DO NOW
What’s the name of the man who traveled on
the Beagle to the Galapagos?
While he was there, what animals did he
study?
His theory is called the Theory of Natural___
or Survival of the __.
The Peppered Moths
Industrial
Revolution
Clean
buildings
light
dark
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
• Before Industrial
Revolution:
dark moths = light moths
• Industrial Revolution:
machines produced
soot which stuck to
buildings
• After Industrial
Revolution:
light moths were eaten
• Then the buildings
were cleaned up.
• After clean up: dark
moths were eaten.
Evolution – change of species over time.
Evidence of Evolution:
Definition:
HOW it proves evolution:
Fossils
Remain or imprint of once
living organisms
Shows how species have
changed (ex: horses)
Homologous Structures
Body parts in related
animals are similar
Prove that the animals
must have a common
ancestor
Vestigial Structures
Structures present in
modern day organisms that
have no function (ex:
appendix, whale hip bone)
Shows that species have
changed because our
ancestors must have used
the structures
Molecular Biology
The more closely related 2 2 species with similar DNA
species are to each other,
must have a common
the more similar their DNA ancestor
is.
Fetal Similarities
The unborn offspring of
many species resemble
each other
There must have been a
common ancestor.
1831- Charles Darwin took the British naval
ship called The HMS Beagle which sailed to
the Galapagos Islands.
He studied:
• Finches, tortoises – noticed that each
island had organisms with slightly
different adaptations. Were they once
related? How did they change?
• Fossils – noticed that modern day
organisms are different from their
ancestors. How did they change?
• He talked to farmers about selective
breeding and understood inheritance.
Darwin’s Conclusions
• On the Origin of Species by Natural
Selection
• Survival of the Fittest = Natural Selection
4 part theory about how species change:
1.
2.
3.
4.
Overproduction
Inherited Variation (mutations)
Struggle to Survive
Successful Reproduction – pass on traits
• Generation Time - the period between the birth of one
generation and the birth of the next one.
• Species with short generation times adapt quickly.
• Species - a group of organisms that can mate with one
other to produce fertile offspring.
Speciation- the formation of a new species as a
result of natural selection.
3 steps:
1. Separation – portion of the population becomes
isolated
2. Adaptation – the part of the population that got
separated has a different environment.
Different traits will be “selected” by the
environment.
3. Division – The 2 groups become so different
that they can no longer interbreed.
Speciation of Squirrels
• The Kaibab squirrel (left) became isolated in the
Grand Canyon approx. 10,000 years ago.
Features have gradually evolved that separate it
from close relative, the Abert squirrel (right) .
Croatian Lizards
• Experiment: Scientists placed 5 pairs of insectivorous
species in a new island habitat.
• Old island habitat very little plants but plenty of insects
– (Lizards diet was 93% insects, 7% plants)
• New island habitat  had an abundance of plants, but limited
insects.
• After 80 generations, the lizards diet was 36% insect & 64% plant
In a few decades the
lizards have developed:
• New digestive structure
• Larger heads
• Harder bite