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Chapter 1Ten Themes In The Study Of Life
Hierarchy of Organization
Atoms
Molecules
Organelles
Cells
Tissues
Organs
Systems
Organism
Population
Community
Ecosystem
Biome
Biosphere
Ecosphere
Emergent Properties
• Order – tendency to self organize
• Reproduction – biogenesis
• Growth and development
• Energy utilization
• Response to the environment
• Homeostasis – self regulation
• Evolutionary adaptation
With each step upward in the hierarchy of biological order, novel
properties emerge that were not present at the simpler levels of
organization.
“The whole is greater than the sum of its parts.”
How do we seek understanding?
• Reductionism – reducing complex systems to simpler components
• Holism – Study the entire system to truly understand it
The Cell Theory
• 1. All living things are composed of cells
• 2. All cells come from other cells
• 3. Cells are the units of structure and function
Two Major Kinds of Cells
Prokaryotic – first cell
Eukaryotic – true cell
E.M. of Prokaryotic Cells
DNA Basics
DNA is the substance of genes
Double helix
4 Bases (Adenine, Guanine, Cytosine, Thymine
Self-replicating molecule
Changes over time
All forms of life employ essentially the same genetic code
Organisms Are Open Systems That Interact Continuously With
Their Environments.
Living things both alter and are changed by their environment
Materials are recycled
Energy is lost as heat and not recycled
Energy Flow In The Ecosystem
Living Systems Are Regulated
Many Biological Processes Are Self -Regulating Through “Feedback”
Mechanisms
Negative Feedback
Positive Feedback
Evolution, Unity, And Diversity
The Evolutionary Connections Among All Organisms Explain the
Unity and Diversity of Life.
The Three Domains of Life
“Descent With Modification”
Connections
• Observation #1– Individual variation
• Observation #2 – Struggle for existence
• Inference – Differential reproductive success or “Natural Selection”
Natural Selection Is An Editing Process
The Process Of Science
“Science Is A Way Of Knowing”
Idealized Scientific Method
Inductive Reasoning
Hypothetico-deductive Reasoning
“If…then” Logic
“Fishing” For Answers
Theories Have Broad Explanatory Power
Theories Are Comprehensive
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