Outline

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Outline

• Defining Life - Emergent Properties
• Materials and Energy
• Reproduction and Development
• Adaptations and Natural Selection
• Biosphere Organization
• Human Population
• Biodiversity
• Classification
• The Scientific Method

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Defining Life (1)

• Living things vs. nonliving objects
• Comprised of the same chemical elements
• Obey the same physical and chemical laws
• The cell is the smallest, most basic unit of all
  life
• Familiar organisms are multicellular
• Some cells independent single-celled organisms

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Defining Life
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Defining Life (2)

• Emergent Properties Biological organization
• Levels range from extreme micro to global
• Each level up
• More complex than preceding level
• Properties
• A superset of preceding levels properties
• Emerge from interactions between components

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Levels of Biological Organization
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Living ThingsAcquire Process Food

• Energy - the capacity to do work
• The sun
• Ultimate source of energy for nearly all life on
  Earth
• Drives photosynthesis
• Metabolism - all the chemical reactions in a cell
• Homeostasis - Maintenance of internal conditions
  within certain boundaries

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Acquiring Nutrients
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Living ThingsRespond to Stimuli

• Living things detect changes in environment
• Response often involves movement
• Vulture can detect and find carrion a mile away
• Monarch butterfly senses fall and migrates south
• Microroganisms follow light or chemicals
• Even leaves of plants follow sun
• Responses collectively constitute behavior

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Living ThingsReproduce and Develop

• Organisms live and die
• Must reproduce to maintain population
• Multicellular organisms
• Begins with union of sperm and egg
• Developmental instructions encoded in genes
• Composed of DNA
• Long spiral molecule in chromosomes

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Rockhopper Penguins Offspring
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Living ThingsAdapt to Change

• Adaptation
• Any modification that makes an organism more
  suited to its way of life
• Organisms, become modified over time
• However, organisms very similar at basic level
• Suggests living things descended from same
  ancestor
• Descent with modification - Evolution
• Caused by natural selection

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Organization of the Biosphere

• Population - Members of a species within an area
• Community - A local collection of interacting
  populations
• Ecosystem - The communities in an area considered
  with their physical environment
• How chemicals are cycled and re-used by organisms
• How energy flows, from photosynthetic plants to
  top predators

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Terrestrial EcosystemsA Grassland
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Marine EcosystemsA Coral Reef
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Human Populations

• Ecosystems negatively impacted by human
  populations
• Destroyed for agriculture, housing, industry,
  etc.
• Degraded and destabilized by pollution
• However, humans depend upon healthy ecosystems
  for
• Food
• Medicines
• Raw materials
• Other ecosystem processes

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Biodiversity

• Biodiversity
• The total number of species (est. 15 million)
• The variability of their genes, and
• The ecosystems in which they live
• Extinction
• The death of the last member of a species
• Estimates of 400 species/day lost worldwide

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Classification

• Taxonomy
• The rules for identifying and classifying
  organisms
• Hierarchical levels (taxa) based on hypothesized
  evolutionary relationships
• Levels are, from least inclusive to most
  inclusive
• Species, genus, family, order, class, phylum,
  kingdom, and domain
• A level usually includes more species than the
  level below it, and fewer species than the one
  above it

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Levels of Classification
Corn
Human
Taxon
Eukarya
Eukarya
Domain
Plantae
Animalia
Kingdom
Anthophyta
Chordata
Phylum
Liliopsida
Mammalia
Class
Commelinales
Primates
Order
Poacae
Hominidae
Family
Zea
Homo
Genus
Z. mays
H. sapiens
Species
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Domains

• Bacteria
• Microscopic unicellular prokaryotes
• Archaea
• Bacteria-like unicellular prokaryotes
• Extreme aquatic environments
• Eukarya
• Eukaryotes Familiar organisms

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DomainsThe Archaea
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DomainsThe Bacteria
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Kingdoms

• Archaea Kingdoms still being worked out
• Bacteria - Kingdoms still being worked out
• Eukarya
• Kingdom Protista
• Kingdom Fungi
• Kingdom Plantae
• Kingdom Animalia

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DomainsThe Eukaryote Kingdoms
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Scientific Names

• Binomial nomenclature (two-word namess)
• Universal
• Latin-based
• First word represents genus of organism
• Second word is specific epithet of a species
  within the genus
• Always Italicized asa Genus species (Homo
  sapiens)
• Genus may occur alone (Homo), but not specific
  epithet

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The Scientific MethodObservation and Hypothesis

• Begins with observation
• Scientists use their five senses
• Instruments can extend the range of senses
• Hypothesis
• A tentative explanation for what was observed
• Developed through inductively reasoning from
  specific to general

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The Scientific MethodA Flow Diagram
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The Scientific MethodExperimentation

• Experimentation
• Purpose is to challenge the hypothesis
• Designed through deductively reasoning from
  general to specific
• Often divides subjects into a control group and
  an experimental group
• Predicts how groups should differ if hypothesis
  is valid
• If prediction happens, hypothesis is unchallenged
• If not, hypothesis is unsupportable

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The Scientific MethodResults

• Results
• Observable, objective results from an experiment
• Strength of the data expressed in probabilities
• The probability that random variation could have
  caused the results
• Low probability (less than 5) is good
• Higher probabilities make it difficult to dismiss
  random chance as the sole cause of the results

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The Scientific MethodConclusion and Review

• The results are analyzed and interpreted
• Conclusions are what the scientist thinks caused
  the results
• Findings must be reported in scientific journals
• Peers review the findings and the conclusions
• Other scientists then attempt to duplicate or
  dismiss the published findings

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Scientific Theory

• Scientific Theory
• Joins together two or more related hypotheses
• Supported by broad range of observations,
  experiments, and data
• Scientific Principle / Law
• Widely accepted set of theories
• No serious challenges to validity

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Controlled ExperimentsThe Variables

• Experimental (Independent) variable
• Applied one way to experimental group
• Applied a different way to control group
• Response (dependent) variable
• Variable that is measured to generate data
• Expected to yield different results in control
  versus experimental groups

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Controlled ExperimentsObservation Hypotheses

• Observations
• Nitrate fertilizers boost grain crops, but may
  damage soils
• When grain crops are rotated with pigeon pea it
  adds natural nitrogen
• Hypothesis
• Pigeon pea rotation will boost crop production as
  much as nitrates
• Pigeon pea rotation will NOT damage soils

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Root Nodules
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Controlled ExperimentsExperimental Design

• Experimental Design
• Control Group
• Winter wheat planted in pots without fertilizer
• Experimental Groups
• 1-Winter wheat planted in pots with 45 kg/ha
  nitrate
• 2-Winter wheat planted in pots with 90 kg/ha
  nitrate
• 3-Winter wheat planted in pots that had grown a
  crop of pigeon peas
• All groups treated identically except for above

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Crop Rotation Study
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Controlled ExperimentsResults

• Experimental Prediction
• Wheat production following pigeon pea rotation
  will be equal or better than following nitrate
  fertilizer
• Results
• 45 kg/ha produced slightly better than controls
• 90 kg/ha produced nearly twice as much as
  controls
• Pigeon pea rotation did not produce as much as
  the controls

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Controlled ExperimentsConclusion Revision

• Conclusion
• Research hypothesis was not supported by results
• However, research hypothesis was not proven false
  by negative results
• Revised experiment
• Grow wheat in same pots for several generations
• Look for soil damage in nitrate pots and improved
  production in pigeon pea pots

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Controlled ExperimentsRevised Results
Conclusion

• Results
• After second year
• Production following nitrates declined
• Production following pigeon pea rotation was
  greatest of all
• After third year
• Pigeon pea rotation produced 4X as much as
  controls
• Revised conclusions
• Research hypothesis supported
• Pigeon pea rotation should be recommended over
  nitrates

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A Field Study
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Review

• Defining Life - Emergent Properties
• Materials and Energy
• Reproduction and Development
• Adaptations and Natural Selection
• Biosphere Organization
• Human Population
• Biodiversity
• Classification
• The Scientific Method

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