Bio 204 Introduction to Evolution, Ecology, and Biodiversity

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Bio 204Introduction to Evolution, Ecology, and
Biodiversity

• Alejandro Acevedo
• Janice Lapsansky
• Winter 2005

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Biology The Science of Life

• Why do we study life?
• How do we study life?
• a matter of scale - - size and time
• Which ideas/concepts guide biologists?

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Organizing the Diversity of Life

• Taxonomy
• the process of naming and classifying organisms
• Three Domains
• Bacteria
• Archaea
• Eukarya
• Five Kingdoms (see figure on next slide)

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Themes in the Study of Life

• Levels of organization
• The difference between living and non-living is
  one of degree, not kind.
• What does this mean?
• Cells are an organisms basic unit of structure
  and function
• What is a cell?
• List one example that illustrates the
  interdependence of structure and function.

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Fig. 1.4
What are some of the main differences between
prokaryotic and eukaryotic cells?
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Fig. 1.2 Levels of Organization
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Themes in the Study of Life

• Emergent Properties
• Each level of biological organization has
  emergent properties that result from the
  interaction of structural and functional
  components
• These emergent properties include those
  characteristics we often use to describe life
  metabolism, growth and development, homeostasis,
  reproduction, and evolutionary adaptation.

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Respond to the following statement Living
things are chemical and physical machines.

• Is your current view more in line with holism or
  reductionism?

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Themes in the Study of Life

• Homeostasis
• the maintenance of a dynamic equilibrium
• Why does an organisms internal environment
  change?
• Why is a stable internal environment important to
  an organisms survival? Describe an example.
• Most homeostatic mechanisms operate as negative
  feedback loops.
• Draw the components of a basic negative feedback
  loop.

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Themes in the Study of Life

• Informational Molecules
• Some biological macromolecules contain code by
  virtue of the sequence of the building blocks
  they contain.
• Name the type of molecule that contains the
  instructions for maintaining the structure and
  function of an organism.
• Name the type of molecule that is made from these
  instructions.
• All forms of life use this same code
• Are there other similarities that unify the
  diversity of life?
• Inheritance of traits relies on accurate
  duplication and transmission of this code to
  offspring
• Can organisms change because they have to in
  order to survive in a challenging environment?

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Themes in the Study of Life

• All living things depend directly or indirectly
  on all other living things for survival

• Briefly describe how an organism changes its
  biotic environment.its abiotic environment.
• Describe the flow of energy and raw materials
  through the biosphere.

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Themes in the Study of Life

• Evolution is the core theme of biology
• descent with modification
• Natural selection is one mechanism of evolution
• Q Which of the following observations made by
  Charles Darwin was/were pivotal to the
  development of his concept of evolution

• Populations never produce more offspring than can
  be supported by the environment
• Individuals in a population exhibit at least
  slight differences in their structure and/or
  function
• Some individuals possess traits that make them
  more fit in their environment
• Human skin cells look exactly like bacterial
  cells from mineral hot springs

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Help Jane with her homework
True or False.
Natural selection creates adaptations.
Justify your answer.
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Themes in the Study of Life

• Scientific Process
• begins with a question
• one way to acquire knowledge
• Can any question be answered by
• the scientific method?
• 2 basic ways to approach a question
• inductive reasoning
• deductive reasoning

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Themes in the Study of Life

• Inductive Reasoning
• generalize from specific observations
• example
• When is inductive reasoning used in the
• scientific process?
• Deductive Reasoning
• propose a model (involving assumptions) that
  provides a tentative explanation that can be
  applied to specific situations
• requires that evidence be collected to test the
  model and assumptions

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?
Hypothesis
modify or abandon
Test
repeat
Support
Reject

• What important skills are critical to your
  ability to formulate hypotheses?
• When is more than one hypothesis appropriate in
  science?
• What is a scientific theory and how is it
  different from a hypothesis?

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Small Group ExerciseAn Introduction to
Correlation
Does smoking cause lung cancer? Does drunk
driving cause accidents? Do thin people live
longer? You may think you know the answers to
some or all of these questions already. On what
evidence and/or reasoning to you base your
answers? The collection and analysis of data to
determine whether two variables are linked are
important elements in scientific investigations.
Finding variables to be linked (i.e. correlated)
suggests the possibility of a cause-and-effect
relationship. The purpose of this small group
exercise is to evaluate information based on the
results of scientific research, reported in a
newspaper article. Read the article and answer
the questions that follow.
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Doing poorly Study links low income with high
blood pressure

1. What two variables are correlated according to
   the article?
2. Is this a direct or inverse correlation?
   Explain.
3. Does either the author or researcher argue that
   one of the variables is the cause? Explain