Topic 1 Introduction to the Study of Life

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Topic 1Introduction to the Study of Life

• 1.1 The Unifying Characteristics of Life
• Biology 1001
• September 9, 2005

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Why Study Biology?

• Rooted in the human spirit
• Curiosity, recreation, enjoyment of nature
• Our connectedness to living things
• Conservation of biodiversity important
• E. O. Wilsons biophilia

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Why is Biology Important?

• Woven into the fabric of society
• - Health and disease
• - Nutrition
• - Agriculture
• - Management of natural resources
• Applicable in diverse disciplines
• - Psychology, sociology, criminal science
• - Even architecture!

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Life Is A Myriad of Diverse Forms
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So How Do We Recognize Life?Unifying Properties
Processes Characterize Living Things

• Response to environment
• Reproduction
• Energy processing
• Growth and development
• Regulation and homeostasis

• Order
• Evolutionary adaptations
• ? Cells as the basic unit of structure
• ? DNA as the hereditary material
• The study of life has both horizontal and
  vertical dimensions!

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Figure 1.2 Some properties of life
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Examples Order Energy Utilization
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Examples Reproduction, Growth Development
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A Hierarchy of Biological Organization

• The study of life
• Extends from the microscope scale of molecules
  and cells to the global scale of the entire
  living planet
• The hierarchy of life
• Extends through many levels of biological
  organization
• The challenge is integration across dimensions!

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Figure 1.3 Exploring Levels of Biological
Organization
1 The biosphere
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Cells

• A diversity of cell form!

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Cells

• The cell
• Is the lowest level of organization that can
  perform all activities required for life
• All cells share certain characteristics
• They are all enclosed by a membrane
• They all use DNA as genetic information
• They all contain a cellular fluid and ribosomes
• There are two main forms of cells
• Eukaryotic
• Prokaryotic

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Prokaryotic Vs. Eukaryotic Cells

• Profirst, eutrue, karyonnucleus
• Eukaryotic cells
• Are subdivided by internal membranes into various
  membrane-enclosed organelles
• Nucleus, mitochondria, chloroplasts
• All other organisms
• Prokaryotic cells
• Lack the kinds of membrane-enclosed organelles
  found in eukaryotic cells
• Are smaller than eukaryotic cells
• Prokaryotes

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DNA - The Cells Heritable Information

• Cells contain chromosomes made partly of DNA, the
  substance of genes
• Which program the cells production of proteins
  and transmit information from parents to offspring

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The molecular structure of DNAaccounts for its
information-rich nature
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Feedback Regulation in Biological Systems
Feedback can be Negative or Positive

• A supply-and-demand feature regulates some of
  the dynamics of living systems
• The output, or product, of a process regulates
  that very process

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In negative feedbackAn accumulation of an end
product slows the process that produces that
product
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In positive feedbackThe end product speeds up
production
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The Emergent Properties of Biological Systems

• A system is a combination of components that form
  a more complex organization
• Biological systems are much more than the sum of
  their parts
• New properties emerge with each step upward in
  the hierarchy of biological organization

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Examples of Emergent Properties

• Non-Living Examples
• Graphite vs. diamond ?
• NaCl
• A hammer
• Biological Examples
• Ecosystems
• Feedback regulation
• Consciousness
• Photosynthesis
• Enzymes other proteins ?

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Systems Biology

• Systems biology seeks to create models of the
  dynamic behavior of whole biological systems
• With such models scientists will be able to
  predict how a change in one part of a system will
  affect the rest of the system
• Is now taking hold in the study of life at the
  cellular and molecular levels
• Includes three key research developments
  high-throughput technology, bioinformatics, and
  interdisciplinary research teams

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Examples of Systems Biology
2. A systems map of interactions between proteins
in a cell
3. The Human Genome Project
1. The greenhouse effect
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Correlation Between Structure and Function at All
Levels of Biological Organization