Vocab
Population- group of organisms of the SAME
species that occupies certain area
Species- organisms that can INTERBREED
and produce FERTILE offspring
Ex) Sauerman Woods Crown Point
-whitetail rabbits -deer
-sparrows -squirrels
Liger (lion and tiger)-infertile
Cama (camel and llama)-infertile
Tigon (tiger and lion)--infertile
Can we capture all the whitetail
rabbits in Sauerman Woods?
Population Sampling- technique uses part
of population to represent whole
population
Capture 100 random rabbits
– These rabbits are a representation of all the
rabbits in the area.
– We can study many things within this group…
Genetics of the Population…
Gene Pool- all of the
genes of every individual
in population sample
Frequency- how often
something occurs
Population genetics
involves studying the
frequency with which
certain alleles occur in a
population’s gene pool.
In 50 years, will the allele
frequencies be the same?
Hardy-Weinberg Equilibrium Principle –
“Under certain conditions, the frequencies of the
dominant and recessive alleles will remain the same
generation after generation.‖
HARDY WEINBERG
5 CONDITIONS
To keep H-W equilibrium there must be:
No mutations
Large population
Population size remains same (no migration)
Random mating
No ―survival of fittest‖ (evolution)
***These conditions are NEVER all met, so populations
are always changing and NOT in
H-W equilibrium.
History of Evolutionary Thought
Before 1850, most people believed…
– Earth formed by supernatural events and never changed.
– Earth only a few thousand years old.
– Each species was made to fit its environment.
– Species never changed and did not go extinct.
History of Evolutionary Thought
Jean Baptiste Lamarck
Proposed that species
DO evolve
***PROPOSED
EVOLUTION
OCCURRED BY
INHERITANCE OF
ACQUIRED
CHARACTERISTICS
Lamarck
Lamarck’s Hypothesis:
1. Desire causes change
Ex.) ancestors of birds had a desire to
fly, so they did.
2. Use and Disuse
Ex.) If species used its arms to swim
over and over, it would develop flippers.
If not, flippers would disappear.
3. Traits acquired during life can
be passed on
Ex.) Tiger Woods’ children will be great
golfers.
WRONG!!!!
History of Evolutionary Thought
Alfred Wallace
English teacher who
collected plants and
insects.
Observed variations
in organisms
Proposed that
species DO evolve
similar to Darwin’s
Sent idea to Darwin
Charles Darwin
At 22, sailed on the ―HMS
Beagle‖ to the Galapagos
Islands.
Was going to school to be
a minister-believed God
created each species to
match its habitat and they
never changed.
Thought Earth was about
6,000 years old and didn’t
change.
Charles Darwin cont.
During journey, he made
observations and
recorded them in a
journal.
Darwin began to doubt
that species remained
―constant.‖
Charles Darwin cont.
In 1859, Darwin published The
Origin of Species.
His book stirred up controversy.
Proposed **EVOLUTION
OCCURRED BY NATURAL
SELECTION
Major points of Darwin’s book:
Organisms have more offspring than can survive.
Certain individuals are more likely to survive than
others (survival of the fittest.)
Species DO change over time.
Gradual changes may cause members of one
species to eventually evolve into new species.
African apes are close genetic relatives of modern
humans.
Darwin Video
What We Know Now
Evolution is a Scientific
Theory
Not a hypothesis, or an
educated guess, or a ―theory‖ in
layman’s terms.
Unending amount of evidence to
support it
Evolution is called ―the unifying
principle of Biology‖
Isn't Evolution JUST a Theory?
Types of Evolution
Evolution - genetic change of a population of
organisms over time- descent with modification
Microevolution:
Small genetic changes of a population
Shorter amount of time
Bengal tiger simulation was microevolution
Types of Evolution
MACROevolution:
– When new species are
formed over long periods
of time.
– Due to tremendous
amounts of accumulated
genetic changes in a
population
– Speciation- formation of
new species due to
accumulated
microevolution and
mutations.
Speciation
Geographical isolation- members of a population
are separated geographically
– Major step that leads to speciation.
– Due to volcanoes, earthquakes, flooding, etc.
– Can lead to divergence and then speciation.
How does macroevolution work?
dibosirdsaur
GEOGRAPHIC ISOLATION
dibosirdsaur dibosirdsaur
10 million years of accumulated mutations
diosirdsaur ibosirdsaur
10 million years of accumulated mutations
diosirdsaur iboirdsaur
10 million years of accumulated mutations
dinoirdsaur boirdsaur
10 million years of accumulated mutations
dinordsaur boirdsur
10 million years of accumulated mutations
dinodsaur boirdsu
10 million years of accumulated mutations
dinodsaurs boirds
10 million years of accumulated mutations
DINOSAURS BIRDS
Darwin and the Finches
When Darwin traveled to the Galapagos he
took interest in the finches.
He noticed the finch species on the islands
were different, but all resembled one from S.
America.
Darwin thought some migrated and new
species evolved. This is what he proposed:
Darwin’s Finches
Finches migrated from
South America to the
islands
– Populations on different
islands adapted to
different environments and
food sources they found.
Darwin’s Finches
Different mutations
accumulated in the
different populations on
the different islands
and they became more
and more different from
each other.
Divergence- the
accumulation
of differences between
species
or populations.
Darwin’s Finches
Over time the populations on the islands became so
different they no longer mated->speciation
Several new finch species evolved from a common
ancestor from S. America
This is an example of macroevolution
Recent finch
research
Darwin’s Natural Selection is the
Driving Force Behind Evolution
Natural selection- organisms best suited to
their environment survive and reproduce.
– Darwin’s proposed mechanism of evolution
– Survival depends on the particular environmental
conditions a species finds itself in—nature!
– If the environment changes, so do the populations
that live there.
Adaptation- using inherited genetic
characteristics to increase chance of survival
in new environment.
Natural Selection and Salamanders
Whose idea for
evolution is this?
Natural Selection
Three conditions necessary for natural selection to
occur:
1. Genetic variation: Individuals within a population must be
genetically different. This is due to mutation.
****Random mutations are the raw material for evolution to
occur!!!!!!!
2. Overproduction of offspring: More organisms are born than
can survive.
3. Differential reproduction: Certain traits enable individuals to
survive and have more offspring than others.—SURVIVAL
OF THE FITTEST
Natural Selection
Result of Natural Selection:
- Genes that help a species survive stay in the
gene pool.
- ―Unfavorable‖ genes gradually decrease.
- This causes changes in the genetics of
populations EVOLUTION!!!!!
- Over a long time, the new populations no longer
can mate with the original they started as. New
species have formed.
Natural Selection Example
The industrial revolution
– In England in the early 1800’s industry boomed
– Factories, trains, smoke and smog
– Peppered moths were dark or light colored, and
the dark ones that were once rare became more
common.
– Hypothesis?
The Peppered Moth
– Kettlewell tested this hypothesis
Released equal numbers of moths in polluted
AND clean forests.
In industrialized areas, dark gray moth was
better camouflaged.
They survived, had more offspring
– The population *as a whole* evolved to be
better suited to the environment more gray
and camouflagedADAPTATION!
– This is an example of microevolution
The Peppered Moth
Peppered Moth
Simulation
EVOLUTION
by natural selection
Microevolution MACROevolution
Changes Accumulated
in gene frequencies microevolution and
in a population mutations to form
whole new species
Examples: Examples:
Shorter times Peppered moth Longer times Darwin’s finches and
and Bengal tiger geographical isolation
Artificial Selection
Artificial selection- human intervention in animal or
plant reproduction to ensure that certain desirable
traits are passed on.
Instead of NATURE selecting which traits are
favorable, HUMANS selectively breed those animals
with favorable traits.
Ex. dogs or racehorses