Introduction to Biology Prologue: The Molecular Perspective Prologue: Packet #1.
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Introduction to Biology
Prologue: The Molecular Perspective
Prologue: Packet #1
Biology in Your World
Biology is believed to be the most influential Biology is believed to be the most influential science of the 21science of the 21stst century century
Cancer cures? Genetic engineering / counseling / cloning Stem cells
But, just because we can…should we?
Prologue: Packet #1
Ethics and BiologyUsing Knowledge Wisely
Ethics – a system of moral principles to distinguish right from wrongWhat are your ethics based upon?
Public Policy – laws and regulations that govern how science is appliedWhat role do you play in deciding public policy?
Example
http://www.csmonitor.com/USA/Justice/2011/0429/Stem-cell-research-Court-gives-Obama-a-victory-but-policy-still-on-trial
Prologue: Packet #1
What is science? An organized way of using evidence to learn about the
natural world
The body of knowledge that scientists have accumulated over time
It is not based on belief or faith, magic, or legend but on actual evidence. Pseudoscience – associating real science to some supernatural
occurrence or pattern without evidence EXs: Palm reading, Astrology, Alchemy, Intelligent Design
Daily Horoscope
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Important Scientific Skills
Observing – process of gathering information using your senses in a careful, orderly way
Inferencing – making a logical interpretation based on prior knowledge or experience Did not eyewitness
Example… Baby was asleep upstairs – heard a loud thump – heard crying What inferences can we make?
http://www.philtulga.com/Riddles.html - Inferencing game
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The Scientific Process Analyzes problems through TESTING
Hypothesis – possible explanation of observations that are testable through experimentation or observation. “If….then”
Theory – a repeatedly tested hypothesis that accurately explains observations and predicts future occurrences. Cell theory, gene theory
Laws – widely accepted and repeatedly tested theories Newton’s Law, Thermodynamics
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Good Scientists….
Are skeptics: they question existing ideas and new hypotheses
Are open-minded: they are always willing to consider new ideas when evidence demands it
Rely on basic natural laws: they understand that the universe functions as a system of interacting processes
Repeat experiments: through an immense amount of research a certain hypothesis might become so well-supported that scientists consider it a theory
Keep up with new knowledge gained through research: they continually revise and re-evaluate ideas. NOTHING IS “FACT”
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What is Life?A fundamental scientific question
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“Life is Organized”
Atoms
C,H,O,N,P,S
Molecules
Organelles
Cells
Tissues
Organs
Organ Systems
Organism
Species
Population
Community
Ecosystem
Biome
Ex: Tundra, desert, temperate forest
Biosphere
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Smallest / most simple
Largest / most complex
How did life begin?An Idea
The Oparin-Haldane Hypothesis (1920s) Verified by Miller-Urey (1953) Built an apparatus to mimic early earth:
Reducing atmosphere;
methane, ammonia, hydrogen Boiled water, shocked it, cooled it Atoms bumped together &
formed hydrocarbons and amino acids!
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Living things…
Are made up of units called CELLS Are based on a universal GENETIC code REPRODUCE GROW and DEVELOP CHANGE over time (evolve) Obtain & Use Materials and ENERGY Maintain an Internal BALANCE
= homeostasis RESPOND to their Environment
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All organisms are uniquely
adapted for their environments.
Scientists know that over long periods of time organisms have changed or adapted to better survive in their environments.
They call this slow process of change evolution.
Natural Selection: Those best adapted survive and reproduce.
EVOLVEWhy does a duck have a rounded bill and a heron have a long pointed bill?
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Life BEGINS…
CELLS with DNA are passed on through
REPRODUCTION
An organism GROWS and DEVELOPS to an age where it can REPRODUCE.
Over time, subtle changes are introduced through mutation of DNA. These changes are selected for, leading to EVOLUTION of a population.
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A Mechanism for A Mechanism for Evolution: Science at Evolution: Science at
WorkWork
The formulation of a Theory
An Example of The Scientific Process
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Jean Baptiste Lamarck (1744 – 1829)
Organisms change over time by using or not using certain features. These acquired characteristics are then passed onto offspring
“Use or Disuse” “If a male and a female increase the size of their
muscles through weight training, then their children will be born with large muscles.”
Mr. Palmé as a 5 yr
old
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Was Lamarck right?
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Charles Darwin (1809 – 1882) A naturalist on a 5-year voyage of the Beagle around the
world Observed numerous, diverse organisms
Influenced by the geologists, Charles Lyell and James Hutton, who proposed uniformitarianism (everything in the
universe acts under the same laws of physics) Geological forces existing in the past are similar to the
forces of today and in the future
Proposed the mechanism of evolution Natural Selection
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Theory of Natural Selection
Organism best suited (specific traits/characteristics) for the environment would survive and reproduce.
The suitable traits would be passed on to their offspring.
The specific traits or characteristics are called adaptations
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Is this how Evolution works?
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Survival of the Fittest
Thomas Malthus (economist) noticed that species numbers exceed food supply
In order to pass on characteristics, an organism must eat enough to live to reproduce. Ultimately, the only organisms alive are those with beneficial
adaptations
What are some adaptations?
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Darwin’s Predictions If organisms with favorable variations are most likely to survive
and reproduce, then those organisms with unfavorable variations would be less successful at reproduction and die out.
If organisms with those favorable adaptations become so different from members of the original species that they can no longer reproduce together, then a new species may have evolved.
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Was Darwin Right?
Whose to say but… Experiments repeatedly show same results
Descent with Modification – related organisms share a common ancestor The greater the similarity between two groups of
organisms, the closer their relationship How is this studied today?
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