This week in AP Biology we learned about the formation of Earth, as well as how life began and evolved into all of the complex species of today. The Earth was formed about 4.5 billion years ago, then life began around 4 billion years. The first life was single celled and very simple, but it evolved into more complicated and eventually multi cellular organisms. This relates to Big Idea 1.D: The origin of living systems is explained by natural processes.
We also learned about atomic bonds, which are the connections between valence electrons of atoms. Ionic bonds are where one atom transfers its valence electrons to a different atom, while covalent bonds are where two atoms share valence electrons between themselves.
One theory that I found interesting is endosymbiosis, which is where bacteria is engulfed by a larger cell and instead of breaking it down, it uses the bacteria to preform functions. Two examples of this is mitochondria and chloroplasts. This related to Big Idea 4.A.2: The structure and function of subcellular components, and their interactions, provide essential cellular processes. At first I thought that the bacteria was being used by the larger cell, but it turns out that they benefit from each other; the bacteria gets protection from the larger cell.
We also learned that extinction plays a big part in evolution, and that 99.9% of all species that have ever lived on Earth have gone extinct. To think that all of the species today are only 0.1% of all living things is incredible. Humans have caused many species to go extinct, but I think we can turn that around in the future by being conscious of our environment and the animals and plants that live there.
Sources:
Mickie Wilkinson 