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Vocabulary
Charles
Darwin
Natural
Selection
The
Galapagos
Evolution
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An adaptation in
which a specific
action, such as nest
building, allows a
species to survive
in its environment.
behavioral
adaptation
A structural
adaptation that
allows an organism
to blend in with its
surroundings.
camouflage
Change in a species
over time.
evolution
The process by which
organisms, with traits that
help them adapt to a
changing environment, are
able to successfully
reproduce.
natural selection
Inheritance of traits
that allow an organism
to survive in a
particular
environment.
adaptation
Who was
Charles Darwin?
Charles Darwin was a
British naturalist. He
sailed his ship the Beagle
exploring South
America and its remote
islands the Galapagos
Isalnds.
Why is Darwin’s work
important?
Based on his extensive
observations he developed
the theory of evolution by
means of natural selection.
His work serves as the
basis of much biological
research today.
What did Darwin
reason from his
observations on the
Galapagos Islands?
Darwin reasoned that perhaps
the organisms in the
Galapagos originally came
from South America and over
time, they had evolved. He
reasoned that each new
population changed slightly, or
evolved, to fit its unique
environment on the island.
What observations did
Darwin make of the
tortoises and finches on the
Galapagos Islands?
Darwin made observations
about the diversity and
uniqueness of organisms.
Many of the animals were
similar, but not the same as
organisms in Mainland
South America.
What did Darwin
observe regarding
the different
finches on the
different islands?
Finches had evolved
bird beak types
that best suited
the food available
in their new
environment.
What is Darwin’s theory of
natural selection?
Organisms with traits that
allowed them to survive
under particular
environmental conditions
produced more offspring.
Eventually those traits
would be common in the
species.
List the four steps or
requirements for
natural selection.
1. overproduction
2. variation
3. inherited variation
and
4. natural selection.
Explain each step pictured
below.
Overproduction
Too many offspring are
born for the environment
to support.
Inherited Variation
Offspring inherit these
varying traits from their
parents.
Variation
Some offspring are born
with certain traits that
others do not share.
Natural Selection
Some animals’ traits help
them survive in their
particular environments.
What are the two
main categories that
scientists divide
adaptations into?
Scientists divide
adaptations into two
main categories –
structural and
behavioral.
List two types of
structural adaptations
and explain each.
How can these
adaptations benefit an
organism’s survival in
its environment?
Camouflage—coloring that
blends with the
environment—makes
organisms difficult to see.
Mimicry is when one
species (the mimic) looks
like another species (the
model) in order to deceive a
third species.
Where did Darwin
observe the most
diversity and
uniqueness in life?
The Galapagos Islands
Where did Darwin
reason the organisms on
the Galapagos had
originally come from?
Mainlaind
South America
What beak type is
pictured below and
what food type is best
suited for it?
Long, narrow beak for
eating insects.
What beak type is pictured
below and what food type
is best suited for it?
Short, large beaks for
“crushing”. Useful for
breaking seeds.
How were the
tortoises of the
Galapagos different
than the Mainland?
They were similar but
much larger! They
were giant tortoises.
Explain why genetic
variation is important
for evolution to occur.
What are some sources
of genetic variation?
Genetic variation is
necessary for evolution
to occur. Sources of
genetic variation include
mutations, formation of
the gametes, and sexual
reproduction.
List two examples of
behavioral adaptations.
How can these adaptations
benefit an organism’s
survival in its environment?
Nesting Instinct: Male
bower bird decorates its
nest to attract females.
Herding Instinct: Animals
that live in large groups or
herds are less likely to be
attacked by a predator
than one animal alone.
What are some
environmental
factors associated
with extinction?
Environmental factors
associated with extinction
include climate change,
volcanoes, earthquakes
and meteor strikes.
List four causes for
extinction and
explain each.
Loss of habitat: As humans develop, occupy more
space, and use more resources, they habitats of
plants and animals shrink.
Loss of genetic diversity: If there are only a few
individuals or if they individuals have limited
genetic variability, environmental conditions
may more easily cause extinction.
Competition with exotic species: If a species has no
natural consumer in the new environment, it
may outcompete the native species and push
them toward extinction.
Inability to adapt: If climate changes suddenly, a
species may not have any individuals that have
genetic traits that allow them to survive.
If a mouse population
develops an adaptation that
results in white fur and they
live in a forest with hawks,
what can you predict will
happen to the mouse
population over time?
The population of
white mice will
most likely
decrease.