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Evolution Notes
Biology 102
Jacobs/Ebener
History of Evolution
Important Scientists:
• Jean-Baptiste Lamarck
• Thomas Malthus
• Alfred Russel Wallace
• Charles Darwin
Jean-Baptiste Lamarck
(1744-1829)
•
Zoologist, forerunner of evolution
INCORRECT theories:
1. Simple life forms continually come into
existence from dead matter.
2. Life forms continually become more
complex or more “perfect” as they
transform into new species.
Examples:
• Lamarck thought that giraffes evolved their
long necks by each generation stretching
further to get leaves in trees and that this
change in body shape was then
inherited. Likewise, he believed that
wading birds, such as herons and egrets,
evolved their long legs by stretching them
to remain dry.
•
Lamarck also
believed that
creatures could
develop new organs
or change the
structure and
function of old ones
as a result of their
use or disuse.
CORRECT Theory:
3. Change in species is linked to an organism’s
environment.
Lamark’s
• His idea of the Law of Use and Disuse
Said that if a body part were used, it got
stronger. If it were not used, it got weaker
and deteriorated. And the Inheritance of
Acquired Traits said that these traits would
then be passed to offspring.
Ex: Blacksmith muscles, Giraffe necks
Thomas Malthus
(1766-1834)
• Realized that producing more offspring than
can survive establishes competition among
a species.
• Populations grow as much as the
environment allows.
• Influenced Darwin & Wallace’s theory of
natural selection and Survival of the fittest.
Alfred Russel Wallace
(1823-1913)
• Came to same conclusions as Darwin
during same time frame.
• Co-published theory of natural
selection/evolution with Darwin.
Who Was Charles Darwin
(1809-1882)
Label your paper :
1.
2.
3.
4.
5.
Write 5 facts from the short video
clip on Darwin…
http://www.pbs.org/wgbh/evolutio
n/library/11/2/e_s_2.html
• Darwin made observations & collected data during
his Voyage of the Beagle through South America
and across the Pacific Ocean.
• Spent much time on Galapagos Islands collecting
information about species that inhabitated each
island.
• 1859: Published the “Origin of Species”
Darwin’s Observations on Galapagos Islands:
• Species resembled those of the nearby islands but
had evolved differences
• He called this descent with modification after
separating from a common ancestor
Darwin’s Ideas:
• Natural Selection states that a struggle for life
exists causing individuals with favorable
characteristics to survive while the other would
become extinct (“Survival of the Fittest”)
Newsworthy Events
• 1925: John Scopes Trial
– Teacher violates anti-evolution law in
Tennessee by teaching evolution to students
• 2005: “Intelligent Design” mandatory to be
taught in public schools
• Darwin explained the
theory of evolution by
Natural Selection.
• “Survival of the Fittest”
means organisms that
adapt to their
environment survive,
while organisms that do
not adapt disappear.
• Natural selection leads
to adaptations within a
population.
Natural Selection Video
• What is Natural Selection?
• As you watch the video, take note of:
(1) definition of descent with modification
(2) explanation of common descent
(3) examples give in the video to explain terms
(4) why Darwin became interested in island
tortoises
(5) the definition of natural selection
Types of Evolution
•
Microevolution- the change of allele
frequencies within a population
•
Macroevolution- large-scale evolutionary changes
: 5 patterns
l. Mass extinctions
2. Adaptive Radiation
3. Convergent Evolution
4. Coevolution
5. Punctuated Equilibrium (and gradualism)
Mass Extinctions
• More than 99% of all species that ever
lived are now extinct
• Mass extinctions wiped out food webs
& ecosystems
• Example: Dinosaurs-many theories
(Possibilities include asteroid,
volcanoes, extreme climate continents
drifting, etc.)
Adaptive Radiation
• A species or group of species evolves into
many new species
Convergent Evolution
• Unrelated organisms come to resemble one another
bird
fish
mammal
Coevolution
• 2 species evolve in response to changes in each
other over time
Central American Swollen-Thorn Acacias
Acacia ants and acacia trees
Acacias are small, Central American trees in the
Leguminosae. They have large, hollow thorns. The
acacia ants live in the thorns. On the tips of its
leaflets, the plant makes a substance used by the ants
as food. The ants defend the tree from herbivores by
attacking/stinging any animal that even accidentally
brushes up against the plant. The ants also prune off
seedlings of any other plants that sprout under
“their” tree
Punctuated Equilibrium
• Rapid evolution after long periods of equilibrium
(balance)
• Why? Migration, mass extinctions, isolation
How does it appear
that GRADUALISM
is different?
Acacia ants and tree video
• Acacia Tree & Ants -Coevolution
1. Genetic Variation
a.
b.
Natural
Selection Video
http://www.pbs.org/wgbh/evol
ution/library/11/2/e_s_4.html
6 min 39 sec
2. Overproduction of
Offspring
a.
b.
3. Struggle for Existence
a.
b.
4. Differential Survival &
Reproduction
a.
b.
EVIDENCE OF EVOLUTION
• Evidence of Evolution
• Stated Clearly video (11:21)
Evidence for Evolution
The fossil record gave
us:
1. Descent with
modification
2. Homologous
Structures
3. Transitional
Fossils
Descent with Modification
• All living organisms are related to one anothercommon descent
• Speciation-new species can arise
Homologous Structures
• structures in different species that may
perform different functions but are similar
in structure because of their common
ancestry
• Examples: bat wing,
whale flipper, cat claw,
Human hand
Vestigial Organs
– structures of no
apparent function to
an organism; leftover
from ancestry
– Examples: snakes
have leg & pelvis
bones; whale rear
limbs
Whale
Evolution
Video
Label Paper
Left Page
# 1-5
http://www.pbs.org/wgbh/evolution/l
ibrary/03/4/l_034_05.html
5 min, 9 sec
Examples of Evolution
• Antibiotic Resistance: natural
selection has occurred within
populations of bacteria
• Mutations cause bacteria to change
their structure…antibiotics cannot
bind to cell surface
• Acquiring new genes…bacteria
have new enzymes that can
deactivate or destroy antibiotic
• Ex:Tuberculosis bacteria
Examples of Evolution
• Darwin’s Finches: Natural selection has
occurred in beak size
Examples of Evolution
• Speciation: begins as a population adapts to its
environment.
Biological Resistance
Antibiotic Resistance
• Tremendous quantities of antibiotics are released and used
in the environment daily.
• Bacteria become resistant through:
– Adaptations (natural selection)
– Acquiring mutated genes that make them resistant.
**Evolution through natural selection can occur
remarkably quickly when natural selection pressures
are very strong and reproduction rates are very fast
(some bacteria reproduce in 10-15 minutes!)
What does this mean for us?
• Antibiotics will be ineffective against bacterial diseases
or infections.
• The drug will not longer bind to the target therefore not
killing off harmful bacteria.
Pesticide Resistance
• The natural occurrence in which the ability of
individuals in a population to survive a plant
protection product treatment that would normally
give effective control is passed on to future
generations
• Insects are among most adaptable organisms on
Earth
• For the past 400 million years they have managed
to survive by adjusting to changes in their
environment, so it should come as no surprise that
they can also adapt to chemical pesticides.
• Example: Colorado potato beetles on
Long Island, N.Y.
Why does Evolution Matter Now?
View the video and take notes on your notes.
http://www.pbs.org/wgbh/evolution/educators
/teachstuds/svideos.html
Stated Clearly: Does Evolution Matter?