Transcript evolution - Laurel County Schools

evolution
evolution
Ch 15 and Ch 16
EVOLUTION
Change in a
population over
time.
Does Evolution mean Man
comes from Monkey?
Charles Robert Darwin
(1809 –1882)
•He was the individual who
contributed more to our
understanding of evolution
than anyone was else.
•Grew up amidst wealth,
comfort, and country sports
•Unimpressive student,
thought of becoming a country
physician (like his father) or a
clergyman
•FYI…born on the same day
as Abraham Lincoln
o Darwin served as naturalist
aboard the H.M.S. Beagle on
a British science expedition
around the world
o Traveld from 18311836
o During his travels, Darwin
made numerous
observations and collected
evidence that led him to
propose a revolutionary
hypothesis about the way of
life changes over time.
HMS Voyage
Galapagos Islands
Darwin's Work
• When the ship would anchor Darwin
would collect plant and animal
specimens.
• He would study and observe these
during travel time at sea.
• His curiosity and analytical nature
were ultimately the keys to his success
as a scientist.
Darwin's Work
• His primary focus was on how and why
some animals and plant life were found in
some specific areas but not others that had
similar ecosystems..
• Why are there no rabbits in Australia? Why
no kangaroos in England? Even though both
habitats seemed perfect for them!
• He also began to study preserved remains of
ancient organisms called fossils.
• Why had animals changed so drastically?
Why had some changed very little?
Darwin's Work
• The Galapogos Islands was a port that influenced
Darwin’s theories the most.
• Several islands that although close together had
very differenct climates.
• Darwin worked primarily with tortoises, inguanas
and finches.
• He made observations about these and other
animals.
• He focused on how these animals were similar to
other species but very unique to the islands.
INFLUENCES ON DARWIN
1. Essay of Population by Thomas
Malthus – stated that human
population increases faster than
the food supply
2. Principles of Geology by Charles
Lyell – stated that the earth is
changing slowly and the forces
that acted on it in the past are
still at work
INFLUENCES ON DARWIN
3. Jean-Baptiste Lamarck- He publishes his hypothesis of the
inheritance of acquired traits. The ideas are flawed, but he is
one of the first to prose a mechanism explain how organism
change over time.
o
He thought that if an animal somehow altered a body
structure, it would pass that change on to its offsprings. By
example…if you lifted weights all the time you could pass on
big muscles to your children.
INFLUENCES ON DARWIN
3. The discovery of fossils in South
America which were similar in
appearance to modern armadillos,
but their size indicated they were a
different species.
4. The Galapagos Island discoveries
which showed the tortoises and
finches were slightly different from
island to island, i.e. variations.
INFLUENCES ON DARWIN
5. The use of selective
breeding to create new
varieties;
Animal and plant
breeders were able to
create new organisms by
selectively breeding
parents for desired traits.
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Alfred Wallace
•About 20 yrs. after Darwin’s
voyage, another young
Englishman went on a venture
to South America and wrote
Darwin a letter outlining a
theory he’d been developing
•Darwin was astonished,
Wallace was describing the
same natural selection that he
had been contemplating for 20
years, but never had the nerve
to publish
• 18 months later Darwin
went on the write On
the Origin of Species by
Means of Natural
Selection, or the
Preservation of
Favoured Races in the
Struggle for Life in 1859
• The Origin of Species
Darwin's Conclusion
• In his book Darwin proposed the
idea of natural selection to
explain how species evolve.
• He then presented evidence that
evolution has been taking place
for millions of years and still
continutes
• His work caused a sensation!!
• But what did he actually say….
Darwin's Conclusion
• One of Darwin's important
insights was that member of
each species vary from one
another in important ways.
• He focused on how variations
of species matters…and in fact
was used even then.
Artificial Selection
• Artificial selection- Breeding
organisms with specific traits in order
to produce offspring with identical
traits.
• Humans have been doing this for
years with both plants and animals.
Natural Selection
• Darwin was convinced that artificial
selection worked in nature.
• Organisms produce more offspring than can
survive. For example fish sometime lay
millions of eggs
• In any population, individuals have
variations. (size, color, speed)
• Individuals, with certain useful variations,
such as speed or being able to avoid
predators, will survive in their environment,
passing those variations to the next
generation.
• This is often referred to as Survival of the
Fittest.
Natural Selection
• Overtime, offspring with certain
variations make up most of the
population and may look entirely
different from their ancestors.
• Darwin proposed this idea of natural
selection to explain how species
change over time.
Natural Selection
• How is one moth
better adapted than the
other?
• Which one will
survive and pass on its
characteristics to its
ofspring?
Natural Selection
• Mimicry!!
Natural Selection
• Mimicry!!
Natural Selection
• Camouflage!
Natural Selection
• Camouflage!
Divergent Evolution
• Divergent evolution, the pattern of evolution
in which species that once were similar to an
ancestral species diverge, or become
increasingly distinct.
• Divergent evolution occurs when populations
adapting to different environmental
conditions changes becoming less alike as
they adapt, eventually resulting in a new
species.
Divergent Evolution
Divergent Evolution
Convergent Evolution
• A pattern of evolution in which distantly related
organism evolve similar traits is called Convergent
Evolution
• This occurs when unrelated species occupy similar
environments indifferent parts of the world
• Because they share similar environmental
pressures, they share similar pressures of natural
selection.
Convergent Evolution
BIOLOGICAL EVOLUTION
If Evolution is real…how can we prove it?
•
•
•
•
1. The fossil record
2. Anatomical evidence
3. DNA similarities
4. Embryological evidence
1. FOSSIL RECORDS
• A fossil is any preserved part or
trace of an organism that once
lived.
• Fossils may be formed when all or
part of an organism is buried
before it can be eaten or before it
decays.
FOSSIL RECORDS
• Fossils are often found in sedimentary rock.
• Sediments such as mud, silt, and sand have
deposited layers on top of one another and are
subjected to great pressure.
FOSSIL RECORDS
• Fossils are important because they
provide a record of early life and
evolutionary history.
• Fossils are found throughout the world.
• While many fossil records are
incomplete the sequences of evolution
can become more clear.
Categories of Fossils
1. Imprints
2. Molds
3. Casts
4. Petrified
fossils
5. Intact fossils
Imprint Fossils
• An imprint fossil forms
when an object is
pressed into mud, such
as a leaf or insect.
• As it slowly dissolves,
the mud surrounding it
can harden and a space
is left.
• A mold of the original
object is formed, which
fills with sediment and
becomes a fossil.
Mold Fossils
• Formed when hard body
parts such as teeth,
shells, or bones form
depressions, that are the
size and shape of the
body part, in the rock
that are shaped like the
organism’s part
• The part decomposed
and leaves its specific
shape because the
sediment had already
hardened around the
original part
Cast Fossils
• Formed when the
original materials
decompose and the
resulting mold is filled
with another material.
• Now think of of
something like a bone
buried in sediment. The
sediment hardens
around the bone, and the
bone rots away, creating
a mold. Over time,
minerals fill in the mold
and harden, creating a
cast of the bone, or a cast
fossil.
Petrified Fossils
• Formed when
the hard
parts of an
organism are
gradually
replaced by
minerals
Intact Fossils
• Occur when an
entire organism or
part of an organism
is preserved intact
• Smaller organisms
may be trapped in
amber, the sap of
trees
• Larger animals have
been trapped in tar
or ice, which
prevented their
decay
2. Anatomical
Similarities
• Many evolutionist study the structural
similarities between organisms to
determine their common ancestry.
Homologous Structures
• Structures with a common evolutionary
origin are called Homologous Structure.
• Scientist view organisms with homologous
structures to evolve from a common
ancestor.
Homologous Structures
• Structures that are
similar due to
evolutionary origin,
such as the forearm
bones of humans,
birds, porpoises,
and elephants, are
called homologous.
Homologous Structures
Analogous Structures
• The body parts of organisms that do NOT
have a common evolutionary relationships
origins but are similar in functions are
called Analogous Structures.
Analogous Structures
Vestigial Structures
• Vestigial structures are remnants of once-useful
structures that are no longer used.
• Limb bones can be found deep inside the body of a whale.
This shows they once had use for legs.
• A snake also has the same type of hind limb bone
remnants.
• Humans have a tail bone and an appendix that we do not
use
• Horses have toe bones.
• Examples like these can be found in other species as well.
Vestigial Structures
Embryological Differences
• An embryo is the earliest stage of growth
and development of both plants and
animals.
• Similarities among the young embryos
suggest evolution from a distance common
ancestor.
Embryological Differences
Embryological Differences
Embryological Differences
BioChemistry Differences
• Biochemistry also provides evidence for
evolution.
• It reveals information between individuals
and species.
• Comparisons of the DNA or RNA of
different species produces biochemical
evidence for evolution.
evolution
• The great diversity of organisms is the
result of more than 3.5 billion years of
evolution that has filled every available
niche with life forms.
evolution
• Natural selection and its evolutionary
consequences provide a scientific
explanation for the fossil record of
ancient life forms, as well as for the
striking molecular similarities observed
among the diverse species of living
organisms.
evolution
•
The millions of different species of
plants, animals, and microorganisms
that live on earth today are related
by descent from common ancestors.
evolution
• Biological classifications are based
on how organisms are related.
• Organisms are classified into a
hierarchy of groups and subgroups
based on similarities which reflect
their evolutionary relationships.
• Species is the most fundamental
unit of classification.
EVOLUTION
Chapter 16
Variation and Gene Pool
• Lets review just a little.
• Mendel concluded that traits are controlled
by alleles and you must have two for every
trait.
• Some plants or animals have several
different alleles in their gene pool that
determine a specific trait. (more that 2
choices…like blood type. A, B, or O)
Variation and Gene Pool
• Genetic Variation is
studied in populations.
• Populations are a group of
the same species that live
together
• Because members of the
same population
interbreed they share a
common group of genes.
• A Gene Pool consists of
all genes, including all
different alleles, that are
present in a population.
• The Relative Frequency
of an allele is the number
of times that the allele
occurs in a gene pool.
• Example: B (black fur)
has a relative gene
frequency of 40%, while b
(white fur) has a relative
gene frequency of 60%/
Genetic Equilibrium
• Genetic Equilibrium- When the ratio of
genes in a population remain constant over
a long time.
• In genetic terms, evolution is any change in
the relative frequency of alleles in a
population.
• Remember..evolution does NOT happen to
individuals but rather to populations
Genetic Variations
• Biologist can explain how variation is
produced.
• The two main sources of genetic variation
are:
– Mutations.
– Genetic shuffling that results from sexual
reproduction. Crossing Over of homologous
pairs during meiosis.
Genetic Drift
• GENETIC DRIFT – When genes in a
population change due to random chance.
Disrupts genetic equilibrium. Usually seen
in small populations.
• Example: Amish population in Pennsylvania.
– Very small population.
– When a young man had a mutation that caused
multiple fingers and short stature. It spread
through the population and caused a change in
the ratios.
Hardy Weinburg Equilibrium
• This is a condition where there is always
balance in the frequency of genes in a
population.
• It states that allele frequency in a population
will remain constant unless one or more
factors cause those frequencies to change.
(add this)
• That means there is never any evolution.
• It has a complicated equation.
Hardy Weinburg Equilibrium
•
In order for the principal to remain
constant 5 conditions must be meet
1.
2.
3.
4.
5.
Random Mating
Large Population
No immigration or emigration
No Mutations
No Natural Selection
Process of Speciation
• We realized that these 5 conditions cannot always
be met…but when do these lead to the formation
of new species or speciation.
• The gene pools for two populations must become
separated for them to become new species.
• When the members of two population cannot
interbreed and produce fertile offspring
Reproductive Isolation has occurred.
Process of Speciation
• Another type of isolating mechanism,
Behavioral Isolation, occurs when two
populations are capable of interbreeding but
have differences in courtship rituals or other
reproductive strategies that involve
behavior.
Process of Speciation
• Geographic Isolation- Two populations are
separated by geographic barriers such as
rivers, mountains, or bodies of water.
• Temporal Isolation- Two or more species
reproduce at different times.
Natural Selection on
Polygenic Traits
• Natural selection can affect the distribution
of phenotypes in any of three ways:
directional selection, stabilizing selection,
or disruptive selection
Directional Selection
• Directional Selection- Favors the
extreme…when individuals at one end of
the curve have higher fitness than
individuals in the middle or at the other end.
Stabilizing Selection
• Stabilizing Selection- favors the average;
Individuals near the center of the curve have
higher fitness than individuals at either end
of the curve.
Disruptive Selection
• Disruptive Selction- small or large are most
successful; individuals at the upper and lower
ends of the curve have higher fitness than
those in the center.
EVOLUTION
IN
TENNESSEE
HISTORY
The “Monkey Trial”
(Tennessee v. John Scopes)
• The “Roaring 20’s”
• Younger modernists no
longer asked whether
society would approve their
behavior
• Alcoholic prohibition
• Jazz Age
• Babe Ruth
1925
• Worst tornadoes in U.S. history
• Hitler published Volume 1 of Mein
Kampf; founds the SS
• Capone takes control of Chicago mob
• Pres. Calvin Coolidge takes the Oath of
Offfice
• B.B. King, Malcom X, and Paul Newman
are born
• In Tennessee…
The Butler Law
• Feb. 1925, Gov. Austin Peay
signs “The Butler Law”
(introduced by John Butler)
• making it unlawful “to teach
any theory that denies the
story of divine creation as
taught by the Bible and to
teach instead that man was
descended from a lower order
of animals”
Dayton, Tennessee
Above: downtown Dayton
Right: Rhea Co. High School
Robinson Drug Store
• ACLU advertised to offer services
to anyone willing to challenge the
new law
• local group of men saw an
opportunity to put town on the map
John Scopes
• 24 yrs. old, from
Illinois
• Part-time teacher
& football coach
• Assigned readings
on evolution from
“Hunter’s Civic
Biology”
The Case
• Group at drug store (including
school superintendent) “summoned”
Scopes
• Scopes showed the men the book he
used (drug store also sold textbooks)
and the assigned reading
• Asked Scopes if he would be willing
to be part of test trial; Scopes agreed
The Case
• Friends of Scopes agreed to prosecute,
local attorneys Herbert & Sue Hicks
• John Neal, law school dean from
Knoxville drove to Dayton, volunteered
to defend Scopes
• William Jennings Bryan heard about the
case and went to assist prosecution
• Clarence Darrow heard about case and
Bryan, so he went to assist defense
William Jennings Bryan
• “The Great
Commoner”
• 3-time Democratic
Pres. candidate
• Sec. of State under
Woodrow Wilson
• Had been leading
“crusade” to banish
Darwin from
American
classrooms
Clarence Darrow
• Perhaps the most
famous American
lawyer of 20th century
• Well known for
defending labor leaders
and radicals, as well as
high-profile murderers
• Leopold-Loeb; wealthy
Chicago teens murdered
schoolmate; Darrow
helped them escape
death penalty
• agnostic
TRIAL HIGHLIGHTS
• Town had carnival-like atmosphere
• 6 blocks around courthouse became
“Monkeysville” - - preachers,
carnival games, live monkeys
• “watched” worldwide by radio and
newspapers
(WGN)
Quinn Ryan and WGN radio made
history in Dayton. The Scopes trial
was the first live broadcast of a trial in
American history. It took a lot of
money and planning to make it
happen. WGN radio, just a year old at
the time, spent $1,000 a day to
broadcast the trial live. They rented
AT&T cables stretching all the way
from Chicago to Dayton, Tennessee.
Their listeners in Chicago and beyond
would have a front row seat at what
was already being called "the trial of
the century."
• Nearly 1,000
people (300
standing) packed
courtroom on 1st
day, July 10
Above: Rhea Co. courthouse
Top right: Judge John T. Raulston
Right: judge & jury
http://www.pbs.org/wgbh/amex/monkeytrial/index.html
• The monkey trial also inspired music -humorous songs like "You Can't Make a
Monkey Out of Me," "Monkey Business
Down in Tennessee" and serious folk
songs. Tom Morgan, who lives in the
hills above Dayton, performs songs
inspired by the trial, like this song
about John Scopes:
• Then to Dayton came a man
With his ideas new and grand
And they said we came from monkeys long ago.
But in teaching his belief
Mr. Scopes found only grief
For they would not let their old religion go.
• You may find a new belief
It will only bring you grief
For a house that's built on sand is sure to fall.
And wherever you may turn
There's a lesson you will learn
That the old religion's better after all.
GOAL OF DEFENSE
• Not win acquittal, but
rather to obtain a
decleration by higher
court, preferably U.S.
Supreme Court, that
laws forbidding
teaching of evolution
were unconstitutional
• L-R: Dudley Field Malone
(international divorce attorney),
Scopes, Darrow
From left: John
Scopes, defense
attorney Dr. John
R. Neal, and George
Rappleyea,
manager of the
Cumberland Coal
and Iron Co. and
one of the original
organizers of events
leading up to the
trial.
GOAL OF PROSECUTION
• Uphold the
Butler Law
• Moral victory
for
fundamentalism
• Right: Bryan
Trial Highlights
• On Thurs. July
16, trial was
moved outdoors
due to heat, to
accommodate
crowds, and fear
of courtroom on
2nd floor
collapsing
• Crowd of 5,000
VERDICT
• Jury
deliberated for
9 minutes
• GUILTY
• Judge
Raulston fined
Scopes $100
RESULTS
• A year later, the Tennessee Supreme
Court reversed the decision on a
technicality; the fine should have been
set by the jury, not Judge Raulston
• Rather than send the case back for
further action, TN Supreme Court
dismissed the case
• Court commented, “Nothing is to be
gained by prolonging the life of this
bizarre case.”
RESULTS
• The Butler Act remained on
the books for another 40
years, until the legislature
repealed it in 1967.
• What happened in the 1960’s
(related to science)?
What happened to Scopes?
• Left Dayton and became a
petroleum engineer
• Died in 1970
William Jennings Bryan
• Died 5 days after the
trial in Dayton
• After eating an
enormous dinner, he
lay down to take a nap
and died in his sleep
• Darrow’s comment
when told he died of a
broken heart, “Broken
heart nothing; he died
of a busted belly.”
Buried in Arlington Natl.Cemetery
Clarence Darrow
• Practiced law for
another 13 years
• Died in Chicago in 1938,
at age 80
• “Inherit the Wind”
starring Spencer
Tracy released in
1960 based on
successful Broadway
play received 4
academy
nominations,
however no Oscars
were won
• Based on the trial
with names changed