Introduction to Biology Prologue: The Molecular Perspective Bio 391 Palmé Why should you care? What...
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Transcript of Introduction to Biology Prologue: The Molecular Perspective Bio 391 Palmé Why should you care? What...
Introduction to Biology
Prologue: The Molecular Perspective
Bio 391
Palmé
Why should you care?What is Science?What is Biology?What is Life?Evolution – What does this major theory say?
Biology in Your World
Biology is believed to be the most influential science of the 21st century
What are some of the ways biology impacts your life now?
In the future?
But, just because we can…should we?
Ethics and BiologyUsing Knowledge Wisely
Ethics – a system of moral principles to distinguish right from wrong What are your ethics based upon?
Public Policy – laws and regulations that govern how science is applied What role do you play in deciding public policy?
Ethics in Biology
Stem cells in research/treatment Prenatal genetic testing for diseases Genetic testing for susceptibility Biotechnology for altering self or offspring Genetically modified (GM) food What are some others?
Science as a way of Knowing
If you are a thinker, you question things you observe and may not understand and you try to find an answer. There are many ways to find these answers. If you are a scientific thinker you find your answer using the scientific method.
Example: Why is the sky blue?
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. It is concerned with the natural world, not the supernatural world This is pseudoscience
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
Example…
The Scientific Process Analyzes problems through TESTS
Hypothesis – 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.
Laws – widely accepted and repeatedly tested theories Can you name any?
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”
What is Life?A fundamental scientific question
What is the difference between you and your desk?
Is a fallen apple alive?
“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
How did life begin?
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!
Early Life Everything is just a bunch of atoms Life began in the sea Oxygen was not used for respiration
How did Oxygen become plentiful?
Evolutionary tree Classification system
Classification
Biologists group organisms to show similarities and proposed relationships. Based on the Theory of Evolution Descent with Modification
Classification systems change with expanding knowledge about new and well-known organisms
Kingdoms and Domains
Three Domain System (based on rRNA evidence)
Six Kingdom System (based on rRNA evidence)
Traditional Five Kingdom System
Bacteria Archaea Eukarya
Bacteria Archaea PlantaeProtista Fungi Animalia
Monera Protista Plantae Fungi Animalia
Humans = .00009%
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
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?
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.
Recap How do the 8 characteristics of life apply
to you? What Kingdom do we belong to? What is a theory? What is ethics?
A Mechanism for Evolution: Science at Work
P.5: The formulation of a Theory
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.”
Was Lamarck right?
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 (1797-1875) and James Hutton, who proposed uniformitarianism Geological forces existing in the past are similar to the
forces of today and in the future
Proposed the mechanism of evolution Natural Selection
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
Is this how Evolution works?
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?
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.
Was Darwin Right?
________ 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?
Recap What is the difference between Lamarck
and Darwin’s ideas? (use an example) Give an example of an adaptation What is uniformitarianism? What makes a theory different than a
hypothesis?
Other Accepted Theories
Cell Theory: All organisms are composed of one or more cells, and those cells have arisen from pre-existing cells
Gene Theory: The Central Dogma that
DNA RNA proteins. DNA is inherited and expressed as protein traits.
Homeostasis: maintenance of a constant/dynamic equilibrium