Transcript Notes without questions

Evolution and its Significance in the
Sciences
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Introduction and Revolutions
Historical context of evolution
Theory of Evolution:
mechanism of action
Origin and evolution of life
Evolution in 2015
Evolution in perspective of the
sciences
Introduction
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Two sides of the same coin: diversity and similarity
Theory of evolution
 Species evolve gradually over time
 Mechanism is natural selection
Gift to biology
 Unifying theory to explain diversity and similarity
 Theory underpinning all of the life sciences (ecology,
environmental sciences, genetic engineering, molecular
genetics, astrobiology, epidemic diseases, etc.)
Revolutions in the Sciences: A
Stroll through Time
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Notable revolutions
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Copernicus
Newton
Rutherford and Bohr
Vegener
Hubble
Darwin
Einstein
Watson and Crick
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Attributes of revolutions
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Challenged existing science/ideas with
heated debates
Challenged concept of spatial
dimension of natural world (e.g.,
universe, sun, flatness of Earth)
Challenged concept of the time
dimension of natural world (e.g.,
Hubble)
Challenged static/fixed view of natural
world
Many more revolutions to come …
but pattern consistent with the above
Evolution’s Place in the Life Science
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Theodosius Dobzhansky
“Nothing in biology makes sense
except in the light of evolution”
(1973)
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Genetics of inheritance (e.g., dominance and recessive traits, 3:1
ratio)
Medicine (e.g., mismatched diseases, transplant surgeries)
Ecology/environmental science (e.g., biodiversity)
Genetic engineering (e.g., mutations, excision/repair, aging)
Molecular genetics (e.g., genetic code, DNA, RNA)
Historical Context: Darwin
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Voyage of the Beagle on the HMS Beagle
(1831)
 Age 22 as naturalist (theologian)
 Convention at the time:
Static view of nature
 The Earth is young (1,000’s of years)
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Frame of reference for Darwin:
UK landscape and biodiversity as
bland as UK food
http://www.sciencenews.org/view/feature/id/40014/title/Darwins_Evolution
http://www.youtube.com/watch?v=rzjHA2eEsCI
Notable Observations by Darwin: HMS Beagle
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South American diversity of
landscapes and biota
 Brazilian rainforest
 Savannas of Argentina
 Dry deserts of Terra del
Fuego
 Towering Andes
mountains
Many structures with intuitive
value in the environment
(adaptations)
Seeding of idea: living systems
are not static but vary in
accordance with the
environment
What are These Adaptations?
Deserts
Tropical Rainforests
Grasslands - Lama
Bipedalism
Galapagos Islands and Darwin
Observations on the Galapagos
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Galapagos Islands: the seminal
event
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Volcanic islands off Ecuador
(500 km)
Fauna (birds, tortoises, etc.)
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Recognized lineage to species on S.
American mainland (e.g., finches,
tortoise), but different
Darwin’s Finches
Seeding of idea for a
mechanism
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Fauna arrived from mainland
Fauna diversified over time in
new environment of Galapagos
showing unique adaptations
Galapagos Tortoise
Darwin and Natural Selection
(1840’s)
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Idea No. 1: Organisms differ in their adaptations and
success in reproduction and therefore contribute
differently to future generations
Idea No. 2: Driving force for this differential success is
natural selection acting on the variability among
individuals
Product: evolution of adaptations enhancing success
(fitness)
Seminal text: On the Origin of Species (1859)
Note: genetics of inheritance unknown – Mendel in
1860’s
Heads: The Impressive Diversity
Hi! You look a bit better
today than last week!
Tails: The Impressive Similarity
100
95
82
Your DNA = 90% Pig!
70
55
14
Evolution: the Mechanism
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Populations and species evolve (hierarchy)
Kingdom
Family
Species
Populations
Individuals
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Evolution at the population level = microevolution
Evolution at the species level and above =
macroevolution
Both based on genetic changes over time
Do individuals evolve?
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Macroevolution: The Evolution of
the Horse (An Example)
Mechanism: Concept of Fitness
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Fitness = relative contribution of an individual to
the next generation
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Given two individuals of dissimilar physical size
(robust vs. small stature) and the smaller
individual with more offspring, which individual
is more fit in an evolutionary sense?
Summary of Mechanism (1940’s)
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Two cardinal tenets
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Natural selection (Darwin)
Individuals differ genetically in fitness (Mendel - decades later;
Watson and Crick – 100 years later!)
Result:
Gene pool of the next generation a consequence of the action of
natural selection on inherited variation at the level of
populations, with some alleles (i.e., traits) contributing more to
the next generation
Over time (1,000’s of years) evolution of new species (speciation)
… macroevolution
First Generation
Gene Pool
Second Generation
Gene Pool
N>100 Generations
Gene Pool
N>1000 Generations
Gene Pool
Gradual Speciation over Time
10,000 to 100,000’s Years
1 - 60 Million Years
Evidence for Evolution
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Fossil record in geological strata
Anatomy
Molecular genetics
Genetic relatedness
Ongoing examples of evolution
Fossil Evidence: Reptiles to Birds
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Examples
Evolution of the horse
(2 slides ago)
 Evolution of
humankind (bit later)
 Evolution of birds
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Macroevolution from
the dinosaur lineage!
Archaeopteryx
I am back!
Anatomical Similarities Among
Animals
Embryos
Molecular Genetics is the Same in
All Life Forms
ATP: Universal Energy
Currency
DNA: Universal
“information broker”
Remember: The Genetic
Code of Molecular Genetics
and Why Viruses are so
Successful?
Evidence: Genetic Relatedness:
HUMAN
CHIMPANZEE
GORILLA
CCAAGGTCACGACTACTCCAATTGTCACAACTGTTCCAACCGTCACGACTGTTGAACGA
CCAAGGTCACGACTACTCCAATTGTCACAACTGTTCCAACCGTCATGACTGTTGAACGA
CCAAGGTCACAACTACTCCAATTGTCACAACTGTTCCAACCGTCACGACTGTTGAACGA
Evolution
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Introduction
Historical context
Processes and mechanisms
Origin and evolution of life (see text)
Evolution in 2015
Virus - H1N1 (earlier lecture)
 Evolution of humans
 Evolution “as you sleep”
 Signs of recent human evolution
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Other perspectives on the evolution of life
Proto-Humans and First Humans:
Who, Where and When
http://www.archaeologyinfo.com/species.htm
Evolution of Humankind
“World’s oldest human-linked skeleton
found: ‘Ardi’ predates Lucy by a million
years, changes scientific view of origins”
Science News October 2009
“Ardi” - 4.5 MY ago (MYBP)
Evolutionary Tree of Hominids
(Bipedal Primates)
Thee and me! (<100,000 YBP)
Homo erectus (1 MYBP)
Is this
macroevolution or
microevolution?
Lucy (3 MYBP)
Ardipithecus ramidus
Ardi (4 MYBP)
Proto-Humans and First Humans:
Who, Where and When
Australopithecus afarensis
Homo habilis
“Lucy”
Ardipithecus ramidus
“Ardi”
Homo erectus
Homo sapiens
Homo neanderthalensis
and Homo sapiens
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Western and Central Eurasia
200,000 - 27,000 YBP
Co-existed with Homo sapiens
Theory: out-competed by
Homo sapiens
Recent theory: 1-4 % of
genome of Europeans from
Homo neanderthalensis
Recent Human Evolution: Ongoing
Microevolution
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Widespread evolutionary adaptations throughout the
human genome from last 10,000 years (hunter/gatherer)
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Genetic adaptations to diet
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Genetic adaptations to northern hemisphere migrations
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Diary products (lactose intolerance) in European races
Lighter skin color at higher latitudes (greater UV and vitamin D)
Changes in blood group chemistry (ABO)
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Role of epidemic diseases in human history (e.g., Bubonic plague)
 Each of you has ancestors (last 10,000 years) who survived multiple
plagues and passed “resistant” alleles to ancestors that conferred
“fitness” … 99% died due to epidemic diseases
Evolution in Action “As You Sleep”
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Antibiotic resistance in
microbes
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100+ antibiotics since 1940’s
(penicillium)
Effectiveness of antibiotics
MRSA (staph infection)
Resistance to insecticides in
cockroaches
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“Godzilla the Cockroach”
Microevolution or macroevolution?
Evolution and its Significance in the
Sciences
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Introduction and Revolutions
Historical context of evolution
Theory of Evolution:
mechanism of action
Origin and evolution of life
Evolution in 2015
Evolution in perspective of the
sciences
Other Theories and Beliefs of Life’s
Diversity and Life’s Similarity
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Lamarckian Theory of Evolution (1800’s)
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Creationism
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Inconsistent with scientific method
Intelligent Design (ID)
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Inconsistent with scientific method
Inconsistent with scientific method
Darwin’s Theory of Evolution
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Consistent with scientific method
Evolution in Perspective of the
Sciences
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Unifying theory in the life sciences (theory versus law?)
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Analogues in the sciences
Copernicus
Wegner
Bohr
Einstein
Newton
Rutherford
Hubble
Watson and Crick
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Darwin discovered the seminal processes in the life
sciences that explains (i) the breadth and diversity of life
in all its forms and (ii) at the same time life’s similarities
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Darwin’s theory = revolution in the life sciences
Evolution’s Place in the Life Science

Theodosius Dobzhansky
“Nothing in biology makes sense
except in the light of evolution”
(1973)





Genetics of inheritance (e.g., dominance and recessive traits, 3:1
ratio)
Medicine (e.g., mismatched diseases, transplant surgeries)
Ecology/environmental science (e.g., biodiversity)
Genetic engineering (e.g., mutations, excision/repair, aging)
Molecular genetics (e.g., genetic code, DNA; RNA)
Evolution and its Significance






Introduction
Historical context of evolution
Theory of Evolution:
mechanism of action
Origin and evolution of life
Evolution in 2015
Evolution in perspective of the
sciences