4. Scope of Biology
This course will focus
primarily on molecules and
5. But what defines something
as a living thing?
• What are some general characteristics?
What about a virus?
An organized genetic unit capable of …
6. Discovery of the Microscope
The study of cells was made
possible by the invention of
Robert Hooke in the 1600s described
repeating units of plant material as
7. Robert Hooke – Plant Cork Cells
Nature Cell Biology 1, E13 - E15
(1999) – reproduced from
8. Early Cell
9. Modern Cell Theory
• All cells come from preexisting cells.
• All cells are similar in chemical
• Most of the chemical reactions of life
occur within cells.
• Complete sets of genetic information
are replicated and passed on during
Change in the genetic makeup of
biological populations through time.
Charles Darwin (1859) proposed that all
living organisms are descended from a
common ancestor by the mechanism of
11. Charles Darwin – Theory of
• Major unifying
principle of biology…
• Natural Selection
Traits that increase the
probability that the organism
will survive and reproduce will
become more common in the
12. So how does Natural
Within a Species, Variation in traits
due to Genetic Mutation gives rise
to individuals with higher
“Fitness”. Natural Selection is a
force that favors these individuals
within a population leading to an
Adaptation in the species.
16. 5 BYA - the Earth is Formed…
No Life on Earth, so how did it get there?
2)Chemical Evolution (Currently
17. 4 BYA –
leads to the
18. 3.8 BYA – Vesicles Form
Biological molecules were then enclosed in
membranes, forming cells.
Increases the chance of interacting.
Resulted in the first single-celled organisms
- Only found in the oceans
19. 2.5 BYA - Photosynthesis
O2 accumulated in the
Ozone layer formed,
which allowed organisms
to live on land
20. 1.5 BYA – Eukaryotes form
Karyon = kernel
eu = true
Organelles allow for
28. Types of Experiments
Controlled Experiments: manipulate the
variable that is predicted to cause
differences between groups.
- Control Group
- Independent Variable
- Dependent Variable
- Field Work