Transcript Descent with Modification

Chapter 22
Descent with Modification: A Darwinian View of Life
Chapter 22
Descent with Modification: A Darwinian View of Life
Hutton and Lyell were geologists
in the 1700’s
Chapter 22
Descent with Modification: A Darwinian View of Life
Hutton and Lyell were geologists
in the 1700’s.
Geologic gradualism:
Profound change can be the
cumulative product of slow but
continuous processes.
Chapter 22
Descent with Modification: A Darwinian View of Life
Lamarck published a theory of
evolution in 1809, the year that
Darwin was born
Chapter 22
Descent with Modification: A Darwinian View of Life
Lamarck published a theory of
evolution in 1809, the year that
Darwin was born.
The fossil record shows lines of
descent
Chapter 22
Descent with Modification: A Darwinian View of Life
Lamarck published a theory of
evolution in 1809, the year that
Darwin was born.
The fossil record shows lines of
descent.
Species adapt to their environment.
Inheritance of acquired
characteristics.
Chapter 22
Descent with Modification: A Darwinian View of Life
Darwin did field research
Chapter 22
Descent with Modification: A Darwinian View of Life
Darwin did field research.
At age 22, he signed onto the HMS
Beagle
Chapter 22
Descent with Modification: A Darwinian View of Life
Darwin did field research.
At age 22, he signed onto the HMS
Beagle.
In the Galapagos islands, he
collected many specimens
Chapter 22
Descent with Modification: A Darwinian View of Life
Darwin did field research.
At age 22, he signed onto the HMS
Beagle.
In the Galapagos islands, he
collected many specimens.
He published his conclusions only
reluctantly, and decades later.
Chapter 22
Descent with Modification: A Darwinian View of Life
Observation # 1:
All species have such great potential
fertility that their would increase
exponentially if all their offspring
survived to reproduce.
Chapter 22
Descent with Modification: A Darwinian View of Life
Observation # 2:
Populations actually tend to remain
stable.
Chapter 22
Descent with Modification: A Darwinian View of Life
Observation # 3:
Environmental resources are limited.
Chapter 22
Descent with Modification: A Darwinian View of Life
Inference # 2:
There is a struggle for existence.
Chapter 22
Descent with Modification: A Darwinian View of Life
Observation # 4:
No two individuals are alike.
Individuals in a population vary
extensively in their characteristics.
Chapter 22
Descent with Modification: A Darwinian View of Life
Observation # 5:
Much of this variation is inherited.
Chapter 22
Descent with Modification: A Darwinian View of Life
Inference # 2:
Those individuals whose
characteristics best fit their
environment are the ones that best
survive to ass on their
characteristics.
Chapter 22
Descent with Modification: A Darwinian View of Life
Inference # 3:
The population gradually changes
over time, with favorable
characteristics becoming more
common.
Chapter 22
Descent with Modification: A Darwinian View of Life
Some subtle points:
Chapter 22
Descent with Modification: A Darwinian View of Life
Some subtle points:
•Individuals do not evolve; only
populations evolve
Chapter 22
Descent with Modification: A Darwinian View of Life
Some subtle points:
•Individuals do not evolve; only
populations evolve.
•Natural selection can only act on
heritable variations
Chapter 22
Descent with Modification: A Darwinian View of Life
Some subtle points:
•Individuals do not evolve; only
populations evolve.
•Natural selection can only act on
heritable variations.
•The same traits that are favorable in
one time and place may be
detrimental in others.
Chapter 22
Descent with Modification: A Darwinian View of Life
Adaptive evolution is an
observable phenomenon in
the world today
Chapter 22
Descent with Modification: A Darwinian View of Life
Adaptive evolution is an
observable phenomenon in
the world today.
•Insecticide resistant insects
Chapter 22
Descent with Modification: A Darwinian View of Life
Adaptive evolution is an
observable phenomenon in
the world today.
•Insecticide resistant insects.
•Drug resistant HIV.
Chapter 22
Descent with Modification: A Darwinian View of Life
Other evidence:
Chapter 22
Descent with Modification: A Darwinian View of Life
Other evidence:
Homologies
Chapter 22
Descent with Modification: A Darwinian View of Life
Other evidence:
Homologies
•Anatomical
Chapter 22
Descent with Modification: A Darwinian View of Life
Other evidence:
Homologies
•Anatomical
•Vestigial
Chapter 22
Descent with Modification: A Darwinian View of Life
Other evidence:
Homologies
•Anatomical
•Vestigial
•Embrylogical
Chapter 22
Descent with Modification: A Darwinian View of Life
Other evidence:
Homologies
•Anatomical
•Vestigial
•Embrylogical
•Molecular.
Chapter 22
Descent with Modification: A Darwinian View of Life
Other evidence:
Chapter 22
Descent with Modification: A Darwinian View of Life
Other evidence:
•Biogeography
Chapter 22
Descent with Modification: A Darwinian View of Life
Other evidence:
•Biogeography
•Fossil record.
Chapter 22
Descent with Modification: A Darwinian View of Life
Just a theory?
Chapter 22
Descent with Modification: A Darwinian View of Life
Just a theory?
“A theory…does not become widely
accepted in science unless its
predictions stand up to thorough
and continual testing by
experiments and observation. …
Even then, good scientists do not
allow theory to become dogma.”
(pg 442)