The Science of Biology

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The Science of Biology

• Chapter 1

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Biology

• What is it??
• What branches does it encompass?
• What exactly is cellular biology?
• What will we cover in this class?

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The Diversity of Life

• Biology is the study of living things
• Living things are diverse
• There are enough similarities among some living
  things that they can be grouped into the same
  kingdom
• Members of different kingdoms are usually very
  different from each other

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6 Kingdoms of Life

• Archae
• Bacteria
• Protista
• Fungi
• Plantae
• Animalia

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The Six Kingdoms of Life
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Properties of Life

• What qualifies something as living versus
  non-living?
• Consider these points
• complexity
• movement
• response to stimulation
• A life-defining property must be exclusive to
  living things

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Properties of Life

• All living things share five basic properties
• Cellular organization
• Metabolism
• Homeostasis
• Growth and Reproduction
• Heredity

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5 Basic Properties of Life

• 1. Cellular organization
• all living things are comprised of at least one
  cell
• 2. Metabolism
• all living things process energy which is used to
  power other processes
• 3. Homeostasis
• all living things maintain stable internal
  environments to optimize conditions for
  metabolism and other processes

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Basic Properties of Life

• 4. Growth and reproduction
• all organisms have the capacity for growth and
  reproduction
• 5. Heredity
• all organisms pass genetic information across
  generations from parents to offspring

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The Organization of Life

• Living things function and interact with each
  other on many levels
• The organization of life is a hierarchy of levels
  of increasing complexity
• cellular
• organismal
• populational

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Cellular Level

• Molecules
• Atoms combine to make molecules
• Organelles
• Structures within cells that perform dedicated
  functions
• Cells
• Membrane-bound untis

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Organismal Level

• Tissues
• Collection of cells that work together to perform
  a specialized function
• Organs
• Group of tissues formed together
• Organ systems
• group of related organs that work together

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Population Level

• Population
• Group of organisms of same species living
  together
• Species
• All populations of a specific kind of organism
• Community
• Populations of different organisms that interact
  with one another
• All species occupy that same area
• Ecosystem
• Created by communities that interact with each
  other

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Biological Themes

• The study of life is organized around general
  themes
• 5 biological themes emerge repeatedly at any
  hierarchical level of biological study
• Evolution
• Flow of energy
• Cooperation
• Structure determines function
• Homeostasis

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Tab. 1.1
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5 Biological Themes

• 1. Evolution
• evolution is genetic change in a species over
  time
• the mechanism for evolution is natural selection
• the diversity of life is explained by
  evolutionary processes

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5 Biological Themes

• 2. The Flow of Energy
• all living things require energy
• energy from the sun flows through the living
  world
• organisms acquire energy differently
• how much energy is available determines how many
  and what kinds of organisms can live together in
  an ecosystem

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5 Biological Themes

• 3. Cooperation
• as energy and other resources are limiting, many
  organisms have evolved cooperation as a means of
  survival
• symbiosis describes when two species live in
  direct contact

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5 Biological Themes

• 4. Structure Determines Function
• evolution favors structures that function in an
  adaptive manner
• many structures are specialized for a particular
  function
• the convergence of structure and function occurs
  at levels of the organizational hierarchy

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5 Biological Themes

• 5. Homeostasis
• homeostasis is a physiological condition of
  steady-state
• the internal environment of organisms is
  remarkably stable
• organisms act to control their internal
  environments so that the complex processes of
  metabolism function efficiently

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How Scientists Think

• Science is a process of investigation, using
  observation, experimentation, and reasoning
• There are different philosophical approaches to
  reasoning

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How Scientists Think

• Deductive reasoning uses general principles to
  explain specific observations
• This form of reasoning is common to many
  disciplines, including
• mathematical proofs
• politics
• computing

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How Scientists Think

• Inductive reasoning is the way of discovering
  general principles from examination of specific
  observations
• Scientists employ inductive reasoning by forming
  and testing possible explanations for specific
  observations
• These possible explanations are called hypotheses

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Deductive and inductive reasoning
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Stages of a Scientific Investigation

• Biology is a dynamic science with new ideas
  appearing and replacing old ones
• Scientists systematically conduct experiments to
  evaluate hypotheses about observed phenomena
• The scientific process has 6 steps
• Observation
• Hypothesis
• Predictions
• Testing
• Controls
• Conclusion

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Stages of a Scientific Investigation

• The scientific process has six stages
• 1. Observation
• science begins with careful observation of
  natural phenomena
• 2. Hypothesis
• scientists make an educated guess that might be
  true
• often scientists formulate multiple ideas about a
  phenomenon these are called alternative
  hypotheses

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Stages of a Scientific Investigation

• 3. Predictions
• if a hypothesis is correct, then specific
  consequences can be expected
• 4. Testing
• scientists conduct experiments to attempt to
  verify predictions made by hypotheses

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Stages of a Scientific Investigation

• 5. Controls
• experiments usually employ a parallel design
• scientists use a control to assess the influence
  of potential factors, called variables
• conditions stay the same in the control in
  comparison to the variable condition
• 6. Conclusion
• a hypothesis that has been tested and not
  rejected is tentatively accepted

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The scientific process
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Stages of a Scientific Investigation

• Scientific research involves analyzing data
  before reaching any conclusion
• Scientists must present their results carefully
  so that others can interpret them

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Theory and Certainty

• The term theory means different things to
  different audiences
• to scientists,
• a theory represents certainty and is a unifying
  explanation for a broad range of observations
• to the general public,
• a theory implies a lack of knowledge or guess

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Theory and Certainty

• Scientists acceptance of theory is provisional
• the possibility always remains that future
  evidence will cause a theory to be revised
• The process of science is not just
  trial-and-error but involves judgement and
  intuition

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Theory and Certainty

• science has limitations
• it is limited to organisms and processes that can
  be observed and measured
• supernatural and religious phenomena are beyond
  the scope of science
• there are also practical limits
• science cannot be relied upon to solve all
  problems

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Four Theories Unify Biology as a Science

• 1. The Cell Theory
• 2. The Gene Theory
• 3. The Theory of Heredity
• 4. The Theory of Evolution

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Classifying Lifes Diversity

• Scientists group organisms based on similarities
  into six kingdoms
• Each of the six kingdoms are assigned, on the
  basis of cell structure into one of three domains

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Classification of living things

• Taxonomy
• Identifying and classifying organisms according
  to specific criteria
• Each organism placed into a classification system
  

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Taxonomy

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• species

• King
• Phillip
• Came
• Over
• For
• Good
• spaghetti!!!

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Taxonomy

• Places organisms into groups called taxa
• 3 main domains
• Bacteria
• Archaea
• Eukaryotes
• 4 or 5 main kingdoms
• Monera
• Protista
• Fungi
• Plantae
• Animalia