This Biology 201 lecture introduces the key concepts to be covered in the course. It defines life as having cell membranes, highly organized structures composed of organic molecules and water, metabolism, regulation, growth, heritable DNA, reproduction, adaptation, response to the environment, and existence within ecosystems. Certain viruses are described as "infectious genetic elements" that have some but not all properties of life. The lecture then covers the hierarchy of biological organization from ecosystems down to atoms, defines species, and outlines seven major themes in biology centered around structure-function correlation, cellular basis of life, heredity via genes, metabolic pathways, organism-environment exchange, symbiosis, and evolution accounting for unity and diversity of life.

1. Biology 201
Don Campanella, Ph.D.
Lecture 1
Properties of Life
Reading:
Chapter 1: 1-11

2. Biology is the study of life
• What is “life”?
• Life = +

3. What are the properties
of living organisms?
• Membrane-bound cells (the unit of life)
• Highly organized
• Composed of organic molecules and water
• Metabolism – acquisition and use
of matter and energy
• Regulation (homeostasis)
• Growth and development
• DNA – heritable information (genes)
• Reproduction
• Evolutionary adaptation
• Ability to sense and respond to the environment
• Exist in ecosystems

4. Certain natural entities have
some but not all of the properties of life
Miller-Urey experiment (p. 59)

5. Certain natural entities have
some but not all of the properties of life
viruses = “infectious genetic elements”
human
immunodeficiency bacteriophage
virus (HIV)

6. Biological Organization:
A Natural Hierarchy
• 1. Ecosystems
• 2. Communities
• 3. Populations
• 4. Individual organisms
• 5. Organs
• 6. Tissues
• 7. Cells
• 8. Molecules
• 9. Atoms

7. What is a “species”?
• A group of populations whose members
have the potential to interbreed and
produce viable, fertile offspring. (p. 489)
donkey
horse
mule

8. Major Themes in Biology
1. Structure and function are correlated at all
levels of biological organization...
• Anatomy (structure)
• Physiology (function)
... which results from
adaptation.

9. 2. Cells are an organism’s basic units of
structure and function.
All cells multiply by cell division.
How many cells make up
the entire human body?

10. 3. The continuity of life is based on heritable
information in the form of genes.
• DNA
• Genes
• Traits
“the double helix”
How many genes are in a human cell?

11. 4. Metabolic pathways
regulate biological systems.
• Metabolic pathways – chains of
biochemical reactions in cells
• Cells use matter and energy
to do work.

12. 5. Organisms exchange matter and energy
with their environment.
sunlight heat
energy
“Food Chain”

13. 6. Symbiosis has a crucial role
for nutrition and disease
• Symbiosis – Two species living in close
association so their bodies or cells are interfused.
• mutualists
• pathogens
normal microbiota

14. 7. Evolution accounts for the
unity and diversity of life.
• “Evolution” = genetic change over time
mutation butterflies at
Fukushima 
mutation = a heritable
DNA random error in DNA

15. 7. Evolution accounts for the
unity and diversity of life.
• “Evolution” = descent with modification

16. 7. Evolution accounts for the
unity and diversity of life.
• “Evolution” = descent with modification
Example – Evolution of
lactose tolerance in humans

17. 7. Evolution accounts for the
unity and diversity of life.
• Evolution
• Natural
Selection
• Adaptation
• Speciation
Tree of Life: tolweb.org