Transcript Biol 178 Lecture 1

Bio 178 Lecture 1
Biology: The Study of Life
Reading
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Chapter 1
Quiz Material
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Questions on P18
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Chapter 1 Quiz on Text Website
(www.mhhe.com/raven7)
Outline
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Definition of Biology
Properties of Life
Hierarchical Organization
Scientific Method
Unifying Themes of Biology
What is Biology?
The scientific study of organisms (living beings).
Properties of Life
• Basic characteristics of living organisms
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Cellular Organization
Order
Sensitivity
Growth, Development, and Reproduction
Energy Utilization (metabolism)
Evolutionary Adaptation
Homeostasis
Hierarchical Organization
• Cellular level
– Atoms
– Molecules
– Macromolecules
– Organelles
– Cells
• Organismal level
– Tissues
– Organs
– Organ systems
– Organisms
Hierarchical Organization
• Populational level
– population
• species
– biological community
» ecosystem
– Emergent properties
• Novel properties that arise at each higher level
The Scientific Method:
The Hypothetico-Deductive Method
Hypothesis - Tentative answer to a question (educated guess)
Deductive - Deductive Reasoning
Reasoning
•Deductive Reasoning (Predictions)
–Apply general principles to predict specific results
Eg. “If organisms are composed of cells (H1) & humans are
organisms (H2), then humans are composed of cells (P)”.
•Inductive reasoning
–Use specific observations to construct general
principles
Stages of a Scientific Investigation
Observation
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Question
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Hypothesis(es)
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Prediction(s)
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Controlled Experiment
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Conclusion
How to Write QHPs
Example 1: The laptop stops working.
O: The laptop is not working
Q: Why is the laptop not working?
H:
Example 2 (include a control): Asprins get rid of headaches.
Q: Do asprins truly get rid of headaches?
H: If asprins truly get rid of headaches, the headaches will clear
FASTER if asprin is taken than if it is not.
Controlled Experiment:
Predictions:
Conclusions:
A Few Definitions
• An experiment is used to test a hypothesis,
and/or eliminate one or more multiple
hypotheses.
• In a controlled experiment, all variables but
one are kept constant in the experimental. In
the control that variable is unaltered.
• A theory is a hypothesis supported by a wealth
of scientific evidence ( is a generally accepted
principle).
Scientific Process
OQ  H  P  Controlled Experiments  Conclusions
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Manuscript preparation for publication
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Peer Review
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Publication
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Replication by other scientists
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Acceptance by the scientific community
Example of the Development of a Theory:
Evolution
Accepted “Belief” in 1831: Species have been specifically created
and are unchangeable over time.
Darwin’s Evidence: Fossil record
Geographical Distribution
Islands
Darwin’s Theory: Evolutionary changes occurring by the
mechanism of natural selection are responsible for the diversity of
life on earth.
Unifying Themes of Biology
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Cell theory
Molecular basis of inheritance
Evolutionary change - Diversity
Evolutionary conservation - Successful
structures are conserved
Unifying Themes in Biology
Cell Theory
Robert Hooke (1665): Discovered cells
Schleiden and Schwann (1839): “All living things are
composed of cells”
Modern Cell Theory
All living organisms are made of cells, and all
living cells come from other living cells.
Unifying Themes of Biology
• Molecular basis of inheritance
– DNA encodes genes which make-up and control living
organisms. Heredity is dependent on the faithful copying
of the cell’s DNA into daughter cells.
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Evolutionary conservation
Some fundamentally important characteristics of
earlier organisms are preserved and passed on to
future generations.
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Eg. Histones
Unifying Themes of Biology
• Evolutionary change
– Life-forms have evolved varying characteristics to
adapt to varied environments. This has resulted in
incredible diversity.