In 1836 Charles Darwin returned home. He returned to England after five years travelling arround the world, taking as many samples as he could. In his travel, he could notice that there were many types of species. He specially observed the tortoises when he was in the Galapagous, each one with different characteristics. You could see that there were tortoise at first sight, but they were different in some way, for example in the neck. Nothing he investigated during his travel matched together to obtend somthing clear. All was mixed up.

While Darwin was in South America, a man called Charles Lyell wrote a book where he sugested that continents move and originally all continents were together in a big one called Pangea. This theory helped Darwin in his deduction, but it wasn’t the only one. Darwin tried to put that puzzle together:

  • Fossils were one of the proves that things had changed. They were similar to nowadays species, but not the same. Evidence of fossils gave support to Darwin’s posterior theory.
  • In his travel he discovered the enormous diversity of species, and because of so, they can’t all been spontaneously generated. He realised that specied had to develope according to the enviroment.
  • Artificial selection was used since very long time in farming. He started to link how humans select animals to how species change.
  • Thumas Malthus wrote an essay called “Principles of population”. That made Darwin to put all the pieces of his puzzle together. Without deaths the world would be overpopulated. Darwin realised that there is always something that prevent overpopulation in species. The big question was, How and Why will they die to prevent overpopulation?

Finally he got the answer. He arrived to this conclusions:

  • Species change, and this changes take a long time to occur.
  • Because of sepecies change, the number of species will increase.
  • As species increase, they all come from a common ancestor.
  • The survivers of all this species will emerge because of NATURAL SELECTION.

“Individuals that are borned with better adaptations will be the ones who will survive”.

 This picture it shows how different species come from a common ancestor.

 

Questions:

1. What is Pangea?

2. What was the essay, that Darwin read related to population, about? 

3. When talking about adaptation, what species will survive?

4. How did Darwin explained that natural selection take place?

 

Source of information:

http://www.5min.com/Video/Darwin-The-Theory-of-Natural-Selection-150606355 

I hope it is useful 🙂

Ruth Moreno

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