Download Finch?

Chp. 14-3
The Theory of
Evolution
Cactus
eater
Insect eaters
Seed eaters
Bud eater
2006-2007
I. Scientific Theory
A. Greeks believed organisms resulted from
evolution but no proof
B. Mid 1800s Darwin & Wallace proved that
evolution occurred
C. Scientific theory
1. an explanation that something has gone
under many tests
2. many theories are in science
a. evolution
b. cell theory
c. germ theory
II. Darwin’s Travels and observations
A. Charles Darwin travel the world from
1831-1836
1. studied fossils and rock
formations
2. found similar organisms in
different rock formations
3. noted that similar organisms had
gone under change & answer
that species do change
4. he collected and made sketched if
plants/animals
5. came up with ideas of how evolution
occurs
a. shared his ideas w/ other
scientists but did not publish work
right away
i. when he heard of
Wallace’s adventures,
hurried to publish book
“The Origin of Species”
B. Alfred Wallace traveled to South America and
East Indies
1. collected info on organism
2. formed an explanation of evolution – similar
to Darwin’s
III. Darwin’s Theories
A. Hypothesis
1. a testable explanation of a questions or
problem
2. Darwin’s hypotheses was tested and much
evidence was found to support him
3. Darwin’s hypotheses were stated as 2
theories
a. first
i. Descent with modification
b. second
i. Natural selection
An explanation of something
that needs to go under many
tests is known as a
67%
1.
2.
3.
4.
hypothesis
theory
guess
pain
33%
0%
1
2
3
0%
4
Who helped Darwin prove
evolution occurred?
100%
1.
2.
3.
4.
Newton
God
Wallace
Charles
0%
1
0%
2
0%
3
4
Who published a book titled,
“The Origin of Species?”
100%
1. Darwin
2. Wallace
3. Both Darwin and
Wallace
4. Neither Darwin
and Wallace
0%
1
2
0%
3
0%
4
What is a testable problem or
question?
100%
1.
2.
3.
4.
A theory
A hypotheses
a guess
Life
0%
1
0%
2
3
0%
4
How many theories did Darwin’s
hypothesis make?
25%
1.
2.
3.
4.
25%
25%
2
3
25%
1
2
3
4
1
4
IV. Decent with modification
A. Theory states that more recent species found
in the fossil record are changed descendants
of earlier species
1. *** today’s species are related to
those of the past
2. *** evolution occurs in nature
B. Darwin observed this when visiting the
Galapagos Islands of South America
Galapagos
Recently formed volcanic islands.
Most of animals on the Galápagos
live nowhere else in world, but
they look like species living on
South American mainland.
800 km west of Ecuador
Darwin found…many unique
species
Many of Darwin’s observations made
him wonder… Why?
Darwin asked:
Why were these creatures found only on the
Galapagos Islands?
Darwin found…clues in the
fossils
Darwin found:
Evidence that creatures
have changed over time
present day Armadillos
Darwin asked:
ancient Armadillo
Why should extinct
armadillos & modern
armadillos be found on
same continent?
Darwin found:
Different shells on tortoises on different islands
Darwin asked:
Is there a relationship
between the environment
& what an animal
looks like?
Darwin found… birds
Darwin found: Many different birds on
the Galapagos Islands
He thought he found
very different kinds but
Darwin was amazed to
find out:
All 14 species of birds
were finches…
Small ground finch
Cocos
Island
Finch
Woodpecker finch
Yellow warbler
But there is only one species
of finch on the mainland!
Darwin asked:
If the Galapagos
finches came from
the
Sparrow?
mainland, why are they
so different now?
Warbler?
The finches
cinched
 different
beaks it!
are
inherited variations
Darwin found:
 serve as adaptations
The differences
between species of
that help birds compete
finches were
for food
Darwin said:
associated with the
 these birds survive &
different food they ate.Large
Ahaaaa!
reproduce
ground
Small
ground finch
Finch?
Sparrow?
QuickTime™ and a
decompressor
finch
A flock
of- JPEGSouth
 pass
onarePhoto
the
needed to genes
see this picture. for

American
those
more finches
fit beaks
weretime
stranded
over
nature on
selected
thedifferent
Galapagos…
for
species with
different beaks
Warbler
finch
Woodpecker?
Tree finch
Warbler?
Relationship between species (beaks) & food
Darwin’s finches
• Darwin’s conclusions
– variations in beaks
• differences in beaks in the original flock
• adaptations to foods available on islands
– natural selection for most fit
• over many generations, the finches were selected
for specific beaks & behaviors
– offspring inherit successful traits
• accumulation of winning traits:
both beaks & behaviors
– separate into different species
From 1 species to 14 species…
Warbler finch
Cactus finch
Woodpecker finch
Sharp-beaked finch
Small
insectivorous
tree finch
Large
insectivorous
tree finch
Small
ground
finch
Cactus
eater
Insect eaters
Medium
ground
finch
Seed eaters
Vegetarian
tree finch
variation
Bud eater
natural selection for best
survival & reproduction
Large
ground
finch
V. Natural Selection
•
– this theory explains how
evolution occurs
– environmental conditions
influence which organisms
survive
– according to natural selection
the organisms that are best
suited for the environment are
more likely to survive
– some may adapt to survive –
this process results in the
evolution of a new species
– Affects all populations of
organisms
Adaptation – the changing of a
species in response to its
environment
C. Ex – snakes have a specialized upper tooth
1. young snakes use this tooth to cut their way
out if their shell and leave it with ease
a. adaptive advantage
i. having a greater chance to
survive because of their
characteristic
2. young snakes w/o this characteristic are not
able to survive and unable to reproduce and
the gene is lost the population
VI. Evidence of Evolution
A. if populations change then evident should be
present
1. fossil records show recent species are
slightly different from earlier species
2. some organism’s embryos go through
similar stages of development
a. a human embryo has a tail and gill
pouches as like a fish embryo
all vertebrate embryos have a “gill
pouch” at one stage of development
3. vestigial structures
a. a body part that appears to be useless, however
was helpful to ancestors
1. snakes/whales have remnants of
leg/pelvic bones – believed to be
leftover from when ancestors had legs
for walking
•2006 fossil
discovery of
early tetrapod
4 limbs
Missing link
from sea to
land animals
Vestigial organs
• Hind leg bones on whale fossils
Why would whales
have pelvis & leg
bones if they were
always sea creatures?
Because they
used to
walk on land!
4. homologous structures (*** see page 374)
a. body parts that are similar to related organisms
b. thought to have first appeared in an ancestor
that is common and had front limbs
Which theory states that today’s
species are related to those
from the past?
1. Descent with
modification
2. Natural selection
3. Both
4. Neither
67%
33%
0%
1
2
0%
3
4
Which theory occurs in nature?
1. Descent with
modification
2. Natural selection
3. Both
4. neither
67%
33%
0%
1
0%
2
3
4
Which theory states
environmental factors influence
the species survival?
1. Descent with
modification
2. Natural selection
3. Both
4. neither
67%
33%
0%
1
0%
2
3
4
Which theory states a species
will adapt to live?
67%
1. Natural selection
2. Descent with
modification
3. Both
4. Neither
33%
0%
1
2
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3
4
A body part that appears
useless now but was once
needs by ancestors is a
1. Vestigial system
2. Vestigial structure
3. Homologous
structure
4. Any of the above
67%
33%
0%
1
0%
2
3
4
Where was Descent with
modifications observed?
100%
1.
2.
3.
4.
US
Europe
Galapagos Islands
Hawaiian Islands
0%
1
0%
2
0%
3
4
ASSIGNMENT:
- embryo w/s
- page 375 review questions # 1 – 5
- w/s 14 - 3