Transcript Homework - District 273 Technology Services

Evolution
Science Department
Post Falls High School
Evolution: What it is and
isn’t!
• Evolution is both
FACT and
THEORY.
Evolution
• Evolution = a change
• Biological Evolution = a change in a
population over time
– Macroevolution = changes in a a
population’s appearance over time
– Microevolution = changes in a population
Accepting these definitions,
EVOLUTION is a FACT.
Theory of Evolution
• The Theory part of evolution is what is
controversial. The theory describes
HOW these population changes
happen.
• Darwin and Lamarck are some of the
key figures in the theory of evolution.
Parts of the Modern
Theory of Evolution
1.
2.
3.
4.
Natural Selection
Genetic Drift
Mutations
Recombination
These parts of evolution
are what is controversial
Evidence for the Theory of
Evolution
• Fossils: Sedimentary layers are
chronological and can show sequences of
species
• Embryology: similarities in embryos of vastly
different species
• Homology: many organisms have related
structures; Vestigial Organs: Human
Tailbone, Appendix, and Whale Pelvis
• DNA and biochemical similarities
5 Major Misconceptions
About Evolution
• Evolution has never been observed
• Evolution violates the 2nd law of
thermodynamics
• There are no transitional fossils
• The theory of evolution says that life
originated, and evolution proceeds, by
random chance.
• Evolution is only a theory; it hasn’t been
proved.
• Evolution results in better organisms
Natural Selection
• English Peppered Moths in the
Industrial Revolution (coal burning)
• Moth color appeared to change as
surface of environment changed
• They both existed, just relative
numbers were changed with majority
matching environment
Genetic Drift
• A gradual shift in the gene frequencies
of small populations (less than 10,000
individuals)
• Alteration of allele frequencies via
chance
• Founder Effect
• Population Bottleneck
Founder Effect
• The difference between the gene pool of a
population as a whole and that of a newly
isolated population of the same species.
• Occurs when populations are started from a
small number of pioneer individuals of an
original population. Due to small sample size,
the new population could have a much
different genetic ratio than the original one.
Founder Effect
• “Dunkers” - German Baptist religious sect that
settled in Franklin County, PA between 1719
and 1729.
• Type A blood % is 60%, U.S. = 42%;
Germany=45%
• Amish of Lancaster, PA - high frequency of
Dwarfism and polydactylism
• First humans to reach North America (across
the Bering Straits land bridge) brought with
them gene frequencies not representative of
the Asiatic population
Population Bottleneck
• A population bottleneck is a period of
time after which only a small number of
the original population survive. As a
consequence, a large amount of the
original genetic variability may be lost
by chance.
Population Bottleneck
• Elephant seal - hunted to near
extinction in the 1800’s; only
about 20 left in 1890’s.
• “Harem” style breeding means
that one male could have
fathered all of the elephant
seals. Genetic analysis shows
that all of the elephant seals
today (30,000) are almost
genetically identical.
Example of Genetic Drift
Resulting in Evolution
*Can* explain the different frequencies of blood types in
different racial groups (isolation of small populations)
Race/Group
A
B
O
AB
U.S.
Chinese
42%
31%
10%
28%
45%
34%
3%
7%
Blackfoot
76%
---
24%
---
Navajo
24%
---
76%
---
Mutation leads to…….
• Sudden change in
heredity (DNA, etc)
• Tail gene (mutation
in only one gene
leads to loss of the
tail)
• Sickle-cell anemia
(confers malaria
resistance)
Variations, which become……
• Differences in alleles present in the
gene pool of a population
Adaptations, which lead to…….
• Differences in alleles present in the
gene pool of a population
Change
• And what do we call change that occurs
over time?
• Webster calls it evolution!
• Examples
– Music
– Electronics
– Clothing
Evolution of Music
Evolution of Electronic Chips
Summary
Mutations (sudden changes in heredity)
cause variations in a species. Those
more successful variations become the
most common form in the population
(are selected by Mother Nature)!
Natural Selection
• Those variations that enable
organisms to better survive their
environment and reproduce soon
outnumber the other alleles
• Those that survive to reproduce
pass on their variation of the allele to
their offspring (resulting in more
organisms exhibiting the variation!)
Contributors
•
•
•
•
•
•
Lamarck
Wallace
Lyell
Malthus
Erasmus Darwin
Charles Darwin
Lamarck’s Theory of
Evolution
• French biologist who introduced the
evolutionary theory called Lamarckism.
• Explains the Theory of Acquired
Characteristics. Can it be?
• States that new traits in an organism develop
because of a need created by the environment
and are transmitted to offspring.
• An example of this would be if a primal fish, in
order to survive, is obliged to swim, it will
evolve a tail.
The Father of Evolution
Charles Darwin (Early Life)
• Born to a wealthy family in England in 1809.
• Darwin’s father, Robert Darwin was a
successful doctor.
• Darwin started school and did not do well.
• He was not interested in doing any work,
instead he wanted answers to his questions
about life.
• Finished school with little interest in college.
• Robert Darwin managed to get him into medical
school.
• Darwin graduated and was asked to attend a
voyage, which began his life long studies.
• Do you want to take a
voyage on the
M.S.Beagle?
• You will travel all
around the world
looking at exotic
animals and
researching them.
• Your pay will be free
room and board, and
the experience of a
lifetime.
The HMS Beagle
Charles Darwin (The
Voyage)
• In 1831 Darwin set out on The Beagle, a ship
sent around the world to gather information.
• Darwin was assigned the job of the naturalist.
• Darwin collected natural specimens such as
plants and animals.
• He discovered many things in the Galapagos
Islands.
• Darwin returned to England in 1836.
Alfred Russel Wallace (1823-1913)
•In 1848, he made an expedition to the
Amazon River with British naturalist
Henry Walter Bates.
•From 1854-1862 he conducted research
in the islands of Malaysia.
•Duplicated Darwin’s summaries
During his trips he noted fundamental
zoological differences between the
animal species of Asia and those of
Australia, and he placed the zoological
dividing line-known as Wallace’s Linebetween the Malay islands of Borneo
and Celebes.
Does science have the
only answers?
No, certainly not!
CREATIONISM
• Some claim that Earth and the universe
are relatively young, perhaps only 6,000
to 10,000 years old.
• Life was created by a supreme being in a
specific sequence in a 6 day span
• Scientists that have studied a
giant crater full of star dust
think the dust contains the
basic chemicals for life.
• The idea that the scientists have
is that the earth was seeded
with the necessary elements for
life came from the
bombardment by comets and
asteroids.
• The evolution process would
take place through natural
selection, much like Darwin’s
theory.
Greek Creation Myth
•A variety of theories to chose from.
•Main theory: Gods started over
again.
•Man became very corrupt.
•Zeus decided to flood the earth for
nine days and nine nights.
•Son of Prometheus and daughter of
Epumetheus were told to build an ark,
and fill it with supplies.
•After the flood the two
survivors asked for humans to
refill the earth.
•They were told to throw rocks
behind their back, which then
became humans.
•Humans filled the earth once
again.
The Iroquois people
And how they believe
We evolved on earth.
Humans came from a women
who fell to earth from the “sky
people”
At PFHS, we do not require you to
believe in evolution. We present it
as an example of a widely accepted
scientific theory that you must learn.
That knowledge makes you better
able to understand the answers
available to you and your belief
system.
And it is required to be
presented by the state of
Idaho, State Achievement
Standard 652.01.a