Oh, wow, oh, oh, wow, oh, wow, oh, man.

The world, like, you're listening to The Science of Everything podcast, episode 25, tissues, organs and systems.

And I'm your host, James Fodor. In this episode, it's going to be a bit of a mishmash of a few

different things. I'm going to go through, first of all, I'm going to discuss the different

levels of biological organization, from the cellular and atomic level right up to the population and ecosystem level

to give you an overview of how the biological world is categorized for study. And then I'm going

to talk in more detail about tissues, that is sort of around the middle level, just between

cells and organs, which is a level that's sort of often neglected a little bit in biological

courses, perhaps. And it's important to have a basic understanding of different types of tissues

before we go on to talk about the different organs and organs systems in the human body,

which we'll do in subsequent episodes. So this will be a foundation for those future episodes.

Okay, so let's get started. First of all, the levels of biological organization.

So the purpose of this sort of categorization is to give some order to the biological world,

because biology is very complex, and it can be studied at many different levels,

or many different degrees of fineness, if you will, just as you can study astronomy from the perspective

of galaxies or clusters of galaxies or solar systems, planets, etc., as described in the Our Place

in the Cosmos episode. You can also look at biology from different levels, different perspectives as well.

So I'm going to go through those now in order from smallest up to largest. And there's three very basic levels of these categorizations.

The cellular level, or the atomic cellular level, molecular cellular level,

that's everything from atoms right up through cells.

That's the sort of the realm of biochemistry, molecular biology, cell biology, genetics, and so on.

The next group is the organismal level.

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