Download Darwin`s Evolution

9/26/2013
• Learning Targets:
– I can describe the events in Charles Darwin’s
life that lead to his development of the theory
of Evolution.
– I can define a species.
– I can describe ways that species stay separate.
Homework: Read pages 378-382 (stop at
Evidence of Evolution) complete problems 2532 on page 389-390
Darwin’s Evolution
From gardens to writing, Darwin’s
evolution of thought
Back in Darwin’s Day….
• Charles Robert Darwin was
•
•
born on February 12, 1809
to a well off family in
Shrewsbury, England.
Charles went to boarding
school and would often
sneak out to see his dog,
Spark. Charles hated
school.
He liked doing experiments
with his brother
A young Darwin….
• In 1825 Charles began
classes at Edinburgh
University to study
medicine.
• He hated it.
• Next Charles went to
Cambridge University
to be a minister.
The Chance of a lifetime…
• A professor friend, Dr. Henslow,
knew that Darwin was adrift, not
knowing what to do as an
occupation so…
• He knew that Captain FitzRoy
was going to circumnavigate (go
around the world) and needed a
naturalist.
• He asked Darwin to go.
The HMS Beagle
The HMS Beagle
• 90’ 4’’ long
• 74 people lived
on board
• Carried drinking
water, food
• Darwin had a
hammock over
the table.
The Beagle’s Voyage:
The Beagle’s Voyage:
• The trip took 5 years to complete.
• While on the trip Darwin read books:
– Charles Lyell – Principles of Geology which
said the earth changes over periods of time.
– Jean Baptise Lamark – wrote that inheritance
of acquired traits.
– Thomas Malthus wrote Essay on the Principle
of Population which said that humans would
overpopulate and compete for food and other
resources.
Lemarkism: Lemark’s Theory of
Evolution
Charles Becomes a Scientist
• Throughout the voyage of the Beagle, Darwin
•
read books and saw many different organisms.
Some of the organisms were new to science.
Darwin discovered a fossil on the coast of
Argentina. He saw that this animal was not on
earth any longer.
Charles Becomes a Scientist
• For Months, Darwin had been reading
Lyell’s book about the Earth, and how
Earth had been formed by natural forces.
• He started to see these forces himself:
– He saw cracks open in the ground,
– He saw seashells at the top of hills so these
must have been underwater at some time.
The Galapagos Islands….
• Lie in the Pacific
Ocean
• Six hundred miles
west of Ecuador
• They consist of 13
major islands and 6
smaller islands.
The Galapagos Islands….
The Galapagos Islands….
Darwin’s Finches
Charles is a Scientist…
• Several things led Darwin to speculate
about the changes that might occur in
species over time:
– Diversity of life (so many different organisms)
– The geographic patterns whereby different yet
related species were found close to one
another.
– Fossils he collected of organisms not alive on
Earth today.
Down House
Artificial Selection
• Since before Darwin’s time, people have
been selectively breeding animals and
plants: chickens that lay more eggs, cows
that produce more milk, flowers that are
brighter and last longer.
• When humans are the selecting agents, we
can alter in a short period of time the
characteristics of an organism.
Artificial Selection
Artificial Selection
On the Origin of Species
• A species is a group of similar organisms
that can reproduce and produce viable
offspring.
• Is a Beagle a species? Why or why not?
• What is a liger?
• How do species stay separate???
September 27, 2013
• Learning Targets:
• I can describe the tenets of Darwin’s
theory.
• I can relate the theory of evolution to the
nature of science.
• I can synthesize the various contributions
of other scientists to Darwin’s theory of
evolution
Prezygotic Barriers
Postzygotic Barriers
Darwin’s Struggle
Alfred Wallace
• In 1858, Darwin received a letter
•
•
from Alfred Wallace with a paper
that he hoped Darwin would help
him publish.
Inside this letter was Wallace’s
theory of how Evolution works –
He had the same idea as Darwin!
Natural Selection!
Alfred R. Wallace was the
codiscoverer of Natural Selection
On the Origin of Species
• On November 24, 1859, On the Origin of
Species by Means of Natural Selection was
published.
• Darwin wrote “My book has stirred up the
mud.”
Summary of Darwin’s Theory:
• Individual organisms differ and some of
this variation is heritable.
• Organisms produce more offspring than
can survive and many that do survive do
not reproduce.
• Because more organisms are produced
than can survive they compete for limited
resources.
Summary of Darwin’s Theory:
• Individuals best suited to their
environment survive and reproduce most
successfully. These organisms pass their
traits to their offspring.
• Species alive today are descended with
modifications from ancestral species that
lived in the distant past.
Natural Selection: The Peppered
Moth
Evolution through Natural
Selection Today
• Today Darwin’s ideas are considered a
cornerstone of modern science.
• He figured out passing traits from one
generation to another without knowing
about cells or DNA.
• The evidence for evolution by Natural
Selection is overwhelming.
• However, Darwin’s ideas are still
controversial.