Evolution
(Part 1)
IN: 163 & 165
Incorrect Theories of Evolution:
Lamarck
• Lamarck proposed an incorrect
mechanism for how organisms
evolve
– Simple life forms continually
came into existence from dead
matter
– Continually become more
complex
– More "perfect" -- as they
transformed into new species.
• He correctly pointed out that change
in species is linked to an organism’s
environment.
Linnaeus (1707-1778)
•
•
•
•
•
Swedish Botanist
Tried to Classify all of life on earth
Kingdoms, Classes, Orders, Genera, &
Species
He influenced Darwin’s Theories
Today we classify life by this order:
1. Kingdom (Keep)
2. Phylum (Pots)
3. Subphylum(Sparkling)
4. Class (Clean)
5. Order (or)
6. Family (Food)
7. Genus (gets)
8. Species (Stuck!)
Who Was Charles Darwin
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’s Observations
• Animals on the coast of
S. America:
– Resembled those on the
nearby islands
– Evolved differences
Or
– Descended w/
modification after
separating from a
common ancestor.
Left page 126: Figure 16-13 page 406
Today’s Activity: Darwin’s Great Voyage!!! IN 128 & 129
http://www.pbs.org/wgbh/evolution/educators/lessons/lesson2/act1.html
1. Plot Darwin’s 17 Stops on map IN: 166
2. Mark the date next to each stop
3. List one observation he made at each stop on the map
Evolution
(Part 2)
IN 169 & 171
Growth of Populations
• Darwin was influenced by Thomas Malthus
• He wrote:
Populations grow as much as the environment allows.
Evolution by Natural Selection
• The process of:
“Survival of the Fittest”
• Organisms that adapt
to their environment
survive while those
that do not adapt
disappear
• N.S. leads to
adaptations in a
population.
Label Paper:
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.
Darwin’s Ideas Updated
1) Change Within Populations
• N.S. causes the frequency of certain alleles in a population
to change over time.
2) Species Formation
• Under certain conditions, change within a species due to
reproductive isolation can lead to new species.
3) The Tempo of Evolution
• Gradualism is a process of evolution in which speciation
occurs gradually
• Punctuated Equilibrium is a process in which speciation
occurs rapidly between periods of little or no change.
Evidence of Evolution-Formation of Fossils
• Evidence of orderly change can be seen when fossils
are arranged according to their age.
Anatomy and Development
Vestigial Structures
• Reduced or nonfunctional vestigial structures
– hind limbs in whales
• provide evidence of an organism’s
evolutionary history.
Whale
Evolution
Video
Label Paper
1-5
http://www.pbs.org/wgbh/evolution/l
ibrary/03/4/l_034_05.html
5 min, 9 sec
Homologous Structures
• Structures in different organism that
indicate a shared ancestry
–include vertebrate forelimb.
Evidence of Evolution-Biological Molecules
Proteins
• MORE differences in amino acid sequences of
distantly related species
• LESS differences between species that are
more closely related.
Nucleic Acids (what is a nucleic acid???)
• MORE differences in DNA sequences b/t
distant relatives
• LESS differences between species that are
more closely related.
Examples of Evolution-Natural Selection at Work
1) Factors in Natural Selection
• Organisms w/traits helping them survive—
reproduce & pass genes.
2) Evolution of Antibiotic Resistance
• Experiments show that evolution through N.S. has
occurred within populations of antibiotic-resistant
bacteria
– Tuberculosis bacteria
3) Evolution in Darwin’s Finches
• Experiments show that evolution through N.S. has
occurred in beak size in Darwin’s Finches.
Formation of New Species
1) Speciation
• Speciation begins as a population adapts to its
environment.
2) Forming Subspecies
• Populations of the same species that differ
genetically b/c of adaptations to different living
conditions are called: subspecies.
• Newly formed subspecies are on the road towards
speciation.
3) Maintaining New Species
• Reproductive isolation through barriers keeps
species from breeding with one another.
Dichotomous Keys
• Tool used when new species is found
• Used to categorize different species based on
physical characteristics
• Classification is a way of separating a
large group of closely related organisms
into smaller subgroups.
• A Dichotomous Key is a listing of
characteristics, such as structure and
behavior, organized in such a way that an
organism can be identified or classified.