Prime Time Replay:

Noel T. Boaz
Author of Eco Homo: How the Human Being
Emerged from the Cataclysmic History of the Earth


MsgId: *infinities(176)
Date: Sun Jul 20 20:58:18 EDT 1997
From: Sherry_Baker At: 152.163.195.9

Welcome to Infinities. I'm Sherry Baker and my guest tonight is paleoanthropologist Noel Boaz, author of the new book "Eco Homo: How the Human Being Emerged from the Cataclysmic History of the Earth." Welcome Noel.
MsgId: *infinities(177)
Date: Sun Jul 20 20:58:50 EDT 1997
From: Noel_Boaz At: 168.100.204.58

Hi there!
MsgId: *infinities(178)
Date: Sun Jul 20 20:59:21 EDT 1997
From: Sherry_Baker At: 152.163.195.9

Could you explain how modern paleoanthropology is working with other geologists and paleoecologists and other fields of science to help the solve the mysteries of how and why we hominids became fully human?
MsgId: *infinities(179)
Date: Sun Jul 20 21:00:59 EDT 1997
From: Noel_Boaz At: 168.100.204.58

A big question. The entire field of paleoanthropology is multi-disciplinary. In a nutshell, you can compare the field today to what we did in 1930-1960. They just went out looking for and studying bones. Today, however, we study these bones within a context -- the context of the surrounding sediments, the rocks, and the animal and plant fossils found with them. We analyze the isotpic signiatures of the rock - -and this tells the age of the rock, and also the temperature under which the rocks were deposited.

What does this have to do with human evolution. The origin of our particular group of primates, hominoids - -including ourselves and our closes living relatives, the apes -- happened within the context of changing environments. Specifically, we evolved in the context of cooling environments over the past 15 million years.

MsgId: *infinities(186)
Date: Sun Jul 20 21:07:52 EDT 1997
From: Sherry_Baker At: 152.163.195.9

The earliest hominids are now known at dates between 4 and 5 billion years ago and the earliest homo sapiens are only about half a million years old. Doesn't it seem that a lot of people think that the only reason for the existence of our ancient ancestors was to develop into modern humans? But many of those species -- like australopithecine -- were successful in their own right for an really long time? Until something happened......You believe the evidence is pretty clear that that "something" was a cooling of much of the planet during the Ice Age?
MsgId: *infinities(189)
Date: Sun Jul 20 21:10:03 EDT 1997
From: Noel_Boaz At: 168.100.204.58

There were hominids at 4.5 million years ago. Modern humans were there at half a million years ago. There are apparently a diversity of early hominids, which we call australopithecines. There were successful in their own right and lived for several million years. We have no evidence that there was a drive toward modern humans. There were robust australopithecine, with huge molars and small incisors. They took a very divergent evolutionary pathway from modern humans, and they became extinct. It is clear that there is quite a bit of diversity from 2.5 million years ago to the present.

Then a series of ecological changes, it is my contention, led us to modern human. The environment became more severe. The onset of these fluctuating conditions was about 2.5 to 2.8 million years ago. It was a continuum. On the average,things started getting colder and colder. And, temperatures started fluctuating more. Colder periods were extremely cold and warmer periods were extremely warm, increasingly, as we moved forward to the present.

MsgId: *infinities(193)
Date: Sun Jul 20 21:16:24 EDT 1997
From: Sherry_Baker At: 152.163.195.9

I think a lot of us grew up with the idea that primitive man was on this steady evolutionary course, constantly going "forward", advancing to modern man. Now there's the idea that these other hominids were successful for a long time.
MsgId: *infinities(194)
Date: Sun Jul 20 21:16:44 EDT 1997
From: Noel_Boaz At: 168.100.204.58

These changing environments drove the evolution of modern humans. Increasing brain size, use of fire and tool use -- in a couple of words, technology and culture -- and increasing body size, were responses to the new extremes in environment.
MsgId: *infinities(195)
Date: Sun Jul 20 21:17:31 EDT 1997
From: Sherry_Baker At: 152.163.195.9

And maybe they would have continued without the cataclysmic jolt from a climate change.
MsgId: *infinities(196)
Date: Sun Jul 20 21:19:33 EDT 1997
From: Noel_Boaz At: 168.100.204.58

Yes, this notion of the evolutionary continuum was a widespread belief. There was no way to understand what was driving that evolutionary change. In the book, I discuss a number of ideas about that. One is the red queen hypothesis.

It holds that there is a certain amount of evolutionary change that occurs through time just to maintain a species in a certain ecological position. For instance, if carnivores feeding on a prey species are evolving to become more effective, then the prey must evolve to survive. This is a feedback relationship. We call it co-evolution. If environment is constant, that would be condusive to gradual evolutionary change.

But in the case of human evolution, we see rapid evolution, particularly in brain size. This is a different scenario than the red queen hypothesis.

MsgId: *infinities(197)
Date: Sun Jul 20 21:20:10 EDT 1997
From: Sherry_Baker At: 152.163.195.9

Could you explain a bit about how culture developed? How ecological changes forced, in fact, the evolution of culture as we know it as a means of a rapid response to environmental changes?
MsgId: *infinities(201)
Date: Sun Jul 20 21:24:21 EDT 1997
From: Noel_Boaz At: 168.100.204.58

Culture is a rapid response system -- much more rapid than change by natural selection, resulting in biological. I use the term "superorganic" to refer to adaptation via culture versus genes. In increasingly fluctuating environments, biological change - -at least for humans -- could not keep up. It did not keep up. And culture emerged as a mechanism for meeting our need to evolve to survive.
MsgId: *infinities(203)
Date: Sun Jul 20 21:25:40 EDT 1997
From: Sherry_Baker At: 152.163.195.9

Let's talk about brain size. You discuss in your book how it took brain power to come up with ways to deal with the changing environment. So bigger brains found better soutions and survived better?
MsgId: *infinities(204)
Date: Sun Jul 20 21:26:47 EDT 1997
From: Noel_Boaz At: 168.100.204.58

Yes, and also, as brain size increases, body size increases. Relative brain size increases. That can be seen empirically. How does brain size translate to improved ability to survive? Bigger brain size enabled the evolution of culture. And culture, in turn, was an adaptive measure to these rapidly fluctuating environments.
MsgId: *infinities(206)
Date: Sun Jul 20 21:29:47 EDT 1997
From: Sherry_Baker At: 152.163.195.9

When certain actions worked for a group, then they were repeated in another similar situation, and that led to the development of culture?
MsgId: *infinities(207)
Date: Sun Jul 20 21:33:13 EDT 1997
From: Noel_Boaz At: 168.100.204.58

The mechanism initially was simpler, initially. Culture probably started out in a repetitive, biologically controlled way, as indicated by research on Homo erectus -- our ancestors to about 1.9 million years back to the emergence of homo sapiens.

Homo erectus used the same tools for over a million years. Modern humans cannot stop culture from changing. It changes automatically, but initially, it was much more closely tied to the biology of the group than culture is today. It was sort of a proto-culture, somewhere between chimps and modern humans. Just the beginning.

MsgId: *infinities(210)
Date: Sun Jul 20 21:35:30 EDT 1997
From: Noel_Boaz At: 168.100.204.58

The brain size for homo erectus was 800-900 cubic centimeters. Could they speak? If so, the theory would be that they would have needed to spend their entire childhood mastering it. The big story with homo erectus, in last four or five years, is that research indicates it was the first species of the genus homo to migrate out of Africa. The same environmental forces that caused erectus to migrate out of Africa -- increasing aridity -- continued and are responsible for the appearance of fully modern culture in the Pleistocene.
MsgId: *infinities(211)
Date: Sun Jul 20 21:38:38 EDT 1997
From: Sherry_Baker At: 152.163.195.9

You note that culture changes its content but not its modus operandi from generation to generation. You also talk about the dark side of the external manifestations of culture -- how cultural solidarity that might be appropriate to meeting enviornmental challenges posed to a tropical primate surrounded by the Pleistocene era's ice can be turned inappropriately toward other groups --- and can account for racism.

I have to say I found it a little chilling when you wrote: "We will either use our advanced brains to figure out that our ethnocentrism needs to extend to the entire human species, or one ethnocentric group will hold sway... allowing the rest of the species to go to extinction."

MsgId: *infinities(216)
Date: Sun Jul 20 21:48:25 EDT 1997
From: Noel_Boaz At: 168.100.204.58

The common thread here is that from early hominids to modern homo, we have had small groups in human evolution. Anthropologists called them tribes; generally they number around 25-50. They typify hunter-gatherers. We have evolved to deal with a group of 25-50 people we have known all our lives. This is in our biology, but the culture we negotiate now does not correspond to those tribal conditions, under which we evolved.

Solidarity that we need for surivival in the beginning can actually be a negative in our global society. The only antidote to our natural proclivity to adhere in small groups is through education. One of the big points of Eco Homo is that we evolved out of nature, and we still exist in that context. We haven't ever escaped that. We still exist firmly attached to the biological world, and if we ignore that we can only go so far before we meet the edge of our biological adaptation. Culture has not extended that limit as far as we would like to believe. Earth will carry on just fine if we drive ourselves to extinction, but as a species we can decide not to do that.

MsgId: *infinities(219)
Date: Sun Jul 20 21:56:26 EDT 1997
From: Sherry_Baker At: 152.163.195.9

What else can paleoanthropology teach us about our future? What are we learning about our basic biological adaptations that may help us continue to survive and thrive as a species?
MsgId: *infinities(220)
Date: Sun Jul 20 21:57:44 EDT 1997
From: Noel_Boaz At: 168.100.204.58

Right now, we ourselves are changing the climate. We are increasing Greenhouse gases, and depleting the ozone layer. These changes are just a blip for the earth, but NOT for our own species. We are not ruining the earth, we are just ruining it for ourselves.

Anthropology and paleoanthropology has a lot to say about group dynamics, and relationships between nations and developing nations. The functional community -- at least in terms of our hard-wiring -- is a small group. Culture will have to define the world community as a small group in order for us to effectively resolve the future.

MsgId: *infinities(222)
Date: Sun Jul 20 21:59:28 EDT 1997
From: Sherry_Baker At: 152.163.195.9

Thanks for joining us for this night's edition of "Infinities". We'll leave you with a quote from Noel Boaz's book, "Eco Homo:" "Since our individual lives are so infinitesimally short,it is easy to forget that we are, still, essentially in the Pleistocene.... The glaciers will come again in a few short millennia. And rewinding just a few frames of our recent evolutionary history puts us squarely back around a blazing fire in an Ice Age cave or in a camp beside a dying stream.... Culture allowed us to survive those challenges. Will it be up to the challenges of the future?"

Thank you for being my guest tonight Dr. Boaz. This is Sherry Baker for "Infinities". Good night.

MsgId: *infinities(225)
Date: Sun Jul 20 22:03:10 EDT 1997
From: Noel_Boaz At: 168.100.204.58

Our biology will not change fast enough to meet with our new challenges. We will have to deal with them culturally to prevail. Before I go, I would just like to add one thing about our cities. They are overcrowded, and different than the conditions under which we evolved. One way cultural change should be played out is to make the cities more livable.

It's been a pleasure. Thanks, and good night.


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