Transcript Chapter 1

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Dishonesty
Assignment
Quizzes and Tests
Assignments (including
lecture and laboratory)
General
Infraction
Penalty
Looking off neighbor’s paper
(whether or not you change
answers on your exam)
Flunk course; Report to
Judicial Affairs
Use “cheat sheets”/notes
Flunk course, Report to
Judicial Affairs
Leave room with exam
0 on exam; Report to Judicial
Affairs
Plagiarize (not using your
own words); no sources cited
0 on assignment; Report to
Judicial Affairs
Too similar to another
student’s work (past or
present student) without
explicit permission from
instructor stating that it is
okay to hand in similar
assignments
0 on assignment, Report to
Judicial Affairs
Forging signatures, lying to
instructor (e.g. about
absences, etc.)
Flunk course; Report to
Judicial Affairs
• Life resists a simple, one-sentence definition, yet
we can recognize life by what living things do.
Fig. 1.2
CHAPTER 1
Exploring Life
1. Hierarchy of life
• Life’s basic characteristic is a high
degree of order.
Atoms
Biological molecules
Organelles
Cells -Basic unit of life
Multicellular
Unicellular
Tissues
Organs
Organ system
• Organisms belong to populations, localized group
of organisms belonging to the same species.
• Populations of several species in the same area
comprise a biological community.
• These populations interact with their physical
environment to form an ecosystem.
The biosphere refers to all life on earth
F
• Energy flow proceeds
from sunlight to
photosynthetic
organisms (producers)
to organisms that feed
on plants
(consumers).
Fig. 1.4
• All organisms must accomplish the same
functions:
• uptake and processing of nutrients
• excretion of wastes
• response to environmental stimuli
• reproduction
1b. Cells are an organism’s basic unit
• The cell = lowest level of structure that is capable of performing
all the activities of life..
In 1839, Matthais Schleiden and Theodor Schwann
• The cell theory- all living things consist of cells.
• A cell theory extension - all cells come from other cells.
• Novel properties emerge at each step upward in the
biological hierarchy.
• Result from interactions between components.
• A cell is not just a bag of molecules.
1c. DNA is the cell’s heritable information
DNA (deoxyribonucleic acid)
• encodes life.
genes
• is the substance of ________
• is composed of two long chains
double helix
arranged into a_________________.
• Contains only four molecules
called______________
.
nucleotides
genetic code
• All forms of life employ the same __________________.
replicate
• Cells ____________chromosomes
and provide an exact copy
to two “daughter” cells
Fig. 1.7
• All cells:
membrane
• Are enclosed by a _______________
• regulates the passage of materials
DNA
• Contain ________
• Two major kinds of cells –
• _______________–
(yeast to mammals)
eukaryotic
• ___________Nucleus contains chromosomes (DNA
+ protein)
• ______________
Cytoplasm - contains membranebound organelles
• Sometimes a cell wall (plants)
• _____________–includes
prokaryotic
bacteria and archaea
• no nucleus, no organelles, DNA in cytoplasm
2a. Emergent properties- more than the sum
of the parts
• The complex organization of life is a dilemma
• We cannot fully explain a higher level of organization
by breaking down to its parts.
• At the same time, it is futile to try to analyze something
a complex as an organism or cell without taking it apart.
• Reductionism, reducing complex systems to
simpler components, is a powerful strategy in
biology.
• Reductionism is balanced by the longer-range
objective of understanding emergent properties.
Where can I look to find answers??
Fig. 1.10- A map of protein interactions in a cell
Bioinformatics- extracting biological information from huge databases
Computer-based mathematical modeling is a must
Requires engineers, chemists, physicists, mathematicitians, biologists
2b. Feedback regulation is important
• Organisms obtain useful energy by breaking down
molecules in regulated chemical reactions.
• Special protein molecules, called enzymes, catalyze
these chemical reactions.
• Enzymes speed up these reactions
• enzymes catalyze the rapid breakdown of sugar
molecules when need energy
• At rest, other enzymes store energy in complex sugars.
• Many biological processes are self-regulating
• Negative feedback or feedback inhibition slows or stops
processes.
• Positive feedback speeds a process up.
Fig. 1.11
Fig. 1.12
3. Diversity of Species
• Diversity is a hallmark of life.
• 1.8 million species identified.
• Includes over 290,000
plants, 52,000 vertebrates,
and over 1,000,000 insects.
• Thousands of newly identified
species are added each year.
• Estimates of the total diversity of
life range from about 5 million to
over 30 million species.
Fig. 1.13
• Taxonomy is the branch of biology that
names and classifies species into a
hierarchical order.
• Pre 1990- five kingdoms.
• Today- Various classification
schemes now include six,
or more kingdoms.
eight,
• Debate that there are three even higher
levels of classifications, the
domains.
• The three domains are the
Bacteria, Archaea, and
Eukarya.
Fig. 1.14
• Both Bacteria and Archaea are prokaryotes.
• Archaea may be more closely related to eukaryotes
than they are to bacteria.
• The Eukarya includes at least four kingdoms:
. Protista, Plantae, Fungi, and Animalia
Bacteria
Protists
Archaea
Fungi
Plantae
Fig. 1.15
Animalia
4. Evolution accounts for diversity and unity
• Life evolves and this process is called
evolution.
• Evolution is a theory that has
become dogma
• It is based on extrapolation from
data from many sources.
• Charles Darwin (1859) presented two
main concepts in The Origin of
Species.
Fig. 1.17
1. Contemporary species arose
from a succession of ancestors
through “descent with
modification” (evolution).
2. The mechanism of
evolution is natural selection.
Fig. not in text
8. Evolution is the core theme of biology
• Darwin inferred that those
individuals with traits best suited
to the local environment will
generally leave more surviving,
fertile offspring.
• Differential reproductive
success is natural selection.
Fig. 1.21
8. Evolution is the core theme of biology
• Natural selection, over vast spans of time, may produce new species from
ancestral species.
• EXAMPLE: The finches of the Galapagos Islands diversified after an initial
colonization from the mainland to exploit different food sources on different
islands.
Fig. 1.23
5. Science is a process of inquiry that includes
repeatable observations and testable hypotheses
• The word science is derived from a Latin verb meaning “to
know”.
• Science seeks natural causes for natural phenomena.
• The scope of science is limited to processes that we can observe
and measure, either directly or indirectly.
• Verifiable observations and measurements are the
data of discovery science.
• The scientific method
consists of a series of
steps.
• Few scientists adhere
rigidly to this
prescription, but at its
heart the scientific
method employs
hypothetico-deductive
reasoning.
Fig. 1.25
Case of Scientific inquiry- Snake mimicry
harmless
Question- Do harmless king snakes
benefit from looking like a deadly
coral snake?
Prediction- King snakes will be not be
attacked as often where the coral snake
lives.
Experiment-place plastic snakes out in
both areas, examine for attack marks
venomous
Control? - plastic
brown snakes to
control for number
of predators
harmless
Fig. 1.28
Fig. 1.27
Results:
Conclusion- It’s good to look
like a deadly snake
• Scientific theories are not the only way of
“knowing nature”.
• Various religions present diverse legends that tell of a
supernatural creation of Earth and its life.
• Science and religion are two very different ways of
trying to make sense of nature.
• Art is another way.
• Science can be distinguished from other styles of
____________by
inquiry
observations and measurements
• (1) a dependence on _________________________
that others can verify, and
• (2) the requirement that ideas (hypotheses and theories)
are ______________by
observations and experiments
testable
that others can repeat.
5b. Science and technology are functions of
society
• Science and technology are associated.
• Technology results from scientific discoveries
applied to the development of goods and services.
• The discovery of the structure of DNA by Watson and
Crick sparked an explosion of scientific activity.
• These discoveries made it possible to manipulate DNA,
enabling genetic technologists to transplant foreign genes
into microorganisms and mass-produce valuable products.
• DNA technology and
biotechnology has
revolutionized the
pharmaceutical industry.
• It has also had an
important impact on
agriculture and the legal
profession.
Fig. 1.32
• Not all of technology is applied science.
• The direction that technology takes depends less on
science than it does on the needs of humans and the
values of society.
• Technology has improved our standard of living,
but also introduced some new problems.