Darwin’s Theory of Evolution
The Puzzle of Life’s Diversity
Chapter 15-1
WRITE A DEFINITION:
EVOLUTION:
change over time; the process by which modern
organisms have descended from ancient
organisms
THEORY:
a well-supported testable explanation of
phenomena that have occurred in the natural world
FOSSIL:
the preserved remains of ancient organisms
________ is a
Evolution
______;
theory a
testable
explanation of
naturallyoccurring
phenomena
theory
evolution
The _______
fossils that
Darwin found
caused him to ask
questions that led
to his proposal of
the theory of
_________.
evolution
Fossils provide
_______
evidence to support
the theory of
_________.
evolution
fossil
The _____
fossil record provides for
some of the evidence that supports
the ______
theory of evolution
REMEMBER !
The total variety of all the
organisms in the biosphere
BIODIVERSITY
= ________________
Where did all these different organisms
come from?
How are they related?
What scientific explanation can
account for the diversity of life?
ANSWER:
Scientific facts
A collection of ______________,
observations and ___________
hypotheses
__________,
known as
EVOLUTIONARY THEORY
________________________
The person who contributed the
most to our understanding of
evolution was
Charles Darwin
______________________
In 1831, at age 22, he joined the crew of
H.M.S. Beagle as a naturalist for
the _______________
a ________
5 year voyage around the world.
During his travels, Darwin wrote thousands
of pages in his journals, drew pictures of
the things he saw, and collected a vast
evidence
amount of ______________
that led him
revolutionary hypothesis
to propose a _______________________
life changes
about the way _____________.
DARWIN WONDERED?
different
Why do Argentina and Australia have ________
animals
similar grassland
______ even though they have _____________
ecosystems
_________?
Why are there no ______
rabbits in Australia and
kangaroos in England?
no ________
Why have so many species
disappeared?
extinct species
How are these ______
related to living species?
_______
Who Was Charles Darwin?
While on his voyage around the world
Beagle Charles Darwin
aboard the H.M.S.
____________,
spent about one month observing life on the
Galápagos Islands
________________.
There, he encountered some unique animals,
tortoises
such as finches
______ and ________.
The Galάpagos Islands are close together
climates
but have very different _______.
Some were hot and dry, with
little vegetation.
Others had more rainfall and were
rich in vegetation
Each island had
unique
its own _____
_________
assortment of
plant and animal
species.
Giant Tortoises of the Galápagos
Islands
Section 15-1
and on Pinta Island, tortoise
necks were somewhere in
between
Pinta
Pinta Island
Intermediate shell
Tower
Marchena
Fernandina
James
Santa Cruz
Isabela
Isabela Island
Santa Fe
Floreana
Dome-shaped shell
while on the lush rainforest of
Isabela Island, tortoises had
short necks…
Hood
Hood Island
Saddle-backed shell
On the desert-like
Hood Island,
tortoises had long
necks…
After his voyage, Darwin spent a great
deal of time thinking about his findings.
He began to wonder if animals living on
different islands had once been members
same species that had
of the ____________
developed different
_________ characteristics
after becoming isolated
_______ from one
another in different habitats.
Darwin’s Theory of Evolution
Ideas that Shaped Darwin’s Thinking
Chapter 15-2
Ideas that shaped Darwin’s thinking:
James Hutton
In 1785 ______________
proposes that the
Earth
was shaped by
______________
geological forces
_________________
occurring over
very long
__________
periods of
time, and is
millions of years old.
_______________
Ideas that shaped Darwin’s thinking:
Charles Lyell
In 1833 ___________
explains that the geological
processes still ___________
occurring now
have shaped Earth’s
features over
long
periods of time
________________
Ideas that shaped Darwin’s thinking:
Theory of Pangaea
…and continental
drift
REMEMBER !
Chapter 3
competition
Living things must compete for
food, shelter, space, mates
Ideas that shaped Darwin’s thinking:
Thomas
Malthus (1798)
_____________________
He observed that babies were being born
faster than people were dying. He
reasoned that if the human population
continued to grow, sooner or later there
insufficient space & food
would be _______________________
Ideas that shaped Darwin’s thinking:
Jean-Baptiste
Lamarck (1809)
___________________________
was one of first scientists
to recognize living things
changed
over time and that
_______________
all species were descended
________ from
other species.
Lamarck published his hypothesis of
Inheritance of Acquired traits
________________________
the year Darwin was born.
The male fiddler crab uses its
front claw to attract mates and
ward off predators.
Through repeated use, the front
claw becomes larger.
The fiddler passes on this
acquired characteristic to its
offspring
What’s wrong with Lamarck’s hypothesis?
Lamarck didn’t know about
genes and how traits are
inherited
_______.
If you lifted weights your
whole young adult life, and
then you had children, would
your kids be more muscular?
NO! Acquired traits may help an organism,
but they won’t be passed on to offspring.
What’s right with Lamarck’s hypothesis?
Lamarck was first to
develop a scientific
hypothesis about
evolution
_______
and recognize that
organisms are
________________________
adapted to their environments
Match the letter of the idea with
the man or men who proposed it:
Malthus
Hutton
Lyell
a.
b.
c.
d.
Lamarck
The earth is really old, and slowly changes
Living things pass changes on to their offspring, leading to species changes
Sooner or later growing populations run out of resources
Living things change slowly over time because of competition for resources,
and pass those changes on to their offspring
c.
Malthus
Hutton
a.
Lamarck
Lyell
b.
d.
a.
b.
c.
d.
The earth is really old, and slowly changes
Living things pass changes on to their offspring, leading to species changes
Sooner or later growing populations run out of resources
Living things change slowly over time because of competition for resources,
and pass those changes on to their offspring
Section 15-3
Concept Map
Evidence of
Evolution
includes
The fossil record
Geographic
distribution of
living species
Homologous
body structures
Similarities
in early
development
which is composed of
which indicates
which implies
which implies
Physical
remains of
organisms
Common
ancestral
species
Similar genes
Similar genes
Darwin’s Theory of Evolution
Darwin Presents his Case
Chapter 15-3
THINK ABOUT IT
What do oranges,
broccoli, and Butterball
turkeys have to do with
EVOLUTION?
(Answers to come in this slide show!)
After Darwin returned to England in 1836
he filled notebooks with his ideas
species diversity and the process
about _____________
evolution
that he would later call _______.
He did not rush to publish his ideas
disagreed with the
because they ________
beliefs of his
fundamental scientific ______
day.
He asked his wife to publish
his ideas when he died
___.
In 1858 another naturalist,
Alfred
Russel Wallace wrote an
_________________,
Malaysia that
essay describing his work in _______
summarized the same ideas Darwin
_____ had
been thinking about for 25 years!
Suddenly Darwin had incentive to publish
the results of his work!
In 1859
On
the Origin of Species
____________________
evidence
presented _______
and proposed a
mechanism
________ for evolution
that he called
NATURAL
SELECTION
__________________
WHAT IS DARWIN’S THEORY?
GENETIC VARIATION is found
_________________
naturally in all populations
WHAT IS DARWIN’S THEORY?
______________________
STRUGGLE
FOR EXISTANCE
means that members of each species
must COMPETE
________ for food, space, and
other RESOURCES
__________.
WHAT IS DARWIN’S THEORY?
Some organisms in a ________
population
less likely to survive.
are ________
WHAT IS DARWIN’S THEORY?
SURVIVAL OF THE FITTEST
_____________________
organisms which are better adapted
survive and
to the environment will ______
reproduce passing on their _____.
genes
________,
Ability of an individual to survive
______
and
reproduce in its specific
____________
environment
= fitness
______
inherited characteristic that
Any ___________________
of survival
increases an organism’s chance
______________
ADAPTATION
= _____________
WHAT IS DARWIN’S THEORY?
Over time, natural selection
CHANGES in the
results in ________
inherited characteristics of a
POPULATION
__________.
increase a
These changes ______
species’ fitness
_____ in its environment.
WHAT IS DARWIN’S THEORY?
DESCENT WITH MODIFICATION
____________________________
suggests that each species has
DESCENDED with CHANGES
___________,
________,
from other species over time.
This idea suggests that all living
TO EACH OTHER
species are RELATED
____________________,
and that all species, living and extinct,
COMMON ANCESTOR
share a _________________.
EVIDENCE OF EVOLUTION:
Artificial selection
1. ________________
Fossil record
2. ________________
Geographic Distribution
3. _______________
Homologous structures
4. _______________
5. _______________
Embryology
DNA
6. _______________
See Natural selection happen
7. _______________
• ARTIFICIAL SELECTION WORKS
In artificial selection, ____________
NATURE
provides the _________
variation through
mutation and _________________
sexual reproduction
_________
and ______________
humans select those traits that they
find ______.
useful
EX: We have selected
for and bred cows to
produce more milk,
turkeys with more
breast meat, etc.
Breeds of Dogs
Chihuahua – bred from Techichi of Mexico
by Mayans, had religious significance
Saint Bernard – bred by monks around 1050 A.D.
to rescue travelers of mountain passes in the
Swiss Alps between Italy and Switzerland
Irish Wolfhound – bred in Ireland to
hunt wolves and elk
Dachshund – bred in Germany as early
as the 15th century to hunt badgers
ARTIFICIAL SELECTION WORKS
How Do We Know Evolution Happens?
2. The Fossil Record –
Fossils
______ are the remains
_______
_________________
of ancient organisms
found in layers of rock
in the Earth.
How Do We Know Evolution Happens?
The layers of rock tell the history of the
Earth
_____, while the fossils
_____ found within
life
the rock tell a history of ___.
The fossils are thought
same age as
to be the ________
the rock they
are found in.
Movement of Earth’s Crust
Earthquakes and volcanoes
cause uplifting of the layers of the
Earth, taking the fossils along
Sea
level
Fish die in
the ocean
and are
covered in
sediment.
Over time
and under
increasing
pressure,
the remains
becomes
fossilized
Sedimentary
rocks form in
horizontal
layers.
When part of
Earth’s crust is
compressed, a
bend in a rock
forms, tilting the
rock layers.
As the surface
erodes due to
water, wind, waves,
or glaciers, the
older rock surface
is exposed.
Fossils of
marine
fish found
on the
mountainsides of
southwest
Wyoming,
which at
one time
was
covered
by an
inland sea
TRANSITIONAL FOSSILS HAVE BEEN FOUND
If Darwin’s theory is correct you would
expect to find closely
____________
related yet
_______________
different species living in a
_________
geographic region as they spread into
nearby habitats and evolve.
That’s EXACTLY what we do see!
REMEMBER THE GALAPAGOS TORTOISES?
Intermediate vegetation
Intermediate necks
Little vegetation
Long necks
Lots of vegetation
Short necks
Tortoises adapted to different habitats as they
spread from the mainland to the different islands.
= DIVERGENT EVOLUTION = ADAPTIVE RADIATION
GALAPAGOS FINCHES
The _____
beaks of Galapagos finches have
______ to eating a variety
_____ of foods
_____.
adapted
If Darwin’s theory is correct you would
species
also expect to find different
_______________
living in far
________
apart geographic regions
but similar habitats becoming more
________
alike
similar ecosystems
as they adapt to ______________.
That’s EXACTLY what we do see!
Whales and sharks have a _____
similar body design
even though they are very _______
different organisms
(one is a fish; the other, a mammal)
because they have _________________
independently adapted to
living in a _____
similar environment.
= CONVERGENT EVOLUTION
Whales are closely related to wolves, but
don’t look or act much like them
= divergent evolution
Conclusion:
The pressure of
the environment
drives evolution
Whales are distantly related
to sharks, but look and act more
like them =
convergent evolution
Structures
4. HOMOLOGOUS
_____________________
4. Homologous Body Structures –
Structures, like the limbs of
vertebrates, look very different
_______,
but are made from the
__________,
same bones because
they are made from
the same clump of
_____________
undifferentiated cells
in the _______.
embryo
Figure 15–15 Homologous
Body Structures
Section 15-3
Turtle
Alligator
Ancient lobe-finned fish
Bird
Mammal
4. Homologous Body Structures –
Some _______________________
homologous body structures
are _______
vestigial and have no useful
function even though they are still
present, like ________in
hipbones whales and
boa constrictors.
Most mammals have a pouch
between their small and large
intestine that contains bacteria
cecum
to digest plants called a _____.
In humans the cecum
is shrunken and unused.
appendix
It is our _________
Why grow a tail and then lose it?
HUMAN EMBRYO
_________________
has
a tail at 4 weeks
_________________
Tail
disappears at
_________________
about 8 weeks
tail
Skinks are a type of
lizard. In some
species, legs have
become so small
longer
they no
_______
function
______ in walking.
Why would an organism possess organs with
___
little
or no function
________________?
One explanation:
code is present to make the organ, but
The gene
________
function
has been lost through ______________.
change over time
_________________
If the organ is not vital to survival, then
natural selection would not cause its elimination.
5. _____________________
Similarities in Embryology
________
Embryos of many animals with backbones are very similar.
It is clear that the same groups of
_____________
undifferentiated cells develop in the
same order to produce the same
tissues and organs of all vertebrates,
evolved from
suggesting that they all _______
a _______________.
common ancestor
Similarities in DNA
6. _______________
Similarities
DNA and
in ____
PROTEIN
________
sequences
suggest
relatedness
Human- 46 chromosomes
Chimpanzee- 48 chromosomes
karyotypes suggest an
Similar _________
evolutionary
relationship
___________________.
PATTERN MATCHES
1. BANDING
________________________
If you take the two smaller
chromosomes apes have that
we don’t, and place them
banding
end to end, the ______
_______________
pattern
is identical to the
we
#2 human chromosome __
have
that they don’t
________________.
IN MIDDLE
2. TELOMERES
____________________
Chromosomes have special sequences
called telomeres
_______ at their ends to
protect the strands during
replication.
2. TELOMERES IN MIDDLE
Telomere sequences are
the ends and
found at
__________
ALSO
IN THE MIDDLE
_____________________
of human chromosome #2
suggesting it was made by
fusing
_____ two other
chromosomes together.
→
→
→
EXTRA CENTROMERE
3. _________________
Chromosome #2 has a
INACTIVE
second __________
CENTROMERE region
_____________
→
Did you ever wonder why dogs and
cats don’t need to eat ________,
fresh fruit but
YOU
_______?
DO
Fish, amphibians, reptiles, and most
mammals can make their own
VITAMIN C but humans need to eat
_________,
fresh fruit or they end up with
________.
SCURVY
Human DNA contains the gene that
codes for the enzyme to make
vitamin C, but it is ________________.
NONFUNCTIONAL
Guess what other group of organisms
lack the ability to make their own
Vitamin C?
PRIMATES…
which includes
chimpanzees, orangutans,
gorillas, and other apes.
Humans have many other
nonfunctional vestigial genes called
________________.
PSEUDOGENES
EX: Humans have more than 99
different odor receptor genes, but more
than 70% of them are nonfunctional
___________.
WHY DOES EVOLUTION MATTER NOW?
Can see Natural selection happen
7.____________________________
EX: Peppered Moths
Typica
There is a natural
variation in populations
of peppered moths.
Carbonaria
Typica form - lighter
________________
Carbonaria
form - darker
___________________
The ___________
light colored form was the predominant form
prior to the Industrial Revolution
in England _____________________________.
Around the middle of the 19th century the ______
darker
form began to appear. It was first reported in
1848. By 1895 98% of the moths in Manchester
were the dark
____ variety.
In recent years, the burning of
cleaner fuels and Clean Air
regulations has reduced the
pollution there and the
lighter colored moths
______
have increased in numbers.
7.____________________________
Can see Natural selection happen
EX: Changes in disease-causing microbes that
produce new organisms and new
__________.
diseases
Bird flu
_______
HIV
___
Antibiotic-resistant
tuberculosis
__________________________