hi in this lecture i'm going to give you some basic biological terms we're going to talk about what makes something living and also just the basics of how biology is organized in other words what are the different levels at which biology is studied i'm going to start with the term biology which really means the study of living things bios means living and logos means the study of so the study of living organisms and it's considering a lot of non-living factors too so two really important terms to know biotic means living and abiotic anytime you see a at the beginning of a word it can sometimes mean without so this would mean without life or non-living and in particular the field of ecology studies the biotic and the abiotic factors in an area so even though biology means the city of living organisms there are some non-living factors that affect living organisms and those are considered by biologists as well what makes something living i think this is especially important to understand in today's world because we're being very affected by something that's considered non-living and that is a virus so viruses are considered to be non-living they are not biological organisms yet they're greatly affecting our lives right now so what is it that makes something living and then we're going to go back to viruses and talk to talk about what makes a virus considered to be non-living and it's basically that it doesn't have all those characteristics of a living organism but the first thing we need to consider is that living organisms are composed of cells and i'm going to put that s in parentheses because there are living organisms that are just composed of one cell those are called unicellular so an organism that's unicellular is composed of just one cell that whole organism is just one cell this includes all bacteria it includes all archaea which we're going to talk briefly about in a few minutes and it includes all protists which we'll also talk about it includes some fungi all other organisms though are what is considered to be multicellular which means composed of more than one cell so this would be the plants the animals and most funjay fungi by the way can be pronounced fungi fungi fungi and we'll talk about them this semester especially as they relate to human health so all living organisms are composed of at least one cell second characteristic that makes an organism a living organism or makes something living is reproduction being able to make a copy of yourself and that can happen one of two ways it can happen through what's called asexual reproduction this is how bacteria reproduce this is how a lot of protists reproduce and other organisms that we'll talk about this semester asexual reproduction means the dna is copied and that cell divides into two identical cells so if you started with one cell that had this bacteria in it and it copies its bacteria oh sorry this is bacteria copies its bacterial dna so now with our two copies of the dna in this cell and now it's going to divide in half to produce two genetically identical cells so that would be asexual reproduction the other option is of course sexual reproduction in which gametes come together to produce a new individual so egg and sperm are called gametes and these gametes unite through what's called fertilization and that first cell is produced called a zygote and that zygote is genetically different from the parents and we'll talk about how that happens semester through meiosis when we say identical cells we mean genetically identical for the asexual reproduction so two categories of reproduction asexual and sexual third characteristic of living organisms is growth and development if an organism is single-celled that growth and development is pretty simple it's just going to start as a small cell and usually develop or grow into a bigger cell multicellular organisms though have a lot of complexity in their development if you think about for example a frog going from that little tadpole as a juvenile all the way to an adult frog i'm not going to attempt to draw an adult frog for you but um an adult frog obviously looks a lot more complex has a lot more complexity than that little tadpole did so that would be growth and development in a multicellular organism think about a baby human becoming an adult human or a caterpillar becoming a butterfly there's a lot of complexity in multicellular organisms developing birth characteristic is all living organisms must obtain and use energy from their environment we're going to talk about two really important energy related processes this semester photosynthesis which is by far the most important chemical reaction that takes place on earth and also cellular respiration you'll learn a lot more about those as time goes on an important term related to energy use that's important to understand from the beginning is metabolism and metabolism is a characteristic of living organisms metabolism is the sum of all chemical reactions that take place in an organism this term is really misused people will say oh i have a low metabolism or i have a high metabolism and they think that means how efficiently they burn calories that is metabolic rate your metabolic rate is different from your metabolism metabolism is an important topic in biology you'll learn a lot about it if you go on to take human physiology we will talk about some metabolic processes in this class as well two of which are photosynthesis and cellular respiration okay number five living organisms respond to stimuli both external and internal so an example of internal stimulus would be your blood glucose levels we will talk about how our bodies maintain a constant supply of glucose in the blood because it's incredibly important and how the body responds when blood glucose levels get too high and how the body responds when they dip back down again external stimulus i'm gonna make the pleural external stimuli because i'm going to give you multiples so these would be things like heat light smell sound those are the external stimuli that were just examples of external stimuli that a living organism would respond to something related to this is really the next factor and that is that living organisms maintain what's called homeostasis homeostasis is an important characteristic of living organisms and i'm going to break this term down for you really that the term tells you what it means sorry i'm trying to change colors here so homeo means same and stasis means state keeping things in the same state homeostasis serves to keep certain factors constant and usually there's what we call a set point which we call the normal value for that factor and if it gets too high there will be something that brings it back down and if it gets too low there will be something that brings it back up so blood glucose level is another example of something that we serve to keep constant in the body things like ph temperature blood glucose your body serves to keep those constant and all living organisms some have some type of homeostasis that they maintain okay number seven all living organisms have dna as the genetic material really keep this in mind when we talk about viruses in a few minutes and talk about why they're not considered living evolving organisms must have dna nothing else as the genetic material and the last one is that living organisms evolve and adapt to their environment the next lecture that you're going to listen to in this class is about microevolution and my micro evolution in evolution in general is also a term that's very misunderstood in biology so i'm hoping to clarify that for you especially with regard to natural selection so this is another characteristic of living organisms in general the the premise is that there are organisms that are better suited to their environment and those are the ones who survive and reproduce passing those adaptive traits onto their offspring so adapting really is in response to the environment and we're going to talk about natural selection which really that's that's the definition of natural selection okay so a virus i'm going to draw a simple virus for you there's this protein coat on the outside and usually surrounding that is what's called the viral membrane and on that viral membrane are some really important markers that are called the spike proteins or the glycoproteins of the virus and then inside this virus is the viral genome and some important enzymes so here we have viral enzymes which are proteins and this would be the viral genome so let's start with the viral genome remember i said remember that living organisms can only have dna as their genome well guess what viruses can have what's called rna as their genome or they can have dna as their genome coronaviruses which clovid19 stands for coronavirus disease 2019 so the virus that has been affecting our lives for the past two plus years is a coronavirus and it has rna as its genome not dna influenza has rna as its genome hiv rna is its genome so some viruses do have dna as their genome sorry about that really sloppy okay but not always some have rna as their genome this virus cannot reproduce on its own and no viruses can viruses cannot reproduce on their own that virus must infect a host cell and use a host cell's machinery to reproduce viruses are not composed of cells what i drew there is not a cell we're going to look at what a cell is in great detail this semester but viruses are not composed of cells viruses do not grow or develop the way living organisms do they do do something called maturation but it's a completely different process viruses do not obtain and use energy so they don't carry out cellular respiration like all other living organisms do viruses do not respond to stimuli either external or internal no homeostasis in viruses but the one thing that they do is they adapt and evolve sorry i'm really writing sloppy now that's how we are getting variants of the virus because viruses do adapt and evolve so if there was anything that would make them possibly considered living it's they do adapt and evolve and they can have dna as their genome but not always in fact most viruses of huge human health significance are rna viruses there are no living organisms that have rna as their genome and viruses do adapt and evolve that is the only process that could be considered living all the other factors that make something living viruses do not have and you're going to learn a lot more about viruses this semester okay now we're going to switch gears and talk about how biology is organized in other words levels at which it's studied including the levels at which we're going to study biology in this course starting with the smallest most detailed level at which we can study biology and that's the level we're going to start at in this class subatomic particles there are many types of subatomic particles but in this class we are going to study protons neutrons and electrons these are particles that make up an atom you might think why are we studying this in a biology class the electrons in particular for each specific element we discuss are going to be incredibly important in determining which atoms bond with which to form compounds and molecules that make living organisms chemical bonding is incredibly important in biology and to understand chemical bonding you have to first understand something about the subatomic particles so we will start with subatomic particles in this class and then we will build up to atoms atoms are the smallest unit of matter that you can break an element down to that still retains all the chemical properties of that of that element so let me write that for you the smallest unit of matter that retains all the chemical properties of that element in other words if i had one atom of gold it would have the same density the same melting point the same boiling point it would be the smallest unit we could break that down to it would have the same number of protons the same number of neutrons same number of electrons as all the other gold atoms anything smaller than that would be considered a subatomic particle matter is another important part of this definition matter is anything that has mass and occupy space so this would be the smallest unit of matter for a chemical element that would still retain all of the chemical properties of that element here i'll write the definition of matter for you matter has mass and occupies space if two or more atoms get together they form a molecule molecules are two or more atoms chemically bonded together we're going to talk a lot about molecules in this class in particular we're going to talk about what we call the macromolecules these are the big molecules that make up living organisms and you'll learn what those are the next highest uh level that or i guess the next would it be the next smallest or the biggest the next level of organization is called cell organelles and that's not really it's kind of a funky one because it's not really a group of molecules even though it's made cell organelles are made of several types of molecules but that's kind of the next level we study it's it's different from the others and that the previous ones don't really all it's not all that really makes the cell organelle but cell organelles are very specific structures within cells and they carry out specific functions within the cell okay so things like the mitochondria the lysosomes the endoplasmic reticulum these are going to be just examples of the cell parts that we studied this semester we're going to talk about the cell in detail and we'll talk about those cell organelles then the next level up is going to be cells we're going to talk about many different functions of cells within the body and you'll learn the various types of cells that that exist in biology specific to the levels of organization and we'll talk about those a little bit more in a few minutes actually that's going to be in the next lecture when i talk to you about how organisms are classified i'm going to talk to you about prokaryotic cells and eukaryotic cells those are the two major categories of cells in biology and i'll talk to you about which organisms are in those categories and what the major differences are between those two types of cells so that will be in in the next lecture cells come together to make tissues so tissues are a group of cells carrying out similar functions and obviously tissues only exist in multicellular organisms so if you're only one cell as all that you are so unicellular organisms don't have tissues so they're just made of one cell this is going to be groups of cells carrying out similar functions um in a lot of biology labs including anatomy you look at tissue types and you can see those similar cells carrying out similar functions they're usually shaped the same they're coordinating with each other communicating with each other to carry those functions different types of tissues come together to form organs so if you took just one organ in your body as an example so something like your kidney your kidney is going to be made out of a lot of different tissue types so organs are made of several tissue types and those tissues come together to carry out the functions of that organ a bunch of organs carrying out similar functions form what's called organ systems so for example your digestive system all the organs of your digestive system are carrying out the function of processing your food extracting the nutrition from that food and eliminating those waste materials at the end so organ systems are really a group of organ organs carrying out similar functions and then all those organ systems come together to form an organism and we've already talked about what makes a living organism but the very important term associated with an organism is this one species we usually refer to a specific species of organism when we're talking about an organism and species as you're going to see when we talk about how organisms are classified in the next lecture species is the most specific so that's where that term comes from species specific it's the most specific level of classification for a living organism to be the same species it means you can mate with that other organism and produce fertile offspring two different species of organism could have babies together but those babies can't have babies okay so the classic example of that is a horse can mate with a donkey these are two different species that baby is called a mule and mules are sterile they cannot have offspring there are no baby mules that came from another mule so once that mule is born it's a combination of a donkey and a horse and donkey and horse are not the same species even though they can produce a baby together so you have to be able to produce fertile offspring to be the same species so that's a very specific level of classification a bunch of organisms of the same species come together to form a very important level of classification in biology and that is a population so a population is a group of organisms of the same species so they can mate and produce fertile offspring and populations are living in the same place at the same time they're interacting with each other they're breeding with each other they're all affected by similar conditions and population is a really important level of organization and biology because this is the level at which evolution occurs populations evolve not individuals sorry i accidentally pushed the crayon get rid of that in a minute so populations evolve not individuals in your lifetime you cannot evolve okay the population that evolves and we'll talk about that very much in detail in the next lecture but population is a really important level to understand in biology the next level of organization is that community i'm still in crayon even though i push the pin again oh well sorry about that let's see if i can get that here we go i was still in crayon a community is all the populations of living organisms in a specific area and the key is that they're all interacting with each other affecting each other competing with each other this is a very important level at which ecologists study biology so a biological community would be all of the bacteria archaea fungi protists animals plants all living together some you know forming food webs competing for resources all that interaction that occurs in a community there are lots of concepts in ecology that are really significant to that but the key is that the community includes the living organisms only this next level of organization is really similar to community but it also includes the non-living factors that affect those living organisms and that level is called the ecosystem so the ecosystem is the abiotic plus the biotic factors of a specific area and we already talked a little bit about what some of those abiotic factors would be but really this is the community right it's all the living organisms plus all of those non-living factors so examples of abiotic factors in an ecosystem that affect living organisms be things like water availability shelter climate sunlight other minerals so those are all non-living things that affect living organisms we could keep going with that list so the ecosystem level of study is very very interesting and then finally the highest level at which you can study biology is what's called the biosphere and this is all the ecosystems of the earth these are big issues in biology such as global warming climate change and how those affect multiple ecosystems on the planet so those are the levels at which biology is studied and in a typical non-major general biology class we cover all of those and if you're taking bio 102 because you're pre-nursing then we don't really talk that much about ecosystems and biospheres and communities but we do talk about populations so all the way up to population level would be in every biology class that we teach and then we would add in communities ecosystems in biosphere if you're taking um a bio 100 class that's all i have for this lecture sorry i'm the tongue is still getting warmed up it's early in the semester my lectures will get better the material will get more interesting and more exciting right now we're just getting a lot of terms out there so you understand those bigger more exciting stories in biology so next we will talk about how organisms are classified and we will talk a little bit about microevolution