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Adaptation:
Darwin’s Voyage
Chapter Seven Holt Text
Charles Darwin
1. Who was Charles
Darwin?
1. British Naturalist
In 1831, set out on a 5year trip around the
world.
Job: to learn as much
as possible about
the living things he
saw.
HMS Beagle
Life Science: Evolution (click here)
Darwin’s Excellent
Adventure
2. What did Darwin
observe?
2. Great diversity of
living things.
Collected 1,000’s of
plant and animal
samples
Took MANY notes
2. What did Darwin
observe?
2. First stops were in
Brazil, Argentina and
later Galapagos
Islands.
2. What did Darwin
observe?
Click
pic
2. Noticed that some
species were present
in several locations;
however they had
some different traits.
3. What is a species?
3. A group of similar
organisms that can
mate and produce
fertile offspring.
1.7 million species
identified so far
Darwin’s Finches
4. How were the
animals different?
4. Finches
Darwin noticed that the
finches on the
Galapagos Islands
were similar to the
ones found in
Equador but slightly
different.
He noticed that the beaks of the finches
had adapted to the way each finch
usually gets food.
Galapagos Finches
4. How were the
animals different?
4. IguanasOn S. America: green
with small claws (live
in rain forest)
On G. Islands: gray
with larger claws (live
on beach)
4. How were the
animals different?
4. On G. Islands
Tortoises had different
shell shapes and
patterns on different
islands.
Darwin’s Thinking
5. What was Darwin’s
hypothesis?
5. Island animals were
separated from
mainland relatives.
Each population
adapted to its
environment.
6. What is an
adaptation?
6. A trait that helps an
organism survive and
reproduce.
7. Example of
adaptation?
7. For finches that ate
insects, those with
sharpest beaks were
able to catch more
bugs.
These survived longer
and were more likely
to reproduce.
Their offspring likely to
have sharp beaks…
7. Example of
adaptation?
7. Iguanas
(Compare those who
lived in the jungle to
those on the island
beach.)
8. What is evolution?
8. Gradual change in a
species over time.
Happens over many
years.
Darwin’s Theory of
Natural Selection
9. What was Darwin’s
book called
9. The Origin of
Species
It summarized his ideas
about how organisms
adapt
Darwin’s Theory of
Natural Selection
9. What is natural
selection?
9. Process by which
individuals that are
better adapted to
their environment are
more likely to survive
and reproduce.
9. What is natural
selection?
9. Nature selects for
certain traits in an
organism because of
conditions in the
environment.
10. Natural selection is
like _________.
10. Selective breeding
It works to produce
organisms with the
best traits.
11. Four factors that
affect natural
selection:
11.
OCVS
11. Three factors that
affect natural
selection:
11. Overproduction:
Most species produce
many more offspring
than can survive.
Increases chances that
at least one will
survive.
11. Three factors that
affect natural
selection:
11. Competition:
Food and other
resources limited.
Offspring must
compete to get food,
escape predators.
The strongest ones will
survive.
11. Three factors that
affect natural
selection:
11. Variation:
Different alleles of
genes give different
traits.
Some traits help
organism survive.
Ex: faster swimmers
11. Three factors that
affect natural
selection:
11. Successful
Reproduction:
The best adapted
organisms are likely
to have many
offspring that survive.
12. Role of genes in
adaptation
12. Genes carry
instructions for traits
and are passed from
parent to offspring.
13. How do new
species form?
13. A group of
individuals gets
separated from the
rest long enough for
traits to evolve.
(By a river, ocean,
earthquake,
mountains)
14. Examples of
adaptation
14. Monarch butterfly
and viceroy moth.
Viceroy Moth
Monarch Butterfly
14. Examples of
adaptation
14. Peppered Moth
Peppered Moth
Light
Variety
Dark Variety
 The usual form of the peppered moth Biston betularia in northern
Europe has a light 'peppered' pattern of coloration. The moth rests
on tree branches and its color pattern camouflages it against
predatory attack. The camouflage only works against the right
background: birds are more likely to eat poorly camouflaged
moths, which therefore have a lower fitness.
 The light coloration of tree branches is mainly caused by lichens
that grow there. Smoke pollution in the industrial revolution in the
UK killed these lichens near to industrial areas, leaving tree
branches black. At about this time, around 1830, a 'melanic' form
of the peppered moth becomes increasingly common in
contemporary moth collections. The melanic form is camouflaged
on dark tree branches. Through the 19th century, the melanic form
increased in frequency until, near industrial regions, it was the
normal type of the moth. The increase was almost certainly driven
by natural selection.