Download - Bio 178 Lecture 1
Bio 178 Lecture 1
Biology: The Study of Life
Reading
• Chapter 1
Quiz Material
• Questions on P18
• Chapter 1 Quiz on Text Website (www.mhhe.com/raven7)
Outline• 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– 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 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 InvestigationObservation
Question
Hypothesis(es)
Prediction(s)
Controlled Experiment
Conclusion
How to Write QHPsExample 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 ProcessOQ H P Controlled Experiments Conclusions
Manuscript preparation for publication
Peer Review
Publication
Replication by other scientists
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
• Cell theory• Molecular basis of inheritance• Evolutionary change - Diversity• Evolutionary conservation - Successful
structures are conserved
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 in Biology
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.
• Evolutionary conservation– Some fundamentally important characteristics of earlier organisms are preserved and passed on to future generations.
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.