Transcript What is Science?

Biology L111: Evolution and Diversity
Instructor: Michael J. Wade
AIs: Tiffany Clark
Harald Parzer
The Thursday Discussion section 14008 that meets at
11:15A-12:05 on Thursdays in JH 440 has been moved to
JH 248 at the same time and day.
Year in School
200
180
Number of Students
160
140
120
100
80
60
40
20
0
Freshman
Sophomore
Junior
Senior
Returning
yc
h
ol
og
he
y
m
is
t
B ry
io
Ex
lo
g
pl
or y
at
En
D ory
vi
ro ent
nm is
en try
ta
lS
T h ci
ea
t
B
us er
in
E d es
s
u
E x cat
io
er
n
ci
se
Sc
i
B
M
io
ch at
em h
is
tr
Fr y
en
O
p t ch
om
N
ut
e
rit try
io
Jo n S
ur
c
na i
lis
m
H
is
to
ry
G
eo
A
nt
hr log
y
op
ol
og
y
D
Po an
c
lit
ic e
al
Sc
i
C
Ps
Number of Students
Majors
160
140
120
100
80
60
40
20
0
Favorite Organisms
80
60
50
40
30
20
10
ng
i
Fu
er
te
br
at
es
s
The Thursday Discussion section 14008 that
meets at 11:15A-12:05 on Thursdays in JH 440
has been moved to
JH 248 at the same time and day.
In
v
A
m
ph
ib
ia
n
ird
s
B
at
es
Pr
im
ro
be
s
M
ic
ts
Pl
an
ile
s
ep
t
R
H
um
an
s
al
s
M
am
m
e
0
M
ar
in
Number of Students
70
Class Website
http://www.indiana.edu/~mjwade/L111/
Postings of Syllabus, Discussion Questions,
Lecture Notes, and Grades
http://www.indiana.edu/~mjwade/L111/
Outline for Week 1

What is Science?


What is Biology?


What do scientists do?
What is Life?
Evolution by Natural Selection explains
Two Fundamental Patterns of Nature
Adaptation
 Diversity


Logic of Darwin’s Theory
What is Science?



From Latin scientia = “to know”
Science is a way of viewing the world that
focuses on objective information, and putting
that information to work to build an
understanding of processes acting in the natural
world to cause patterns.
Scientists test hypotheses using observations,
manipulations or experiments, or mathematical
models.
What Scientists Do


All science begins with observations about the
natural world; scientists are ‘pattern detectors.’
Scientists suggest an hypothesis to explain or to
account for the pattern of observations.
 Scientific
testable)

hypotheses must be falsifiable (i.e.
Experiments are used to test an hypothesis,
and/or to eliminate one or more competing
hypotheses.
 In
a controlled experiment, all variables, but one,
are kept constant.
Theory ≠ Hypothesis
Theory = Tested and Supported Hypotheses


In science, a theory is:

A set of hypotheses with supporting evidence.

A body of interconnected concepts, supported by
mathematical or logical reasoning and experimental evidence.
This is different from the colloquial use of “theory”


Opinion-based rather than evidence-based.
A hunch, a guess, or a belief about cause and effect.
Scientific Theories are constantly compared with new physical
discoveries and experimental results.
New Theories explain MORE not LESS.
Process of Science
Figure 1.4
X
Rejected Hypotheses
Are NOT
part of Theory
X
Hypothesis 5
becomes part of
“Theory”
Many Lines of
Supporting
New Evidence
Biology is the Study of Life

From Greek bios = life and ology = science or study of
What is Life?

Seven Basic characteristics of living organisms:
 cellular organization
 Sensitivity and response to the environment
 growth, development, and reproduction
 energy utilization
 evolutionary adaptation or ‘fit to the environment’
 homeostasis
 DNA and RNA, replication and information
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Hierarchical Organization of Life
Fig. 1.2
CELLULAR LEVEL
ORGANISMAL LEVEL
POPULATIONAL LEVEL
Darwin
Atoms
Population
Tissue
Molecule
Organ
Species
Organ system
Community
Organism
Ecosystem
Macromolecule
Organelle
Cell
Evolutionary Biologists:
1] Identify patterns in the diversity of life, especially
puzzling ones, that appear to be problematic for the theory.
2] Hypothesize processes or forces that might be creating
those patterns. They provide an explanation for the pattern in
terms of one or more of the five evolutionary processes.
3] Test the adequacy of their hypotheses by experimentation
and by further study of the history of life.
The term, “evolution,” appears many times a week
in national newspapers, like the Washington Post.
1. NATIONAL FIREARMS MUSEUM -- Permanent exhibits
tracing the evolution of firearms and their role in the history of
the United States. Open daily 10 to 4. National Rifle Association,
11250 Waples Mill Rd., Fairfax.
2. NATIONAL MUSEUM OF HEALTH & Medicine -- Open
indefinitely: "Evolution of the Microscope"; Open daily 10 to
5:30. Armed Forces Institute of Pathology, Walter Reed Army
Medical Center, Building 54, 6900 Georgia Ave. NW.
3. THE ART BEAT: Review of Braswell’s stage musical, "Paying
the Price" which debuts at the Kennedy Center on Labor Day The
play, says Braswell, recounts his father's evolution from a
happy-go-lucky enlistee to a battle-weary prisoner of war in
Romania.
In colloquial contexts, “evolution” is a synonym for
“change over time.”
Usually, the change is “for the better,” so that evolution
is interpreted to mean “improvement with time.”
Evolution is a process of change and it does result in
adaptation over time. But, NOT all change is evolution
and adaptation is NOT always improvement.
Evolution
Ecology
Change
Change
in Kinds
in Numbers
Pleistocene (2 mya)
Today
14 species of elephants
3 species
# declined
3-4 species of hominid
1 species
# increased
50 species of Hawaiian
Drosophila (fruit flies)
> 500 species
# did not change
Ecology: Study of the change in the numbers and
distribution of organisms.
Evolution: Study of the change in the kinds of
organisms.
Darwin’s theory of Evolution by Natural Selection is the
corner stone of modern biological science.
"Nothing in biology makes sense but in the light of
evolution.”
Theodosius Dobzhansky
(1900-1975)
Evolutionary Geneticist
Genetic Model of Speciation
Charles Robert Darwin
Born 1809
Voyage of the H. M. S. Beagle
December, 1831- October, 1836
On the Origin of Species (1859)
Two Patterns of the Nature

Adaptation:


The remarkable “fit” between organisms and
environment.
The Diversity of Organisms:
Why there are so many different species (5 to 50
million living species)?
 Fossil record indicates that >99% of species that
have ever existed are extinct
 500,000 beetle species alone
