Visit: http://academyofone.org courses: http://www.academyofone.org/courses Royalty free music licensed by http://www.stockmusic.net Royalty free photos licensed by http://www.bigstockphoto.com Script: It’s a dog eat dog world. For every man who makes a million, a man wont and will live on the street. The world today is cruel. But the world today is nothing when you compare it to the early days of earth. In this world you have single-celled eukaryotes and prokaryotes literally eating each other in order to stay alive. So one good way to survive then was to become bigger than the rest of the cells and just eat up the smaller ones. The other way to survive is to be like three kids in a trench coat and pretend to be bigger. Well luckily, most single cells teamed up and this gave us multi-cellular organisms. What’s going on everybody! My name is jack Jenkins and this is Academy of One. Today we are talking about creation of multicellular organisms as well as finally explain the evolutionary timeline. So why did single cell organisms become multicellular? Well one of reasons is because of being eaten by bigger cells like I said in the introduction. Another reason is that there is a huge danger of being a big cell. Believe it or not being big has it’s disadvantages. One of the big disadvantages is not having enough membrane. Everything must go in and out through the plasma membrane including food and waste. The larger the cell the more cytoplasm the cell has and the less membrane per micron of cell. This means the cell either needs to have slow metabolic rate, like algae, or it needs a more efficient way to grow but with more plasma membrane. The solution is to have more than one cell within an organism. I would like to introduce you to Grypania spiralis. Grypania spiralis is the oldest eukaryotic multicellular fossil. This puppy is two point one billion years old. The fossil shows the impressions of ancient algae that contains chloroplast. The Grypania spiralis is great and historically important for a few reasons. First it shows that organisms became eukaryotic before they became multicellular, giving us a nice little timeline for the evolution of organisms. Secondly, this proves the subtle movements of evolution, so I’m not just talking out of my butt. Lastly, it’s a great word to say... Grypania spiralis. So fun. So that’s basically it for multicellular life. For the rest of the video we are going to lay out a timeline for the evolutionary history of life. In the first video we talked about Protocells and the formation of them. The time period of this area is the hadean eon. This era is from the beginning of earth to four billion years ago. The big events for this era is the creation of the organic molecules necessary for life and the giant impact hypothesis. The giant impact hypothesis is how the moon is formed. A planet called theia collided with the earth and theia broke apart. Eventually one of the little moonlets got stuck in our orbit and we have a moon. From four billion years ago to two point five billion years ago we have the Archean eon. This is when we have our Protocells forming into prokaryotes. This is also where we have our buddy luca, last universal common ancestor and the split between bacteria and archaea. The last big thing this eon holds is the formation of a primitive form of photosynthesis which creates a bunch of oxygen. The last eon we have and then we’re all caught up is the Proterozoic eon. The Proterozoic eon held everything we talked about in this video and including the formation of eukaryotes as a response to the increase oxygen as well as the before mentioned multicellular organisms. Also thanks to eukaryotes absorbing small cells and giving us chloroplast, we have enough oxygen to form an ozone layer. Also the first protozoa appears. Got to love that protozoa. So congratulations. You now know the history of life so far. You learned about the hadean eon which is the beginning of earth, the Archean eon which is the formation of life and the Proterozoic eon which is the formation of complex life. Tomorrow we will add to the timeline and learn about the Paleozoic era at the end. The main topic will be on how life came on land. Now Before I go i have to do one last thing to you guys, the three main points. First, multicellular organisms formed because small single celled organisms we’re being eaten and growing into big cells provided a lot of work. Second, Grypania spiralis is proof that this formation of multicellular theory is correct. Lastly, the three eons we covered in the past three videos were the hadean eon, the Archean eon and the Proterozoic eon.

• published: 07 May 2015
• views: 6