How fire and lava may have made us who we are | Michael Medler | TEDxWWU

hello good morning I've got to say following someone who was really honing in on my fear of public speaking was not really how I wanted to do this but all right one more all right well today what I want to talk about is essentially what makes us who we are why are we different than other animals are we and how did we get this way now for the last couple decades a couple folks in particular a guy named Richard Wrangham from Harvard have been proposing that what really makes us who we are is that we eat cooked food which sounds a little quick and trite but he has now written a book and a great many papers and worked with grad students he's got a really strong body of evidence that what makes us different than other Apes and many of our ancestors is that we had access to cooked food and all the extra calories that makes available and it freed up energy for our great big brains which are a great big part of many of the other things people would point out without our languages and our cultures and many things that make us special and he argues that it's that cooked food that was the link that lets us all get going now we have a lot of physical adaptations that he would argue that are linked to having access to cooked food and fire we're not just like the rest of the apes on the planet now or not just like a lot of the ones that have come before us in the last five six million years particularly we have very small teeth very small jaw muscles we can't chew all day most other eighths do gorillas chimpanzees to four hours 12 14 hours a day we can't do that if we have to live on raw food we lose weight it's a great diet in fact if you go on the raw food diet um you'd be in trouble probably without access to airplanes to move food around without oil presses without an almond industry in California it's rough in fact the raw food diet does have side effect for some women that actually read eliminates reproduction which is not a great evolutionary adaptation so Wrangham may be on to something this argument about the raw food he talks about other adaptations besides just our teeth and jaws and our brain size and some people talk about adaptations such as our tool use and our bipedalism and over the last four five six million years there are quite a few folks back there in our family tree there are arguably a dozen or two dozen different hominid species coming through to finally end up in us and these species tend to be smaller have much smaller skulls much smaller brains and for example over here on the on the side sagittal crest s' what makes a gorilla look kind of like the mohawk thing is going on there is a big bone across the top of their skull and that's where the big jaw muscles attach that let them chew for twelve or fourteen hours a day we don't have that crest that's why we don't look like Klingons right so we don't have the jaw muscles that are gonna let us do that kind of all day work now this all seemed to have changed pretty quickly I mean there's a lot of adaptations happening to Lucy and different species before us but somewhere around two million years ago things really changed Australopithecus gets loose in bellingham runs in here that creates a bit of an emergency we have an animal in the room you know there's no there's no faking it for him he's coming in somewhere around two million years ago Homo erectus shows up in Africa Homo erectus shows up here perhaps with the nudity issue but you would be thinking dude get some clothes on or something along those lines more or less recognizable as us in a short period of time couple hundred thousand years brain sizes essentially doubled from the size of a fist to two fists Wrangham and others argue that's because of all of the extra calories available from cooked food the brain is a hugely energy hungry thing it needs a lot of energy now the way we have traditionally viewed our evolutionary processes here are that all these different adaptations have been taking place through millions of yours bipedalism useful for moving fuels around small teeth for quite some time enable to do some of the chewing the other Apes do the arrival of tools the arrival of our big brains all this stuff is taking place and until fairly recently we thought all this happened and then somewhere around a half million years ago thank goodness we started having fire so in that last time period there what you have to believe is that there were big brained animals with jaws that couldn't chew the food all day somehow getting by without airplanes and oil presses and almond orchards now Wrangham would argue there's plenty of evidence that fire was going back at least 2 million years it's our bodies it's the teeth it's the jaw muscles it's the short intestines it's the way we need cooked food now in the last couple of years literally we've been seeing more and more evidence of fire further and further back in the record getting closer interestingly to that two million year point we've seen evidence now in South Africa fire probably being used by ancestors perhaps up to like 1.7 million years so we're starting to see this idea that perhaps we were living in the presence of fire for a much longer time than we thought now this still raises some interesting chicken and egg puzzles now for example bipedalism evolved quite some time ago now I've got to say it's a very useful feature for moving fuels around if you want to make a fire standing on two feet is a great thing moving fuels around but just moving fuels if I move a big wet branch like that and set it on a fire it's gonna just go out right you need intellectual capability to understand dry fuels and moving fuels around is tricky for anything bigger than a stick you need tools to break up fuels you need something that'll break up wood into smaller pieces I've spent a lot of time in the Forest Service fighting fires and we spent a lot of nights on fires trying to stay warm and I'll tell you nothing comes in as handy as a chainsaw to make a bunch of big fires to sleep around when it's raining at night and rains on fires I promise you that interestingly enough we our ancestors have had stone tools for around 1.7 maybe more million years and one of the interesting these tools they're really big here's the sizing I have a big hand pointed out again to me today it's just somewhat of a mystery people argue about what the heck did our ancestors used axes for since there wasn't fire until a half million years ago they must have been really doing an odd job on those mammoths or something um I would argue that even just the name we call them axes we look at that and we know what the tool is now all of these things require mental capabilities making a fire hands up who has ever made a fire just with sticks they found in the woods without matches without a bow I'm waiting for the hands down because you use the bow all right out of a thousand people I got I got about seven it's very tricky I am NOT in that Club this is a failed attempt by the way lots of trying on a hearth with dry kindling lots of videos lots of lessons dried tinder this is technology you know many different people have arguments one way or another but this is the technology all of the rest are impossible without fire go make a go make a chip for your computer without making something hot I dare you and it's hard to do it's a technology it requires thinking it requires language it requires communication that requires culture over probably centuries of sharing this information until whole groups of our ancestors were able to make fire so here's the chicken and egg problem if eating cooked food is what allowed our brains to double in size if eating cooked food and having access to extra energy and heat is what made us evolve literally into who we are today then how the heck did we have access to the fire before we had the brains to do the clever stick tricks and stuff like that before we had language and culture to tell our children hey check out this trick with the stick we can do it's a puzzle and that's actually one of the the criticisms of ragams work is there probably wasn't just enough random fire on the landscape like hey it's Africa let's go over here hey there another fire let's evolve here for a couple million years hey there's another one I've worked around fire fire is tricky to keep going fire is tricky to manage requires a lot of work it requires moving fuels around so just like going out and trimming branches off with this that axe tool would be really useful for knocking off branches if you think back to all the diagrams of our family tree you've seen we're one last little branch up top and a dozen two dozen maybe different species have been chopped off on this tree coming along and evolved to us and in this environment mostly we're talking about in Africa there were variables and factors that led to us and selected out many other alternative species now think about that family tree and think about what you know about evolution here's the classic example Darwin's finches Darwin's on the Beagle he heads to these islands and he notices wow there's finches on all these islands but they sure look different some have big beaks for breaking up seeds others have little beaks what's going on now Darwin not being a geographer took way too long to take a look at where the finches were from on each Island but the key here is Islands evolution doesn't happen really great in billions of individuals spread over whole planets it works really well in isolated pockets we're just a few individuals that might have a particular advantage get to reproduce more get to change over time multi generations so Islands are a big factor in how Ellucian occurs and Darwin finally figured that out and all that so another set of stories however in Africa we had Islands the part of Africa the cradle of life the Great Rift Valley is where we think life was going on in a way that somehow led to us now what is a Rift Valley or Rift Valley is where continental plates are spreading apart lavas coming up and unlike the lava flows in Hawaii today the slob is pouring into internal valleys miles tens of miles wide it has nowhere else to go it's not going to dump into the ocean so forth thousands tens of thousands arguably hundreds of thousands of years and in the Great Rift Valley there were giant lava flows that would have had front edges warm spots hot spots that you could go now some people always tell me you can't get close to that stuff well no you can and we've all been watching Hawaii's people are getting close and enjoying the pleasures of living near lava now in these lava flows in our Africa were immense and there were Islands all over the place for millions of years I've been working with graduate students and undergrads for years making maps now trying to get my head around where these lava flows were occurring and when I've also been having the grad students and undergrads try to figure out where of all of our ancestors were and we have very little evidence we have dozens not hundreds of digs where we've identified australopithecines artifice all these different species I'll let that map sink in a minute the Great Rift Valley of Africa is where all that lavas been flowing into in huge flows and hey look that's where most of our evolutionary story plays out for millions of years there's a few other down in South Africa there's a couple spots over here but this is where we're talking about and the students and I have been working to zoom in and look at different eras particularly this two million year ago point where our brains double in size what was going on wherever the lava flows now this is just a beginning element of research at this point but what we've been finding is pretty exciting stuff most of these ancestors of ours we're living close not necessarily right at lava flows and had exposure to these what I would call islands in the pyrosphere for tens of thousands maybe longer viewers there would be front edges in these huge lava flows in which a small group could live and get used to eating cooked food get used to not needing fur get used to needing two feet and a hand to bring wood maybe back to their campfires that around the front edge of this lava creating a situation in which they'd have access to the food to allow their brains to continue to develop to where we are today once again the parts around the olduvai gorge parts up in Kenya and Ethiopia have this remarkable coincidence in space I'm a geographer what I think is why there what was going on there and this is what I see going on there there are some things happening in the same places in the same time that are worth thinking about and we're gonna keep working on this research here in the near future what I want you to take away from this is this one I big idea we are the fire species we're the only species on earth that makes fire we're the only one I've seen that's good at controlling it I mean you can train a dog to run with a burning stick but I bet you actually you probably can't that's tricky so we have evolved but we've also co-evolved with the fire we take to the planet and in this time when we're thinking about climate change and our effect on the globe and our effect on the landscape it can be very useful to embrace this idea we are the fire animal this is what we bring to the planet this is what we bring to the climate is our interests in fire that are millions of years old it's and we're committed we have to wear clothes we have to have metal we have to have all these tools and we are burning the heck out of everything we touch we bring fire everywhere we go and I think that can be a useful starting point when you think about problems like climate change development deforestation remember you are a fire animal thank you you

Channel: TEDx Talks

Views: 115,731

Rating: 4.8067012 out of 5

Keywords: TEDxTalks, English, United States, Science (hard), Evolution, Human origins, Science

Id: qv6kcj6Uv2Y

Length: 14min 44sec (884 seconds)

Published: Fri Jun 19 2015