So I'd like to take the opportunity this
morning to explore with you some of the
core characteristics of science and I'm
going to do this through the lens of
biodiversity and more specifically
through the Tree of Life. So I'm a plant
evolutionary biologist. I work at the
Florida Museum and my research expertise
is on plant evolution and so I'd like to
share some of these concepts about the
nature of science through examples from
my own work and this entails an
examination of the Tree of Life.
So before we start talking about science
and research, I thought it would be
important to trace the concept of the
Tree of Life back through ancient
cultures and really nearly all ancient
cultures have a tree of life concept
that explained the origin of life or the
relationships among living beings and
those relationships also with the
underworld and with the beyond. And so on
the left here, we have a diagram of the
Assyrian Tree of Life which dates back
6,000 years. And on the right, the Maya
Tree of Life which dates back
approximately 2,000 years just as a
couple of examples. Now in science, the
the concept of the Tree of Life as a way
of organizing what we know about
biodiversity traces back to Plato and on
the left we have the scale and a tree or
the ladder of being or the great chain
of being which is the way that Plato
Aristotle and their students thought
about how to organize the diversity of
life around them. And this of course is
not a tree. It's a ladder. But it's an
organizing principle that basically
shows increasing complexity of life with
humans at the apex or at the top. Now
this sort of view of biodiversity was
really the way that people thought about
life for almost two centuries and really
until the 1800s.
Now on the right, we see an interesting
pre-darwinian view of life and how it
might be organized. In this case by
Edward Hitchcock, through the lens of
geology. So we see different forms of
life tracing back to different
geological time periods. Now everything
in biology changed dramatically with
Darwin and the theory of evolution. So as
early as 1837, Darwin was sketching out
his ideas about how organisms were
related to each other and some sort of
family tree and you can see this in the
little sketch from Darwin's notebook on
there in the center. And then in the
Origin of Species published in 1859, he
wrote the affinities of all beings of
the same class have sometimes been
represented by a great tree. I believe
this simile largely speaks the truth. And
this figure below that quotation is the
only figure in the entire Origin of
Species and it shows his thinking about
common ancestry and branching points and
the origins of new species. And he put
all of this into the context of a large
family tree that represents all species
that are currently alive and that have
ever lived.
Now biologists have continued to
refine our understanding of the tree of
life ever since Darwin. So for example, on
the Left we see Ernst Haeckel who was a
zoologist from germany and a beautiful
diagram that he used to convey his
concept of the Tree of Life and this was
a field of Endeavour that really
exploded quite quickly after Darwin's
publication of the Origin. But today we
continue as a large international
community to try to refine our
understanding of the tree of life. And
today we use four living species mostly
DNA data and the figure on the right is
taken from a paper that was published a
few years ago that is meant to represent
all main groups of organisms with the
eukaryotes being down to the right and
all of the prokaryotic diversity sort of
scattered in an arc around the top.
So I think this brief introduction
illustrates some of the characteristics
of science that we'll explore further
through the next few minutes. So really
what is science? Well science is both
knowledge about and the process of
studying the natural world. So an
emphasis here on the natural world. It's
also evidence-based. It's testable. It
changes with new evidence and it's
reproducible. So let's unpack these
statements. Now as I mentioned I study
plant diversity and one of my goals is
to take all of the plant diversity about
500,000 species of plants and try to
understand how that diversity is
organized in a family tree that goes
back to the beginning of the plant
branch maybe about a billion years or so
ago. So we take this diversity and we try
to convert it into a family tree which
is what you can see on the right and you
can think of this as sort of Darwin's
Tree of Life but switched on to its side.
Now the evidence that we use has changed
over time and over 100 years ago if you
look at the figure on the left this is
sometimes called Bessey's cactus. This is
one of the first depictions of the
family type relationships in flowering
plants. And it looks sort of like a cactus and this represents really
the intuition that the scientist Charles
Bessey had about how different groups
were related. And of course, it was based
on morphology. The overall shape and
structure of the plants. Now this is the
sort of approach that was used for the
next 50 years or so. And by 1981, we have
Cronquist view here in the center. The
sort of bubble diagram that shows his
concept of relationships also intuitive
but it doesn't take into account only
morphology. It also uses things like
plant anatomy, plant biochemistry,
chromosome numbers
and other sorts of evidence and it
provides a refined version of the
hypotheses that went before. And then on
the right, we have again this
phylogenetic tree or this evolutionary
family tree that shows how we currently
understand relationships based on
molecular sequence data. So science is
based on evidence but that evidence can
change through time. Now science is also
a testable and I think one thing
that we need to keep in mind at all
times is that our scientific conclusions
are really hypotheses for the next round
of experiments. So this diagram here
shows sort of a complex version of
Cronquist's view of flowering plant
relationships and the only things I want
to point out are that some groups are
labeled in blue and some groups are
labeled in green. The blue groups are
those groups that would fall under
dicots. The green groups under monocots. And I'm
sure everybody is familiar with these
terms. These are terms that have long
been with us as a way of classifying the
flowering plants. So this is a hypothesis.
All family trees like this are
hypotheses and so we wanted to test this.
We as a large community using molecular
data. So we add DNA sequences. We add some
computation and we want to see what
sorts of results come out of that. Do
they support this long-standing
hypothesis about the split between the
dicots and the monocots? And in fact, if
we look at this result published in 1993
by a group of 43 authors, we see that the
monocots do form a group but the dicots
don't. And if you think that to what
you might have learned about monocots,
monocots have a single cotyledon. They
have all of their parts in threes.
The dicots - there's some variation
there. And certainly when we look at how
the dicots are spread across this tree,
we can see that the dicots don't
really form a group. So if this is true,
if they really don't form a group,
then we shouldn't refer to them anymore.
And in fact, all of our data over the
past over 20 years 25 years or so now
indicate that the dicots are no
longer a group we should recognize. And
therefore, we should not teach about it.
That's just a little pet peeve and a
little soapbox. So I'll get off of that
now. So scientific knowledge changes with
new evidence. So now we know
that we don't want to recognize the
dicots as a group in our taxonomy as in
because it doesn't represent the product
of evolution. And as we compare the
diagram on the left with these two
diagrams that were published just last
year, we can see not only that this idea
of the monocots being a group in the
dicots not is upheld but there are
other sorts of changes that that we now
acknowledge. So the scientific knowledge
changes as we have new evidence. Also
science is reproducible. So if I were to
download DNA sequences from GenBank at
NCBI and to sit at my computer and
analyze the data in a particular way in
the same way that the authors of the
tree on the right did, I would get that
same tree. And what happens here is that
scientists are trying always to be
explicit about the work that they do and
explain it in a way that it can be
repeated and validated. And so
reproducibility is really one of the
things that sets science apart from many
other endeavors. So again, the same gene
sequences analyzed in the same way
should give the same tree and there's
really currently strong emphasis
on open science and reproducibility. But
science can't answer all questions.
Science is appropriate for certain types
of questions but not others. So science
does not make aesthetic judgments. It
can't tell us what's beautiful. We can
use the beauty of art to help us convey
scientific principles but
the science can't tell us that the art
is beautiful or not. Likewise science can't help us make
moral judgments. It may give us
background information but it can't tell
us how to use the knowledge. So for
example, should scientists use CRISPR to
increase crop yield? Science can help us
understand CRISPR technologies and how
we might want to apply it for certain
sorts of applications but science does
not tell us whether or not it's
appropriate and science does not address
the supernatural. And just by definition,
supernatural means outside of nature. So
there are certain things that science
can tell us and certain things that
science can't. And included in the latter
are issues of faith. Now I'd also like to
point out that not all focus thought is
science. There's a lot of scholarly
effort that's also devoted to many other
areas such as epics or the arts or
theology and religion. And so we wouldn't
want to think that only science is
rigorous and scholarly. Other areas also experience the same sort of devoted
effort. And finally, I'd like to comment
on the fact that science is a human
endeavor. And that the entrances are
influenced by the experiences of the
scientists. So scientists carry their own
biases and this is one reason why
science scholars are now recognizing the
value of teams in scientific projects. So
team science particularly teams made up
of diverse groups can help to look at a
problem from a number of different
perspectives and what this means is that
the conclusions are less likely to be
biased by a single perspective or point
of view and more likely to incorporate a
much broader view or perspective on
whatever the scientific
one might be. Now the other thing though
about science being a human endeavor is
that there may be differences of opinion.
And these differences of opinion may be
expressed in different ways by different
scientists. Often there can be sort of
fads in how we analyze data or in
thoughts and these may be led by whoever
has the loudest voice. Whoever is the
biggest person and takes up the most
room in a conference. All sorts of things
can lead to sort of dominant theories or
hypotheses in science. But it's also
possible that different points of view
and different interpretations can
actually lead to new discoveries and
this is what happens when scientists
have valuable dialogue rather than
continue to push sort of divergent
points of view. So I have these two
diagrams here and these represent some
really complex biological information
but we just need to focus on a couple of
different things. So on the diagram on
the left, group one and group two are
closest relatives. But on the diagram on
the right, groups two and groups and
three are closest relatives. The diagram
on the left was built with DNA sequences
from the chloroplast genome and the
diagram on the right was built with data
from both the nuclear genome and the
mitochondrial genome. So at first when
groups of scientists came up with these
two competing hypotheses, there was a
little bit of this "no, I'm right." "No, I'm
right." Back and forth. And at
conferences a little bit in the
literature but in fact when scientists
started looking at this problem together
it became clear that in fact it wasn't
one group being right and the other
group being wrong. Both groups are
actually right and what we
have now inferred happened is that there
was an ancient event of hybridization
that brought the data brought the gene
sequences together and so both
of these diagrams are actually right. The
chloroplast tree is right. The nuclear
and mitochondrial tree is right. And if
scientists had continued to argue about
what was right rather than thinking
about things collaboratively, we would
have never had this essentially a
paradigm shift about the ancestry of
this really prominent group of flowering
plants. So I hope I've been able to help
demonstrate just a little bit that
science is both knowledge about the
natural world and also the process of
studying the natural world. It's
evidence-based. It's testable. It changes
with new evidence and it's reproducible.
And with that, I'll say thank you very
much for your attention and I'm not sure
if we have time for questions or if
you'll address those later but I'm happy
to answer questions if you have any and
if there's time thanks dr. Soltis we
absolutely do have time for questions
and if you all do have questions please
type them in the chat box and I'll be
sure to get them answer for you um I
actually am going to come back and it's
a shame that dr. Clough had to leave
early from us today he's over in Texas
and had other engagements but I do have
a question I'm going to start off with
that was really directed at dr. Clough
but I'm hoping that perhaps either Pasha
or Bruce might be able to address this
or Pam as well so I'm going to throw it
out there and if any of you want to take
it please do the question is from Carla
she's making a statement here that an
issue today that seems more prevalent
than before is the instantaneous
gratification a lack of perseverance in
the face of challenge so in other words
if there isn't a simple answer they
don't want to put any effort in to do
anything we're talking about students
here in particular why do you think that
is and and how can teachers come back
that in a classroom anybody want to take
that one for us yeah I just want to say
that science is not necessarily simple
she's mean science is not simple and I
know that people want instant
gratification but that really is not
what science is about science is a
deliberative process where you have to
be patient and you have to persevere so
that's what that's the kind of culture
that I would like to see instilled in
students for them to understand it's
it's a misconception based on how they
view society and you know the iPhones
and all the things you can get instant
gratification about science is not like
that so that's what I would say so my
next question Pam I'm gonna ask you this
one how can science win the trust of the
general population and maybe kids as
well so with this Instagram if ocation
issue is there a way for us to engage
the public and maybe those folks that
are less inclined to be interested in
science I think some of the points that
dr. Clough made earlier are really
relevant here and that is that I think
when people understand that as Bruce
just said also that science is a process
and there's not necessarily a single
right answer at any point in time
there's our best interpretation there's
not necessarily the final word I think
that sort of understanding could go a
long way to helping people appreciate
science a little bit better I mean I've
seen we've all seen in the news over the
last few months confusion by the media
and by members of the public about well
you know last week you told us this
about kovat and now you're telling us
this and well of course we now know much
more than we did a few months ago and so
of course our ideas and our inferences
and our interpretations are going to be
evolving so I think that basic
understanding that that it's science is
a process and appreciating that and
accepting that and maybe celebrating
that can help draw children into wanting
to be scientists and help them and
adults actually understand
better how to relate to scientific
aspects of society that's actually an
excellent explanation and the fact that
as things evolve and change clearly we
have to change our perception and widen
it's like the expanding universe there's
more and more that you learn or as you
get older there's more and more
knowledge that you accumulate over time
so clearly your perception of the world
starts to change so that's great thank
you there was another question that is
referenced to you nature of science
being problematic with state standards
because they're separated for k-12
education they're taught as an isolated
unit and that paradox of not being
integrated into the unit's themselves in
actuality the the question I think is is
it is there a way that teachers can
better incorporate that how can we do a
better job of making that connection
between nature of science and the
content specifically
so that was partially my reflection that
what dr. Clough said is it that really
the nature of science should be
integrated with the content of science
and if you could pair standards together
in a single lesson that have both the
nature of science that they're teaching
about and also some content of science
then you're integrating the two as
opposed to saying okay first first week
in November we're going to only talk
about the nature of science and that's
that's divorced from the content of
science and the important point to
understand is that the nature of science
is all about the process how you get how
you get at the the content of science so
they really should try to be integrated
in lesson plans I would think so we've
got lots of great discussion happening
in the chatbox right now
between the teachers and I think one of
the things that is coming to my mind and
reading some of the commentary here is
how can how many times science has to be
tested before it's considered credible
and how do we communicate that to people
as well what is consumed you know in
school we talked about three trials how
how do we better paint a picture of what
considers to be what's considered to be
credible
maybe I can dad that someone else please
feel free to jump in so you know
different fields of science have
different standards for what is for how
how to go about reaching that level of
acceptance and in some cases if you know
if we're exploring the Amazon and we
want to know what what species are there
we do a collecting trip and we we sample
the species are there that are there you
know maybe it's the plants or the
insects oh the vertebrates or whatever
we bring them back to our museums we
catalogue them we we describe them we
compare them with other things in
museums and then we put the information
today what we do is we put this
information out there
online and allow other scientists to
look at it and that provides a sense of
validation and and and so you know
that's that's a very different way of
doing the science than what people might
think of with in terms of test tubes in
a lab you know when under very
controlled circumstances and so there's
a whole range in terms of scientific
endeavor and how we actually reach
validation and it depends so much on the
on the type of science so experimental
design is really important for those
sorts of things where you can have
controls you know certain types of
chemistry or biochemistry years some
types of biology physiology but you
don't have a control of your studying
ecosystem dynamics and so there there
are a lot of different ways I think that
we approach you know validated science
and making it all reproducible it helps
us do that excellent yeah so stepping
I'd like to also comment and follow up
on what Pam said and that that science
is about constructing hypotheses and
then corroborating those hypotheses with
evidence and the more credible the the
hypothesis though those hypotheses that
are more credible are also more robust
meaning that additional data supports
those hypotheses and those hypotheses
are not rejected in the light of new
evidence so a more credible hypothesis
or a more credible idea and science is
more robustly supported by repeated sets
of evidence let's say that support the
hypothesis and that's just a process of
science we're not trying to find
absolute truth in science we're trying
to we have we construct hypotheses about
the natural world and we use evidence to
defend or support them and sometimes
evidence changes like Pam said with when
you look at new kinds of evidence you
might say well that hypothesis we can no
longer to corroborate that so it's no
longer credible and that's just the way
science works it's a process of
discovery and support based on evidence
of hypotheses and the more evidence you
have and then
times you try to test those hypotheses
the more robust that hypothesis is and
therefore it's more credible excellent I
would like to jump in here as well if I
might so I'm a learning scientist a
little different from Bruce and Pam I'm
more like dr. Clough and one issue that
we deal with a lot in educational
research is when our students come to us
and say oh but there is the study that
proves this business research that
proves that and then we talk to them
about how we don't do research or what
they will do science to prove anything
we are only as good as our theories are
and actually according to Karl Popper a
philosopher of science we do research to
see if we can disprove a theory that's
why we test the null hypothesis right
and so it's an interesting conversation
and the gifts at this point of nothing
is certain in science and the game
series change all the time with an
excellent book the structure of
scientific revolutions by Thomas Kuhn
who talks about how all these theories
always evolve and nothing really stays
please for a long time and that's the
parrot and Thomas Kim also talked about
the paradigms there that the concept of
the paradigm which is a very robust set
of hypotheses that explain the natural
world in sort of a large way and the
paradigm for example the Connell drift
or plate tectonics relates to something
like that and that's the book that
you're talking about by Thomas Kuhn the
philosopher of science I've got a really
interesting question from Celeste and
another question I'm not sure who wrote
this but they're kind of very similar so
I'm going to couple them together here
the question is how can we teach
vocabulary that's tested on the FCAT the
SS they test through activities teachers
who have taught without activities and
focused on vocabulary have had higher
scores the other person is asking can we
replicate what's done in research within
classrooms to help students better
understand that vocabulary how can we do
those things
yeah so rather than teaching to the test
and just doing vocab quizzes how do you
get them to understand the vocabulary
through the action of researcher
activity
I would I would say personally again
I'll just say I do this a lot they
design a lot of curricula and now
designing a curriculum for example for
little kids in elementary school to
learn about cryptography and we're using
this words all the time in all of the
activities we talked about encoding
encryption decryption and that they get
it really quickly if you use it
consistently in your own language you
know and when we talked about nature of
science being integrated with the rest
of the curriculum it's the same idea as
integrating scientific literacy more
generally in your curriculum right we
don't do a unit on how to read well we
may do a units on how to read a
scientific article but really this kind
of stuff should be embedded throughout
and a lot of it the teacher is a model
you guys are models and so you've got to
use that language yourself consistently
pervasively and they'll pick it up and
they will start using it too that's my
perspective when you worry thanks
Patrick Vickie has a question for dr.
Silva's pan they want to know she wants
to know how do we teach monocots and
dicots in the textbook they actually
have them as two groups that's really
unfortunate a lot of textbooks even
several years ago had shifted away from
teaching that from you know listing the
dike the dicots as a group and that they
focused on monocots and then on this
other you know big group called the you
die cuts which makes up about 75% of all
of the flowering plants and then what
what's left are some of the so you have
the monocots which are maybe about 25
percent and you have no they're about 20
percent you have new dicots which is a
group of about seventy five percent and
then there's only just this few
percentage maybe like three to five
percent that don't fall into either of
those groups and those are the ones that
are really interesting because they
represent some of the very first sort of
experiments of being a flowering plant
and so a lot of so a lot of textbooks
have made a shift over if the the ones
that are you know recommended for
Florida schools I guess haven't then one
possibility would be and I think I mean
as a student in high school I would have
hated this but that's because I liked I
liked that I was noticing that some
people were noting that they liked
vocabulary they liked memorizing the
processes that you know I was very rigid
in the way that I thought you know back
then and and it you know it helped
because I was able to organize a lot of
information but what I think could be
interesting would be to say this is the
way the book presents this and this this
was the the understanding until
scientists more recently have determined
that this isn't really the case and it
actually provides this whole you know a
teachable moment
relating to the nature of science and
how you know new evidence has overturned
this long-standing hypothesis so I think
you know you could do it without like
totally overwhelming them with with new
information that's not presented but but
pointing out that it's it's been a shift
that there's a shift there and how we
view plant diversity could be a way of
sort of bringing in these nature of
science characteristics in perhaps even
locating something article wise that
shows the updates and and having that
conversation about science changing yeah
this is a great you know way of going
back and looking at science through
various resources and not taking one
credible resources being the only credit
finding out the path what's going on
it's I want and there are nice articles
written in like bioscience and
Scientific American that are more
accessible versions that describe some
of this information that could certainly
be you know accessible to upper level
high school students excellent thank you
um so one other question a big thing
that happens every year is science fair
and I know that a lot of teachers
struggle because students struggle with
what is a testable question and it's
it's geared things
spirit that we are testing doing
experimental design but we've heard
today that much of science does not
follow that particular pattern how do
you how do you help teachers help
students come up with projects that
would be appropriate for a science fair
and how do you explain or how that
conversation with students that not all
science fits that mold
anybody want to take that one I have a
lot of thoughts about science fair but I
don't know if anyone else would like to
comment first go ahead
we're usually gonna go well I'm just
thinking it so I don't do I don't really
do experiments I'm a paleontologist so
I'm sort of a historian of deep time and
we use evidence to test hypotheses but I
don't construct an experiment like if
I'm using a mass spectrometer and if I'm
a physicist using a Collider where I
predict how particles are going to react
that's a different kind of science that
that's test that's tested but what I
there are other types of science that
are more historically based like what I
do looking at the rock record and seeing
patterns of evolution from the rock
record and then constructing hypotheses
about how animals and plants were
interrelated in the past and maybe what
they did for a living by looking at the
chemistry of their bones or something
like that so yeah I understand about the
scientific method and how you're
supposed to ask testable questions and
stuff but that's not the scientific
method can also encompass other ways of
looking at science what you like
paleontology and the work that I do is
also along the lines of what what Bruce
does in many cases where we're trying to
reconstruct evolutionary past with you
know with different types of evidence
and I have to say you know as a mother
of two daughters I always detested
Science Fair and it was a horrible thing
to you know express that to my children
because the ways that the science fairs
were conducted were were just you know
but they were so rigid with the way that
they viewed science so one of my
daughters wanted to compare seashells
from the Atlantic and Gulf Coast's
because she had always collected
seashells and she thought I could
identify these I could go to the museum
I can do this stuff and her teacher told
her that was not and this was in middle
school this was not an acceptable this
was not acceptable science because it
didn't have you know control and things
like that and she said yeah but I have a
high
offices my hypothesis is they're gonna
be different because they're in
different places and anyway it was you
know we had to we ended up struggling
with the teacher to try to explain to
the teacher that this is like real
biology you know people actually do
those kind of work so the irony that's
crazy
interesting okay so I think what we're
gonna do now is switch gears for a
little bit we want to thank dr. Soltis
for being with us and of course I could
Clough earlier for taking the time to
share with us a little bit of your
perspective of nature science through
the lens of what you do and how this
might help teachers in the classroom so
again thank you so so much for being
here
