concluding point The next section discusses how the cultural evolution of religion may be informed and directed by already occurred biological evolution... They then discuss a cargo cult (modern religion) under the context of the framework they have outlined. We are now dealing more heavily in cultural evolution. Although the discussion of the cultural evolution of religion is interesting, it does drift from the idea of adaptive biological reasons for religion so I will ignore that section of the paper. Effectively they seek to crush the idea that the OP question is a meaningful one, and set about to create a conceptual framework that can stimulate a meaninful discussion on the biological and cultural evolution of religion and moral based behaviour. I favour biological mechanisms that had adaptive functions that gave arise (edit. subsequently) to much religious behaviour, evolutionary speaking the evolutionary origins of various of types of relgiious behaviour may be evolutionary separate. The idea that a belief in god is linked to the evolution of morality and the evolution and successful function of a highly intelligent self-aware being is definitely an interesting idea imo.
  9. It's difficult for me to evaluate your post as I am not sure what you mean when you refer to religion. It doesnt address it directly, but thinking of religion in terms of the evolution and adaptive uses of morality can be a very productive means of providing useful speculations on potentially adaptive causes of religion. [mp][/mp] I am in the process of trying to summarise this very long article for the thread on the issue http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4345965/ One that attempts to analyse the difficulty in defining the question and the framework, and provide a literature view (further down) of the different possible evolutionary causes of religion that are currently popular in the field, not just the byproduct/spandrel theory.
  10. There are a lot of different ways modern religion could be a spandrel in evolutionary terms. The underlying mechanisms that facilitate religion would be adaptive, possibly more adaptive than Dawkins would care to admit. I like the spandrel theory, one possible link is the idea of HADD's (Hypersensitive agent detection devices). The idea that humans possess mental modules which favour the assumption of the existence of agents in a given scenario. Human hears a rustle in the jungle, assumes there is a lion, takes preemptive measures, even if the vast majority of times there is no lion, evolutionary speaking it pays to assume the presence of an agent, as the safety measures cost far less valued against the loss of being eaten. This mathematical imbalance would lead to humans evolving to assign agents to events and scenarios even when they don't exist. The speculation is such a mental module predisposes humanity to believing in God. Gray and Wenger discuss this idea, linking it to the evolution of moraility in their excellent article, extending HADDs into the evolution of moral reasoning. To understand the later quote fully you'll need to read the article in full which covers a lot of ground and it would be pointless for me to summarise it. http://www.scribd.com/doc/32966805/Blaming-God-for-Our-Pain This is just one of a half dozen theories on the evolution of religion, I will post up on the others shortly.
  11. I think prenatal hormone exposure is the most important factor in explaining variation of masculinity, femininity in the personalities of people of all sexual orientation. This factor has both underlying causes based on genetic variation and non-genetic factors, although I would guess genetic causes being the most significant. Extending this to explaining variation in sexual orientation is an altogether different matter, but maybe, maybe there is a link... I'm not sure how important epigenetic factors are in regard to homosexuality, but when you look at twin studies on the matter, and the number of twins that do not have the same sexual orientation despite identical DNA, it is very suggestive of something very important going on apart from genetic factors that hold steady to development of sexuality. I am not saying anything specific just to be clear (Jodie foster et al.), just speculating on fruitful areas to direct thoughts on the matter.
  12. Yes, mars could be a game changer. I hadn't heard of that finding from 4.1 billion years ago, interesting. It does seem very early, but I know there is some shift in the narrative of the early earth and its condition. It may even spark renewed interest in panspermia (although I doubt it). Although caution must be urged. http://www.smithsonianmag.com/smart-news/did-life-really-start-41-billion-years-ago-not-so-fast-180957006/?no-ist
  13. To add to already mentioned cooling down from its molten state and appropriate conditions developing through abiotic processes that would have accounted for much of the time, can probably add a long period of chemical evolution that was surely a precursor to the evolution of life as we loosely define it, along with the time that was required for the unlikely in the short term to become the inevitable in the long term. There is a perspective that life was not inevitable, maybe even statistically unlikely, even over the time scales available, and that luck may have brought it about, in so much as you can define an unlikely event that actually occurred as luck. I wouldn't subscribe to that perspective. Deterministic processes and physics and all that...
  14. Wolf populations are low density and they track long distances to make kills, it hard to imagine it being a practical strategy for humans to steal wolf kills if that's want you mean. Tapping the potential of dogs in such a manner does seem like a good strategy but they have to be familiar with the concept, obviously it occurred eventually, with or without the wolfs having become tamer initially. I wonder if it was not companionship and human curiosity that drove this early dog domestication more so than hunting and warning potential... Competition usually occurs most fiercely intra-species, so I imagine dogs would have been more useful in fighting other humans...but still I would speculate all this occurred after the fact...
  15. http://www.bbc.co.uk/news/magazine-35350886
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