Study of Life
Basic Themes
I. Introduction
A. define: Biology = ?????
1. "bio" refers to "life"
2. "ology" refers to "the study of"
B. define: Life = ?????
C. define: Hierarchy = ?????
1. examples of hierarchy outside of biology
a-
b-
c-
2. examples of hierarchy within biology
a-
b-
c-
D. Themes in Biology
1. Life can be organized into hierarchial levels
a. atoms
b. molecules
c. supramolecular structures
-eg:
-eg:
d. cells
-lowest level of organization with all
properties of life
e. tissues
-found in some multicellular organisms
-similar cells with specialized functions
-do not display all properties of life
f. organs
-found in some multicellular organisms
-associations of several tissues with an
overall specialized function
-do not display all properties of life
g. organisms
-next level with all properties of life
-one or more cells which function together as
a reproductive unit
h. populations of organisms
i. communities of different organisms
j. biosphere = totality of all organisms on earth
-some biologists (eg: L. Margulis consider
populations, communities and even the
biosphere, to be "alive")
k. theme of organization through cells
will be emphasized in 241
2. Life displays emergent properties
a. define: emergent properties = ?????
- eg: molecules have properties different from
isolated atoms
- 6 carbon atoms, 6 oxygen atoms and
12 hydrogen atoms mixed together have
very different properties than 1 glucose
molecule
- eg: supramolecular structures have properties
different from molecules
-eg: cells have many properties that go
beyond the properties of molecules
-eg: ____________________
-eg: ____________________
-eg: ____________________
-eg: organisms have properties that go beyond the
properties of cells
-eg: ____________________
-eg: ____________________
-eg: ____________________
b. be able to list emergent properties for each of
the hierarchial levels
c. theme of emergent properties will be
emphasized in 241
3. "Cells are lowest level of organization which CAN
display all properties unique to life"
a. important statement => courses based solely on cells
-at WSU----Cell Biology 308
b. why the "can" in the statement above?
-???????
c. original cell theory = all organisms are composed
of one or more cells
-Schleiden and Schwann (1839)
d. current cell theory = all organisms are composed of
one or more cells and all cells come from
pre-existing cells
e. properties of all cells
-surrounded by a plasma membrane (PM)
-PM regulates contents of cell
-PM maintains condition of low entropy
-have cytoplasm within the plasma membrane
-dissolved macromolecules and small molecules
-have genetic information
-deoxyribonucleic acid (DNA)
-divide to form new cells
-be able to list the properties above
f. theme of cells as the lowest level
organization which has all properties
of life is emphasized in 241
4. Continuity of life requires that information
be heritable (Genetics)
a) offspring are similar to parents
-similarity is due to heritable information
b) DNA contains the heritable information
-information present in sequence of bases
c) when cells divide, each daughter cell gets
exact copies of DNA molecules, and thus, gets
exact copies of the heritable information
d) theme of genetics emphasized in 241
5. Structures are related to Functions
-wings:flight
-legs:running
-enzymes:catalyzed reactions
-membranes:lowered entropy
-etc
-theme of structure/function emphasized in 241
6. Organisms are "open" and must interact with
their environment
-define "open" = ?????
-define "environment" = ?????
-theme of "openness" emphasized in 242
7. Organisms regulate their various processes
and activities
a. eg: hot day, you _____________
b. eg: body needs energy, you ___________
c. eg: during sleep your metabolism ________
d. theme of regulation emphasized
in 242
8. Life displays great Diversity
a. biologists have identified and named 1.5 million species
-260,000 plants
-50,000 vertebrates
-750,000 insects!
-fungi?????
-prokaryotic organisms?????
-protistans??????
b. biologists estimate that there may be 5 million
to 100 million species on earth
c. biologists group similar organisms together
-cats: lions, tigers, leopards, house cats
d. Taxonomy= branch of biology which names
and classifies species and groups into a
formal scheme
-5 kingdoms
1. ????????
-eukaryotic autotrophs
2. ????????
-all prokaryotic organisms
-many biologists favor two kingdoms
-bacteria (formerly the eubacteria)
-archaea (formerly the archaebacteria)
3. ????????
-unicellular eukaryotes
-a few simple multicellular eukaryotes
-many biologists favor multiple
kingdoms within protista
4. ????????
-multicellular, eukaryotic heterotrophs
with extracellular digestion
5. ????????
-multicellular, eukaryotic heterotrophs
which ingest other organisms
e. theme of "Diversity" emphasized in 242
9. Unity of life
a. this is a major focus of this class
b. emphasize the similarity of all living things
c. how are all living things similar?
- all life has genetic information in the
form of DNA
- all life is cellular
- all life uses proteins to catalyze its
various processes
- great unity in the basic life processes
d. theme of "Unity" emphasized in 241
10. Evolution
a. "The history of life is a chronicle
of a restless Earth, billions of years old,
inhabited by a changing cast of living forms."
b. life changes
c. similar species have common ancesters
-eg: horses and zebras are very similar,
both descended from a common ancester
-eg: domestic cats and lions are very similar,
both descended from a common ancester
-go back far enough, and all life came from
an orginal prokaryotic organism
d. Charles Darwin was one of the most influential
scientists in developing modern biology
-a great naturalist
-made two key observations:
1. Individuals within a population of a
given species vary in many heritable traits.
2. A population of a species has the potential
of producing more offspring than the
environment can support with food, space
and other resources. This overproduction
of offspring forces the offspring to compete
for the limited resources necessary for
survival and reproduction.
-Darwin made an important inference
based on the observations
-Those individuals with heritable traits best
suited to the local environment tend to be
more successful at surviving and reproducing
than are those individuals with heritable traits
which are not as well suited to the local
environment. This leads to differential
reproduction. Darwin called differential
reproduction natural selection.
-Darwin proposed that natural selection could
produce new species, given enough time.
e. much of biology today is focused on documenting
natural selection and practicing artificial selection
f. theme of "Evolution" emphasized
in 241 and 242 and most other
biology courses
11 Science is a process
a. science is a "way of knowing"
b. biology is the "science of life"
c. biology answers questions relating to life
d. biology uses scientific method to answer questions
-science only deals with topics which can
illucidated with experiments or observation
-scientific method has series of steps
| Step | Description | Example |
| General Observation | Any aspect of life is observed | Flies were once killed by DDT but now they are no longer killed. |
| General Question | Broad question relating to the general observation. | Why does DDT no longer kill the flies? |
| Testable Hypothesis | Hypothesis = answer to general question which can be tested with an experiment. What if a hypothesis can't be tested????? | DDT does not kill flies because now flies can metabolize DDT and render DDT nontoxic. |
| Test the hypothesis with an experiment | Experiment designed to test the hypothesis. | If the hypothesis is true, then we should be able to measure the abilitiy of the flies to metabolize DDT, converting DDT to a nontoxic form. |
| Experimental Results | Collect the results of the experiment. | One possible result is that we find that DDT resistant flies DO NOT metabolize DDT and do not make the DDT nontoxic. |
| Analysis and Conclusions | Analyze the data collected and draw conclusions. | In this case we conclude that hypothesis is not supported. |
| Consider hypothesis | Tentatively accept supported hypotheses and reject unsupported hypotheses | Reject original hypothesis |
| New testable hypothesis | Develop a new testable hypothesis | DDT resistant flies do not allow DDT to enter their bodies |
| Test the new testable hypothesis | Devise experiment to test the new hypothesis | Measure whether or not DDT can enter cells of flies using radioactive DDT |
| Continue process until understanding is complete | | |
E. Reznick and Endler Experiments
1. carefully read pp 15-17 in Campbell et al. and become
thoroughly familiar with the Reznick and
Endler experiments
2. be prepared to do the following:
a. cite the Hypothesis #1/Experiment/Predicted
Result/Result as detailed in the text
b. cite the Hypothesis #2/Experiment/Predicted
Result/Result as detailed in the text
c. cite the most likely explanation (according
to Reznick and Endler) for the observed
differences in guppy populations
d. relate the Reznick and Endler experiments
to the theory of evolution by natural selection
F. Theories = broadly applicable generalizations that
explain many observations and facts
1. to be accepted, theories must be supported
by a large body of evidence
2. evolution by natural selection is a theory
widely supported by all branches of biology
a. there is essentially no uncertainty in the
scientific community about the theory
of evolution
b. see Gould's article in Time, August 23, 1999
-nicely summarizes the attitude of most biologists
++++++++++++
Define: Biology = the study of life
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Define: Life = a set of energy driven, self replicating,
changeable, chemical reactions
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Define: Hierarchy = arrangement into a graded series
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Emergent properties of cells: reproduction, metabolism, use of energy, simple movement, LIFE
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Emergent properties of organisms = thinking, complex movement, vision, hearing,
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"Open" in this context means that
organisms need a continuous supply of energy to
keep functioning. The major source of energy input
for most animals and plants on earth is light energy
from the sun.
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Environment of an organism = the sum total
of the physical and biological surroundings of an organism.
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emergent properties = unique characteristics associated with a level of organization which are not found in the levels below
emergent properties arise from the "organization" of the lower levels
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Not all cells DO display all of the properties of life. Eg: mammalian red blood cells do not reproduce.
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