It's now time to talk about Charles Darwin and how he came to his idea of evolution by natural selection. But you'll notice here our title is actually Darwin and Wallace, and that's because in the mid-1800s, two naturalists came to the same conclusions about evolution. Alright. So, we're going to talk about Darwin first. Let's introduce you to him.
Well, Darwin was born in 1809. Interestingly, he's actually born the exact same day and year as Abraham Lincoln. Darwin, however, is from a wealthy family of intellectuals. His grandfather, Erasmus Darwin, is a very famous physician and poet, who actually wrote his own ideas about evolution. Now, Darwin himself is training to become a physician, but doesn't like it very much, and he faints at the sight of blood.
So he switches his studies to become a parson, which is basically like a minister in the Church of England. He graduates from doing that, but what he really likes doing is studying nature and collecting beetles, a popular pastime at that time. Then in 1831, the ship, the HMS Beagle, is going to go on a surveying expedition to South America, and they put out an ad for a naturalist, someone who will study the geology and the organisms along the way. Darwin convinces his dad to let him go. Now this is actually a pretty big ask because this naturalist has to pay their own way, and Darwin's dad ends up spending, in today's dollars, a few $100,000 paying for Darwin to go on this trip.
But, of course, it's hugely influential. So, the boat leaves from England. It goes to South America, and along the way, he's making all these observations. He observes fossils. So he actually digs up fossils of the extinct giant ground sloth, the same organism that others have talked about.
And Darwin sees firsthand how the Earth in the past is different from the Earth that we see today. It travels to Chile. And, in Chile, when he's there, he experiences one of the largest earthquakes in modern human history. And he sees how that can change the land, just how Hutton and Lyell said it could. He goes to the Galapagos Islands, and Darwin sort of recognizes, using the ideas of Hutton and Lyell, that these must be kind of young volcanic islands.
And its unique organisms, we're going to say here, on the Galapagos, that make a big impression on Darwin. Right? Things like Darwin's finches. All these different species of birds on these different islands that, in some ways, are very similar to each other, but you don't see anywhere else on Earth. The marine iguanas, these iguanas that swim in the ocean that eat algae that you don't see anywhere else, the iconic Galapagos tortoises.
And Darwin's wondering, why are these young islands so weird? Why are the organisms here so weird? And he rightly surmises, well, if these are new islands, maybe these are the first organisms to get there, and they colonized it and changed to live in this environment. Well, Darwin the boat ends up sailing all the way around the world, and by the time he's getting back to England, he's putting these ideas together. But he realizes this idea, it's a big one, and it's going to be controversial.
So he wants to make sure he has the facts to back it up. He spends the next 20-plus years researching and developing this theory, and in that time, he only tells a few of his closest friends. Now in that time, he also writes a book about traveling around the world, a popular book. It makes him quite famous. He's already quite rich, becomes a very famous scientist.
He's living the life of a wealthy intellectual scientist. And then in 1858, Darwin receives a letter from Alfred Russel Wallace describing a theory identical to his, the theory that Darwin has been working on for all these years. Now Wallace is someone that Darwin knew. They've been exchanging letters. So, let's introduce you to Alfred Russel Wallace then.
Alfred Russel Wallace, well, he's kind of like the working-class Darwin. He's 14 years younger than Darwin. He has a limited formal education. He comes from a family of surveyors. He's trained as a surveyor, but the family businesses tend to fail.
He's teaching, surveying. What he really likes doing is being out in nature, collecting organisms, collecting beetles. And he and a friend decide, you know what? Let's just do it. And together, inspired by people like Darwin, they travel to the Amazon.
And he spends 4 years going up and down the Amazon and the Rio Negro River, charting it, collecting organisms. He almost dies several times. His brother comes to visit him, gets yellow fever, eventually dies. And so, apparently, Wallace gets out of there on a boat back. The boat catches fire, sinks.
He loses all his collection. He does manage to survive and make it back to England. And 2 years later, he goes on another expedition, this time to the Malay Archipelago, what we think of today as Malaysia and Indonesia. Well, here, he's going around from island to island, and he observes the distribution of species. And kinda like Darwin, he's wondering, why are these islands so weird?
He's collecting organisms. He actually collects something like over 100,000 specimens. Now he has assistants, very talented locals who are helping him do this. But as he's doing it, he realizes well, he draws on this map a line, and this line is today known as the Wallace Line or Wallace's Line. And what he sees is that if you're sort of the south or east of this line, what we have here in yellow, these organisms on these islands are much more like the organisms from Australia.
Things like marsupials, like kangaroos. But to the north and the west, well, these organisms, they're much more like the organisms from Asia. Things like tigers and orangutans. Now some of these islands, you can see from each other. So why would you have such differences on islands that have such similar environments so close to each other?
Well, Wallace thinks if the organisms came from Australia and kind of changed along the way, and if the other organisms came from Asia and kind of changed along the way and sort of meet in the middle, that makes sense. And he, in his own words, has malaria. He's having a fever dream, and this idea comes to him. He writes it up, and he sends it to an elder scientist who he's been exchanging some letters with. He sends it to Darwin.
Well, Darwin gets this letter. He realizes that Wallace has had the same idea as him. He shows it to his friend, Charles Lyell, and they decide what they're going to do. Darwin very quickly writes up his own paper, and that same week, these two ideas are published together. Now, Darwin, remember, has been working on this idea for 20 years.
So he spends the next year writing and publishing his book 'On the Origin of Species'. Now because Darwin has been thinking about this and researching it for so long, that book is really well documented, and it's hugely influential in both the popular and scientific communities. So today, because of that book, we largely think of it as Darwin's theory of evolution by natural selection. But if we are being fair, we need to credit the idea to both Darwin and Alfred Russel Wallace. Alright.
We're going to dive into this idea in a lot of depth coming up. I'll see you there.