Wow, Darwin isn’t as nearly stuffy as I thought he’d be. I’m thoroughly impressed with his candor toward the reader, and his commentary and prediction regarding potential reader outrage or disagreement. He still sounds like an academic (read: big words), but the reading was slightly less of a bore than I dreaded.
So I may be interpreting this wrong, but it seems that Darwin uses animal domestication and artificial selection as a guidebook for grouping and categorizing natural genetic differences. On page 264 he writes:
“Organic beings in a state of nature present some varieties, – that their organization is in some slight degree plastic; granting that many animals and plants have varied greatly under domestication, and that man by his power of selection has gone on accumulating such variations until he has made strong marked and firmly inherited races; granting all this, how, it may be asked, have species arisen in a state of nature?”
So domestication can, from a certain viewpoint, be considered natural selection on steroids…right? Darwin’s use of the domestication blueprint aims to discover the signs of similar ancestry between species; fair enough. But we can’t really take the comparison any further, can we? Because the goals of natural and artificial selection can vary wildly. Nature (and if this is wrong, please skewer me for it; I’m not actually referencing a source for this) seems to focus solely on the survival of a species or organism, while humanity’s aims for domestication can vary wildly. So shouldn’t an organism’s current state of domestication also vary wildly than if we had otherwise tampered with it?
This was alluded to in post from last week as well. The question here I think is – how plastic are animals? What are the variables? With enough time, can you completely change a creature’s composition? For example, with enough time and tampering, could we theoretically go from horse to fish? And how much of this will we actually find in nature? Darwin seems to be on a line of thought (although he disregards it in favor of species classification) that says nature will never have the breadth of change that domestication does. The parameters aren’t set. There seems to be a need for ‘total manipulation,’ a requisite for every variable to point in the proper direction to elicit truly drastic changes. This makes sense to me when we compare it to the paleo readings, and the discovery of evolution having varying rates of speed. Hell, this reminds of the chaos theory discussion that permeates Jurassic Park. My math major is showing, but to me, it all comes down to variables.
My conclusion – domestication provides such a greater species variety and difference than nature because the variables are controlled. It’s like psychological reinforcement, strict selection of desirable domesticate traits ‘reinforces’ natural selection (you can tell me that’s a stupid analogy). The better we control the variables, the greater the differences between domesticates and natural creatures, and the more careful we have to be with classifying the two by the same template. Especially if we forget about a certain reproductive amphibian variable that allows dinosaurs to breed and then kill us all.
I think you’ve hit on something that has been bugging me for a while–namely evolution vs domestication. On the surface, they seem to be similar forces. Namely that both involve an adaptation to one’s environment, but domestication is an adaptation triggered by a companionship with humans as opposed to the natural environment. However, the natural rate of evolution is much slower than domestication because the environment itself changes slowly as well. Thus the adaptation is delayed over sometimes millions of years. It definitely hides the plasticity of animals because we tend to think of evolution as being this natural, perfect force that tailors living creatures to their environment. I’m curious about the scientific implications of domestication: My question is this: If we genetically manipulate a species, is that a form of domestication?
First off I agree with you that reading Darwin was much less of a struggle than reading some other scientific book or paper from the 1800’s. In regards to you post, domestication does seem to provide a greater variety in species on the surface, but when you look at the big picture, nature has taken one, or maybe a couple, small little single celled organisms, and turned it/them into everything from a giraffe to an ant to a shark. That seems to be a lot greater diversity to me than what we have created with domestication. Most of the animals that we domesticate and alter aren’t even considered new species, just sub species. Take the dog for example, even with all of the modifications we have done, the dog is still genetically a wolf. Now I know that nature has a little bit longer to work (millions and millions of years to be exact), but I think it still might be a bit early to decide whether it is us or nature that has more ability in regards to speciation. I do agree that we are able to make changes much faster than nature does, but are these changes really as unique as those found in nature? This could probably be debated all day but I think that is what makes it a really interesting topic.
I like the idea about your two different goals of natural and artificial selection. I might argue that the goal of artificial selection is what you present – greatly varied purposes perpetuated by human intention (which is collectively global consciousness). Natural selection is the survival of an organism, sure. So, how do you think human change to global ecosystems (and then the subsequent ecosystem adaptation or rebalancing to those effects) alters the idea of “natural selection” as survival of the fittest? Maybe it does not change the idea at all because natural selection is based on individual species. However, it is undeniable that human agency has profound implications on the natural world and animal relationships.
I disagree that domestication has produced greater species variety, thinking about the globe as a whole. Remember, Diamond explained that domestication (and geographic luck) lead to the inequalities and ways that humans use and have used nature to meet their needs.
Check out this graph of extinction: http://www.global-greenhouse-warming.com/images/SpeciesExtinctionRate.jpg
(Here comes some future talk – I can’t help it – it’s how my thinking is framed as an environmental planner) I have come to learn it is clear that we must begin the preservation of genetic diversity, the maintence of ecological processes, and the sustainable utilization of natural recourses. If we can do these things (because today we know how and why it’s imperative) then the ideas of artificial and natural selection become less complex from their influence to the overall global ecological state.
I would argue that in one way, organisms in nature have had much MORE breadth of change than have domesticates. Obviously, within a species, we have created huge amounts of variability (for example, the variability we have created in the dog). However, in nature, we got (somehow) from the first single-cell organisms emerging from the primordial soup to US! Natural selection and random mutation have worked pretty well.
However, the speed with which evolution happens when a selection pressure is applied is very interesting (think fast-growing chickens and antibiotic-resistant bacteria). I wish any of us lived long enough to attempt a selection project aimed at turning a fish into a horse.
It’s interesting that on the one hand, recent scientific advances have allowed us to think seriously about the possibilities of “creating” and modifying life forms without any apparent limit. At the same time, the variability and diversity of “wild” species is infinitely greater than among domesticates. And most importantly, as Erica so wisely reminds us, escalating extinctions in the wild are a huge but under-appreciated problem.