Welcome to class!
Today we all got to know each other better. You learned that my name rhymes with a hairy ape and not a cheesy snack. I learned that most of you want to go into the health professions and some of you (including myself) aren’t sure what lies ahead for you. No worries, we have time to figure all this out.
We discussed the structure of the course. Here are the most important points:
- You need to fill out your homework forms BEFORE coming to class
- HW should be turned in with the folders at the end of class
- There will be a HW quiz at the beginning of each class
- Weekly reflections are due at the end of each week on Friday at 11:59PM
We all got into teams which we will be in for the rest of the semester. We practiced the IF-AT group quiz scratcher and we did our first in-class assignment.
Finally, we set the weights of all the course assignments. I *hope* that everyone was at least partially satisfied. The updated syllabus with the weights can be found on iCollege.
After a short break……
We discussed the not-at-all controversial topic of how life began on the planet. Miller and Urey did an amazing experiment where they showed that you can create the molecules important to life on earth with just a few basic building blocks, and an input of energy. They “recreated” the atmosphere of early earth in a glass contraption, gave it a spark, and showed that amino acids could be produced. But don’t take my word for it, let the OG celebrity chef Julia Child explain it (fast forward to 2:19, I wonder what would happen if I used that “pointer” in class????)
But more interesting to me is how these molecules then started “acting alive”. To get more to the heart of that debate, we watched Martin Hanczyc’s Ted talk and discussed how he created “non living” but “acting alive” protocells in the lab.
Those little blobs sure do look kinda-alive, don’t they?
Next we talked about how Eukaryotes came to be. This is just as controversial in the science community, but no one seems to unfriend me on Facebook when I start talking about this one.
The prevailing theory about eukaryotic cells showing up is that a pre-eukaryotic cell started developing internal membranes when its plasma membrane folded inwards and then it engulfed a smaller cell capable of a different type of biochemistry (aerobic respiration or photosynthesis).
Once this first cell appeared on Earth, it diversified by spontaneous mutation and natural selection chose the most fit mutants to thrive in each different niche. A few billion years later, we have all the amazing diversity that we see in microbiology today.
Last on the docket was a brief introduction to how viruses may have gotten their start. How you may ask? Well…..
But scientists never let a little thing like “not knowing” get in their way of formulating hypotheses…..
So, we have the Regressive Theory, the Cellular Origin theory, the Co-evolution theory, The RNA World hypothesis/Hydrothermal Vent theory, and the Panspermia theory.
If one theory is good, five must be better… right?
So, for today’s lecture I would like you to focus on:
- The characteristics of life. What are the characteristics of life, and do bacteria always fulfill all of them? Do viruses?
- Fully understand the Endosymbiotic theory. How does it describe the appearance of mitochondria and chloroplasts?
- What are some pieces of evidence that support the idea that mitochondria are descendants of bacteria?
- Be able to describe how random mutation, natural selection and reductive evolution all play a role in determining what types of microbes we see around us today.
- What determines a microbial species?
- Understand the Regressive theory, the Cellular origin theory and the co-evolution theory of viral emergence.
Any questions? Please leave them below!