Biology Basics and Organization

Hello BISC 130. This is the beginning of Recorded Lecture 1-1. Yeah, Chapter 1, very beginning of things. So this chapter is The Study of Life. Very kind of generic intro chapter, but this is going to lay down a lot of foundation, a lot of groundwork that we're going to build off of when we get to more exciting stuff later in the quarter. So biology, compared to all the other sciences out there. Biology is the study of life, of living things. So our first order of business is to define what this is. What does it mean to be? alive what is a living thing and what is not a living thing so we're going to list out and describe the properties of living things which conveniently can be you know fit into this single diagram all all eight of these are meant to represent the eight different properties that living things have so let's start up here in the top left hand corner this is a bunch of cells filled with photosynthetic organelles. What this is meant to represent is how living things are all organized. They're all ordered. This is a very ordered array of cells and the structures they have within them. This sort of organization is something we see on a microscopic level and on a macroscopic level in all living things. So we're going to call this ordered. Organized structures, cells are organized structures, organs. or organized structures just to you know name a couple of these things all living things have this kind of organization and importantly you know side note uh part of this organization means having a cell or cells by our definition all living things are made of one or more cells that means if you ain't got a cell we don't consider you to be alive this becomes very relevant when we talk about virus viruses. They're very impactful to living things. They're very important to understand. They're definitely within the purview of biology. But if we're talking about what is alive and what is not alive, viruses are not made of cells. Therefore, we do not call them, we do not consider them to be living things. So kind of a side note, but very important note here. All living things have one or more cells. All right, what do we got next? Let's move on this top row. This is an unusual example. And sometimes I like an unusual. example instead of a very obvious example. This is a species of mimosa tree. Not all mimosas do this, but this is a plant that folds its leaves up when touched. So yeah, not many plants respond to being touched like this, but this is meant to indicate a response. Again, unusual for plants, pretty common for animals, but all living things are going to do this in one way or another. Sometimes it's obvious, a lot of times it's less obvious, the phrase used. is respond to stimuli. All living things in one way or another, whether it's getting poked or whatever, aren't going to respond to something happening to them instead of just sitting there and having no changes at all. Some examples of this, moving away from danger. Again, yep, plenty of animals are going to run away if they hear or smell something dangerous or move toward nutrients, whether it's plants growing towards a nutrient or, you know, Bacterium or something swimming towards nutrients. This is responding to the world around them respond to stimuli What we got next continue on the top row another unusual example. So this is a starfish or sea star And one limb looks conspicuously bigger than the others. It's because this limb was ripped off of the original sea star and it has started to grow into a new individual this is an example of asexual reproduction obviously not everything can do this but what everything can do is reproduce you know whether it's asexual or whether it's sexual reproduction, making more of themselves is a thing that all living things do. So instead of moving on clockwise, let me move to the next row down here. So yeah, if you're staring at this, this looks like maybe another plant example. If you stare a little bit harder, you may notice this stick looks a little weird. It's got some, looks like legs coming out. And yeah, in fact, This is not a stick at all. This is an insect. called a walking stick. And it greatly resembles the sticks of trees in its environment. This is so it doesn't get eaten by birds and other predators. You know, it looks like a harmless, non-delicious stick. And so it avoids being eaten. eaten. Importantly, this adaptation for survival, this, you know, blends in and doesn't get eaten, this adaptation does not come from the insect, you know, picking up loose sticks and rubbing them on its body or picking up bark. and sticking it to its exoskeleton. This adaptation comes through the process of evolution. So evolution is something we're going to talk about a lot later in the quarter when we get to those chapters, but it's important here because it's something that all living things do. And again, most of these examples are plants and animals, but when we're talking about living things, we have to include fungi, we have to include bacteria, microscopic, single-celled organisms. They're going to go through the process of evolution to adapt as well. Okay, let's move on to this one here. So in the in-person class, I make students guess what they think this embryo is becoming. And it's deliberately a difficult question because this early on, a lot of things look very similar. In fact, this is going to be a mouse, or it is a mouse, but it's going to be more mouse-like as development goes on. And this is meant to illustrate that, development, growth and development, in fact. So not only is this getting bigger as the... this embryo matures, but it's changing and it's becoming less generic mammal and, you know, more mouse-like as time goes on. The phrase here is grow and develop. All living things are going to grow and develop. Importantly, according to instructions in the DNA, so there's a blueprint, there are instructions that you're supposed to, if you're a mouse, you know, grow four limbs and, you know, grow a head at one end and a tail at the other end, you know, very important instructions All living things are doing this. What's next? Ah, the very confusing one here. So I could not come up with a better figure for this. Indeed, by the time we're done with this course, you should understand this. This is an example we'll talk about later in the quarter in a specific chapter. This is meant to illustrate the process of regulation. So just like there are complicated instructions in the DNA telling organisms how to... they're supposed to grow and develop. There are complicated instructions in the DNA telling these organisms how to regulate cell functions, how the cells are supposed to operate, how they're supposed to go about their business and continue working. So again, this one's kind of vague because this is a very abstract kind of property, but it is an important one. All living things regulate themselves through complex genetic mechanisms that regulate uh how the cell functions okay on to onto an easier less abstract one so this is a jackrabbit it's got a couple of conspicuous features here uh these big old ears so they're they're great for hearing things but if you're staring closely at this you can also see these uh these veins the blood vessels throughout these ears these uh organs are great for cooling the animal down, sort of like a s***. heat sink to dissipate heat energy from the blood. This is an example of something called homeostasis. So homeostasis, ah, it's the first key term we've run into. I explained key terms in that recorded lecture zero. Hopefully you watched that one so you kind of know what these lectures are like. The key terms document defines homeostasis as the ability of an organism to maintain constant internal conditions. So yeah, body temperature is an example of that, making sure it doesn't overheat. We do a similar thing by sweating. Other animals, you know, will pant or have other mechanisms for this. Their pH is another example of some normal body condition that needs to be maintained. We'll see examples of that throughout the quarter, actually, of how within our cells and outside of ourselves we maintain normal ph so yeah body temperature several other things they're part of this sort of normal situation that all living things maintain called homeostasis. Okay last one down here this is actually a two-for-one so you know we got a hummingbird here but we also have a flowering plant. This is about energy so the hummingbird is getting energy to you know beat its wings very very quickly it's getting energy from the nectar in this plant. The plant is also getting energy and it's got leaves here. It's capturing energy from sunlight. It's doing photosynthesis. You know, whether it's eating something or doing photosynthesis or several other more obscure ways of doing this, all living things. are going to utilize energy in some way or another and that's what this property is called process energy. All living things take in energy in one way or another and use that energy. So examples include photosynthesis. and eating. Now the last thing about these eight properties I want to point out is that all living things have all of these properties. Again there are some non-living things that have some of these properties. I mentioned viruses before. Viruses absolutely adapt through the process of evolution. But viruses are not made of cells, and viruses don't maintain a normal environment or response. Yeah, so viruses have some of these things, but not all of them. We don't consider something to be alive unless it has all of these things. Okay. Moving on to the other topic in this chapter one, levels of organization. So going to be a lot of key terms in this section, but again, these are terms that hopefully you're all familiar with. with at least a little bit through high school biology or even high school chemistry classes this is just a bunch of terminology that we're going to use throughout the quarter so as far as levels of organization let's start let's start small and get big. So our first level of organization is going to be the atom level. So yeah, pretty small here. There's a big periodic table filled with different types of atoms that we'll see in the next chapter. But as far as biology goes, it's mostly just these six. Most of our biological molecules, most of the stuff that we care about in biology is going to be combinations of just these six atoms. carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. This is not the easiest thing to memorize. However, if you rearrange the letters, you can make S-P-O-N-C-H, which is more fun to say than schnapps or whatever. And, you know, makes me think of this delicious candy. Yeah, sponge, sulfur, phosphorus, oxygen, nitrogen, carbon, and hydrogen. So again, I said there were a lot of key terms definitions. The key terms say an atom is, got my key terms here, starting to have a paper rustling, an atom is defined as the smallest unit of matter that retains all the chemical properties of an element. We'll talk more about atoms in the next chapter, but yeah, this is the smallest thing we're talking about here, and again, these are the six that we really care about in biology. If we take atoms and connect them together, we end up with molecules. So yeah, here's an oxygen and a couple of hydrogen. Hydrogen's attached to it. That's water. Here's something a bit more complicated. Again, we've got nitrogens, oxygens, phosphorus, hydrogen. The carbons aren't shown, but all these things here at the joints, those are all carbons. It's just not listed. This is an example of something called a nucleotide. So we call these structures molecules. Again, key terms definition of molecule. A chemical structure consisting of at least two atoms held together by one or more chemical bonds. And yep, nucleotides are an example of a molecule. H2O water is also an example of a molecule. To get even bigger, we can make even bigger structures. So yeah, does this little thing, this five-sided shape, and then one little thing sticking off on the left, one little thing sticking off on the right. Yeah, that's a nucleotide. So we've taken this big, this complicated molecule, and we've reduced it to kind of a cartoon here. but we've taken not just one nucleotide but another one another one another one another one another one another one if you take a bunch of molecules and put them together you can form larger structures called macromolecules so yeah this is showing how nucleotides come together to form the macromolecule dna here's another quick example this is an individual amino acid You know, the little beads here, individual amino acids. acids, but if you take a bunch of these and string them together, we form the macromolecule called a protein. So the formal definition is a large molecule typically formed by the joining of smaller molecules. DNA and protein, both great examples that we'll see more of in later chapters, both great examples of macromolecules. Now, if you take a bunch of proteins and DNA and carbohydrates and lipids and other. macromolecules, put those together, we can make big complicated structures called organelles. So here's a mitochondria, here's a nucleus. These things look like a Cell this is not a cell. This is smaller than a cell. This does not live Independently these are things that you will find within a cell. So our next level of organization organelle our formal definition a small structure that exists within cells and carries out cellular functions. Again, these do things for the cells, but they are not themselves cells, they're smaller. And yeah, mitochondria and nucleus, two fantastic examples of very important organelles. If we take mitochondria and nucleus and an endomembrane system and lysosomes and a bunch of other organelles, we can finally form an individual cell. So this is a living thing. Organelles do not meet the criteria of being a living thing. Macromolecules are not living things. Molecules and atoms, these are not living things. However, once we get to this level of organization, the sell. level, this is something that can meet our criteria for something that is alive. We've got a bacterium here, and here's a cardiac muscle cell over here, both examples of cells. So what do the key terms say? The key terms defines a cell as the smallest fundamental unit of structure and function in living things. Yeah, like I said earlier, all living things are made of one or more cells. So yes, the smallest unit. A bacterium is is a cell, a muscle cell is a cell. Importantly, we're going to see this throughout the quarter, but I'm pointing this out here. Cells come in two types, prokaryotic cells and eukaryotic cells. So before I read these key terms, let's just look at this visually. Basically, Prokaryotes are simple cells. Eukaryotes are very complex. uncomplicated cells uh yeah not to scale uh but you know i've blown them up about the same size just so we can see our details here uh yeah prokaryotic cell look at what's inside you know there's some dna floating around there's a couple of smaller things here but this is a very simple kind of cell in contrast the eukaryotic cell oh my goodness look at all these different there's a mitochondrion we recognize that and the nucleus and a bunch of other organelles that we maybe don't know yet but will will by the end of the next couple of chapters, there's a ton of stuff going on in this eukaryotic cell, including this nucleus. So our key terms definition, you can always think of prokaryote as simple, eukaryote as complicated. If we want to read the key terms, though, the prokaryote says a single-celled organism that lacks a nucleus and membrane-bound organelles. So yeah, this is kind defined on whether they have a nucleus or not. Very important organelle problem. prokaryotes do not have a nucleus and yeah this includes bacteria so yeah when you hear prokaryote you should think single-celled organism just think of bacteria microscopic organisms eukaryotes let me read the key terms here an organism with cells that have nuclei and membrane bound organelles again a lot more complicated these include us uh so yeah we are eukaryotes uh so are plants and fungi. So again, we're going to going to talk about prokaryotes and eukaryotes throughout the quarter, but I wanted to introduce these here. These are two different types of cells, prokaryotic cells and eukaryotic cells. Oh, I mentioned that these were not to scale. If I wanted to put this to scale, it would look like this. So not only are the prokaryotic cells a lot simpler than the eukaryotic cells, if we put them approximately to scale, they are a lot, lot, lot, lot smaller. Prokaryotic cells are about a tenth the size of eukaryotic cells. Very important to just keep in mind, because we're going to see a lot of figures like this, where they're side by side. It's good to always remember these prokaryotes are a lot smaller. Okay, so as far as organization goes, sometimes the cell is the entire organism. You know, this is a single-celled organism. But sometimes this is just a building off point for something much less. larger. This is not an individual living organism, this heart muscle cell. Sometimes we could take cells and put them together to form bigger structures. Our next level of organization is called tissue. So here we have a bunch of muscle cells put together to form muscle tissue. The key terms defines tissue as a group of similar cells carrying out related functions. So yeah, muscle tissue is a bunch of muscle. cells working together to do a job. we could take a bunch of tissues and put those together to form an organ. In this case we've got the heart, so yeah there's cardiac muscle tissue here, there's also adipose tissue and vascular tissue, and there's connective tissue here, but yeah take in a bunch of tissues and forming an organ. The key terms definition of organ is a collection of related tissues grouped together performing a common function, and yes the heart is an example of an organ. You see See what I mean? Lots of... definitions in this chapter but hopefully most of these are pretty straightforward. If we take a bunch of organs and their accessories and their supporting structures we can form something called an organ system. So here we've got the heart but also all the veins and arteries and capillaries everything connected to that this is the circulatory system. The key terms define an organ system as a level of organization that consists of functionally related interacting organs. So yeah, bunch of organs put together, you got an organ system, circulatory system, good example of that. Now... it may feel like we're done because we've gotten to an organism. Key terms definition, an individual living entity. So yeah, this may seem like the most complicated we can get when we put out circulatory and respiratory and digestive and all the other organ systems together, we get an organism. But actually, we're not done yet. if we take a bunch of individuals and put them take Together, as a group, we do get another level of organization, which we call a population. So a population is, to read from the key terms again, all of the individuals of a single species living within a specific area. So I'm seeing giraffes here. It's not one giraffe. It's several giraffes. there is a population of giraffes in this part of the world does this include every single giraffe in the entire world no it's it's about the the giraffes in this area of africa wherever this happens to be There's also a population of lions. There's also a population of elephants. Hey, there's also a population of termites in this mound. There's also a population of specific bacterial species in this soil. Again, population is a group of individuals of the same species in a specific area. Now, we can get more complicated than that. If we want to look at all the different species, we call that level of organization community. The key terms reads, Community is the set of populations inhabiting a particular area. All of the individuals of all species living within a specific area. So the population was just the lions. The community is the lions and the giraffes and the warthogs and the aardvarks and the zebras and the hyenas. All these populations put together within a specific area. We call that the community. There's a couple more. you ecosystem so the key terms definition of ecosystem is all of the living things in a particular area together with the abiotic or non-living parts of that environment so what do i mean by non-living parts well uh in this example i'm talking about the water uh the air the sunlight sunlight is not alive, but sunlight's pretty dark. important for the living things in this ecosystem. Water is not alive, but it's pretty important that soil and the mineral nutrients in the soil, all these non-living components, we start talking about when we talk about the ecosystem level of organization. And finally, one last one, biosphere, that's just all the ecosystems together. How do I put this formally? Yeah, biosphere, reading from the key terms, the collection of all the ecosystems on Earth. So all the savannas, all the tropical rainforests, all the temperate deserts, all these things put together, the biospheres, all the ecosystems together. So, again, a lot of key terms here. But, yeah, that will do it for the end of this chapter one. And, incidentally, this is also the end of lecture one one. So we'll pick up with the next chapter in the next recorded lecture.

Biology is the study of life, of living things. So our first order of business is to define what this is. What does it mean to be? alive what is a living thing and what is not a living thing so we're going to list out and describe the properties of living things which conveniently can be you know fit into this single diagram all all eight of these are meant to represent the eight different properties that living things have so let's start up here in the top left hand corner this is a bunch of cells filled with photosynthetic organelles. What this is meant to represent is how living things are all organized.

They're all ordered. This is a very ordered array of cells and the structures they have within them. This sort of organization is something we see on a microscopic level and on a macroscopic level in all living things.

So we're going to call this ordered. Organized structures, cells are organized structures, organs. or organized structures just to you know name a couple of these things all living things have this kind of organization and importantly you know side note uh part of this organization means having a cell or cells by our definition all living things are made of one or more cells that means if you ain't got a cell we don't consider you to be alive this becomes very relevant when we talk about virus viruses.

They're very impactful to living things. They're very important to understand. They're definitely within the purview of biology.

But if we're talking about what is alive and what is not alive, viruses are not made of cells. Therefore, we do not call them, we do not consider them to be living things. So kind of a side note, but very important note here.

All living things have one or more cells. All right, what do we got next? Let's move on this top row.

This is an unusual example. And sometimes I like an unusual. example instead of a very obvious example.

This is a species of mimosa tree. Not all mimosas do this, but this is a plant that folds its leaves up when touched. So yeah, not many plants respond to being touched like this, but this is meant to indicate a response. Again, unusual for plants, pretty common for animals, but all living things are going to do this in one way or another.

Sometimes it's obvious, a lot of times it's less obvious, the phrase used. is respond to stimuli. All living things in one way or another, whether it's getting poked or whatever, aren't going to respond to something happening to them instead of just sitting there and having no changes at all. Some examples of this, moving away from danger.

Again, yep, plenty of animals are going to run away if they hear or smell something dangerous or move toward nutrients, whether it's plants growing towards a nutrient or, you know, Bacterium or something swimming towards nutrients. This is responding to the world around them respond to stimuli What we got next continue on the top row another unusual example. So this is a starfish or sea star And one limb looks conspicuously bigger than the others.

It's because this limb was ripped off of the original sea star and it has started to grow into a new individual this is an example of asexual reproduction obviously not everything can do this but what everything can do is reproduce you know whether it's asexual or whether it's sexual reproduction, making more of themselves is a thing that all living things do. So instead of moving on clockwise, let me move to the next row down here. So yeah, if you're staring at this, this looks like maybe another plant example. If you stare a little bit harder, you may notice this stick looks a little weird. It's got some, looks like legs coming out.

And yeah, in fact, This is not a stick at all. This is an insect. called a walking stick.

And it greatly resembles the sticks of trees in its environment. This is so it doesn't get eaten by birds and other predators. You know, it looks like a harmless, non-delicious stick.

And so it avoids being eaten. eaten. Importantly, this adaptation for survival, this, you know, blends in and doesn't get eaten, this adaptation does not come from the insect, you know, picking up loose sticks and rubbing them on its body or picking up bark.

and sticking it to its exoskeleton. This adaptation comes through the process of evolution. So evolution is something we're going to talk about a lot later in the quarter when we get to those chapters, but it's important here because it's something that all living things do. And again, most of these examples are plants and animals, but when we're talking about living things, we have to include fungi, we have to include bacteria, microscopic, single-celled organisms.

They're going to go through the process of evolution to adapt as well. Okay, let's move on to this one here. So in the in-person class, I make students guess what they think this embryo is becoming. And it's deliberately a difficult question because this early on, a lot of things look very similar.

In fact, this is going to be a mouse, or it is a mouse, but it's going to be more mouse-like as development goes on. And this is meant to illustrate that, development, growth and development, in fact. So not only is this getting bigger as the... this embryo matures, but it's changing and it's becoming less generic mammal and, you know, more mouse-like as time goes on.

The phrase here is grow and develop. All living things are going to grow and develop. Importantly, according to instructions in the DNA, so there's a blueprint, there are instructions that you're supposed to, if you're a mouse, you know, grow four limbs and, you know, grow a head at one end and a tail at the other end, you know, very important instructions All living things are doing this.

What's next? Ah, the very confusing one here. So I could not come up with a better figure for this.

Indeed, by the time we're done with this course, you should understand this. This is an example we'll talk about later in the quarter in a specific chapter. This is meant to illustrate the process of regulation.

So just like there are complicated instructions in the DNA telling organisms how to... they're supposed to grow and develop. There are complicated instructions in the DNA telling these organisms how to regulate cell functions, how the cells are supposed to operate, how they're supposed to go about their business and continue working. So again, this one's kind of vague because this is a very abstract kind of property, but it is an important one. All living things regulate themselves through complex genetic mechanisms that regulate uh how the cell functions okay on to onto an easier less abstract one so this is a jackrabbit it's got a couple of conspicuous features here uh these big old ears so they're they're great for hearing things but if you're staring closely at this you can also see these uh these veins the blood vessels throughout these ears these uh organs are great for cooling the animal down, sort of like a s***.

heat sink to dissipate heat energy from the blood. This is an example of something called homeostasis. So homeostasis, ah, it's the first key term we've run into. I explained key terms in that recorded lecture zero.

Hopefully you watched that one so you kind of know what these lectures are like. The key terms document defines homeostasis as the ability of an organism to maintain constant internal conditions. So yeah, body temperature is an example of that, making sure it doesn't overheat.

We do a similar thing by sweating. Other animals, you know, will pant or have other mechanisms for this. Their pH is another example of some normal body condition that needs to be maintained.

We'll see examples of that throughout the quarter, actually, of how within our cells and outside of ourselves we maintain normal ph so yeah body temperature several other things they're part of this sort of normal situation that all living things maintain called homeostasis. Okay last one down here this is actually a two-for-one so you know we got a hummingbird here but we also have a flowering plant. This is about energy so the hummingbird is getting energy to you know beat its wings very very quickly it's getting energy from the nectar in this plant.

The plant is also getting energy and it's got leaves here. It's capturing energy from sunlight. It's doing photosynthesis.

You know, whether it's eating something or doing photosynthesis or several other more obscure ways of doing this, all living things. are going to utilize energy in some way or another and that's what this property is called process energy. All living things take in energy in one way or another and use that energy.

So examples include photosynthesis. and eating. Now the last thing about these eight properties I want to point out is that all living things have all of these properties. Again there are some non-living things that have some of these properties. I mentioned viruses before.

Viruses absolutely adapt through the process of evolution. But viruses are not made of cells, and viruses don't maintain a normal environment or response. Yeah, so viruses have some of these things, but not all of them. We don't consider something to be alive unless it has all of these things.

Okay. Moving on to the other topic in this chapter one, levels of organization. So going to be a lot of key terms in this section, but again, these are terms that hopefully you're all familiar with.

with at least a little bit through high school biology or even high school chemistry classes this is just a bunch of terminology that we're going to use throughout the quarter so as far as levels of organization let's start let's start small and get big. So our first level of organization is going to be the atom level. So yeah, pretty small here.

There's a big periodic table filled with different types of atoms that we'll see in the next chapter. But as far as biology goes, it's mostly just these six. Most of our biological molecules, most of the stuff that we care about in biology is going to be combinations of just these six atoms.

carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. This is not the easiest thing to memorize. However, if you rearrange the letters, you can make S-P-O-N-C-H, which is more fun to say than schnapps or whatever. And, you know, makes me think of this delicious candy.

Yeah, sponge, sulfur, phosphorus, oxygen, nitrogen, carbon, and hydrogen. So again, I said there were a lot of key terms definitions. The key terms say an atom is, got my key terms here, starting to have a paper rustling, an atom is defined as the smallest unit of matter that retains all the chemical properties of an element. We'll talk more about atoms in the next chapter, but yeah, this is the smallest thing we're talking about here, and again, these are the six that we really care about in biology. If we take atoms and connect them together, we end up with molecules.

So yeah, here's an oxygen and a couple of hydrogen. Hydrogen's attached to it. That's water.

Here's something a bit more complicated. Again, we've got nitrogens, oxygens, phosphorus, hydrogen. The carbons aren't shown, but all these things here at the joints, those are all carbons.

It's just not listed. This is an example of something called a nucleotide. So we call these structures molecules.

Again, key terms definition of molecule. A chemical structure consisting of at least two atoms held together by one or more chemical bonds. And yep, nucleotides are an example of a molecule. H2O water is also an example of a molecule.

To get even bigger, we can make even bigger structures. So yeah, does this little thing, this five-sided shape, and then one little thing sticking off on the left, one little thing sticking off on the right. Yeah, that's a nucleotide. So we've taken this big, this complicated molecule, and we've reduced it to kind of a cartoon here. but we've taken not just one nucleotide but another one another one another one another one another one another one if you take a bunch of molecules and put them together you can form larger structures called macromolecules so yeah this is showing how nucleotides come together to form the macromolecule dna here's another quick example this is an individual amino acid You know, the little beads here, individual amino acids.

acids, but if you take a bunch of these and string them together, we form the macromolecule called a protein. So the formal definition is a large molecule typically formed by the joining of smaller molecules. DNA and protein, both great examples that we'll see more of in later chapters, both great examples of macromolecules.

Now, if you take a bunch of proteins and DNA and carbohydrates and lipids and other. macromolecules, put those together, we can make big complicated structures called organelles. So here's a mitochondria, here's a nucleus.

These things look like a Cell this is not a cell. This is smaller than a cell. This does not live Independently these are things that you will find within a cell. So our next level of organization organelle our formal definition a small structure that exists within cells and carries out cellular functions.

Again, these do things for the cells, but they are not themselves cells, they're smaller. And yeah, mitochondria and nucleus, two fantastic examples of very important organelles. If we take mitochondria and nucleus and an endomembrane system and lysosomes and a bunch of other organelles, we can finally form an individual cell. So this is a living thing. Organelles do not meet the criteria of being a living thing.

Macromolecules are not living things. Molecules and atoms, these are not living things. However, once we get to this level of organization, the sell.

level, this is something that can meet our criteria for something that is alive. We've got a bacterium here, and here's a cardiac muscle cell over here, both examples of cells. So what do the key terms say?

The key terms defines a cell as the smallest fundamental unit of structure and function in living things. Yeah, like I said earlier, all living things are made of one or more cells. So yes, the smallest unit.

A bacterium is is a cell, a muscle cell is a cell. Importantly, we're going to see this throughout the quarter, but I'm pointing this out here. Cells come in two types, prokaryotic cells and eukaryotic cells. So before I read these key terms, let's just look at this visually.

Basically, Prokaryotes are simple cells. Eukaryotes are very complex. uncomplicated cells uh yeah not to scale uh but you know i've blown them up about the same size just so we can see our details here uh yeah prokaryotic cell look at what's inside you know there's some dna floating around there's a couple of smaller things here but this is a very simple kind of cell in contrast the eukaryotic cell oh my goodness look at all these different there's a mitochondrion we recognize that and the nucleus and a bunch of other organelles that we maybe don't know yet but will will by the end of the next couple of chapters, there's a ton of stuff going on in this eukaryotic cell, including this nucleus. So our key terms definition, you can always think of prokaryote as simple, eukaryote as complicated. If we want to read the key terms, though, the prokaryote says a single-celled organism that lacks a nucleus and membrane-bound organelles.

So yeah, this is kind defined on whether they have a nucleus or not. Very important organelle problem. prokaryotes do not have a nucleus and yeah this includes bacteria so yeah when you hear prokaryote you should think single-celled organism just think of bacteria microscopic organisms eukaryotes let me read the key terms here an organism with cells that have nuclei and membrane bound organelles again a lot more complicated these include us uh so yeah we are eukaryotes uh so are plants and fungi.

So again, we're going to going to talk about prokaryotes and eukaryotes throughout the quarter, but I wanted to introduce these here. These are two different types of cells, prokaryotic cells and eukaryotic cells. Oh, I mentioned that these were not to scale.

If I wanted to put this to scale, it would look like this. So not only are the prokaryotic cells a lot simpler than the eukaryotic cells, if we put them approximately to scale, they are a lot, lot, lot, lot smaller. Prokaryotic cells are about a tenth the size of eukaryotic cells.

Very important to just keep in mind, because we're going to see a lot of figures like this, where they're side by side. It's good to always remember these prokaryotes are a lot smaller. Okay, so as far as organization goes, sometimes the cell is the entire organism. You know, this is a single-celled organism.

But sometimes this is just a building off point for something much less. larger. This is not an individual living organism, this heart muscle cell. Sometimes we could take cells and put them together to form bigger structures. Our next level of organization is called tissue.

So here we have a bunch of muscle cells put together to form muscle tissue. The key terms defines tissue as a group of similar cells carrying out related functions. So yeah, muscle tissue is a bunch of muscle.

cells working together to do a job. we could take a bunch of tissues and put those together to form an organ. In this case we've got the heart, so yeah there's cardiac muscle tissue here, there's also adipose tissue and vascular tissue, and there's connective tissue here, but yeah take in a bunch of tissues and forming an organ.

The key terms definition of organ is a collection of related tissues grouped together performing a common function, and yes the heart is an example of an organ. You see See what I mean? Lots of...

definitions in this chapter but hopefully most of these are pretty straightforward. If we take a bunch of organs and their accessories and their supporting structures we can form something called an organ system. So here we've got the heart but also all the veins and arteries and capillaries everything connected to that this is the circulatory system. The key terms define an organ system as a level of organization that consists of functionally related interacting organs.

So yeah, bunch of organs put together, you got an organ system, circulatory system, good example of that. Now... it may feel like we're done because we've gotten to an organism. Key terms definition, an individual living entity. So yeah, this may seem like the most complicated we can get when we put out circulatory and respiratory and digestive and all the other organ systems together, we get an organism.

But actually, we're not done yet. if we take a bunch of individuals and put them take Together, as a group, we do get another level of organization, which we call a population. So a population is, to read from the key terms again, all of the individuals of a single species living within a specific area. So I'm seeing giraffes here. It's not one giraffe.

It's several giraffes. there is a population of giraffes in this part of the world does this include every single giraffe in the entire world no it's it's about the the giraffes in this area of africa wherever this happens to be There's also a population of lions. There's also a population of elephants. Hey, there's also a population of termites in this mound. There's also a population of specific bacterial species in this soil.

Again, population is a group of individuals of the same species in a specific area. Now, we can get more complicated than that. If we want to look at all the different species, we call that level of organization community. The key terms reads, Community is the set of populations inhabiting a particular area. All of the individuals of all species living within a specific area.

So the population was just the lions. The community is the lions and the giraffes and the warthogs and the aardvarks and the zebras and the hyenas. All these populations put together within a specific area. We call that the community. There's a couple more.

you ecosystem so the key terms definition of ecosystem is all of the living things in a particular area together with the abiotic or non-living parts of that environment so what do i mean by non-living parts well uh in this example i'm talking about the water uh the air the sunlight sunlight is not alive, but sunlight's pretty dark. important for the living things in this ecosystem. Water is not alive, but it's pretty important that soil and the mineral nutrients in the soil, all these non-living components, we start talking about when we talk about the ecosystem level of organization. And finally, one last one, biosphere, that's just all the ecosystems together.

How do I put this formally? Yeah, biosphere, reading from the key terms, the collection of all the ecosystems on Earth. So all the savannas, all the tropical rainforests, all the temperate deserts, all these things put together, the biospheres, all the ecosystems together. So, again, a lot of key terms here.

But, yeah, that will do it for the end of this chapter one. And, incidentally, this is also the end of lecture one one. So we'll pick up with the next chapter in the next recorded lecture.

Transcript for:Biology Basics and Organization

Transcript for:
Biology Basics and Organization