The second COSMOS episode was all about evolution and described why we have millions of different types of species on Earth today. In fact, the show actually drew up some controversy from the creationist camp.
[A “creationist” is someone who believes in a literal account of creation via the Book of Genesis and denies evolution altogether. Now to be clear, the term “creationist” is confusing, because there are plenty of people who believe in God who also understand that evolution happened (I avoid using the phrase “believe in evolution” here because science is not something you “believe” in, it is something that occurs and at some point you understand it).]
The controversy was introduced by the astronomer/creationist Danny Faulker, who argued that the show COSMOS should give fair show time to creationist viewpoints.
"I think the media has to sort of come out of this ethos that I think was in principle a good one, but doesn't really apply in science. The ethos was, whatever story you give, you have to give the opposing view, and then you can be viewed as balanced," Tyson said, adding, "you don't talk about the spherical earth with NASA and then say let's give equal time to the flat-earthers."
So that happened – now, on to 2 big takeaways from the second episode of COSMOS:
1. Artificial Selection – How dogs were “made”
NDT explained artificial selection by using the example of domesticated dogs. Some 20,000 years ago dogs did not exist as they do today. Instead, there were only wild wolves. Some of these wolves learned to survive by becoming friendly with humans. Humans then handpicked which wolves they liked best and these dogs survived alongside people. This was the first time in history that humans took evolution into their own hands. We turned grey wolves into the domestic pets we see today in the short time period of 15,000 – 20,000 years. In fact, some of the most popular dog breeds today were “created” just in the last few centuries.
If artificial selection could be this powerful in less than 20,000 years, what could natural selection do, operating over the time period of a billion years?
2. Natural selection – “the most revolutionary concept in the history of science”
NDT explained that as living things (both animals and plants) reproduce they make exact copies of their DNA to pass on to the next generation. However, nothing ever works out perfectly. Every once in a while a completely random mutation occurs in the offspring. This could result in different height, different color fur, and sometimes – completely randomly – a trait which gives that offspring a particular advantage. For example, bears with white fur in an arctic environment will have a survival advantage over brown bears living in this snow-covered environment. In that particular environment, the white bears will outlive the brown bears and pass their genes on to the next generation. Boom. Evolution.
Other really cool facts!
- Life started in the sea - therefore, animal eyes had already evolved for a very long time underwater before certain sea animals moved to land. Eventually, humans evolved from *an ancestor* of (see Myke's comment at the bottom of blog) land-living chimpanzees – Because of this, our eyes are not optimized to function in the air – we still have a lot of evolving to do (our eyes at least)!
- Tardigrades (aka “Water Bears”) have been around for a half billion years. They can survive in the vacuum of space and in boiling water. They don’t even need water to survive. They have survived multiple mass extinctions on Earth, including the one that wiped out the dinosaurs - These robust animals have made us question what is required for life to exist.
- Almost every plant and animal that we eat today was bred from a wild, less edible ancestor
- There are as many atoms in a single molecule of your DNA as there are stars in the average galaxy. The same is true for every living thing.
- An individual animal does not evolve – a population of animals evolve over time
- Evidence for natural selection was first presented by Charles Darwin in 1859 - this does not seem like a very long time ago considering evolution is absolutely essential for understanding the concept of life in the universe.
- Biologists have cataloged over 500,000 beetles. That is a ridiculous amount of variety in one specific type of bug. This is just a small example of the crazy amount of different types of living things on Earth today.
- Scientists have not yet discovered most of the forms of life on Earth. This is just mind boggling to me – an example as to why science and terrestrial exploration still has a long, fun, way to go.