Download Introduction to Evolution

Introduction to Evolution
Tree of Life
• All species are related
• All species share a
common ancestor
• Evolution…is how the
tree of life gets bigger!
Fixed Species Hypothesis
• All species had always been the same, and would
never change (Aristotle, 2000 years ago)
1800s – Fossils are Discovered
Transmutation Hypothesis (1800s)
• Jean Baptiste de Lamarck
• Acquired traits could be
passed down to offspring
Charles Darwin
• 1831-1836: world voyage on HMS Beagle
Natural Selection
• “Survival of the Fittest” –
only the best adapted
individuals survived to pass
their genes to offspring
• Over time, a population’s
traits can change
Gregor Mendel
• Basic principles of genetics –
how characteristics were passed
down to offspring
• How organisms could change
from one generation to the next
Putting it all together
• Genetic mutations = changes in organisms
• Environmental changes = changes in organisms
• How? Natural Selection (Darwin)
What is a scientific theory?
Hypothesis
-suggested explanation
-uncertain
-limited data
-educated guess / idea
Theory
-supported explanation
-lots of certainty
-lots of data & test
-general belief
Evolution is THE major theory that underlies the field of biology!
A theory can be wrong
• How? If new evidence disproves it
I can…
• Explain the Fixed Species hypothesis
• Explain Lamarck’s Transmutation hypothesis
• Explain Darwin’s and Mendel’s contributions to the
Theory of Evolution
• Explain the difference between a scientific
hypothesis and a scientific theory