Darwin starts off his argument by beginning with the idea of change over time, and the irrefutable geological evidence. He begins with laying out facts. You cannot argue that the layers of rock and sediment below the earth’s crust is a geological time scale and shows periods in the earth’s progression. He later explains this due to evolution essentially, and gives pieces of evidence; one of which is variability in reproduction. By setting up his argument beginning with facts and common knowledge, it allows him to really hone in on his argument with distinct pieces of evidence that are hard to dispute.
In my opinion the most convincing piece of evidence was reproductive variability. If the environment directly affects the health of the next generation and offspring of current group, this proves that the environment has an impact on the way species live their lives and affect the health of a species. To further explain, an animal that is living in a bad environment and is susceptible to disease and starvation and can be negatively impacted by it’s environment, their offspring would also be born into a sick environment. This deducts to natural selection, because only the healthy, hearty, fit animals survive to reproduce effectively and produce long lasting genetic lines. “Under domestication we see much variability. This seems to be due to the reproductive system being eminently susceptible to changes in the conditions of life; so that this system, when not rendered impotent, fails to reproduce offspring exactly like the parent-form.”(Darwin, 488).
4 thoughts on “Variety is the spice of life”
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It is interesting that you think the most convincing argument is the variability in reproduction. It might have been one of the biggest obstacles for Darwin to hurdle, since people were considering everything a different species, because of the variations. He said that geological record was too small and that we need to think of the entire earth as the geological record instead of just what is in a museum. It is nice that all federal construction projects have to go through cultural resource management to get projects done, but it is not universal law for any construction project, unfortunately.
I think I would agree that he has a very good argument for natural selection causing evolution. I think that the environment making us who we are provides some objective evidence for Darwin’s argument. I had forgotten about his arguments when it came to domestication until reading your blog. Do you have any thoughts about his opinions about genetic modification? I would agree that stratification in the rock does provide a evidence of a geological time scale. I just don’t Darwin explains this phenomenon to the extent it requires for the argument. This does not mean him saying the geological time scale is imperfect is a bad argument. It just means it needs more explanation/evidence.
With the offspring variability theory in mind, I wonder why the idea of “transitional fossils” has survived as a legitimate claim against the theory of evolution. “Where are the transitional fossils” seems to have become a rallying cry for critics, while they never seem to consider what would constitute a transitional fossil, or why species forms seem to be more or less similar. I wonder if it is viable to say, for example, that all ungulate species could be considered transitions. For instance, there is very little difference between deer, elk, sheep, etc, and there are both extinct and extant species that are equally similar. Additionally, there is an example of a variety of recently extinct (10,000 years ago, absolutely no time at all relative to evolutionary timescales) reindeer that featured a terrifying 15 foot antler set and would have stared down a moose with no problem, that directly relates to today’s reindeer. I feel that the descent with variety “transition problem” can be explained by saying that a viable and distinctly recognizable form could persist in a environment that experiences a spectrum of evolutionary pressures for as long as those pressures do not exceed the spectrum. That spectrum will, however, inevitably be breached, and for the duration of the breach, evolutionary pressure selects much more harshly in favor of those who can survive the new environment. Eventually, the new environment will be inhabited by the descendants of the original species who are now quite comfortable and will proliferate accordingly. I found this subject quite interesting both because of my own fascination with prehistoric biology, and because I happened to be listening to Jurassic park on audible at work. In any case, thank you for your opinion! I hadn’t considered Darwin’s methods in defending his theory before reading this piece and also your post.
I agree with you that reproduction is the most convincing factor of variability. We see it every day, that offspring tend to take of traits given down from their parent. Which is this case, are the surviving species. I thought your point about species that are ill die off and only hearty healthy fit species live. I completely agree and shaped my own thought Species that are exposed to ill environments tend to die off or adapt–meaning that the species that do survive are the ones that reproduce. Those survival traits are given to the next generation which continues to change throughout time.