Warm Up 2/1

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Warm Up 2/1 2/4

1. What is speciation? Give an example.
2. Which type of selection (directional,
   stabilizing, or disruptive) occurs when only the
   individuals at one end of a bell curve have high
   fitness?
3. What are the two sources of genetic variation?
   Which one primarily leads to inherited traits?

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HW

• Cladogram/ Classification WS
• Kingdoms of Life/ History of Life Chart
• Study for Quiz 3 (Chs 17 18)
• Work on packet! DUE test day (2/11 2/12)

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Today

• Quiz 2
• Ch 17 Notes
• Cladogram Activity
• Ch 18 Notes?

Turn your quiz in to the top box and work on
your HW
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Chapter 17
History of Life
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Evolution

• is change in the inherited traits of a population
  of organisms from one generation to the next
  (over VAST amounts of time). These changes are
  caused by a combination of three main processes
  variation, reproduction, and selection.

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• The Record of Life
• A. Earth is believed to be about 4.6 billion
  years old
• This age was determined from meteorites and moon
  rocks
• The earliest atmosphere contained H2 (hydrogen),
  CH4 (methane), NH3 (ammonia) and H2O (water
  vapor)

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• B. Fossils and Ancient Life
• A fossil is any evidence of previous life
• Ex amber, trace fossils, molds casts,
• imprints, tracks
• Fossils are usually found in sedimentary rocks
• Made from particles of sand, silt, and clay

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• The simplest dating method is called RELATIVE
  DATING, where the rocks closer to the surface are
  considered younger and the deeper layers are
  older.

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• C. Radioactive Dating
• Radiometric dating involves using radioactive
• isotopes to detect the amount of decay.
• Ex C14 dating

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• D. Geologic Time Scale
• A scale which is a kind of calendar that
• communicates all the events of the Earth since
  its formation is known as the Geologic Time
  Scale.

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II. Origin of Life

• E. Origin of Life
• Spontaneous generation - process by which life
  was thought to be produced from non-living
  matter.
• Fransesco Redi partially disproved this, but not
  until the experiments of Louis Pasteur was the
  theory of spontaneous generation totally
  disproved.

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• Biogenesis living organisms come only from
  other
• living organisms.
• The beginning of life is thought to have
  originated
• in the oceans from protocells. All the
  ingredients
• for life were present in the atmosphere and
• oceans.
• Primitive life forms are considered to most
  closely
• resemble Archaebacteria (most primitive kind)
• Cyanobacteria type of photosynthetic
• bacteria believed to have been the
• earliest group of organisms to evolve.

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cyanobacteria
stromatolites
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III. First Organic Molecules

• Atoms today do not assemble themselves
• Because atmospheric O2 is reactive and would
  destroy any organic molecules
• Bacterial organisms would consume for source of
  energy
• Early Earths atmosphere is more conducive to
  molecular assemblage
• Stanley Miller and Harold Urey questioned
  composition of early atmosphere

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Miller-Urey Experiment (Abiotic Synthesis) Made
Amino Acids (mostly GLYCINE)
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History of Life Timeline

• Earth formed 4.6 bya
• Earth cooled, LIQUID water is present 3.8 bya
• Organic molecules form, including simple carbs,
  lipids, proteins, and RNA 3.7 bya
• Prokaryotic cells arise 3.5 bya
• Photosynthesis arises, oxygen added to atmosphere
  2.8 bya
• Eukaryotic cells arise 2.1 bya
• Sexual reproduction and multicellular organisms
  arise 1.5 bya
• Plants colonize land 1.2 bya

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Important Milestones

• Photosynthesis releases O2 into the atmosphere
• Kills all anaerobic organisms exposed to O2 Leads
  to aerobic processes being selected for
  (precursor to cellular respiration)

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Important Milestones

• Prokaryotic ? eukaryotic
• Provided compartmentalization for the cell, more
  diverse functionality
• Endosymbiotic theory eukaryotes were created
  when one prokaryote engulfed another but did not
  digest it

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Important Milestones

• Sexual Reproduction
• Leads to more genetic diversity in a population,
  increases long-term survival of a species (gene
  shuffling)
• Multicellular organisms
• Bigger organisms
• Cell differentiation (driven by gene regulation)
• Not constrained to limits of simple diffusion

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Patterns of Evolution WS

• Finish as HW