Hi this is the beginning of the lecture
1 which is about the scientific method. Now
each one of these screencasts is
approximately 15 minutes long so if it
takes me longer than 15 minutes to give
you the lecture then we have two
parts, and you have to watch two separate
videos. Anyway so today we're going to learn about
the scientific method, and this is the
underpinning are pretty much all of the
sciences. So we're talking about biology
chemistry physics maths etc and
it's a way of thinking about the world
that we hope you will be able to take
with you even when you leave biology. So
let's start: Biology is the scientific
study of life,  and we see life as
structured on a size scale that ranges
from molecules all the way to the entire
globe. And as a result you can study
biology many different levels.
Now, what are the things that would fall
into the realms of biology?
What is alive? Well living organisms
tend to have some features in common
with each other...
The first of these is order so if you
have a look over here at this pinecone
there is a structure to it.
Molecules are arranged  in particular
ways and you can study how they are
arranged, and interactions between them.
Regulation this is the second thing that
you'll notice living organisms have. They
can often regulate chemical reactions: so
for example that lizard is lying there
warming itself in the Sun and that extra
warmth is going to allow it to be able
to increase its chemical reactions. Your
body regulates things like how much
water is in your body. If you don't have
enough water in your body,  hormones will
switch on a system that tells you to be
thirsty and you'll want to go and drink
water.
Growth and development is quite common
in living organisms: so here you see a
little snake hatching from an egg. Many living organisms will go through
various different stages of development
where they change what they can do and
oftentimes they grow as well, just like a
human: we grow from a very small infant to
fully grown adult. Living organisms need
energy in order to regulate themselves
grow and develop and here we see a
puffin eating sardines. They are fish eating
birds and the Puffin is what we would
refer to as a carnivore. It's eating meat,
but other organisms can get their energy
in different ways. Plants get their
energy from the Sun,  and some bacteria
can get their energy from other sorts of
chemicals. All organisms have a response
to the environment, and I love this
picture of a Venus flytrap eating a
dragonfly!
It's a little bit of a photoshop i'm
sure.. but the Venus flytrap is a great
example of a plant that has to respond
to its environment. These plants normally
live in areas where there's not very
much nitrogen in the soil, and so it's
hard for them to grow because nitrogen
is important for proteins. What these
plants do is when there's not enough
nitrogen in the soil they grow special
leaves called fly traps,  and those leaves
can capture insects by using trigger
hairs (actually three of them) you can see
them on this picture  here: there is 1, 2, 3...
right underneath the dragonfly
so when a fly triggers the hairs, the
leaf snaps shut, and the decomposing body
of the insect will
drip small amounts of proteins and
amino acids that contain nitrogen,  and
that will drip all the way back down to
the root of the plant and feed the plant! It's
actually a wonderful example of the
response to the environment organisms.
Organisms also reproduce as you can see from this
cuddly little hippo family, and there are
many different ways in which organisms
reproduce. You may be more familiar with
the traditional male plus female results
in a baby but there are all sorts of
ways in which organisms can reproduce
and it's actually quite interesting. Evolution
is a central tenant of biology. Here
we have a katydid (which is related to a
grasshopper) If you can see it looks a
little bit like a leaf and it has
evolved what we would refer to as
camouflage coloration so that it can
avoid being eaten by predators. The
scientific method and the concept of
evolution are going to be two things
that you will hear over and over again
this semester.
The reason behind it is that evolution
really is the driving force for living
organisms and it has resulted in some
tremendous adaptations and we'll
learn a whole bunch about those.
ok so what are the levels of biological
organization? As I mentioned the living
world can be looked at from the
molecular level
so here's a molecule all the way to the
global level (the biosphere) and the
in-between levels actually have names..
the levels of organization include
cellular organization, tissues (tissues are of
groups of cells that work together to
perform function) organs (organs are made
out of two or more tissues, and include organs
such as your heart or your brain) and
organism which is a
whole living creature that natural
selection can act upon. It can reproduce.
You would be considered an organism.
When large groups of individuals of the
same species live together we refer to
that as population. We could talk
about population of wolves in
Yellowstone National Park or we could
talk about the population of Phoenix
Arizona,  where we would be referring to the
human population. Now you are not
isolated in the world... there's a concept
called "community". In biology the word
community refers to the populations of
different species that live in the same
place at the same time, so in this
picture here you can see fish that live
with coral,  and there are many different
species of fish or living together, and
they interact with each other.
Biologists often study the interactions
between different populations. Sometimes
species can help each other, sometimes
they can hinder each other. You think
about your own body-  you are actually
community because your body has tons of
bacteria that normally live in your body
and help you to survive and to be a
healthy person. In your digestive
system you've got bacteria that help you
to produce B vitamins and if you
get sick you might need to actually
eat something like yogurt to help bring some
of those good bacteria back to your
system. Those the first levels of
organization. Ecosystem is one level
higher than community and the ecosystem
refers to both the living and the
nonliving parts of place. The ecosystem consists of the communities of
living organisms and the nonliving
such as the rocks,
what kind of weather patterns you have got, where are the nutrients and
minerals found in that system? Now
let's start talking about
the scientific method.  So we refer this as a
hypothesis-driven science and this means
that we've got some steps that we need
to talk about. A hypothesis is a proposed
explanation for a set of observations
proposed. It is a tentative explanation.
It's a possibility. Now a good hypothesis
can't just be any explanation for the
phenomenon. So you know,  for example,
when you're a kid you lose a tooth and
pu the tooth underneath your pillow and you're told the Tooth Fairy brings you the
money. Now as a child you may be able to
adventure in unrealistic or
non-logical statements for explaining
phenomena,
however in science a good hypothesis
actually has to be based on logic.
You can't reach into the supernatural
in order to provide an explanation. Now
once you have a hypothesis
you can use what we call deductive logic
to test it. So that logic is flowing from
general to specific so we say you know
if this big thing happens all the time
then we can have a look at our specific
case and see if that's going to be true
as well.
now normally the deduction takes the
form of predictions about experimental
results so i'm going to show you an
example where we will use deductive
reasoning to say *if* this particular
hypothesis is supported then I expect to
find the following results. Now what is
the scientific method?
well it's a process and the process
involves the following things: you make
observations about the world, or
particular phenomena.  From that you ask a
question or questions
how does this work? Why? and then you will come up
with hypotheses. Youur hypotheses are your
tentative explanations for your
observation. Then you would design a test
or an experiment to test your
predictions you'll find particular
results and those results you can use to
either explain your observation or to
generate more questions
not all the time does a scientists
actually have the ability to immediately
say whether or not hypothesis is
accepted or rejected sometimes you have
to do many experiments and so you know
it's it's not always just a linear
process, sometimes you go from the
explanation back to a question back to
another hypothesis. We're going to use an
example
coral snakes to test the scientific
method.  You heard old children's rhyme where it
says black on with it
oh I can never remember it....  "red on black
venom lack, red on yellow kill a fellow!"
depending on where you are the the rhyme
is a little different
either way normally when you see a snake
that looks like this you probably better
not pick it up because it might be
really venomous and that could be quite
dangerous. In costa rica there's a
biological station and a lot of
different snakes that have different
color patterns so here are some of the
repeating patterns most of the ones that
have got repeating patterns are really
toxic there are a few funny ones that
while they look just like the toxic
individuals they themselves are not
toxic specie. And then of course you
have brown snakes which more of them
tend to be friendly ones than toxic ones.
the big question is what advantage does
a non-venomous snake have in possessing
the color pattern  of a venomous snake?
well there are some reasons why you
might expect happening
three bright and one example we find in
biology is something called a
aposematic coloration: it's also
known as warning coloration and it
basically says I'm really nasty and
toxic don't touch me
otherwise I'll fight you, poop on you,
hurt you in some way
so we've got three examples:  here we've
got poisin dart frogs, here are nudibranchs
which are toxic sea slugs that are beautiful and
they're deadly,
and then of course- your classic wasp.
another reason behind why you might have bright colors is actually cryptic
coloration-  and it's a way to avoid being
detected by others. We've got two examples: an okapi which is a relative
of a giraffe-  on its bottom it has
stripes like a zebra; and a Jaguar has
got spots. Now you might think I'm crazy
saying this is cryptic coloration
because it really stands out to your
eyes. But you have to think about it
from the perspective of biology-  I want
you to think about herd of zebras...
so yes the patterns really bright,  but if
you put 20 Zebras all together and
they're standing close together, and you're
predator and you want to pick one
individual out from the crowd
it's going to be really difficult
because you don't know where one zebra
ends and the next one begins .... so how do
you know who to aim for?
so this is one of the premises behind
these bright colors and patterns on the
back end of things like zebra and okapi: it actually makes it more difficult
for a predator to see it. Now the Jaguar
has spots because it tends to live in
forested areas and if you've ever been
into a forested areas... and if you've ever been in a forest and seen the light patterns... it blends in
