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TEDx Talks
Published: 2013-12-02
Source: https://www.youtube.com/watch?v=18YwBwIK_no
uhhuh hello today one to tell you about a story that's very interesting to me which is that when Charles Darwin published his origin of species in eighteen fifty nine the world was on average how much more religious world than it is today the ones become much more secular of course his one book didn't have that much evidence but within ten or fifteen years the scientific debate
over evolution was over Dow once book was victorious in international scientific community accepted that evolution was the fact by the eighteen seventies now the question is how could that have happened in a world that was so against evolution and so religiously conservative or is today when the world is relatively speaking much more secular and we have billions of times more evidence many people seem to think
that evolution is controversial these two things to me don't seem to make sense but I think the history of how evolution came to be uncovered in the first place coming Cup can clear this up of course centuries ago people believed that the earth and the animals and plants in its have been created %HESITATION by supernatural deity rather assist depicted in this illustration from Rufus Bible from
the from fifteen thirties a century later archbishop Oscar from Ireland try to estimate the age of the earth by counting the number of generations of particular people named in the Bible he came up with an age of about six thousand years for the age of the earth but of course there are things in the F. called fossils fossils have always been known than not news even
the ancient Greeks and Romans knew about fossils and they explain them as the remains of the giants and monsters from their mythology so here's a an image of of one such these monsters in more recent centuries a clean Europe things like this were very common the set shall like object which we now know is related to a type of oyster was explained as the devil's toenails
and apparently the devil has some pretty nasty problems with his toenails but anyway and needs a pedicure but these were drops in in the millions all over the the well but this is a folk Larisch explanation simply for these objects these were believed to be lightening bolts but it hit the ground when lightning strikes the ground it makes one of these these we're called snake stands
for the obvious reason that they look like coiled up snake there's just one problem with that explanation of course which is none of the snakes have heads but some local craftsmen were able to fix that by carving some heads on to them here's another very common type is a cold tongue stones I'm not sure why they look much like a tongue to me but anyway it
was tongue stones that first unlocked the secret of what fossils actually are and was this man AM Danish bishop name Stina who first establish that the reason these tongue stones look just like the teeth of sharks is that they are the teeth of shocks only that they'll fossilized and that got him to think very seriously for the first time how could it object part of a
dead animal like a tooth become embedded in the middle of a rock I'm in shock Steve was once in the sea well he he M. discovered various things about stratigraphy that is that in places in the us where the rocks are said a man treat they began as model silt and settled in a horizontal fashion the bottom of the sea or lake and that any hard
objects that fell in that mud would slowly be buried and if more and more sentiment accumulates on top eventually those layers become compacted and they become %HESITATION shale or sat and sun stems but one of the important revelations of this work of course is that that means that players settle sequentially on top of each other which means that the lower layers are older and the upper
layers on newer and thus it was possible to start to unlock the mysteries of the history and the earth by examining the earth itself a hundred years later the Scottish geologist Hutton there was you such studies like in this diagram here he's just describing something called in and unconformity the land is at the bottom also originally accumulated horror horizontally somewhere in the depths of time they
have become tilted up vertically then they had been raised up above the sea so that the top above them has eroded away from the erosion of being in the on the surface of the the land then that sometime after that it is all gone down into the sea again and new layers were deposited on top he said that this sort of thing showed that the earth
must be practically from our perspective eternal it is on imaginatively ancient what about the fossils well it's one thing to say that a little oyster shallower snakes down home if it really is the remains of a living thing they could still be in the ocean somewhere it's very deep or maybe they live %HESITATION and an honorable the remote region that we haven't discovered but fox is
like this you couldn't dismiss in the same way this is the fossil of a mastodon discovered around the beginning of the nineteenth century and the great French comparative anatomists to be a the person to establish for the first time something that was up until then very objectionable that is that living things can go extinct those little shells you could argue well they might still be alive
which you couldn't argue that about a gigantic elephant creature running around North America four cent nobody for centuries had seen any of these giant things running around they were not hiding behind a bush or tree that way stinks and he also prove they were related to the living species of elephants this species called the mega Therion peak beast was discovered in Brazil to reestablish once again
okay this this animal was the size of a car but from its bones and teeth he was able to prove that it was related to a soft which but you'd live uniquely in South America where this fossil was found this also is just way too big to be hiding somewhere they were extinct so extinction was that became an accepted principal in science could we also conducted
very extensive examinations of the Paris basin with his colleague and was able to prove that there had been many different eras in the in the earth's history in this particular region there had been different %HESITATION ecosystems with different plants and animals which have been followed by some sort of flawed or disaster then there had been another age with different plants and different animals and that same
family been wiped away and there's another age all of those species were different in each era and once they vanished they never appeared again they went extinct the Serbs images on the side there are some of his reconstructions of what these animals look like they will mammals but they want like any mammals that were alive today they were unknown types then these were found gigantic ocean
living creatures at first they were thought to be fish but their bones and teeth demonstrated that they were in fact reptiles one of the top with its was they called it and it feels so all fish lizard they didn't have very big give all the best names away the beginning big animal right could use that later too bad and the low one supply CSO these were
also obviously extinct no fishermen had dried up any of these they also were found in a deposits with these bizarre objects they were scattered the millions in the same rock Levitt layers as speak fuel source and indeed with close examination they were even found inside the fossilized bodies of XTO source and soon they figured out what they were these are nothing less than fossel who for
fossil feces if you prefer this is if you're so prove and what it showed was that it could be a source what Connie voice Guzman slicing hoping these copper lights as they are called they contain fish scales and the crime stoppers bones of small XTO souls which led some people to claim what they must've been carnivals an icon of those M. cannibal CF so this allowed
people to start to reconstruct a very realistic idea of what this ancient world looked like and this is the first depiction of the ancient earth you've all seen something that drastic pocket Sentra yes yes very fancy those computer modeling this is the first one the first image of an ancient earth and that they are like this so that's at around see each other and presumably producing
lots of copper let's and shortly after that the dinosaurs were discovered the the so called extinct family with which we are most familiar of giant creatures well all of this was put together by the eighteen thirties so picture that was something like this the world was unbelievably ancient and the fossils that had appeared in it had appeared in a sequential story of progress that is to
say that in the earliest rocks with the most primitive creatures shells and muscles later they were fish after that the reptiles appeared and after that the mammals appeared this was universally accepted by all these men of science long before domino yvolution run the scene because this was not evolution for that this is simply the history of the us and these will all religious man as you
can see from the Reverend William Buckland whose book we're looking at this is a close up of the same diagram just to show you that no where in this history of the earth was any human remains ever found all of human history it's composed of that tiny little white layer of scum at that's all so there was no doubt at all that these ancient worlds existed
before the appearance of human beings and so this is the way these pre Darwinian stupid did the history of life on earth was a story of progressive change over time presumably they thought it was a series of new creations one year after another this is another one you see that most ancient if it's at the bottom and you come up towards the age of mammals then
of course they're all the animals that were being found alive in the world today the diversity of living things was mindboggling was far beyond what had been expected centuries before and so this became a very fashionable subjects to study and try to figure out what was going on with all these living things and they began to categorize them in ways like this which to our modernized
looks like and evolutionary tree but this is not simply a diagram arranging different kinds of mollusks according to groups it's a bit like say mammals you have dogs cats mice those are all different groups but there underneath one group the mammals and then of course we meet Charles Darwin recent graduate of the university of Cambridge get the opportunity to travel around the world on the government
ship beagle as as a naturalist he made some amazing discoveries including his own fossel animals this one the glittered on on the top wasn't extinct giant mammal also almost as big as a car fountain South America and it struck him immediately that this mumble some dinosaur this mammal with bony armor plating on its back was strikingly similar to the only other mammal in the world with
bony arm on its back the armadillo which listen to same place similarly discovered this one called the macro Kenya pata Konica the big neck of Patagonia how would she was told later tonight being correct that it was a giant extinct llama and the same thing was true for Australia they found giant extinct tango ruse killer kangaroos they're fossils were found in caves again the same kind
of creature from the ancient past as in the present of course most famously down went the Galapagos islands and he saw some pretty little birds what was interesting is that he noticed there was seem to be different type of bird on different islands why should that be Darwin as a geologist knew that these islands had erupted as volcanoes out of the ocean they were sterile and
naked and dead species to colonize them as an expert from South America he knew the spurs will obviously south American sort of birds but they were different species it was obvious in those days bats at a local variety could emerge you could take say cattle and horses from Europe taken to America after a hundred years or so they were bit different that wasn't even Lucien that
was just the formation of a local variety they were sure there was some sort of limit beyond which things couldn't change what about those in the Galapagos they they are six hundred miles away from South America they obviously came from South America but that each species independently arrive at its own islands and no other course not it's much more likely that they arrived somehow to the
Galapagos and then diverged and down figured they must have evolved when he got home he took a little bit of time off from theorizing to get married and the consummate not shows that he wants the eggs on his notes on whether or not to get married pros and cons marry not marry I don't have time to read all of them to you but I will just
point out that on the path on the positive side here a constant companion a friend in old age one to fill interest in one at an object to be beloved Emplate with well with any rights above that line better than a dog anyhow the case he was not a romantic he was a scientist and around the same time he drew this notebook sketch which is the
first time that a real and even if your family tree was drawn to represent how living things tend to send from common ancestors and divergent disk into many family groups so this is the same diagram with the dogs I've photo shop the dogs on the downs diagram but to explain from the common ancestor of the dog groups they have all these possible descendants with lots of
them at that I've gone extinct so how to explain that some groups are very similar but others around the different it's from differential relatedness somebody with his idea of natural selection his most famous idea M. but won't go into that so much because I actually had very little to do with the acceptance of his idea which was that all individuals vary some survive and some die
with other evidence was an equally powerful for down series such as embryology embryos the embryos of animals do not start out as little tiny adults that just get bigger and double embryos go through weird set of stages and shapes which all resemble each other despite them being completely different adult organisms so this diagram of total a chicken a dog and a human that embryos all look
remarkably similar at the same stage why because they are related by a common ancestors simply with homologies the same structures in the bones of all of these different animals there was no other explanation and there still isn't whether they share common ancestry why should of the wing of a bat or the paddle of a whale have the same identical bone structure then there are vestigial organs
why should the manatee have fingernails on its flippers what whales that are born and with no teeth when their embryos have teeth in that office well birds that a flightless that have wings well this young man Alfred Russel Wallace came along and the identical theories endowment and promised him into print after twenty years of working on that they publish the origin of species in eighteen fifty
nine shortly after that even more evidence arrived a new fossel this one the Archaeopteryx still one of the most famous fossils in the world halfway between at the dinosaurs and the birds in the shop because it is a dinosaur skeleton but as friends misses the shocking point you've always been told that the dinosaurs are extinct that is not true one family the dinosaurs never went extinct