This book comes with a certain gravitas as its author is Curator of the Spitzer Hall or Human Origins at the famed American Museum of Natural History in New York City, and one would suppose that it is reflective of the most recent research, as it is only a couple of months old at this point. I suppose, then, that it's somewhat unfair of me to find myself wishing that Ian Tattersall's Masters of the Planet: The Search for Our Human Origins was more engaging than it was.
This is not to say that the book is boring or “textbooky”, as it's not, it's just that it seems to take a very long time to get where it's going … of course, one could certainly argue that the hominid line itself took a very long time to get to current humanity too. As regular readers of my reviews my recall, as I read I generally put in little slips of paper to flag things I want to revisit, either choice bits to drop into one of these scribblings, or information that I want to follow up on. A book which really “grabs me” will have a forest of these sticking out of the top of the book, this had a scant few, and none of them appearing in the first 80% of the text.
My “take away” therefore is that the book spends the first 4/5ths setting up the key final bits. Obviously, in a survey like Masters of the Planet, the author can't necessarily assume that the reader is coming to the text with any in-depth knowledge of the subject (and I found that much of what I have read on the subject has, perhaps, been superseded by subsequent research), so there is a sense that Tattersall is having to fill in the first six or seven million years of hominid evolution as efficiently as he can, a challenging task given the very slim material that researchers have to work with.
It helps to keep in mind that in very many, if not most, cases, what evidence we have of previous hominids may be a leg bone here, a jaw there, a skull if we're lucky, with the occasional nearly-complete skeleton like Lucy. From these scanty remnants, the development of our species is conjectured across millions of years. What complicates matters is that it appears that, through most of that history, there were multiple “types” of hominids living in various niches. As we are used to being the only example of our immediate family extant in history, this is hard to get a hold of, but if you think of it in the way that there are many types of monkeys out there, so there were, at various points in time, multiple hominid lines existing concurrently. As you can imagine, this muddies the waters in terms of sketching out a lineage which leads to modern Homo Spaiens.
One of the things that Tattersall keeps returning to here is that, although these species were related, and similar to us in many ways, they were profoundly different. What qualitatively sets modern man apart from his predecessors and surviving more-distant relatives (the other great apes), is a hard-to-fossilize sense of symbolic relationship with the world. Even recent lines such as the Neanderthals, who may have even had larger brains than ours, don't seem to have had the level of symbolism which enables language and rich, rapid, cultural development. Tool-making preceded our species by several hundred thousand years but it, with few exceptions, stayed very limited, and “frozen” in form and technique generation after generation.
From genetic tracking, we know that the human genome is remarkably non-variant, with the entire of humanity having less variety than some chimpanzee populations in Africa. This suggests two things, that modern man is a very recent development, and that our population has been through some near-extinction “bottlenecks”. Both the genetic markers and geology point to the most dramatic of these being the explosion of Mount Toba in Indonesia some 74,000 years ago, which appears to have created a “volcanic winter” in which the hominid line that was going to emerge as modern Homo Sapiens was reduced in number to the extent where they all could have been seated in a large football stadium. The fact that the variation we see in humanity today came out of adjustments from that small pool of genes and in that short period of time is amazing.
The other thing that is suggested here is that, for whatever reason, there was a change in these hominids, and a part of the brain began to develop called the “angular gyrus”, which is large in our brains but small or missing in other primates. This is in an area of the brain which seems to exchange information in a new way, and may be the seat of symbolic thought. Once this ability to name objects and communicate the symbols was established, it allowed for the development of culture, and the spread of our kind across the planet (not by design, but by simply groups “expanding their range” by a mere 10 miles a generation).
Again, Masters of the Planet is a detailed over-view of the development of our species out of its assorted primate and hominid forebearers, but is far more interesting towards the end (which, I suppose, is a better “arc” for a book than the opposite!) … although this, admittedly, could just be my reaction to the material here. As one would expect for a brand-new book, there aren't many inexpensive options out there, although the on-line guys currently have this at a fairly substantial discount. As it's only been out a few months, your odds of finding it in your local brick-and-mortar book vendors are pretty good. If you're “into” paleoanthropology, or looking for an up-to-the-moment look at the current models of how we got here, this is certainly recommended.