Download What is Evolution?

Terminology
Variation- different individuals in a population have different
characteristics
Heritable characteristics- the variation in characteristics that can
be inherited by offspring
Fitness-the ability to survive and produce offspring which are capable
of reproducing
Adaptation- a characteristic that increases an individual’s fitness
Evolution by Natural Selection- heritable adaptive characteristics
become more common in a population over many generations
What is
Evolution?
Simply put: all of the changes that have transformed life
over an immense time
A biological history of life on Earth!
Phylogenic Tree
All life on Earth is united
by evolutionary history;
we are all evolutionary
cousins — twigs on the
tree of life.
Phylogenetic Systematics
is the formal name for the
field within biology that
reconstructs evolutionary
history and studies the
patterns of relationships
among organisms.
Terms to discuss before we start:
Speciation
Speciation- formation of a new species through evolution
Adaptation
Adaptation- a feature that allows an organism to better survive
in its environment
Fitness
Fitness- measure of the ability to survive and produce more
offspring (compared to other members in the
population in the same environment)
A little history…
• Pretend you are living in the 1600s. Think about
the technology that is available. How much do you
know/understand about the world around you?
• Theories moving through your village:
– Species are fixed and permanent. They do not change.
– Earth is less than 10,000 years old and hasn’t changed
much.
What is this? A fossil? Hmmm…
• Mid 1700s: Georges Buffon studies fossils
– “I think Earth is older than 10,000 years…”
– “These fossils resemble animals that are alive
today…but they aren’t exactly the same…”
•
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Early 1800s: Jean Baptist Lamarck
“I think I know why…
…life evolves (or changes).
Species are not permanent. They adapt.
Jean Baptiste Lamarck
1744-1829
The Principle of Use and Disuse:
New structures developed in an
organism during the course of
evolution because they were
needed and unused structures
were lost.
Inheritance of Acquired
Characteristics:
Characteristics gained during a lifetime
were passed onto offspring.
What is wrong with this theory?
CHARLES DARWIN
(1809-1882)
• Sailed on the H.M.S Beagle- spent 5 years
collecting data
• Extensive research on the Galapagos
Islands (particularly with finches)
• Theory of Natural Selection
• Wrote The Origin of Species
Well-known geologist: proposed that
gradual and observable geologic
processes (erosion) can explain
Earth’s physical features
Lyell's work formed the foundation
of belief in a universe billions of
years old.
Sir Charles Lyell His work heavily influenced Charles
1797 -1875
Darwin.
Darwin's concept of gradual
evolution lacked an acceptable time
frame until he embraced Lyell's oldearth theories.
Thomas Malthus (1766-1834)
Charles Darwin credits Thomas
Malthus in formulating his theory
of Natural Selection.
Malthus said: populations can grow much faster
than the rate at which supplies of food and other
resources can be produced.
DARWIN’S THEORY
2 main points:
1.Descent with Modification
-Species of organisms living on Earth today descended
from ancestral species
= diversity of life!
http://homestudy.ihea.com/wildlifeID/043jackrabbit.htm
http://www.animalspot.net/snowshoe-hare.html
DARWIN’S THEORY continued…
2. Natural Selection
- in an environment, some individuals with
inherited characteristics are better suited to
the environment and leave more offspring
= “most fit”
http://en.wikipedia.org/wiki/Peppered_moth
http://en.wikipedia.org/wiki/Peppered_moth
Example of natural selection:
2 color beetles: green & brown
Green beetles are eaten by birds more
often because they are visible in the dirt.
Brown reproduce and
thrive, green goes extinct.
Natural Selection Principles:
1. Genetic variation exists among individuals.
2. Reproductive ability of species causes populations to
increase.
3. Organisms compete for resources.
4. Offspring with most favorable traits most likely to
survive.
EVIDENCE OF EVOLUTION
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Geologic record
Fossils
Comparative anatomy (homologous vs. analogous)
Vestigial structures
Comparative Embryology
Comparative Cytology
Macromolecules
Geological Record:
Through radioactive dating the
oldest rocks in the earth’s crust, the age of the earth is
4.5 – 5 billion years old.
http://video.pbs.org/video/1978170520/
Fossils:
Traces of once living organisms. Fossils found in
the upper strata of sedimentary rock are younger than those
Found in the lower strata
In Rock
Top 15 Clones
http://www.youtube.com/watch?v=qJ9Syd3GqQc
In Amber
Petrifaction 
In Ice
http://www.youtube.com/watch?v=JZ7f-C83X2Y
Comparative Anatomy:
Homologous Structures
Same structure, different function
Evidence that
these organisms
evolved from
the same
ancestor
Human
Cat
Whale
Bat
Analogous Structures
different structure BUT same function
Butterfly Wing
Bat Wing
Both fly, but did NOT evolve from same
ancestor
Vestigial Structures:
Structures in an organism through
evolution have been lost or reduced in size because they were
no longer necessary trait for survival.
Comparative Embryology
Comparative Cytology
Comparative Biochemistry- The chemical composition of insulin
Found in sheep is almost identical to the insulin found in humans.
Evidence of common ancestry.
Embryology
• Same group of embryonic cells
develop in same order and in
similar patterns in all vertebrates.
• Tail, pharyngeal
pouches, buds
Macromolecules
• DNA base sequence similarities
• The more similar the biochemistry, the
more closely related the organisms are.
• Human and chimp hemoglobin differs by
one amino acid.
Patterns of Evolution
-Coevolution
-Convergent Evolution
-Divergent Evolution
Coevolution
Change of 2 or more species evolve in response to changes in each
other- dependent on each other
= selective pressures
• Predators and prey
• Parasites and hosts
• Plants and pollinators
EXAMPLE: hummingbird feeds on nectar of flower, slender
beak, pollen gets stuck on birds face: flowers are light in color,
fruity odor
**Find another example of coevolution. Be specific in the
organisms you list.
Convergent Evolution
• Evolve similar traits, but are not related; when
environment selects similar phenotypes
Example:
• sharks and porpoises - not related, but look
similar
**Would convergent evolution result in homologous
structure or analogous structures? Explain.
Divergent Evolution
• Closely related species evolve in different
directions, become increasingly different
• (may end up in new species)
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Geographic isolation
Reproductive isolation (i.e Galapagos finches)
Adaptive radiation
Artificial selection (i.e. domestic dogs)
All members of the species Brassica oleracea
Same species?
Spilogale putorius
Spilogale gracilis
What is a “species”?
• Population, or group of populations, whose
members have the ability to breed with one another
in nature and produce fertile offspring
Microevolution
Evolution involving small-scale changes,
Generation  Generation changes
i.e. within the species level, occurring over a short
period of time that results in the formation of new
subspecies.
Macroevolution
A process thought to produce
relatively large (macro)
evolutionary change within
biological organisms.
Over long periods of time.
Can’t be observed directly.
Evident in the fossil record.
New species.
Extinction.
Evolution of features.
New species = More diversity
• What is biodiversity?
• Why is biodiversity important?
Geographic Isolation
A body of water or mountain range separates a population of a species
resulting in evolution of new species.
Reproductive Isolation
Some sort of barrier that keeps two species from interbreeding.
-Timing (i.e. different mating seasons)
-Behavior (i.e. courtship behaviors)
-Habitat (i.e. lake bottom vs. surface)
-Other (i.e. incompatible reproductive structures; producing
infertile offspring)
Adaptive Radiation
Species adapt to different environments and result in diverse
separate species
-Hawaiian Islands are a good example
- about 4,000 km from nearest continent
-each island is physically diverse
- due to differences in altitudes and rainfall
-there are many native species there that are found nowhere
else in the world
Asio flammeus sandwichensis
Lasiurus cinereus semotus
– Artificial selection
• Breeders developing many varieties of
domesticated animals in a few generations
• Plant varieties, such as kale and broccoli,
developed from wild cabbage
Artificial
selection in
chickens:
“Big Bird”
Artificial
selection in
Brassica
oleracea
Antibiotic Resistance
Molecular biology
• Biochemical pathways
• Genetics:Did humans evolve…..??????
Microbiology: TB and antibiotic resistance…….
Artificial Selection Activity
1. Use the stick worm activity to write your own description of
Natural Selection to show me that you understand how variation,
adaptation, selective forces and reproduction play a role in natural
selection and thus evolution.
2. Write a paragraph describing how artificial selection supports the
theory of evolution. Be sure to use and underline the VIST Terms
(variation, inheritance, selection, time) in explanation.
3. Provide 3 examples of how artificial selection was used (at least 1
plant and 1 animal) to create a current product you use/consume or
see in every day life. Do these selected organisms have economical
advantage? Support with evidence.
4. In your own words write a concise definition for evolution.