Chp' 1: Biology Today

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Chp. 1 Biology Today
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BiologyWhat Is It?

• Study of life
• Molecular to global
• Medicine
• Ecology
• Agriculture

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The Many Levels of Life

• Cellular level
• Ecosystem level

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Two Main Kinds of Cells

• Prokaryotic
• No nucleus
• Simple, small
• Bacteria
• Eukaryotic
• True nucleus
• Many organelles
• Plants, animals, fungi, protists

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Life Is Diverse

• How many species have been named?
• How many species are there?

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Taxonomy

• Naming classifying species
• Carolus Linnaeus
• Domain highest level
  of classification
• 3 Domains
• Bacteria (prokaryotes)
• Archaea (prokaryotes)
• Eukarya (eukaryotes)
• 4 Kingdoms

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Three Domains of Life
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3 Domains 4 Kingdoms
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Taxonomy An Example

• Human classification scheme

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Evolution Biologys Unifying Theme

• Change over long periods of time
• Characteristics organisms
• Populations evolve (not individuals)
• Who came up with the idea?

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Evolution How Does It Work?

• Lamarck
• Adaptive evolution
• Wrong!!!

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Evolution How Does It Work?

• Natural selection
• Process that determines which individuals within
  a species will reproduce more effectively
• Charles Darwin

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Charles Darwin

• Naturalist
• Sailed around the world HMS Beagle
• Galapagos Islands Darwins finches
• 1859 The Origin of Species

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Natural Selection

• Five main ideas
• Individuals within a species vary
• Typically more offspring produced than survive
• Excess individuals results in a struggle for
  survival
• Variation gives some an advantage
• Over time, percentage of individuals with
  favorable variations will increase those with
  unfavorable variations will decrease

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Darwins Inescapable Conclusion

• Overproduction struggle for existence
• Individual variation
• Conclusion unequal reproductive success

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Natural Selection At Work
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Artificial Selection
Weve been doing it for years!
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Results of Evolution

• Speciation new species produced
• Extinction (natural) loss of a species

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Evolutionary Tree
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Evolution Misconceptions

• Survival of the fittest survival of the
  strongest
• Evolution has a master plan

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The Process Of Science

• How do we do science???
• Observation(s)
• Question research
• Hypothesis
• Prediction
• Experimentcontrol
• Conclusion
• Retest
• Share findings
• Does not have to be done in order!

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A Simple Experiment
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Science At Work!

• Mimicry in snakes
• Observations
• Poisonous coral
  snakes are brightly colored
• Scarlet kingsnakes mimic these colors
• Question Why mimic these colors?
• Hypothesis Mimicry of coral snakes protects
  kingsnake from predators

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Science At Work!

• Prediction If predators confuse kingsnakes with
  coral snakes, then predators should attack fewer
  colored snakes than brown snakes
• Experiment Brown snakes vs. colored snakes

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Science At Work!
Results

• Conclusion Brown snakes attacked more
  frequently ---gt hypothesis supported

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Theories in Biology

• Hold a lot of weight
• Tested over time
• Supported by abundant evidence
• Accepted to be true
• Laws more prevalent in other sciences

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Tour of The HMS Beagle
Back
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Darwins Finches
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