Just a note on all
narrated lectures you might be viewing throughout the semester.
Most of these lectures have been abbreviated when we are going through
the narration and that's just so you're not spending a
lot of time watching the video on the computer.
With that in mind, always make sure that you go back and
read through the powerpoint presentations to catch up on some more of
the fine details that might be skimmed over or may not be
elaborated on during this narrative lecture presentation. Now in
this first chapter, as we begin this view into biology, we are going to
look at some of the themes that this textbook in particular uses to kind
of guide you down the path of understanding what biology is
and how we can explore biology in different frameworks.
So, first we want to emphasize the fact that with biology,
we are looking at an underlying principle or
theme of evolution and evolution itself we're going to see
later on has a different definition than we're giving you today.
We're going to start just by saying evolution is this process of change
and essentially one of the things as biologists that we look for
in the world around us is how have life forms changed,
how have plants, animals, fungi produce help any one of those things change in
terms of our ability to live on this planet
now later on as we get back into evolution in this chapter and then later
on in the semester uh you will see that we give evolution a
more defined definition and we will say that beyond
the process of change it's also considered this descent with
modification essentially the same idea still we're
looking at the fact that as we do go on to reproduce generation
by generation we are hoping that our offspring are
changed in some way or modified in some way to make sure
that they are adapted to their environments
and capable of surviving in those current conditions
so as we look at other things throughout the semester evolution is one of the
ideas that will always be kind of in the back of our understanding and we will
try to almost always connect your quality chapter link
back to that core idea because it's our basic
basis of understanding for a lot of biology in terms of why things work the
way they do or how things are going to function in that living
world so as we begin this journey with biology
though we want to first kind of start out with
very basic ideas and the first thing is is what is biology what are we looking
at if we are a biologist and the most basic definition for
biology is simply studying life and with that study of life we also have
to think about what is something that's alive and we
could say why the most basic form that it's doing something you think
about a rock versus say a plant a plant can undergo
photosynthesis a plant can take up water a plant can respond to the
environment in terms of maybe adjusting leaf position
for the sunlight it can respond to varying conditions with nutrients or
predation a lot of things that it can do the rock
in the other hand though really doesn't do much it might absorb
energy but it's not going to process it it might have some change over time
through weathering but it's not really doing that
process so we said that life itself in general
is recognized by doing something and we'll come back and emphasize kind of
why that doing something is critical especially in the case of things maybe
like viruses which may not fit our complete
definition of what life is but we can still see that they do something
in terms of this simplicity so in terms of things that can be done
by life forms you can see these several properties or some
of the things that every life form on this planet has to undergo
and if we think back to evolution as the underlying principle underlying theme
we can always start here with reproduction the fact is that every
organism out there is kind of ingrained in their genetics
that they want to reproduce they want to carry
on their genetic line the next generation and that's the one thing that
will allow evolution to continue is the fact that
we are making more individuals every single generation uh to take our
place or to carry on that line of genetics for
that species so everything else beyond the reproduction kind of will follow
suit and the fact that if we reproduce we've
got to have growth and development if we're trying to grow and develop
features you've got to build a process energy
to make sure that's going to the right areas to grow
thicker skin or to grow larger body size you also have to have the process of
regulation and that does tie into our energy processing
but also regulation in terms of things like temperature
regulation of water supply regulation of even food supply you know at food
supply will go along with energy processing
as well but regulation basically means that we're going to maintain
a set of conditions oftentimes we could say as a homeostasis where you're
maintaining the conditions that allows the organism to survive
in those conditions the other thing we can look at is the
fact of ordering this is actually one idea or one property
that we will come back and revisit as we move into our energy chapter
and talk about the rules of thermodynamics and one of the things we
will point out is that with thermodynamics or the flow
of energy within a system you will see that energy itself
tends to want to go to a more disorganized or
disordered state but as a living system we have the capability
of again processing energy in such a way that we can utilize that to actually go
against that disorder or the process of trying
to make more unorganized forms and we instead will go
through and make order which is what's going to allow us to
develop in the process of our reproduction
the process the growth the process even of regulation
the last few properties here will tie back into that coordinate evolution
and that's the fact that as we respond to our environment
we also have this ability to adapt as well
so this venus fly trap responding to the environment
uh where it needs a greater input of nutrients
uh than what the actual soil can provide it's adapted to have
a type of trap mechanism to gather the insects which means it's going to have a
way to lure them in a way to trigger the trap and a way to
digest them so that in itself is an evolutionary
adaptation it's an adaptation that is based on a
response to the environment where it needs to be able to go through
and maintain to build and survive those conditions
again the one core thing out of all these life-giving properties
does come back to this factor reproduction
in fact we think about these later on we're going to see that
when it comes to defining what a life form is made of in this case
called the cell we're going to see one of those key
properties is the fact that a cell has to be able to go
through this process of reproducing or this life form
of reproducing to make more of those cells
now all of this understanding of biology is actually going to focus along what we
call the biological hierarchy essentially with the hierarchy we're
going to look at in a framework where we can move
from the most basic structures so looking at some very small atomic forms
or molecular structures even to our cell
configuration and from there we can move all the way
up into understandings of the entire planet
now throughout our course we're going to focus primarily
in this bottom section of the biological hierarchy
in fact we'll spend the next couple of chapters probably chapters two through
five uh looking at the structure of the atom
and the molecules that we can form from there
and then as we're moving to chapter five look at the macromolecules
we'll start to hit off and go into some of the organelles
which we'll see later on in chapter six and some of those
features that we're gonna form into our cell configurations
now as we do branch off into other forms like reproduction
or looking at evolution as a whole we do momentarily take a glimpse into some of
this population organism structure with a hierarchy but
most of the introductory form for biology is
looking at these core principles because if you want to understand what
happens at a community level you've got to have the basic
understanding of what's happening down here in this molecular and this cellular
form now one thing that we do hope to see and
it'll be quite evident as we go into our chemistry
is the fact that as we move from level to level as we go from one smaller piece
to a larger piece we will see what are called emergent
properties and essentially emergent properties
are taking what is already there and allowing it to arrange in such a way to
produce some new functionality so we have the example here with a
bicycle and all the parts if we give the instructions and we
assemble all those parts correctly you get a functioning bicycle to emerge
but if you happen to misconnect a piece or you leave a piece out or you
rearrange a different way you may not get a functioning bicycle
but you might have something else maybe a pulley system maybe a
unicycle instead of a bicycle but you're going to find that
as you rearrange these smaller bits and pieces it does provide a capability of
having some new functionality as you move up into larger and larger
forms now another thing we're going to look at
again this is going back to the idea of that ordering
within our structure in the thermodynamics is the fact that
for a life form to survive and to reproduce or
to grow and develop it's got to have a way
of taking energy in and transforming it or
transferring it from form to form now typically when we look at most of
our living systems think back to that hierarchy there we
talked about the planet or you can see a little level down below
maybe the community or ecosystem we would say that most energy will flow
into our ecosystem as a source of sunlight in this case
sunlight is a form what we call kinetic energy it's motion as that
energy makes its way through things like the plants out of
the consumer or sorry as a producer and then into maybe a consumer like an
animal it's ultimately going to leave that
ecosystem this case leaving our planet per se as a
form of heat heat is also a form though of kinetic
energy now in amongst all those conversions you
will find that it's not kinetic energy all the way we
do go to other forms like potential energy
this is based sometimes on the chemical structure of an item
or even the location of some of these forms
so structure and location would be our potential energy
motion we're going to see as kinetic energy
now we'll come back and revisit this idea in more detail as we get into
our metabolism and looking at how energy itself can be processed through
an idea like respiration or a process through a form like
photosynthesis and we're going to see how each one of
those will use the energy as a way of transforming or transferring
it forward to form within our system
so to give you an idea of kind of how we approach biology especially in terms
of things like energy or even going back to kind of biological hierarchy
we have a very basic diagram here of the cycling of elements or chemicals in our
system as well as the flow of energy in our
environment and you can see that ultimately here the
energy comes in as this kinetic energy or the light energy and it's going to
leave as this heat which is also kinetic energy
in those processes of transfer or transformation though in between
you do have some potential energy in many cases
be in the chemical structure or the chemical energy but any motion an
organism does so a caterpillar climate of the plant
that's also a conversion back into kinetic energy based on the
motion that's being produced now where the
light energy itself is useful especially to our producers
this heat later on we're going to see is not as useful
in fact this is one of the items that we will go back in to show that
in terms of thermodynamics or this flow of energy
that is actually one of things maintaining the order that we want to
see within our ecosystems now the other thing about we talked with
say those molecules as the lower level of the biological hierarchy
is the fact that if you want to examine a population
of organisms or a community or even just say a tissue structure
one of the critical pieces is understanding where these chemicals come
from and where they're going to end up so in
this case for a plant that's growing and utilizing that solar energy it's
bringing up the chemicals from the soil in terms of the nutrients so maybe
nitrogen or phosphorus or even the water as part of a chemical
being brought in but those materials will be returned
either through the dropping of a leaf the dying of the plant
or even the excrement of a caterpillar that's fed on that leaf tissue
gets returned back down to our soil and things like our microbes which are
decomposers will return it back to a more basic form
so going from more complex structure down
to more simple one and part of this process for that
chemical cycle now another thing we'll get into which
is apparent right off the bat in chemistry is the
fact that as we look at the organization of this biological
hierarchy the structure of an item just in general
is highly correlated to its functionality
so we just saw a plant gathering sunlight there in our last diagram
if that blade of that leaf is very flat or so the leaf surface is very flat
that's going to maximize how much light can be converted
through our photosynthesis uh the process by capturing it with a
chloroplast if we look at the bird wing at the
bottom we can see the bird wing itself is a really light bone
but it's also very rigid and it's what's going to allow that bird to achieve
flight due to a lighter structure but also rigidity to withstand
those forces it's also the same thing we're going to
see our chemistry if we're looking at a structure of a carbohydrate or a protein
or even a lipid that structure is going to correlate to
its functionality whether it can dissolve easy with water
or not dissolve with water whether it can store high amounts of
energy or low amounts of energy these are one of the things especially
as you move through our chemistry that we're going to look at in greater detail
to show how the structure itself if it is
changed is going to potentially alter the functionality
of that form so going back to our first idea with
biology in terms of understanding that it's the process of
describing what living things essentially can do if we want to give a
better definition beyond just doing something to what a life form
is we're going to see that every life form
out there has two basic kind of things it has to
do the first one we saw was reproduction
and that's what's going to fall into most of our organisms the second
part though is the fact that all life on our planet
is typically defined by having a cell configuration
now before we go further in looking at that cell we do want to take
one kind of side step here and think about a virus
we're going to see later on a couple of our little examples
probably in other chapters that a virus itself does not
have the same features that a cell does and so we talk about later on here that
a cell has a membrane you're not going to see this same kind
of membrane-bound structure in a virus now a virus will have genetic material
either dna or rna but the last thing that this
virus is not going to have is the capability of cell free production
it does reproduce but it reproduces by using another organism
as a way to direct that reproduction so think about viruses again as a
general idea we could say that viruses do something they're able to
make more of themselves by hijacking another cell but it's not
kind of the true level of life we normally consider
where we have a cell configuration and they can reproduce on their own
so every bacteria every produce every plant every animal every fungus
they're all going to have a cell configuration that can reproduce
now when it comes to describing that cell for these life forms
we can go very basic so we have a membrane that's going to enclose it keep
it all nice and safe and we have the genetic material typically
going to be in the form of what is called
dna now we can add on two more to this idea of what builds a cell and
essentially the reason why we want to add on two more features here
is the fact that with just a membrane in dna
that cell doesn't have much functionality so when we add in the last
two one of which is what's called the cytosol or the cytoplasm
you're going to find that that now gives us ability to support the inner
structure of that cell we could also add in the final feature
called the ribosome and the ribosome is a structure within
the cell that can convert or translate the dna
which is our genetic information into a functional product
typically in the form we call a protein now again having these extra pieces of
the cytosol or also the cytoplasm and having the ribosome this will make
it so that that cell is now not just a
structure that can store material but now it's a
structure that can store information and can
convert the information into doing something as a functional
product so membrane and dna basic start parts of
our cell but adding in the cytoplasm or the
cytosol and the ribosome that makes it complete to do
all those different properties so reproduction the growth the
development the response that's what's going to make
that a truly functioning system in terms of self-configuration now we'll see later on as we come back
to the cell in chapter six that there are two main categories of
cells that consist of a life on our planet
we have the much larger and sometimes considered more
complex eukaryotic cell so this is our large one we see on the diagram here
and we have the much smaller a lot of times we call simpler
prokaryotic cell which we see up here kind of representation of a bacteria now
before we go into these in great details in the next chapter chapter six
we will see that in this basic understanding for chapter one
we want to see the difference between these two as the fact that a eukaryotic
cell has this nucleus this is the place where
that cell is going to store the dna in the prokaryotic cell
there is no nucleus you're simply going to have the dna in what is called the
nucleoid region essentially means there's no
membrane surrounding that dna inside that cell
nothing to protect or nothing to separate in the eukaryote though you've
got the membrane which acts as a barrier to separate
this fluid in the cytoplasm here and the rest of that cell content
now looking at these two cells you will go back and see kind of the basic
functionality of what a cell was both have a membrane so membrane on this
one here membrane over here both have the dna both have the
cytoplasm the lighter brown and what's not labeled
though on here is the factor ribosomes and you can
probably consider here all these tiny tiny little specks
all throughout that lighter tan with cytoplasm those essentially are the
ribosomes that help to carry out this process
with our transformation of the dna inside that cell
into a functional product like a protein and they're over here in the bacterial
cell as well so looking at eukaryotes and prokaryotes
in the big takeaway between these two essentially is the eukaryote
has a nucleus it's this membrane enclosed structure
called the organelle and the prokaryotic cell
lacks the nucleus and it lacks any kind of membrane balanced structure
in fact one way to remember this is the fact that
part of the name here the karyote corresponds to
a actual nucleus so the eu in the eukaryote corresponds to true so
true nucleus here for eukaryote where in the prokaryotic or the prokaryote cell
we have pro being before so before nucleus
so no nucleus in these small bacterial type of cells versus habit of nucleus
and things like our eukaryotes what you consider things like the
animals the plants the fungi and the protists so because that dna is universal among
all of our cell types out there you will find that
dna itself is this one piece that again going back
to kind of evolution is part of our process of modifying life
on the planet and part of the process of ensuring that
life can adapt and survive if conditions change
now as we talk about dna in the upcoming chapters especially going back to our
cell configuration you're going to see several different
ways of visualizing this information dna itself
is the most basic form it's going to consist of a double helix
in terms of the structure if we look at a
sub part of that dna we can look at what are called the genes
and the gene essentially is a small little set of instructions
within that dna that says this is what you
can carry out so eye color hair color skin color production of an
enzyme to carry out digestion of a sugar these are all sets
of information that are carried within that dna molecule as a
unique actual set of instructions called the
gene now if we condense down that dna into a
much more consistent packaging we can go from dna
to what is called the chromatin to alternate what is called the chromosome
and the chromosome was one way that we can actually visualize
uh this information in terms of seeing where it is in that cell environment
this idea we'll come back to as we get into cell division later on
where we will show how dna itself can go through a transformation into the
chromatin and then into the chromosome but you're
not changing any information you're basically just repackaging so this little double helix over here
we're seeing this essentially is your dna molecule you've got these
two strands and those two strands have this core
consider what's our structural backbone of sugar and phosphate
and coming off of that structural form we have these individual letters
the a the c the t and the g and essentially these individual we call
nitrogenous bases make up the main part of how
nucleotides which are the subunit of the dna
are going to store information so when your body says that you've got
this gene that's going to make an enzyme one way or somebody else has it
make it another way or you've got blue eyes and somebody else has green eyes
it all comes back to the sequencing here in these letters
and it could be a simple change that instead of being a c t
it's a gt causing that change in that sequence
so these four letters that we see here the a the g the c
and t this is the information that stores everything within the dna
based on just four letters now of course there's a whole process in
trying to convert those four letters into
functional products like proteins and that's something we'll explore later on
what is called a gene expression towards the anabor our semester now one side stuff we're going to do
here just for a moment as we think about the idea of
genes and regulating processes is the fact that in our system if we
think about the idea of the regulation as one of those properties
the dna is regulating what our our cells are doing
and it's kind of controlling them based on what instructions are being read or
not read and as part of that process uh we will
see that a lot of the sequences of the dna that we
carry out in terms of convert to functional material is
used to make what are called enzymes and enzymes really are kind of the
workhorse within our system if we want to convert
a product that we consumed so a large mass of carbohydrates
into an output of smaller sugar molecules or even some like atp
which is the fuel for our cells we're going to use these
typical we call metabolic pathways we're converting material from one form to the
next one and the way that we can convert from say
material a to b and b to c and c to d is using different
enzymes now in these little metabolic pathways
there are two ways of regulating whether we make more or less of that
final product and the majority of our system relies on
what is called a negative feedback regulation and essentially here
as you build up this end product the product itself
is going to come back in and hinder or block or stop
this initial enzyme will be able to convert the first set of material into
the second set and essentially what this does is it
makes the body use up whatever remaining end product it has
before more of it is made so you're going to slow down the process
in terms of that production now in the positive feedback pathway
it's the reversal and there aren't quite as many of these
in our system in terms of regulating a metabolic pathway but for
this one now the end product itself is going to
speed the process up and it's going to make more and more of
the end product allow that to accumulate now we think
about this as a general idea we'll come back again focus this
more in our metabolism chapter the first one makes more sense for negative
feedback and part of our body is that we don't
want to waste energy we don't want to waste material
if we're not going to use it so negative feedback allows us to
maintain that regulation we can maintain that homeostasis of our
body to make sure things are processing
correctly but in some scenarios say the production
of milk to feed a baby or the process of
trying to clot a wound we want to have that positive
feedback we want to make more and more of that
product because it's needed at that point in time there through that
process again this kind of idea of feedback
regulation kind of an odd time we bring it up in our chapters but
it's one of the things that we think back to the idea of what dna is
and what the genes are this actual regulation itself does come back
into play with the enzymes because the enzymes here what's going to
cause these pathways to be able to convert
material material and produce these end products so going back to our evolution idea
because this is one of the core themes that we will see
come up in pretty much every chapter in the very beginning we said that
evolution is this process of change that's modifying life on our planet we
can also say that evolution itself is
defined as a descent with modification and so essentially you're going to see
that every time you reproduce as an organism
you're hoping to modify your offspring what we call
descendants and to show that those modifications are going to make them
better suited to their surroundings now you as an organism right now you are
a modified descendant of a common ancestor so if we look back
to say one small little bit on the evolutionary
tree of human race you're going to find that
as a human a homo sapien you are not the only
only homogeneous has ever existed uh you're going to find that there have
been multiple other homo genuses that have existed
in terms of evolution but we're the one that has made it
thus far in terms of a descendant from a common ancestor
you could also find that as descendants we are linked back along the primate
line to a common ancestor that also branched off to produce the modern-day
chimpanzees modern-day gorillas modern-day even
orangutans if you want to go that far but those are all based on the fact that
evolution is describing how the modern form has been modified
from those previous generations
so with evolution what we're trying to show is that first of all
there's a great unity among all life and going back to that dna you're going
to see that because dna is every one of the living forms out there
whether it's bacteria whether it's plant whether it's
animal whether it's fungi that's a unifying feature
but you're also going to find because that dna can change
simply in what letter is there for the a's the g's the c's and t's
that also leads to the great diversity and the fact that you can have
organisms surviving uh in the soil organisms surviving
in water organisms surviving in complete darkness order and surviving
and all kinds of habitats that is all based again on the dna
that unifies them but also creates this diversity
among organisms now one of the things we'll see later in
evolution is that as an idea there needs to be a process
behind it that is driving this descent
modification or deriving this change and that process is what is called
natural selection natural selection is an idea or this
principle that basically demonstrates the fact that an organism
is selected for or resulted against
by the environment essentially what the natural selection idea
is trying to show is that as an organism you are
suited to your environment in order to allow you to survive
you have this adaptation so you can see here
that the beetles in our bottom picture initially have a whole range of colors
you've got light ones you've got dark ones you've got some in between now
this essentially shows the population starts out or
at this point in time has a variety of traits
now one principle of natural selection that has to always be there
is that those traits that we're seeing have to be able to be inherited
so if they'll pass on to the genetics now when you're bringing a selective
pressure like a predator in this case the bird
this is now showing that the environment the predator's case is selecting for
the lighter beetles and as you go by generation by generation
those lighter beetles are being removed allowing the darker beetles to
proliferate and they're reproducing more and more
each generation as the darker beetles the only ones
primarily reproducing you're going to see a shift in the
population having a greater dark beetle consistency due to the
pressure in this case of that predator eating
these prey items so natural selection as a process here
you see that the environment is selecting in this case
for a certain condition but you will notice that even though it's looking for
the darker color it's not a hundred percent change
every single beetle is the exact same color there's still variation
and that's because the environment itself is always going to be changing
and as it changes it's got to have variation there
within that population in order for it to be able to go with you and select
the lighter one or the darker one or the larger or the smaller the more spot of
the left spot or whatever that variant might be
there has to be variation there in order for natural selection to go through and
select were to favor one trait over the other now we'll come
back to these core principles with evolution natural selection again
towards the end of our semester and we'll see that a man named charles
darwin is really kind of the founding father
with these principles laying out the framework to how
all this works and kind of drives our process of understanding
as to what biology is and how the world around us is going to work
based on evolution through natural selection
now one thing we can look at here just as a general idea
is kind of the diversity of life so we said unity is that dna
and we said diversity comes from how that dna is going to
transform the different parts of the organism
now this idea of diversity brings us into what's considered taxonomy
and taxonomy essentially is the branch of biology or the
sectional biology that looks at classifying
these species into their groups based on similarities now with taxonomy
uh you're going to find that this is probably the only time all semester
that we'll focus in this great detail on it we'll probably come back and look at
a little more as we examine some of the kingdoms of
our eukaryotes but for the most part taxonomy is
reserved in terms of the actual understanding
and the actual use of this would show and diversity
more in a bio2 course where it looks at the
different arrangements with the microbes with the plants the fungi and the
animals but with taxonomy one thing that you're
going to focus on is the fact that as you look at a more
all-encompassing part of the taxonomic group in this case
you're the domain the domain is a much greater inclusion
of the organisms so in this first one here with the domain eukaryote you have
pretty much every single eukaryote on the planet you've got the produce you've
got plants you've got the fungi you have all
the different animals so quite a diversity amongst other
organisms as you keep narrowing down your focus
though essentially what's the goal of our
taxonomy to the species you start to eliminate different
features so going from the main eukaryote to the kingdom
animalia you're moving the plants the fungi and the produce
they're changing what some of the characteristics are
or from the kingdom animalia to the phylum chordata
or down to the class mammalia or all the way down to our species versus
americanus that we're defining based on a key set
of principles that shows that it's different from the polar bear that
grizzly bear but they still share this commonality
now this is also one way we think back to evolution
to show how we have again a diversity we've got that distinct species versus
unity so all among this domain eukarya they're
unified by the future of having in this case a nucleus
or the kingdom animalia all unified by the feature
that they're going to have to go out there and find their food
in some way or another now in our taxonomy we do want to
emphasize the fact that there are three main domains in terms
of classifying the life of the planet the first two
are both prokaryotes so these are two organisms that
are going to not have a nucleus they've got dna but there is no membrane-bound
organelle or no membrane enclosed structure
to store the dna and these are also very small or microscopic organisms
now on the hand side here the orange this is our domain bacteria
on the right hand side here we have the domain archaea
and essentially these two organisms if we looked at the scale
of the magnification here you're probably seeing in the range of
maybe about at least maybe 2500 times magnified for the bacteria
maybe 5 000 times magnified in the case the archaea
but these are two distinct domains of life on our planet and even though
they look very similar in terms of how small they are the fact that they lack a
nucleus they're quite different in terms of the
diversity and one of the biggest differences is
the fact that the archaea tend to be more of extreme individuals
so leaving in very hot environments or maybe a very acidic
environment or maybe a very chemical rich environment
where the bacteria sometimes live in those conditions
but tend to be generalists that live in a wide variety of conditions
in fact probably right now in your body your bacterial cells
will outnumber your animal cells and that's just because the number of
bacteria around us are there in such high quantities
now one thing about bacteria is that they tend to usually get the bad rat
in terms of bacteria not good for us and that's because there are some bacteria
out there that do cause problems but you as an organism along with all of
our ancestors and evolution would not be here today if it wasn't for
the bacteria because bacteria essentially are going
to make us individuals who we are today and allow
us to survive based on how we interact with our bacteria or how the bacteria
can transform materials in the way that we use them within our
system now beyond those first two domains of
the bacteria in the archaea which are prokaryotes
we go into the main eukarya and these are all
organisms that are going to have a nucleus
so that's the unifying feature as you start to branch out from that domain
eukaryote though in the kingdoms we get into the plants the fungi and the
animals now these first three divisions of
domain eukarya into these three kingdoms are based on
how food is obtained so plants are going to go through and
make their own food by photosynthesis fungi are going to absorb their food
basically move it right across their cell membrane
and animals have to go out there and ingest their food so i have some kind of
mouth-like structure or some kind of hole to bring that food
in from the environment now the last little kingdom here part of
our demandia carrier is the protist and you'll notice that we
don't say the protos as being classified by one particular way of finding food or
another and that's because within this protist
kingdom you're going to find some that are more similar to animals
and the way they ingest their food some are more similar to the fungi
in terms of absorbing their food and some more similar to the plants
which i'm going to go photosynthesis but you will find that in the produce
kingdom here that these are organisms that do not
quite fit with the other kingdoms and now if at
one point in time they were part of the different plant fungi and animal
kingdoms but based on the current taxonomy we had
them separated as their own group and a lot of times they tend to be very
small microscopic organisms but there are some as a multi-cell
structure like say our algae particularly in the kelp
along the pacific coast of north america they are ones that even though not
plants they look like plants maybe they are actually multi-cell protists so
they're quite large in size but they're part of that protestant all right now the last little bit of
this chapter is based on more of the discovery approach
uh and so kind of looking at how do we examine the world around us
and what kind of methodology would we use to show how things are going to
function so because biology is part of this much
larger grouping of kind of understanding basically part
of a science you will find that any one of the parts
of science so looking at chemistry looking at geology looking at
biology is basically this search to know more such as science
itself means to know so as part of a
biologist's goal you're going to find that we're always
in the search of understanding trying to figure out
why things are happening the way they are
so part of this idea of inquiry is forming some kind of process
to go through and give us a better methodology to go through the
process of trying to figure out what in fact is happening in the world around
us so one of the first steps in scientific
method is making observations this is one of the things that even if
you're saying you're not a biologist you actually do on a regular basis and
essentially as biologists our goal in observations is describing
what is happening around us with the natural
structures so looking at the plants looking at the
fungi looking at the animals looking at even more detail the insects and
essentially trying to understand or trying to describe what they're doing
so let's say you're a farmer and you go out to your field and notice that your
field is wilting well let's make an observation you're
now going to go out about the process of trying to remedy
that why that crop is wilty or let's say you're sitting at
home listen to this lecture your dog is next
to you and your dog starts to go through and throw up a
whole bunch of grass who knows you're gonna describe that
process to happen right next to you there and never try to figure out maybe
why your dog is storing up or maybe why your dog is peeing on the
floor who knows but said you're trying to describe this
natural phenomena so if you're a chemist you're trying to
describe why the atoms maybe come together a certain way
physicists trying to describe why certain forms of energy transfer one
way versus another essentially those observations you're
making are the very first step in understanding what is happening
around you now as you go about making observations
the second idea you have to think about is how are you going to support the
observation how are you going to go through
and classify what is happening based on trying to give support later on
and that comes to data essentially data is a way for us to go through
and make a record of what the observation was
so take an idea of you know the crops that are wilty you might go
through and make a description you might describe the color of the leaf
uh you might describe the conditions of the environment how
hot how cold how dry how wet whatever it is you might
describe that as a scenario but you also might go
through and do what is called quantitative data and make a recorded
measurement so beyond describing that it's hot or
cold you might take an actual measure and say that it's you
know 27 degrees celsius or maybe it was
110 degrees celsius who knows but you're going to make a recorded measure
which then you can go through and use as an analyzing technique
trying to show why things have or have not changed based on the observation
now this approach of collecting data is also one thing you'll do
through your lab exercises throughout this course and you will find that in
most of the lab exercises we rely on quantitative data
it's one of the easier ones that we can do and it's one that we can put
into a nice little table or a nice little graph to show the results
so if you record the measurement of a change in temperature
or a change in weight or you go through and look at the difference in heights of
individuals these are all quantitative data
measurements but you will find in some experiments
that having qualitative data is just as important so instead of actually
measuring how many molecules are made maybe we do a description
i'm going to say that this is a lighter color or darker color and that color
then corresponds to the relative number of the molecules
that were were not present in that experiment was being done now beyond the whole idea of making
observations and deciding on what kind of data might help you support that
we now move into what is called inductive reasoning
and inductor reading essentially is a conclusion that you will come up with
based off what you have been exposed to in the past
and so for everyone this idea of inductive reasoning is a little bit
different you might find that as an individual if
you are older in your years or if you're you know not as experienced and you're
younger you have different ways of viewing the world around you
but essentially inductive reasoning allows you to draw a conclusion about
the observation you're seeing without having to do any kind of
experimentation so for example if we look to the east
every morning this inductor of reasoning within us will tell us that the sun
should be rising in the easterly direction because we can see it every
day if something looks to the west at
nighttime more expect the sun to be setting at a certain time of day there
it's repeat observation that we are seeing that says okay oh yeah
we know we're looking at the sun in the morning it should be easterly direction
we see it at night it's a westerly direction
we could also take it in this different framework if you've got a child
and let's see that child in the kitchen and you've got a hot burner on the stove
the likelihood that child will touch that burner
versus say you as an adult touching that burner
is probably much greater because that child has not experienced that much life
around it in that case if the child does touch the
hot burner they're going to form some inductive reasonings that says well that
stove could be hot sometimes and that means the next time they're
around the stove they might have a better chance of making observations
maybe not going near it maybe staying away from it maybe even putting
a handle because if it's warm before they actually go and touch
something and that's basically what we do as
every individual even if we're not biologists we go about our life
forming these inductive reasonings that we can draw upon to help us figure out
why things are happening the way that they are so from the
observations from the data and inductive reasonings we now go into
forming a hypothesis an essential hypothesis is
an explanation to a question asking about the
observation around us we can best say that this is a tentative
answer so essentially a hypothesis is just a
blanket statement so let's say your dog is throwing up
next to you your hypothesis might be well my dog ate some bad food
or if your plants are wilting my plants have not gotten enough water
these are very simple explanations as to why
something is happening but with a hypothesis
though you want to be able to go out and test it
so you wouldn't say necessarily that your dog is puking
or throwing up because there are ghosts inside of it making it throw up
or that your crops are wilted because the ghosts have gone through
and there's a spiritual awareness in your in your plants
causing them to be upset and they're wilty
we can measure water we can measure intake of food for the dog we can do all
those things but we can't go off and examine that kind of
spiritual or that ghostly presence so hypothesis done
by this scientific method has to be one that we can go out and test
we can do observations or experimentation on those ideas
hypothesis itself essentially your answer to what you're observing
so to give a really quick example in this scenario here we've got an
observation that a flashlight is not working
now even though we are looking at this based on biology on a regular basis
your mind is carrying out this kind of scientific investigation
every time something around you is not working your brain goes into this
automatic mode which essentially is make an observation that is a problem
leading you right into the the idea of asking a question why this
is happening and then hopefully down the path of
trying to find an answer so in this case with the observation the flashlight not
working you might automatically say well i
dropped it in the water so maybe that's why it's not working
or i haven't used it in two years maybe the batteries are dead
or my dog chewed on it and there's you know saliva different often maybe
that's why it's not working so you're going to go through this idea
of making up these statements or these ideas as to why
you're seeing this observation right away
now in the true scientific kind of mind frame though
we have to provide all these explanations i have to do one at a time
in terms of testing to figure out which one is causing the problem which
one will give us an answer as we're seeing for the observation so
in the idea of the flashlight here if our first explanation is that the
batteries are dead we can make a prediction if you take the
batteries out put new ones in just fix the problem that means that we
can test the stent take all batteries off putting batteries
in if we come out to our conclusion and it doesn't work you're going to see
that this test in this case is going to falsify
the hypothesis we could also reword that we could say
the test failed to support the hypothesis so once that first
hypothesis doesn't pan out we can go with second
idea maybe the bulb is burnt out so we say okay the explanation in this
case the bulb was burnt out that's our our statement prediction replace the
bulbs to fix it so take the old bulb up a new bulb back in that's our testing
here and it works so in this case we could say
that the test does not falsify hypothesis or that our
data we collected the observation that we have like at the
end of the flashlight is supporting this hypothesis for this
point in time you will notice however though that none
of those hypotheses showed the word proof and that's because
especially in biology proof is a very strong word proof for biologists means
that it's going to be the same thing every single time based on that data
collection so if we took the batteries out put them
back in it didn't work and we said that this test
proves our hypothesis wrong as biologists in our mind we say well
that means never mean the batteries if we said the bulb proves a hypothesis
to be correct we might say that every time the ball is gonna be the problem
but it's not and that's because when you're looking at this kind of idea of
the flashlight here even though it's not a
living system for us you're gonna find there are many
variables many other things that could have happened
to lead us to this change in the flashlight working
so maybe for the batteries maybe you put them the wrong way
maybe with the bulb the actual flashlight wasn't screwed all the way
down tightly there are many things that could
have caused this to work beyond the battery beyond the bulb that
we didn't see or account for in that scenario well
that's the same thing for most science we come out do a day experimentation we
collect the data we say yeah okay well this supports it this doesn't support it
but it's not a concrete set of evidence that will be there every single time now
of course if we do the experiments over and over and over again
we will start to go to understand that based on our observations
we now have what we call deductive reasoning
and deductive reasoning basically establishes that if we have some known
premises so we have these known ideas that are
widely supported by lots and lots of data
that we can combine these premises to make
a new prediction so it's kind of like going through and using what we already
know and saying okay well if these two are
established what happens when you combine them
does it hold true does it come out to show that it does work
so inductive was based on what you'd already learned
deductive now is saying okay we know this what can we learn now from those
new premises so in the example we can see here that
premise one is that organisms are made of cells
so we'd have a checklist that say what an organism is
okay oh cells are on there for premise two we would say humans are
organisms again we have a checklist that describes
what maybe the human is or what the organism is
that will allow us to support that understanding
your new reasoning then is a fact that well
humans then should be composed of cells that's our prediction
so you can go out there and test it go out to take a skin sample take a cheek
sample take a blood cell look at that and say
yes we have composition of cells now if we modify this idea just a little
bit if we said that organisms are made of cells
keep that one the same and we said aliens are organisms we
could then say that aliens are composed of cells
so based on that prediction if we found some alien life form
and it comes out to show that there really aren't any cells there
this means that one of our two premises has to be changed
or modified and that's the whole part about biology
in terms of being a science it's always got the possibility to change
we go off and look for evidence we try to support it and it works for a long
time but if something new shows up which means we have to go back
and change the understanding change our thought process as to why that may have
happened again with your hypothesis it's got to
be testable it also means that we can't use
supernatural or religious explanations because it's outside the bounds of why
we're explaining why things are happening
all right last little part of this chapter then is give a nice little
example about how this might apply to a real world scenario
and for this one the scientific investigation is using
the idea of mimicry uh in organisms in this case mimicry in a snake
population and the general idea behind this
experiment is that there are poisonous snake species out there and the
poisonous or say venomous ones tend to be very brightly colored to warn
the predators that they need to stay away
there are also mimics though which have the same coloration
but don't carry that venom so our scientist henry bates here
had a hypothesis that the mimicry itself evolved in that harmless or non-venomous
species as an adaptation so a modification
to reduce that chance or in this case to increase their chance of surviving
in those habitats so this hypothesis was tested
with two snake species we have the dangerous one the
venomous eastern coral snake and we have the non-venomous
of the scarlet king stick now both these snakes have a very similar colorations
they're going to be red black and yellow but the pattern is slightly different
now the other thing for most memory to actually work is that these species have
to be in overlapping ranges so for this one
we're looking at north and south carolina
and you're going to find there are areas where the non-venomous king snake
overlaps with that venomous coral snake and there are areas where the king snake
is all by itself and there's no overlapping range with
that venomous one so based on that hypothesis bates comes
out with the prediction that the inheritance of that avoidance
pattern for that coral snake coloration should
cause then those kink snakes be attacked less frequently
if in fact the present where those coral snakes were present there
as well so looking at our little area of study we've got north and south
carolina you can see the range here of the non-venomous king snake
is much greater than the range here of that coral snake
now the coral snake we're going to see is again pretty
similar coloration we've got the black yellow red
the king snake though has it as a yellow red black
now as a child i was taught kind of the phrase that
red on yellow deadly fellow or some might say kill a fellow
and i said red on black was friendly jack
now looking at the coloration itself here if you take the standpoint of a
predator let's say a bird of prey or a larger animal you're probably not
going to sit there and examine the exact pattern
if you have inherited this annoying evolution's pattern and you see this
bright coloration or just a pattern in general you might
say well no i'm going to avoid that i'm not going to go near that structure
if you don't have that known avoidance though you might see this bright
coloration and say well gee there's lack of camouflage i've got free
dinner right in front of me because it's standing out against that
background now as part of the experimentation then
you're going to find that we take that prediction
and we design the setup and so with this hypothesis
we're going to have two different groupings we have the control group
which is one we're going to use as a baseline to see
how many attacks there are on this kind of configuration with this clay and
the actual shape and we have the experimental group
which is actually going to resemble in this case the banding pattern of that
king stick now in terms of the setup we're going to
put same numbers in each one of these species out there at multiple field
sites and we're going to put them in areas
where there's overlapping range of those snakes and
areas where the king snake is not overlapping with
that coral snake now as part of the setup
you will see that we have what are called independent variables
and dependent variables the independent variable is important because this is
what you decide as a researcher that you want to manipulate in this case
the coloration so banded versus just brown and the
location are ones that we can manipulate we could
have also gone through manipulated size length shape all kinds of things but you
want to keep to a very limited set of variables that you're going to change
because the more variables you change the less of a chance you have a
certainty of seeing why the results come back from
just one of those variables now the dependent variable then is what
we're going to measure so this could be again that qualitative
versus the quantitative data in this case we're going to use the
quantitative data which is the number of attacks on that snake
and that variable we're choosing or that we're measuring and is directly linked
to both the coloration and location so the snakes were put out there and
after four weeks they're retrieved and they count the number of bite or
claw marks on there and the data itself does support the prediction of the
hypothesis and they were shown that those banded
snakes had less attacks on them if they were in
that same region where those venomous coral snakes
were present but if those snakes that had the abandoned pattern weren't areas
where the coral snakes were not present you're going to see a much greater
attack rate on that manning pattern because there's no known avoidance of
that coloration now this kind of experiment helped us to
show that in any kind of investigation it's important that you control your
experiment basically means you want to control as much as possible
and only change a limited set of material minimum
of of the actual variables so in this case the variable of color the variable
of the location those are the only two
we're going to say as contributing to why we had more or less
bite marks now we could have gone and done this with just abandoned snake
the problem here is that if we don't have a baseline to compare two
there's no way of saying whether or not it was the banding that caused the bite
marks whether it was the coloration whether it
was the clay whether it was maybe even a scent coming off those snakes
but with having that control group we can use that control group and say
whatever happened with those bite marks is now basically eliminated and we can
show that if we had more or less bite marks on that experimental one
we can say that's attributing that to the change we made in that experiment
now of course we can control only so much here it does not mean that we
have gone through and limited any kind of variable whatsoever
but you must always try to limit as many of the variables as possible so weather
could have been a part of this could have had a predator population
size being part of this uh you could have had even just the
scent of the clay in the center of the paint
that was put on the clay as a way that changes this kind of
experimentation again the goal here in this kind of
experiment is to show that we can collect data
and potentially support our hypothesis now for this to really be a sound
experiment we want to be able to go back and do this again and again
so we want to go back and have the experiment run again
and we want to see that these results are repeated over and over again
to show that this experiment was in fact a valid one
and being supported by the data that we collected
now if we do this enough times and we start to develop kind of a trend
with this concept eventually enough hypotheses in the same kind of
general idea can lead to what is called a theory and
the biggest difference between the theory and
hypothesis is that the hypothesis is really
narrow in terms of what it's trying to examine so in this case the snake
mimicry there were those two snake species a
theory though is much broader it wouldn't just be snake species it would
have to be all animals or maybe all life forms in general showing that
we can show data or have data that supports that again and
again the idea of hypotheses though is that we
can have these which lead us to new investigations
which lead down to new hypotheses and essential hypotheses are what makes
up most of our understanding they're kind of an educated guess based
on what we collected from the data to show that this is how this is happening
in terms of that scenario a theory though
is one that uses widely accepted and it's one of these that has so much data
behind it that nothing else is shown to negate
that idea so we're going to see the evolutionary
theory is really one of our biggest understandings we've got with biology
later on we'll also discuss things like the cell theory
uh we'll see some in terms of what's called the endosymbion theory
there's other theories we will see in biology but a lot of biology still is
based on hypotheses it might be supported by large amounts
of data but we're still not at the point of saying that well this
is the exact cause because we're are we discovering new species we're always
discovering how things are happening around us and it's always
a constant kind of process of trying to figure out why things are happening
the way that they are so that will include our end of chapter
one for us and this kind of introductory chapter just to give you a heads up
as you how other chapters are kind of organized and kind of how we're going to
do material throughout the semester um as we do move on though into our
second chapter with chemistry we will start with a very low level
there for our biological hierarchy and then start to move up further and
further trying to show how things start to rearrange and produce some of
those emergent properties you