Video Transcript: Biology

Biology

Hi. It's Mr. Andersen and in this podcast I'm just going to give you an overview of biology.

Biology, as most of you know, is the study of life. But former students that I have don't usually go on to major in biology, they go into major in biochemistry or molecular biology, or wildlife ecology or evolutionary biology, or they become a biophysicist. And so there are lots of different disciplines that use the concepts that you're going to learn in biology. And even myself, I worked in a biofilm lab for a couple of summers. And just having a basic understanding of biology, I was able to follow most of the conversations that the professors were having, just understanding some of these four concepts. And so basically, those four big ideas were developed by the College Board as they develop the new AP Biology framework, but they're pretty good, pretty good standards. And so those are evolution, free energy, information and systems. In other words, these are four big ideas that are going to cover all of biology. And so as you watch the other podcast, you should always be looking back to these concepts and figuring out which ones, if many it might fit into.

The first one we'll start with is evolution; this is where I always like to start the year. And this right here is a picture of Charles Darwin early in life when he was starting to formulate his ideas on natural selection. And if you ask people, "What did Charles Darwin do?" lots of times, they will just say, "Oh, he invented biology", or "he invented evolution." And that's really not super accurate. He was a proponent of evolution. And I love this right here. It's taken right out of his notebook. And basically, he's, this is a private notebook. And what he's saying is, I think that all life shares common ancestry, there was one life form on the planet. And that split into too and mini after that, and if we look at this is the phylogenetic tree of life that we have today. It looks a whole lot like that early drawing of Darwin with bacteria, archaea, bacteria and eukaryotes on the side. And if we find us, we're way up here on the animals. He was a proponent of what we call macroevolution, in other words, species forming new species. But what really makes him special is that he was the first one to come up with a mechanism to explain how adaptation and evolution actually works. And that's called natural selection.

The quintessential examples with the peppered moths. Peppered Moths in Europe have two different phenotypes or physical appearances: dark and light, the trees were light, relatively, but during the Industrial Revolution, so much soot coming from the coal was making the trees turn black. And so if you're a bird, back in the day, you would pick on the white moths. But as the trees got darker and darker and darker than they started to blend in, and the tree and the birds were starting to isolate on these white moths. And so we saw a change in the number of each of those. And so basically, the MAS aren't changing their appearance. It's just selection in nature that's determining that. And so basically, it's the idea of natural selection. Now, the 

one thing that you should remember is that there are actually five things that can cause evolution. And natural selection is simply one of those five, the other four are small sample size, non-random mating mutations, and then immigration or emigration movement into or out of a population. But if we ever get change in the frequency of a gene pool evolution has occurred. Natural selection is that fifth one. And the nice thing about natural selection is it allows organisms to become better adapted to their local environment. And that's all evolution really is.

Next one is the idea of free energy. And what this means is the energy is going to flow from the Sun to the Earth; on the earth, plants or producers are going to use the process of photosynthesis, to convert the energy into that into sugar. So converting it into sugars that they can build plants out of. And they can use for energy, because plants also do another process called respiration. respiration is a way to release the energy found in sugars, generally in the form of ATP. And so energy is going to flow in this direction to the earth through photosynthesis, to sugars to respiration to ATP, and then it eventually all leaves us something called heat. And so free energy is a big concept. Basically, what it means is it's energy that's a bail available to do work, or energy that's available to do something.

Now another thing that's important, though, within this idea of free energy is just maintaining a stable internal environment. In other words, in this cruel universe where energy is flowing, it's important that you maintain what's called homeostasis. Within this big theme of free energy is the idea of homeostasis, maintaining a stable internal environment, and that's what a plant does. If you can't maintain homeostasis, then you're dead. And so the way we do that is using a feedback mechanism. 

The best example I can come up with for feedback mechanisms are the speed times like this. So you drive by your speed is 30 miles an hour is supposed to be 30 miles an hour. And so you notice that your speed is a little fast, and so you slow down. And now all of a sudden, let's say it's 26, then you speed up. And our body's doing the same thing. Like, for example, inside our body, it's 98.6 degrees Fahrenheit. And how do we maintain that we maintain that through homeostasis, but there's so many other things that we maintain inside our body, like blood, glucose level, blood, calcium level, all of these things have to be maintained osmolarity, in order to keep ourselves alive, and we're utilizing free energy to do that.

Next thing would be the idea of information. That's information flow from organism to organism, generation to generation. And remember, the one thing that we use to do that is DNA. DNA has really taken over biology. When I learned biology, it wasn't as big of a role as it is today. And when your grandparents studied biology, really, they didn't know much about DNA at all; in fact, it was in the 50s, when they finally unlocked the shape of it, but this is what we would call the central dogma of life. And what that means is that basically, the DNA sits in the nucleus of your cell, it makes RNA and that RNA makes proteins. And then those proteins make you. And so you are basically the result of proteins and protein action. But it's the blueprint or the DNA inside you that says this is the proteins that you need to make and when you need to do them. And so that information flow is super important. And if we were to go back to that first organism, what did it have? Well, it had DNA, and that DNA has been copied and mutated and changed and selected through time to create all the organisms that we have on our planet. So information super important.

Within this would be the idea of genetics and genes. This over here is Gregor Mendel and he unlocked that idea. You probably learned how to do Punnett squares, but what a gene is, what an allele is, is important. And then one thing we're starting to really figure out is that you're not static. In other words, you're able to respond to your environment. And so a big thing that's becoming more and more important is cell communication. In other words, cells are communicating communication, hope is spelled that right, cells are communicating with one another. So this right here would be a signal transduction pathway where a lie again hits on a protein, and you have a series of chemical reactions. And so we can actually express a gene and we can make a protein to do something. But nerves, hormones, pheromones, all these things are examples of cell communication. So it's the transfer of information, even a wolf howling at night, is an example of information transfer. So that's another major theme.

And then the final one is the idea of systems. In other words, in biology, we're built on this hierarchy of life, it's sometimes referred to as, and what that means is, that living things are made up of carbon compounds, those are organized into macromolecules, which make organelles which makes cells which make tissues which make organs which make organ systems, which make organisms which make populations which make communities and ecosystems and biomes, and biosphere. So there's this hierarchy of life. We have all these different systems. And at each of these different levels, what we start to get are emergent properties or properties that weren't there at the level before. And so systems and the way systems are organized is important, but just as important is that are interactions. And so this right here is EO Wilson, he's, he's probably the most famous biologist alive today. But basically, you would refer to him as the father of biodiversity. And what he has become famous for showing is that in these major ecosystems, we have interactions between different populations symbiosis, and so all these systems are interacting together. And so all the organs in an organ system like the circulatory system are working together, but so are all the populations in a community. And so, systems and interactions are also another major theme in biology. And so that's kind of the four major themes in biology. It's again, something that you always want to look back to when you're when you're studying new material. And I hope that's helpful.