Homo erectus and the paradox of human tools

Over the weekend, at the Earth Day tweetup at the Science Museum of Minnesota, I heard an interesting fact: Human beings are now the dominant agent of landscape change on this planet, more than any natural process. (That's right. Suck it, glaciers!)

We tend to think of this kind of thing as a result of modernity. But I think that's only partly true. Modern technology has given us the tools that enable us to change the landscape of Earth in massive ways we weren't capable of in the past. But throughout human existence—even before we were technically human—we have made relatively large alterations to the world. It's not like human beings woke up one day and thought, "Hey, it's the 20th century, let's start messing around with stuff!" In reality, what makes our modern impact on the planet different from past—other than scale—is mainly that we've developed more self-awareness about our impact on the planet, and have actually started talking about whether we like the side effects those impacts bring.

Case in point: A recent study of ancient African animal species that suggests our ancestors drove a huge proportion of fauna to extinction basically as soon as they were technologically capable of doing so. Here's how Ann Gibbons described it at Science Now:

After comparing fossils of 78 species of carnivores that lived during five different periods of time between 3.5 million years ago (when large carnivores were at their peak) and 1.5 million years ago, Werdelin found that all but six of 29 species of large carnivores (animals that weighed more than 21.5 kilos) had gone extinct in that time. Moreover, the mass extinction began just before H. erectus appeared in the fossil record 1.9 million years ago. He also found that the community of carnivores alive 2.5 million to 2 million years ago ate a much broader range of food—with species within a community filling a wider range of dietary niches. By 1.5 million years ago, just hypercarnivores that ate only meat, such as lions and leopards, had survived while omnivores that scavenged and ate a wider range of foods, like civets, had disappeared. "Even I was surprised by the dramatic drop," Werdelin says.

Those omnivores that went extinct were in direct competition for scavenged carcasses with hominins.

This sounds kind of depressing, but I think it should actually make us feel a bit optimistic. Two million years ago, Homo erectus might have killed off 23 species of large carnivores. They had the tools to hunt and the desire to eat. But, even if they'd wanted to, those H. erectus wouldn't have had the tools necessary to organize other H. erectus' and better manage their own use of natural resources.

And that brings me to another interesting point that folks from the Science Museum of Minnesota kept making over and over at the Earth Day event. Modern life has created some pretty serious environmental challenges. But, at the same time, it's also put us in a much better position to deal with those challenges. Humans today are better educated, healthier, wealthier, and better connected with one another than any humans that have ever lived before. Our tools have helped us create some pretty big problems. But our tools are also exactly what we need to solve those problems.

Read the rest of the article at Science Now

Image: Homo erectus tools, a Creative Commons Attribution Share-Alike (2.0) image from hmnh's photostream



  1. The balance of nature seems to be up there with economic equilibrium as elegant mental concepts that has exactly zero to do with reality. Nature keeps displaying large swings in population numbers. Ever so often the Lemming population in Norway will explode, and have been doing so repeatedly for so long that it has become known as a “lemming year”.

    1. It’s been known for decades that population models display chaotic behavior such as booms and busts.  Here’s a parameter-space diagram based on the logistic function (a simple population model):link
      I’m not sure what you mean by “balance of nature” but I doubt it is news to anyone that species sometimes boom and sometimes go extinct.  Not sure that’s indicative of any deeper principal.

  2. I remember Jared Diamond saying something in one of his books about how scientists can always tell approximately when humans first entered a new territory (eg Americas, Australia, New Zealand) because that’s when the mass extinctions occured.

  3. “Our tools have helped us create some pretty big problems. But our tools are also exactly what we need to solve those problems.”
    So what you’re saying is: humans are a buncha tools.

  4. Human beings are now the dominant agent of landscape change on this planet

    Does that explain the popularity of HGTV?

  5. Our tools have helped us create some pretty big problems. But our tools are also exactly what we need to solve those problems.

    Some of the tools you’re talking about are the methods of manufacturing consent used by think tanks, advertising firms, and media companies.  As long as some people benefit from the problems or causes of the problems these tools can be used to divide and confuse the rest of the population.  This is happening right now.

    Tools are like the force.  Using them productively requires restraint; using them destructively doesn’t.  Humans are not good at restraint.

  6. Maggie: Could you please give examples of  “But our tools are also exactly what we need to solve those problems.”  Cases where our tools are helping solve large scale, long term problems without creating even more, similar problems – problems such as resource depletion & species extinction.

    1. The ozone holes? Our phyical tools caused the problem in the first place, but the analytical tools we’ve created enabled us to spot the problem before it got obvious and really serious, and the social tools worked to start to undo that problem.

        1.  It’s the first one I thought of, but I’m not a professional journo, and I’ve no interest in further feeding a depression-troll, so you’ll have to manage on your own.

  7. I’m a’gonna let you finish Maggie, but glacial age erosion was the biggest planet changer of all time! ;)

    1. True. 
      But one could argue that current flora and fauna are far more influenced by humans than by the last ice age that ended 9- to 8000 years ago. 
      I guess they are.  

    2. I think the clincher is “was the”, whereas the post referred to “is the”. If you look historically, we would have asteroid strikes, continental drift that would have had a larger impact than Humans.

  8. What if the decline in carnivore species and the appearance of Homo erectus around 1.8 mya are both consequences of larger climatic and ecological changes? i.e. what if we didn’t hunt them down or outcompete the beasts….the big pointy stabby kitties were going extinct anyway and erectus stepped up to fill the voids? It just doesn’t seem like this study does anything to show why erectus was necessarily the thing doing the extinct-ing.

    1. I was thinking that myself–on the bare fact that we are the last omnivore standing, they have concluded that we knocked down all the other omnivores.  As too often happens in this sort of work, the data does not support the conclusion. A little self-hatred can go a long way in filling in the blanks.

      I’ll file this one with the Scientific American article of a few years back that blamed early agriculture for ending the last ice age (AGW started 6,000 years ago, wouldn’t you know).

  9. I was talking with a co-worker yesterday, who had an interesting idea.  He maintains that the one positive ability humans bring to the planet (whether or not we choose to use it is another question) is our ability to deflect an extinction-event sized asteroid.

    Then again, if we’re the major extinction event ourselves, that might not be much consolation to other species…

  10. > Our tools have helped us create some pretty big problems. But our tools are also exactly what we need to solve those problems.

    I pray that you’re right.  and I’m an atheist.

  11. The arrival of humans to Australia – over 40,000 years ago – closely correlates with a mass extinction of large animals on the continent. It has been suggested that the connection is causal, either directly through hunting, or indirectly through environmental change (there was a large increase in large-scale fires at the same time).
    The theory is contraversial (of course) but the very fact that it is plausible that a stone-age culture of hunter-gatherers could alter the eco-system of an entire continent is significant.

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