Dawkins vs. Gould Part 2: The Development of Life

Dawkins vs. Gould Part 2: The Development of Life July 5, 2018

Dawkins and Gould describe the history of life on Earth in very different ways.

We continue our discussion of Kim Sterelny’s Dawkins vs. Gould: Survival of the Fittest by focusing on the disagreements between the two scientists concerning the history of life on Earth.

Punctuated Equilibrium vs. Gradualism

Dawkins has always been clear that the cumulative effects of small selection-driven changes are what constitute evolution. The development of life on Earth, according to him, is explained by natural selection driving evolution. Large-scale changes in species are just extrapolations of lots of small-scale change. Gould, however, denies this because it doesn’t jibe with the evidence as he sees it: the physical structures of nearly all living animals are based on body plans that developed in the Cambrian era five hundred million years ago. This difference in viewpoint could be attributable to the fields in which each of the authors worked. Dawkins is an ethologist, after all, so he’s interested in the behavior of organisms. As a paleontologist, Gould approaches the matter from a perspective that reflects body structure and long-term patterns and not just the pressures on the immediate population.

The fact that most species simply appear in the fossil record fully-formed, and remain basically unchanged throughout their existence, is persuasive evidence that strict gradualism doesn’t explain either the rate or the nature of species evolution. Punctuated equilibrium was the model of evolutionary change that Gould and Niles Eldredge formed in response to these challenges, and gradualists like Dawkins either dismissed the idea or made it seem like it was stating the obvious.

The other advantage that Gould has over Dawkins as a paleontologist is that he analyzes a lot of extinct species and speculates on how extinctions, particularly mass extinctions, have made the course of evolution seem more like a series of upheavals than a smooth and gradual development. Sterelny agrees that simply extrapolating local processes can’t give us a valid picture of natural history:

In the case of the dinosaurs, perhaps the meteorite only administered the final blow to a group on the way out. But I do not think that this can be in general true of mass extinction. The changes they impose are too vast. That is particularly true of the catastrophe that struck life at the end of the Permian. Probably more than 90% of animal species then alive went extinct. Extinction on this scale must have caused fundamental reorganizations of life. If so, we cannot understand the overall history of life by projecting, onto the largest scale, processes we see operating in local populations. Mass extinctions are not just local bad news scaled up.

Moreover, Gould, drawing on the work of David Raup, argues that there is a distinctive evolutionary regime in operation in periods of mass extinction. These are not casinos ruled by chance alone. There are principles which would enable us to pick winners and losers. The game has rules. But they are different rules from those of normal times. The magnitude of the upheaval at the Permian/Triassic boundary, and the pace of the upheaval at the Cretaceous/Tertiary (if the impact was important), make it unlikely that the game was fair. Adaptation, we recall, is adaptation to a specific environment. Scramble the environment—drop a polar bear in the desert—and even a species superbly adapted to its previous environment will be in very deep trouble. So, as Raup puts it, extinction was probably ‘wanton.’ Species survival is not random, but the properties on which survival depends are not adaptations to the danger mass extinction threatens. If a meteor impact caused a nuclear winter, then the ability to lie dormant would have improved your chances. But dormancy is not an adaptation to the danger of meteor impacts.

The Meritocracy of Nature

Dawkins’s emphasis on the non-random aspect of evolution serves a political purpose, because we consider competition a positive thing in Western society; not for nothing has “survival of the fittest” come to represent the core truth of evolution in our market-oriented culture. Gould has always remained skeptical of applying Darwinian theory to social and cultural phenomena. His constant battle against sociobiology and evolutionary psychology is motivated as much by his disdain for systems that blame natural processes for social inequities as his scorn for reductionism.

Contingency vs. Convergence

A fundamental disagreement between Dawkins and Gould about natural history is whether, if life had to develop all over again on Earth, it would come out the same way. Gould considers the development of life on Earth a process characterized by contingency, subject to stochastic elements that make a repeat unlikely. Paleontologist Simon Conway Morris took issue with Gould’s thinking, pointing to convergent evolution as evidence that evolution can be characterized as predictable up to a point. Dawkins took Morris’s side, saying he shared Morris’s “enthusiasm for convergence” even if he found some of the paleontologist’s rhetoric quasi-religious. Not surprisingly, Sterelny notes, the jury is still out:

Conway Morris, in Crucibles of Creation, argues that evolutionary convergence shows that history cannot be as contingent as Gould supposes. In convergence, two independent lineages come to resemble one another when both face similar environmental pressures. Old- and new-world vultures, for example, are not closely related birds, but they are very much alike in terms of appearance and behavior.

But there are problems with this line of thought. First, most examples of convergence are not independent evolutionary experiments. For they concern lineages with an enormous amount of shared history, and hence shared development potential. This is true of the standard example of convergent streamlining in marine reptiles, sharks, pelagic bony fish like the tune, and dolphins. Second, the scale is not large enough. The fact that eyes have often evolved does not show that had, say, the earliest chordates succumbed to a bit of bad luck (and become extinct), then vertebrate-like organisms would have evolved again. Third, Gould’s main concern is not with adaptive complexes (the source of Conway Morris’s examples) but with body plans—basic ways of assembling organisms.

I think we have to score Gould’s contingency claims as ‘Don’t know; and at this stage don’t know how to find out.’

Conclusion

Even though they agree that Darwin was right and evolution is an ongoing, natural process, Dawkins and Gould disagree on many fundamental issues concerning natural history. Can life on Earth be explained as a series of gradual increases in fitness adding up eventually to the dizzyingly complex biosphere we see today? Or are other forces and patterns necessary to understand natural history?

Next: Gould and Dawkins disagree on the nature of scientific inquiry itself.

"You got caught in a lie and are clearly acting in bad faith."

The Lacka Ebbidence Ploy: When Science ..."
"Per an update on my blog post which includes the linked Venn diagram, while Kuhn, ..."

Redefining Science With Thomas Kuhn
"Kuhn gets hung up on "established paradigms".The Big Bang didn't really re-write a paradigm....... unless ..."

Redefining Science With Thomas Kuhn
"His description of the social-institutional context of scientific inquiry makes the idea of "self-correcting" science ..."

Redefining Science With Thomas Kuhn

Browse Our Archives

Follow Us!


TRENDING AT PATHEOS Nonreligious
What Are Your Thoughts?leave a comment
  • Thanks for writing this. Dawkins and Gould are 2 of my favorite scientists, and amazingly good writers. I’ve read 11 of their books. However since I’m not a professional biologist, I couldn’t figure out who was right in their huge disagreement on how evolution worked.

    As soon as I finish watching my little grandson this morning, I plan to read your other articles on them:-).

  • Thanks for commenting! I’m not sure the important thing is figuring out who is right, it’s acknowledging that there is a range of opinion in expert circles about the complexities of natural history and empirical inquiry. By all means let’s discuss who you think makes more sense; I tend to lean more toward Gould’s side on most of these issues, but Dawkins makes more than his share of good points too.

  • Based on my own amateur knowledge of biology and evolution and deep history (for a while I majored in anthropology at university), I, too, think Gould’s view of evolutionary history is closer to how it really was. I think this is so even though it seems that Richard Dawkin’s amazing history of evolution back to the start, The Ancestor’s Tale, is the best book on evolution in the last 40 years.

    Side Note: My preferring Gould’s view may be partially my own philosophical bias, because I am more inclined toward the view that some chance and openness characterize reality than the more deterministic views of such as Simon Conway Morris, Sam Harris, Jerry Coyne, etc.

  • Major Major

    There are limitations to the fossil record, which Gould would have known, correct? It is a very difficult process for an organism to form a fossil in the first place, and while it looks like there are jumps in the process of evolution, wouldn’t it be the case that some transitional species might not have fossilized in a recognizable manner?

    Also, we can hypothesize about what conditions where in prehistory, but there could have been localized catastrophes which could have affected certain populations but not others?

  • Gould’s questioning whether what we see in the fossil record is solely due to the spotty nature of the record itself or whether there’s a need for a better explanation for the sudden appearance and stasis of species. Maybe it’s just that the rate of change isn’t constant, but it could be that the processes that create small-scale evolutionary change aren’t the same ones that give rise to new species or body plans.

  • Clancy

    With no formal training in biology, it seems to me that applying Darwinism theory to social and cultural phenomena has to be wrong because the mechanism of change is completely different. Biological evolution operates on the genome in a Darwinism way, but social and cultural phenomena are expressing genes and are subject to imitation and learning, which makes the inheritance and adaptation of changes operate in a way that seems to me to be Lamarckian, not Darwinian.