Transcript Darwin`s Theory of Evolution The Puzzle of Life`s

Theory of Evolution
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
What is biodiversity?
Where did all these
different organisms
come from?
How are they related?
The person who contributed the
most to our understanding of
evolution was
Charles Darwin
______________________
In 1831, at age 22, he joined the crew of
Beagle as a naturalist for
the H.M.S.
_______________
5 year voyage around the world.
a ________
During his travels, Darwin wrote thousands of
pages in his journals, drew pictures of the things
he saw, and collected a vast amount of
______________
evidence that led him to propose a
revolutionary hypothesis about the way
_______________________
life changes
_____________.
While on his voyage around the world aboard
H.M.S. Beagle Charles Darwin spent
the ____________,
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 but have
climates
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
Pinta
Pinta Island
Tower
Marchena
Intermediate shell
Fernandina
James
Santa Cruz
Isabela
Santa Fe
Hood Island
Floreana
Hood
Isabela Island
Dome-shaped shell
…while on the lush rainforest of Isabela Island,
tortoises had short necks…
Saddle-backed shell
Darwin began to wonder if animals living on
different islands had once been members of the
same
species that had developed _________
different
____________
characteristics after becoming isolated
_______ from one
another in different habitats.
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
now
processes still occurring
_____________
have shaped Earth’s
features over
__________________.
long periods of time
Ideas that shaped Darwin’s thinking:
SINCE THEN
Theory of Pangaea and continental drift
Ideas that shaped Darwin’s thinking:
Georges Cuvier developed
French naturalist _______________
his theory of catastrophes.
He studied fossils and found that animal and
plant species are destroyed time and again by
deluges and other natural cataclysms.
After each time and only after, new species
evolved.
What is 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 would be
_______________________.
insufficient
space & food
Ideas that shaped Darwin’s thinking:
Jean-Baptiste
Lamarck (1809)
___________________________
was one of first scientists
to recognize living things
changed
over time and that
_______________
descended from
all species were ________
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 _________mates
and fight
attract
predators
off _____________.
repeated use, the front claw
Through _________
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?
NOT be __________
ACQUIRED traits can ____
PASSED ON to their
NO! ________
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 acquired changes on to their offspring
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 acquired changes on to their offspring
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
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
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!
http://www.thesecondevolution.com/wallace&darwin.jpg
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
__________________
http://www.loc.gov/exhibits/world/images/s125.jpg
Isn’t evolution just a theory?
A theory is well-supported
a ____________,
testable
_______, explanation of phenomena
that have occurred in the natural
world, like
gravitational
the theoryattraction
of
cell
__________________,
theory
atomic theory
________,
and _____________.
WHAT IS DARWIN’S THEORY?
GENETIC VARIATIONis 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
________,
VOCAB
Ability of an individual to survive
______
and
reproduce in its specific
____________
environment
= fitness
______
VOCAB
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. ________________
2. ________________
Fossil record
Geographic Distribution
3. _______________
Homologous structures
4. _______________
5. _______________
Embryology
DNA
6. _______________
7. _______________
See Natural selection happen
• ARTIFICIAL SELECTION WORKS
NATURE
•In artificial selection, ____________
•provides the _________
variation through
•_________ and _________________
mutation
sexual reproduction
select those traits that
•andhumans
______________
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
How Do We Know Evolution Happens?
2. The Fossil Record –
Fossils
______ are theremains
_______
_________________
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
fossils
_____, while the
_____ found within
the rock tell a history life
of ___.
The fossils are thought
to be thesame
________
age as
the rock they
are found in.
TRANSITIONAL FOSSILS HAVE BEEN FOUND
Fossil record
shows change
over time
If Darwin’s theory is supported 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!
•THE GALAPAGOS TORTOISES
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
adapted
______ to eating a variety
_____ of foods
_____.
If Darwin’s theory is supported 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
different organisms
even though they are very _______
(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
_____________________
They are parts of the body that are similar in structure to other
species' comparative parts.
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
_______.
4. Homologous Body Structures –
Some homologous
_______________________
body structures
are vestigial
_______ and have no useful
function even though they are still
present, likehipbones
________in whales and
boa constrictors, or atail
____ and
________________in
cecum (appendix)
humans.
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
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,
suggesting that they allevolved
_______
from
common
a _______________.
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 eatfresh
________,
fruit
YOU
but 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
PRIMATES…
Vitamin C?
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
nonfunctional
are
___________.
Why does evolution matter now?
Can see Natural selection happen
7.____________________________
EX: Peppered Moths
Typica
Carbonaria
There is a natural
variation in
populations of
peppered moths.
Typica form - lighter
________________
Carbonaria form - darke
_________________
__
The light
___________
colored form was the predominant
form in England
prior to the Industrial Revolution
_____________________________.
darker
Around the middle of the 19th century the
______ form began to appear. It was first
reported dark
in 1848. By 1895 98% of the moths
in Manchester were the ____ variety.
In recent years, the burning of
cleaner fuels and Clean Air
regulations has reduced the
lighter
pollution there and the
______ 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
__________________________
• Natural Selection:
– Process by which species adapt to their
environment
• Genetic Drift:
– Mechanism for evolution
– Change in the frequency of a gene variant
(allele) in a population
– Entirely random process (unlike natural
selection)
• It doesn't work to produce adaptations