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As a geologist, it is rather frustrating to see criticism of the geologic record coming from people who have no knowledge of either the record itself or how it is compiled. Many of these critics rarely demonstrate knowledge of even the most basic concepts of geologic science.
I agree with you, but your post is written with such passion that it makes me wonder if you think the field of geology has been misrepresented in this thread. Were you just thinking about the way it has been misrepresented elsewhere?
I took a geology course in college and enjoyed it very much. In retrospect, perhaps it could have been a good career choice for me, but my interests were elsewhere at the time.
Erm, if you will note who you are responding to, you will find that I am not rifleman.
Meaning that the species were a priori alive to Hume; therefore, the eyes of humans watching still were dead to the following thinkers like Mill, Smith, and (maybe not) Spencer.
I agree with you, but your post is written with such passion that it makes me wonder if you think the field of geology has been misrepresented in this thread. Were you just thinking about the way it has been misrepresented elsewhere?
I just want people to understand that things like the geologic time scale isn't something that geologists pull outta their arses, that it has been painstakingly compiled over a long period of time, and is constantly revised. I posted the link for anyone who wants to know more about the geologic time scale (which is one of the foundations of Earth science, and critical to understanding the evolution of life on Earth).
BUt you get paid for such things as geologic time. I know you mean well for me, but I don't question the geochronologist who defines it Anthropic by the universe. Of course there stratigraphy but we DO make theories in advance for what to look for. Hume I understand was biotropic.
So, I’ve now talked about variation, genetic recombination, mutations – both harmful and beneficial, heritability, and tracing lineage through inherited mutations, even across species. Now, let’s talk about something that thankfully isn’t common among us humans today, but was more prevalent in the past and is still prevalent now among other animals: high mortality rates. Lots of kids died; some from disease, some from predators, some from lack of enough food, or lack of proper nutrition, etc. Those kids who were best suited for their environment lived; those who were not died. So, if you were lucky enough through genetic recombination or mutation to have a stronger immune system, or you could run faster to get away from predators, or smart enough to outwit your predators or prey or enemies, stored calories better, etc, etc, then you survived whereas your brothers or sisters without those traits didn’t. So, you passed on your traits to the next generation, and as a species your species became better fit to survive and reproduce in its environment.
Now, suppose, your brother leads a small band of followers across the mountains down to the sea. So, he and his band are now in a different environment with different predators, different prey, different diseases, etc. So, his descendants become better and better fit for their unique environment. After a very long time and many generations, his descendants and your descendants are very different, both optimized for their own environment. They are so different that were they to ever meet and try to have children, they can’t. By definition, they are now different species. There is fossil evidence (which I haven’t talked about yet) that there have been other “human” species in the past living at the same time as our ancestors, but our human species was the only one that survived.
I have to jump in here. Most of the evolution that occurs in geographically distinct organisms is usually NOT due to natural selection but rather genetic drift and founders effect. I know in high school and even undergrad we really pound the natural selection thing in to people but most of the evolution that leads to speciaton occurs due to genetic drift, population bottlenecks, etc.
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An example of evolution by human selection we all are familiar with is the human selective breeding of dogs. The domestic dog is a domesticated form of the grey wolf. From the wiki entry on dogs: “There is conclusive evidence dogs genetically diverged from their wolf ancestors at least 15,000 years ago…The bulk of the scientific evidence for the evolution of the domestic dog stems from archaeological findings and mitochondrial DNA studies”. While all dogs are genetically very similar, selective breeding has reinforced certain characteristics in certain populations of dogs, giving rise to dog types and dog breeds.
Ok, I love dog/wolf evolution. I wrote my undergrad capstone on it (maybe I should mention here I have my BS in biology (and oceanography) and my masters in biology with a concentration in environmental and evolutionary ecology). Now while dogs are an incredibly interesting case of evolution there are some really good reasons they should NOT be used for a classic example of evolution by natural selection. People inevitable confuse the selective breeding of dogs that resulted in dog breeds with the natural selection that resulted in dogs from wolves. Additionally, "dogs" likely evolved multiple times in multiple places (due to the genetics). Add to that they fact that dogs and wolves are still genetically the SAME species (as are almost all wolves, coyotes, etc) and you can see it become more of an interesting case study rather than a classic example.
I will give the most likely natural selection briefly just because I cannot help myself. People during in the new world (where the first dogs likely evolved) had a habit of disposing of bones and other trash away from the village. Wolves being scavengers in addition to hunting were naturally attracted to these areas. Because people were present this caused the wolves to be cautious. Now "fear" and "caution" in most mammals varies due to the amount of adrenaline they produce. Those with more adrenaline tend to be more cautious and those with less, less cautious.
Wolves that were less cautious got to eat more of the food/trash because they were less spooked by people. This started a very strong selection pressure for the genes which produced less adrenaline. Very quickly wolves (and we know they were still morphologically wolves at this point because we have found fossils with the archaelogical sites of these "trash" areas) became less aggressive and less spoked by people. At this point, it is suspected people began to take pups of the "calmer" wolves and keep the ones that stayed puppy like the longest (a process called neoteny) and breed those.
The "interesting" part at least to me, is that the natural selection for adrenaline led to most of the other traits we call "doggy" as opposed to wolfish through a process called genetic hitchhiking. Floppy ears, dark coat and white feet, white belly, dropped tail, etc are controlled by genes right next to those of adrenaline. For example on the actual chromosome, the genes for melanin are right next to those for adrenalin. When we breed for less adrenaline we get less melanin and get the classic coloration of dark back, light feet (like border collies, mountain dogs, even huskies).
All of these was replicated by mistake in the domestication of silver foxes. Russian fur breeder wanted foxes that were easier to handle so they intially only breed those foxes that were calmer in the presence of people. Within a few generations not only had they gotten calmer foxes but their coats now had while feet, tips of tails, they had floppy ears, and they barked.
I thought I pretty much did cite sources if I was not using my own words. I am not ruling out that I may have accidentally left out a source, but I just reviewed my post again and I am not seeing any missed citations.
Paraphrasing, which is putting someone else's specific ideas in your own words, still needs citation. This is a standard in science but I understand why you did not do it in this venue.
BUt you get paid for such things as geologic time. I know you mean well for me, but I don't question the geochronologist who defines it Anthropic by the universe. Of course there stratigraphy but we DO make theories in advance for what to look for. Hume I understand was biotropic.
The first geologists, who were evaluating the evidence and finding a long universe did so, without making any money for it. Geology was one of the earliest, widely practiced sciences. No one was getting paid for their ideas 200 years ago and many came to their scientifically support conclusions about the age of rocks, DESPITE wanting their to be a young earth due to their religious beliefs. People like James Hutton, Charles Lyell, etc who did not make money off of their findings. Both of these men had well paying careers outside of their science, and pursued geology for the love of knowledge alone.
How you can cast aspersions about their motives I have no idea.
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