Genetics and Evolution Ch. 5

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Genetics and Evolution Ch. 5

• SelectionNatural vs. artificialFitnessGalapagos
  FinchDirectional, Stabilizing, Disruptive
  SelectionPolymorphism several forms of a
  species in same habitat
• Microevolution vs. MacroevolutionMicroevolution
  change in allele frequencyMacroevolution
  formation of new species

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Field Assistants
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Chesapeake Bay Retrievers

Newfoundland
Water Spaniel
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English Peppered Moth Example
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English Peppered Moth Example
Before industrial revolution After industrial
revolution
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Darwins 2 Major Ideas

• Variation within an species
• (organisms of the same species do not look
  exactly alike)
• Not all the offspring produced survive(there is
  a struggle for existence)

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Genetics

• Chromosomes are made of DNA
• DNA holds genes
• Different forms of a gene allelei.e. brown vs.
  blue eyes
• Dominant alleles that cover other alleles
• i.e. brown eye allele B
• Recessive alleles covered up by other alleles
• i.e. blue eye allele b
• How many alleles for each trait???

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2 alleles for each trait!

• Homozygous your 2 alleles are the samei.e. BB
  (what color eyes?)
• bb (what color eyes?)
• Heterozygous your 2 alleles are differenti.e.
  Bb (what color eyes?)
• Genotype genetic make-up, what alleles you have
• Phenotype appearance, what it looks like

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Macroevolution formation of new species

• Allopatric Speciation formation of new species
  due to geographic (physical) barrier
• Sympatric Speciation formation of new species
  due to genetic mutation or reproductive isolation
  (although they occur together)
• Adaptive Radiation formation of new species due
  to new opportunities (niches)i.e. islands

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Origin of Life

• Big Bang Theory formation of the universe (20
  billion years agobya)
• Earth formed 4.5 bya
• First atmosphere hydrogen, water vapor,carbon
  monoxide, carbon
• dioxide,nitrogen, methane, ammonia
• What is missing??
• FREE OXYGEN

Crust
Core
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Miller Experiment
Inorganic Molecules
Organic Molecules
Electricity
(carbohydratessugars, Lipidsfats,
proteins, DNA)
(hydrogen, water vapor, CO2, CO, nitrogen,
ammonia)
No electricity 3.5 bya, so what could cause a
spark?
First life on earth 3.5 bya, prokaryotic cells
Prokaryotic cells
Eukaryotic cells (1.5 bya)
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Miller Experiment the origin of life
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Plate Tectonics
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Plate Tectonics

• What is it called, when plates move against each
  other?
• An earthquake!
• What is it called where the plates meet?
• Earthquake fault
• What earthquake fault do we live near?
• San Andreas Fault
• Earthquake Kit??

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Continental Drift
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Continental Drift

• Pangaea
• continents in one land mass

Gondwana Africa, S. America Australia,
Antarctica, India
Laurasia N. America Europe Asia
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• Quaternary modern man
• Tertiary radiation of mammals___________________
  _______________
• Cretaceous mass extinction of dinosaurs
• Jurassic dinosaurs dominant
• Triassic first dinosaurs
• __________________________________
• Permian mass extinction of marine life
• Carboniferous first reptiles
• Devonian first amphibians
• Ordovician first fishes
• Cambrian marine life abundant
• Precambrian first life on earth

Cenozoic
Mesozoic
Paleozoic
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Past vs. Current Extinction

• Past
• Slow
• Natural Causes
• Extinction with
• replacement

• Current
• Fast
• Human Causes
• Extinction without
• replacement