WEEK 1 – READINGS
ENERGY AND ECOSYSTEMS
This chapter begins by lamenting the human impact on the environment and the constant changes to the environment as a direct consequence of human existence. However, when I read this type of writing (and others like it), I always question why the writer considers human beings as something distinct from the environment. Humans are a part of nature, and alterations to existing environments by organisms prevalent in nature happens ever single day. Species are driven to extinction in areas by a number of factors, and human beings are not the only catalyst for such drastic change.
The author writes that the rippling extinction of megafauna “probably owe something to human expansion and hunting.” (page 81) To me this seems like correlation implying causation, which is not the case. A major factor in human beings becoming as prolific as we did is the change in global environments and a shift in global climate. Such a shift would have certainly caused rippling extinctions throughout the world, regardless of the proliferation of humans.
I disagree with the authors conclusions that a calorie is a calorie, whether in fuel or in food. Perhaps that would be accurate if we were discussing only calories lost from the environment, but the reading discusses it in terms of calories gained by human beings. In the discussions of humans as K-selected species, the reading completely fails to mention the most obvious reason that human beings were able to grow so rapidly despite our classification as a species that might not ordinarily to so: space to move. When humans began filling out the carrying capacity of a certain environment, we simply moved somewhere else. Granted, the movement consumed the environment in different ways and altered it drastically, but the text never goes into this detail.
Neanderthals are actually not an evolutionary dead end in the sense that they were wiped out by competing species or gradually died off on their own. There’s a growing body of evidence that shows that Neanderthals interbred quite readily with Homo sapiens, and thus might have naturally bred themselves into extinction (combined with other factors). It wasn’t a case of being outcompeted.
WILD LIFE OF OUR BODIES
In the introduction Dunn mentions a host of diseases that are emerging and links them to our changing relationships with the world around us, especially all the animals, plants, fungi, and bacteria that we might not be interacting with on a daily basis. However, many of his diseases do not belong on such a list. Sick cell anemia, for one, is a direct result of a genetic mutation that lends the carrier immune to malaria. Distancing ourselves from mosquitoes doesn’t cause sick cell anemia, simply living long enough to the point where the symptoms would become evident does. Autism rates are increasing, that is certainly true. But there’s much evidence for the conclusion that the reason autism rates are increasing is because we are becoming better at diagnosing it, not because the disease itself is on the rise.
Dunn’s introduction reads almost like he believes that we were healthier in the age before technology, in the age of our ancestors. He says we are headed to a time in which our daily lives are more removed from nature and we are “sicker, less happy, and more anxiety-ridden for it.” (Introduction, I can’t find the page number on the ebook). Frankly I believe his entire attitude is delusional. He briefly touches on the fact that we should avoid reverting to wilderness and the dangers associated with it, but then laments repeatedly about our increasing dissociation with nature. Life was brutal and short before we started altering nature to fit our needs. Probably the single biggest life saving feature ever implemented in human society was the chlorination of water systems. Yet chlorinating water is a great removal from Dunn’s attitude of embracing nature. There’s a reason human beings changed their environment and removed ourselves from nature. Nature isn’t some happy environment in which we all thrive and grow equally. Nature is brutal and leads to very short, hard lives.
He comments on how we as a species used antibiotics to rid ourselves of one bacteria and in the process killed off the entire microfauna in our guts. That is utterly ridiculous. Antibiotics certainly are coming around to bite us, because they’ve been abused and misused. Yet there’s a very good reason they were used in the first place. Preserving the microbiome in someone’s gut is an excellent goal, but it’s a hollow victory when that patient subsequently dies from syphilis (or some other bacterial disease, take your pick).
Here’s Ardi, for those interested in what she might look like.
Great post. Two things I’ll respond to…
You mention that Neanderthals may have bred themselves out of existence, and that their extinction was not a result of competition. I’d be careful there.
I’d speculate that competition most certainly played a role, though not an exclusive one. Humans, particularly along (illusory) racial divides, have been very competitive historically, and mass genocide of populations is one thing we’re best known for (e.g., Nazi Germany, Native American genocide, etc.). This competition occurs without precluding our obvious willingness to interbreed.
I’ve just read that human and Neanderthal genomes different by about 0.3% — double the difference found between some human populations. Doesn’t sound like much, but when you consider that humans share 60% of their DNA with bananas, this suggests that a 0.3% difference would probably be enough to seriously exacerbate psychological processes that would lead to conflict. We are programmed to recognize and categorize differences, and to project our negative emotions onto out-groups. Neanderthals were probably more likely to be categorized as out-groups than other groups of Homo sapiens and therefore more likely to be a target of competition than cooperation.
A couple of things with your comment:
Good call on the competition. I meant that where previous theories dealt with a type of warfare that may have extinguished Neanderthals, the truth is that warfare may have only played a (minor) role. Also, regarding racial divides, there are indeed such divides, they’re not illusions. Now don’t get me wrong, I absolutely do not believe the divisions are worth noting or have the slightest bearing on what people are capable of or are worth or anything like that. But biologically speaking there are certainly differences between the races of man. If you’d like we can discuss this at length in person on Tuesday, but I don’t want to have a potential internet discussion that might lead to misunderstandings and accidental racism.
Regarding the differences of DNA, be careful with your numbers. A lot of people don’t understand how much we have in common with almost every living thing, certainly every animal. So the 60% doesn’t really mean much. And yes I agree that out groups lead to conflict, and I’m certainly not discounting conflict as a reason for Neanderthal extinction. However, in anthropology the theories regarding Neanderthal extinction used to run primarily along the lines of warfare between them and Homo sapiens, and today with the new DNA evidence of interbreeding the idea of simply breeding themselves out has become much more accepted.
Great comments though!
There are differences across human populations, yes. For instance. Southeast Asians commonly have a mutation that causes them to be intolerant of alcohol. About 1 in 27 Jews are carriers for Tay-Sachs disease.
My point is that race as most people conceptualize it is not based in fact. I’ve recently watched a TED talk that pointed out that a Nigerian and a Kenyan are more genetically distinct than a Nigerian and a European (can’t recall the exact country in Europe). Our racial divides in society are primarily a product of biased psychological processes that automatically categorize a light-skinned and dark-skinned person as more different than they are. After all, the dark skin of African natives is a product of a single gene involved with melanin production, which is an adaptation to the intense climate and sunlight of Africa.
My point about genetic differences isn’t so much that species are more different than we think. My point is more that our brains are programmed to be keenly aware of differences, even small ones. A 0.3% difference between humans and Neanderthals would certainly be enough for our biased brains to lock onto minute differences and produce erroneous stereotypes and prejudices that would lead to conflict, especially since this happens with a 0.15% difference between human populations.
We can talk about this more in class tomorrow, but Tanner is right – “race” as we use it today (and for the last few hundred years) is a social construct not a biological given. When talking about humans (homo-sapiens) and Neanderthals, we are in that grey area of defining species (a scientific category) – and that definition is debated as well (with inter-breeding being one of the contested areas).
I agree with Dunn that there is much that ties us to our ancestral plains and trees, but I think he romanticizes the old biomes in humans. Taking intestinal worms as an example, the worms provoke a body response to release chemicals that encourage healing not only in the intestines, but also in the lungs. In modern times, healing lungs could be done with different or even the same drugs, but without the damaging parasites. We’ve crafted an environment and a technology that either makes these kind of relationships obsolete, or co-opts their mechanisms and produces the same effects without the negative effects.
On Neanderthals, there seems to be some evidence of interbreeding (2), though to a small extent as would be expected since they could fall into a kind of uncanny valley, being both too much like us and too different for most people.
Thanks, Peter – I should have read this before posting the comment above. Great links to the Smithsonian site on Neanderthals!
I’m glad I read your post! Your thoughts on Dunn complete the uneasy feelings I had with the reading, however I was unable to quite pinpoint why. For some reason, I had an issue with the complete separation of everything humanity has accomplished from nature. That just doesn’t feel right to me, and reading your much more detailed and deeper understanding of the reading gives some weight to the feelings I was having. It certainly seems unfair of Dunn to give an abridged version of humanity’s accomplishments and twist them all in a way which seems very negative. I do see Dunn’s point in that not every process humanity has created has been perfect, (such as the misuse of antibiotics you mentioned) however it’s completely unfair to not credit any of the positive impacts of modern medicine and technology,. I also appreciated your Ardi link. I was really curious to see how she looked!
I do side with your viewpoint on disagreeing that “a calorie is a calorie,” in the reading on Energy. From a fitness standpoint, many would argue that actually counting calories does not produce the dramatic weight loss many seek. Why? In my personal opinion, the body requires a balanced diet, not solely based on the input and output of energy, but the proteins, vitamins, grains, etc. necessary for our growth and development. This applies much to the environment, not everything is used efficiently. As a matter of fact, only 10% of the energy remains as it travels up the food chain, so how can that one calorie come out as one calorie in the end? The basic math does not support this generic statement on energy flow. I also love how involved your post was; it covered various topics in an organized fashion and provided us with a visual to accompany our readings. However, I disagree with your claim that the passage treats humans as an exception to basic evolution. I thought that of the Dunn’s passage, when he stated humans chose to (as some would say) “claim our right” to the top of the food chain, but I found a contrasting viewpoint in the Energy article. One point on page 93 suggests that we co-evolved with the other animals, which in my opinion, puts us in the same gene pool as them. It also would suggest that we depend on the animals to prosper both in natural selection and in the modern world, which brings us to the point of the class; the relationship between man and animal.
Losing 10% of calories for every step of the food chain doesn’t mean the calories vanish into thin air. It means they get used up and are no longer in a form for the next higher animal to consume and utilize. So a calorie can still count as a calorie in the end regardless of what step on the food chain you’re talking about.
I’m not sure where you got that I was saying Dunn treats humans as an exception to basic evolution, I didn’t write that.
Co-evolution does not mean that we share a gene pool. Gene pools refer to the genetic makeup of a species or population, from which all the genetic variations of that species are drawn (not a great explanation but good enough). We co-evolved with dogs, but humans and dogs do not share a gene pool any more than humans and scorpions do.
I don’t really understand your point about how we depend on animals to prosper, are you saying I disagreed with that?
Thanks, Megan, for referring us back to the reading (p. 93 of Stiner and Feeley-Harnick). There’s a quote there we might want to keep in mind as we start talking about domestication today: “Domestication, like every other aspect of hominen existence, arose out of coevolutionary relations of mutual dependence, and the process continues to change both us and our partners in domestication today.” I’m really looking forward to talking about the many good issues raised in the posts during class this afternoon!