Transcript Examining Theories And Their Evidence

SCIENTIFIC THEORIES AND
THEIR EVIDENCE
Cell Theory


What is Cell Theory?
Cell Theory:


All living things are made up of one or more cells. All cells
arise from existing cells. The cell is the basic unit of structure
and function for all organisms.
Evidence:
First formulated in 1839
 Began from the work of three scientists: Schleiden, Schwann
and Virchow
 Has since been verified by 1,000’s of scientists

Evolutionary Theory

What is the theory of evolution?
 Change
in the heritable characteristics of a population
across successive generations

Evidence:
 Work
of Charles Darwin (Finches)
 Fossil Record
 DNA Sequencing
 Anatomical Similarities between life forms
What is Gene Theory?

What is Gene Theory?
 Traits

are passed from parent to offspring via genes.
Evidence:
 Work
of Gregor Mendel on pea plants and other
organisms
 1,000’s of scientists, since Mendel’s time, have
conducted experiments that confirm this theory
 New DNA technologies continue to confirm this theory
and help us learn more about the role of genes in some
diseases.
Germ Theory of Disease

What is Germ Theory of Disease?
 Microorganisms
are the cause of some diseases.
 Has led to important things such as antibiotics and
good hygiene practices

Evidence:
 Resulted
from the work of numerous scientists, but is
mainly attributed to the work of Louis Pasteur and
Robert Koch
 Microscopic observations and experimental evidence
since late 1800’s continues to confirm this theory.