It’s second week of lecture. Today, we started the class by discussing the worksheet on “Darwin Observations” and “Evidence for Evolution”. Through these exercises, I understand that common ancestry among the species can be come from sources like fossils, biogeography, embryology and anatomy. 

In Darwin’s theory, he stated that all the species have evolved over time from common ancestors through the process called natural selection. Natural selection is a process whereby organisms that are better adapted to the environment tend to survive and produce more offspring. Natural selection happens because of the change in genetic material but not physical traits. And there are 4 principles of natural selection which are variation, overproduction, adaptation and descent with modification.

Later, we were asked to form a group of 4-5 people and started our group activities. Our first group task given by Dr. was choosing the fittest crab among sharpy crab, big spotty and little crabbie. Most of the groups chose little crabbie because it produces large amount of offspring and have better adaptation to the environment.  Actually there was neither right nor wrong in this section, Dr. just wanted to ensure that each of us understand the concept of evolution and natural selection through this interesting activity. After that, we proceeded to the next topic which was history of life. I had difficulty understanding this topic because I don’t like history and I never learn this topic before. 

What I learned in the lesson was the origin of life occurs through chemical evolution and biological evolution. The earth was formed about 4.6 billion years ago and the first life began at 3.8 billion years ago. The first cell began from small organic molecules bonding together to form macromolecules, and packaging macromolecules into protobionts which are able to replicate itself. Prebiotic broth hypothesis explains the chemical evolution occurred on the earth.  This topic is quite long but I will take my time to understand it because history of life is very important, at least we have to know how is life formed and what is our ancestor. The following part of this topic is systematic, taxonomy and classification. I feel much easier learning this topic because previously I have learned about it. Archaebacteria and eubacteria are something I have never learned before.

Their characteristics are almost opposed to each other where cell wall of archaebacteria doesn’t have peptidoglycan while cell wall of eubacteria has peptidoglycan. Phylogenetic tree is new to me as well but I found that it is quite interesting because from the branches I know that whether the species are from the same ancestor.