Agenda 1/24: Guest Lecture

Louise Mead of the non-profit organization, National Center for Science Education gave us an educational lecture about evolution.

Her lecture had 6 major parts:

1. the "Big Idea" of Charles Darwin;
2. the processes or mechanisms of evolution;
3. the patterns of evolution;
4. approaches to understanding divergence;
5. evidences; and
6. Louise Mead's own research on salamanders.

According to the lecture, evolution can be defined as descent for modification or common ancestry. Charles Darwin, an English naturalist, proposed that all species of life have evolved over time from one or a few common ancesters through the process of natural selection.

As shown in the image above, scientists group species by different characteristics, including hair, pre-orbital fenestra, amniotic egg, four limbs, hair, bony skeleton, and vertebrae. Louise Mead explained that the organisms could either suvive or extinct. Yet, many extant and non-extant animals are very closely related. For examples, crocodiles, birds, and dinosaurs shared a common ancester. Moreover, she also clarified that humans are not descended from chimpanzees, gorillas, or bonobos, but the fact that we actually share a common ancester. As shown in the figure below:

The processes of mechanisms of evolution are: natural selection, genetics drift, evolution development("evo-devo"), and mutation. Louise Mead said that mutaion is a very significant factor of mechanisms because without mutation, there would not be evolution.

The patterns of evolution are also very important. Speciation is a process that happens of geological years. Louise Mead showed us a map of the world million of years ago in order to provide us a vision of how geography changes over time. She also used examples such as butterflies and Ensatina eschscholtzii to help her explain.

There are many approaches to understanding divergence. For instances, examine patterns, geographic matters, and test for sexual compatibility.

Lastly, the evidences for evolution are biogeography, comparative anatomy, comparative biochemistry and molecular biology, fossil records, and developmental biology. They have strongly supported the process of evolution and shaped the idea over many decades and are still being discovered.

Reflection

I like the lecture alot because it was very informative and easy to understand since Louise Mead used many pictures to explain. Also, she gave us many useful examples which we did not learn from the class. For examples, the world map that showed how geography changes over time. Moreover, her special lecture, which is different from normal biology lesson, helped to build up my interest on learning evolution. Futhermore, she made the lecture even more interesting by giving us the historical information about evolution and real life information from news article couple days ago, which showed how evolution relates to life today. However, I wish we could have more time because Louise Mead wasn't able to finish the whole presentation.