The Sceptic Blog

Random thoughts of a random chappy

Question: evolution

with 7 comments

1.  This is a genuine – not rhetorical – question about the scientific theories of evolution (much of many of which is compatible with Torah thought).  It will display my complete scientific ignorance – but it may be possible for someone reading this to explain in easy lay terms what it is I want to know.

2.  If the process of evolution from micro-organisms to intelligent life was a completely natural one, why did some organisms only get to animal stage and then stop, while others went through the animal stage to become human?  Or, if no species has stopped evolving, is it thought that all species will eventually evolve human intelligence, and if so why are some doing it so much slower than others?

3.   Perhaps even the question doesn’t make sense in scientific terms and just shows how little I understand about the theories of evolution: but if it is possible for anyone to offer me a (polite) answer I will be very grateful.  Please use the comment bar.

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Written by Daniel Greenberg

February 24, 2008 at 8:50 am

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  1. Simply because certain organisms encountered different conditions around them and adapted to suit them better.

    As a hypothetical example, small four legged mammal creature is very comfortable in it’s current environment. It has a steady and secure source of food and no real predators. It has no need to change and so they don’t expend the energy on it (to put it as simply as possible, it’s not a conscious decision to evolve by any stretch of the imagination).

    Whereas a few of their number venture north where it’s colder. This cold is a new environmental factor, so over many generations they start to develop thicker fur and such to combat it.

    Humanity is evolutionary special in one regard; instead of evolving physical attributes to find our own niche in our environment, we instead developed our intellect. We are one of the very few species to regularly use tools and such. As our brain structure changed and adapted over generations as it encountered new information and found that it’s particular method of solving problems worked for it.

    Other species, in the same environment, had similar problems but instead adapted to them in different means. Whereas they developed longer limbs and such and stayed in the trees, humanities ancestors (and again, this is putting it as simply as possible) made the move to the ground and adapted to conditions down there where they were able to survive.

    Hence the horrible reliance and bad weight distribution on the human spine, it’s a throwback to when our ancestors had greater reliance on four limbs instead of the two we use to bare all our weight most of the time. Also the change in jaw shape, human lower jaws are tending to recede even in more recent generations, due to the change in humanities overall diet.

    Matt

    February 24, 2008 at 10:17 am

  2. This is very helpful – is it generally regarded as sound science by others reading it?

    Daniel Greenberg

    February 24, 2008 at 11:29 am

  3. Yes, Matt is offering rather sound descriptions. What I would emphasize, but Matt leaves out, is that much of evolution is downward in terms of morphological complexity, rather than upward. Evolution does not represent a ladder, with intelligence at its pinnacle, and all life striving towards that – nor is being vertebrate or multicellular the direction of much of life on Earth. Sure, we are biased and think that all life should want to be like us, but simplicity works much better for bacteria, which represents more than half the weight of a human being (rather than his or her own cells); alternatively, all the bacteria on Earth have been estimated by some to weigh more than all the non-bacteria on Earth.

    Rather than a tree, it might be helpful to view evolution as a bush, diversifying in all directions, not just towards us or for our sole benefit.

    Dan

    February 24, 2008 at 4:04 pm

  4. In Origin of the Species, Chapter 4, Darwin asked a similar question to the one you have raised. He asked, “…if all organic beings thus tend to rise in the scale, how is it that throughout the world a multitude of the lowest forms still exist; and how is it that in each great class some forms are far more highly developed than others? Why have not the more highly developed forms everywhere supplanted and exterminated the lower?

    He answered that question this way: “… the continued existence of lowly organisms offers no difficulty; for natural selection, or the survival of the fittest, does not necessarily include progressive development- it only takes advantage of such variations as arise and are beneficial to each creature under its complex relations of life. And it may be asked what advantage, as far as we can see, would it be to an infusorian animalcule- to an intestinal worm- or even to an earthworm, to be highly organised. If it were no advantage, these forms would be left, by natural selection, unimproved or but little improved, and might remain for indefinite ages in their present lowly condition. And geology tells us that some of the lowest forms, as the infusoria and rhizopods, have remained for an enormous period in nearly their present state. But to suppose that most of the many now existing low forms have not in the least advanced since the first dawn of life would be extremely rash; for every naturalist who has dissected some of the beings now ranked as very low in the scale, must have been struck with their really wondrous and beautiful organisation.”

    Although that question is close to the question you have raised, it may not be exactly the same because you began your question with “If the process of evolution from micro-organisms to intelligent life was a completely natural one, …” Darwin did not ask the question with that conditional clause in mind. I think you may be raising a question that involves a tension between theology and science. In a way, Darwin addressed this tension. In Chapter 6, he asked, “Have we any right to assume that the creator works by intellectual powers like those of man?” He asked that question rhetorically, but it is an interesting theological question, an interesting Biblical question or Torah question.

    In my reading of Darwin’s work and the Bible, I find so much to think about – points of tension and the points of harmony.

    Ken

    February 25, 2008 at 5:05 am

  5. the new scientist, march 1st ( this week) explores current theory of evolution in some depth and argues against the “ladder myth”. it confirms the bush/tree with splaying branches model whereby for example, monkeys ” evolve” along a different branch to humans and are ” irrelevant” to it. All pause for thought.

    Emma

    March 2, 2008 at 2:17 pm

  6. I’m not sure if anyone fully answered this part of the question…

    “Or, if no species has stopped evolving, is it thought that all species will eventually evolve human intelligence…”

    It is correct to say that no species (including humans) has stopped evolving. But I think very few scientists think that it is inevitable that biological evolution gives rise to human, or any other kind of higher intelligence. The Earth had complex animals with brains for hundreds of millions of years. The fact that they lived and died and evolved for so long without evolving higher intelligence would seem to suggest that there is nothing inevitable about the emergence of higher intelligence. That higher intelligence “suddenly” evolved in the last million years would seem to suggest that higher intelligence might be a fluke, e.g. a series of very rare mutations that happened to co-incide with certain environmental conditions. Now that higher intelligence has arisen in the form of humans, I would have thought that the rise of any additional intelligent species would either be blocked by us (it has effectively happened before, in that we have eliminated or outcompeted other branches of human intelligence e.g. the Neanderthals) or – more likely – be fostered by us (e.g. if we continue to breed dogs for another million years) in which case it is not natural selection but intelligent (i.e human) design. If human were to suddenly disappear I would not be surprised if higher intelligence does not evolve again in the billion or so years that remain for the Earth as a habitable zone. And if it does arise again, the new higher intelligence would either block or foster the emergence of any further species.

    Will Truth

    June 20, 2011 at 3:44 pm


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