One topic that is both controversial as well as difficult to write about is human evolution. For some reason, some people don't feel evolution pertains to us. In fact, as recently as 2012, less than half of the United States believed that humans evolved either with the assistance of, or in the absence of, a God. This is fairly troubling given the number of scientific discoveries and medical therapies that are used by everyone today that would not be possible without the study of human evolution. Evolution is the central tenet behind biology, so much so that trying to "do" biology without evolution would be like trying to fly a plane without the principles of flight. Medicine is not possible without biology, so one can safely conclude that medicine is not possible without evolution. The reason that human evolution is so controversial, and also why it is so difficult to discuss, is that it is far from settled. What Chip Walter does with his book Last Ape Standing is discuss the available evidence and form a story for how we got to where we are today. He does a fantastic job of doing this.
From the beginning of the book, Chip makes you feel quite comfortable with his knowledge base on the topic. He fills you in on how evolution works through natural selection and why the argument that evolution is a random event therefore humans cannot be involved in the process is flat out wrong. What you've become is far from a mistake, you are the product of nearly 4 billion years of the environment on Earth engineering you to become something that can succeed at life in that environment by being born, maturing to the point you can pass on the genes that were passed on to you by your parents, and the same cycle repeating for your offspring. In fact, humans downright thrive on a planet where most organisms just struggle to stay alive long enough to pass on their genes. Who you are now is no more of a mistake than a car having 4 wheels or a plane having 2 wings. Sure, there is the potential that there is a better way, but we don't have it yet. A great example of this is similarities in body plans between water dwelling mammals and fish.
If you compare a land mammal to a fish, there is not a clear similarity between their body plan. Sure, both have 2 eyes, 1 mouth, and a few other similar characteristics, there are quite a few differences. Probably the most obvious is that fish have fins, flippers, and tails while land mammals do not. However, mammals that live in the ocean tend to have all 3 or at least 2. This is because to be successful in the water, one would require these traits to be successful. This is no random mistake, if you don't have a way to move to get food which helps you make it to your reproductive years to pass on your genetic material, you're a goner.
With that basic understanding of evolution, Chip brings you on a journey as to why we are the most successful primate, and why our other human cousins are no longer here. He takes you on a ride to explore the human family tree and the traits of those who came before us and some who were around alongside us for a while. The fact that we are the last one standing is a testimony to not only those traits that solely belong to us, but the traits that our forebears passed on that make us better adapted to the environment we are in. Sure, our brains are far more advanced than any other that came before it, but it would not have been possible to shape that brain had we not come up off all fours, moved from the trees to the savanna, began scavenging food sources high in Omega 3 fatty acids, and eventually began cooking our food.
Many factors apparently played out to make the human brain develop the way it has. Fasting causes cell growth to slow down in every way except for brain cell growth, which increases in times of food scarcity. Our brains are extremely rich in the omega 3 fatty acid DHA that can be found in fish and organ meats, but is not efficiently attained from plant sources. Finally, cooking food makes many nutrients available that we were unable to get to before we cooked food, particularly in meat. Cooking food gives our digestive systems a break and digestion, particularly in other primates that need to break down fibers that we can't, is an expensive process from an energy standpoint. When resources don't need to be directed to digestion, they can be directed to brain development, another expensive process. This is called the expensive tissue hypothesis and is covered in the book.
Another important concept to human development covered in the book is called neoteny.
Compared to other primates, we are born much sooner, develop much slower, and as a result, develop bigger and better brains. While humans and chimpanzees have nearly identical coding genes, our genes are expressed differently. Put another way, it's not the genes, it's how they are used. And how genes are used is dictated by the environment the organism is in. This is what epigenetics and evolution is all about. Chip gives an excellent example of this when he discusses a chance encounter by an anthropologist and a tribesmen who believed a herd of water buffalo in the distance were a type of insect. Since this tribesman's village was in the dense jungle, he never developed the ability to comprehend long distances such as those he was experiencing on the wide open plain they were standing. Since the tribesman was never exposed to that type of environment, the genes that would allow him to comprehend that environment in his brain were never expressed, so he never developed teh abiity to process that type of information.
In a similar light, Chip theorizes that one of the reasons we are still here is possibly because we left Africa when the time was right. Other human species left Africa much earlier than us, but because they were unable to successfully adapt to their environment, or because they adapted to that environment and the environment quickly changed, we took over. Neanderthals left Africa long before us and became adapted to much colder climates than we were at the time. Theoretically, they should have been more suited to the climate and environment of the more northern latitudes that we began creeping in to as they had been there longer, but somehow we either out-competed them for resources, killed them off, or simply bred with them until they folded in to us. An interesting point that Chip makes is that they were unlikely to be able to communicate at the level we could because of the structure of their skull. They likely communicated, but probably not in as sophisticated of a manner as we could. With communication comes the sharing of ideas, the ability to cooperate to attain food, and culture. With all of that, comes creativity.
Toward the end, Last Ape Standing goes over how cooperation and culture are 2 constructs that helped us become who we are. He also discusses some very interesting ways in which some of our behaviors that are seemingly unrelated to our environment that may be a product of our environment. He discusses a theory that people prefer younger looking mates because it would be an indication of the concept of neoteny mentioned earlier. Younger looking people give the impression that they are aging more slowly, and aging more slowly, if it leads to better brain development, would be a desired trait. He also discusses how both schizophrenia and autism may both be products of the brain misfiring during development, essentially neoteny gone wrong. Again, timing is everything.
Honestly, I could have gone on and on about so many of the things that I pulled out of this book. I can't think of another book that is under 300 pages that I pulled so much quality information from. It's hard to hold my attention but this book managed to do it, so much so that I read it in 3 days. This review could easily have been 3-4x as long as it was, but I have a felling Chip Walter wouldn't want me plagiarising his book on my blog. I highly recommend anyone who wants to learn about what got us here to buy this book. It is well written at a level most people with a high school education can understand. Once I get done with a couple of other books that I just bought, I will buy Chip's earlier book Thumbs, toes, and tears: And other traits that make us human.