Life: Biological Principles and the Science of Zoology

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Chapter 1
Life Biological Principles and the Science of
Zoology
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Outline

• Intro
• Properties of life
• Physical laws of life
• Guiding principles in the biological sciences
• The nature of science
• Scientific method
• Experimental vs. evolutionary sciences
• Evolution and heredity
• Darwin
• Mendelian heredity
• Chromosomal theory of inheritance

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Intro

• Guiding principles
• laws of physics and chemistry
• use of scientific method
• principles of heredity, variation, and organic
  evolution
• theory of evolution by natural selection
• chromosomal theory of inheritance
• Zoology scientific study of animals

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What is Life?

• No simple definition
• General properties
• chemical uniqueness
• 4 building blocks confers biochemical unity
• review
• complex organization gives rise to great
  diversity
• complexity and hierarchical organization
• levels of hierarchy
• macromolecule ? cell ? organism ? population ?
  species
• cell is basic unit of life
• reproduction
• heredity transmission of traits from parents to
  offspring
• variation differences among traits

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What is Life?

• possession of genetic program
• encoded in nucleic acids (DNA, RNA)
• review
• genetic code arose early and same in bacteria
  though humans
• highly conserved, alterations disruption of
  life
• evidence of single origin of life
• metabolism (interaction of catabolic and anabolic
  pathways)
• acquire nutrients and S from environment
• respiration, photosynthesis
• development
• pass through characteristic life cycle
• change is size/shape and differentiation,
  metamorphosis in some
• early stages similar among related organisms
• environmental interaction

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Physical Laws

• Life obeys laws of chemistry and physics
• Laws governing S and its transformation
• 1st law of thermodynamics S is neither created
  nor destroyed but transformed from one form to
  another
• sun ? plant ? animal ? heat
• 2nd law of thermodynamics physical systems tend
  to proceed toward greater disorder (entropy)
• living organisms are highly organized
• life at cell and organismal level maintained only
  as long as S put in
• no S input death, decomposition, heat loss

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Zoology

• Animals form distinct branch on tree of life
• originated 600 MYA
• part of eukaryotic branch (also includes
  plants/fungi)
• characteristics
• consume other organisms
• cant undergo Ps, lack cell walls (plants)
• lack hyphae (fungi)

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What is Science?

• Way of asking questions about natural world
• modern science arose in last 200 yrs
• characteristics of science as stated by Judge
  Overton in the Arkansas courts regarding
  creation-science
• guided by natural laws (both chemical and
  physical)
• explanatory by reference to natural law (not
  supernatural being or forces)
• testable against observable world
• conclusions are tentative and not necessarily the
  final word
• it is falsifiable
• while anybody is free to approach a scientific
  inquiry in any fashion they choose, they cannot
  properly describe the methodology as scientific
  if they start w/ a conclusion and refuse to
  change it regardless of the evidence developed
  during the course of the investigation

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Scientific Method

• a.k.a. hypothetico-deductive method
• Steps
• observation
• generate hypothesis to explain observation that
  can be falsified
• conduct experiment, analyze data, make
  conclusions, repeat
• if very strong evidence supports hypothesis for
  explaining wide variety of related phenomena,
  then theory
• theory in science is supported by massive
  evidence

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Animal Rights Controversy

• READ

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Experimental vs. Evolutionary Sciences

• 2 categories of questions in biology
• questions that seek to understand proximate or
  immediate causes
• how animals func. metabolically/physiologically/be
  haviorally at molecular/cellular/organismal/popula
  tion levels
• addressed by experimental sciences using
  experimental method
• make prediction of how system will respond to
  disturbance
• make disturbance
• compare observed results w/ preditions
• replications
• controls lack the disturbance
• subfields
• molecular biology, cell biology, endocrinology,
  developmental biology, community ecology,
  physiology

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Experimental vs. Evolutionary Sciences

• questions that seek to understand ultimate causes
• what are the evolutionary facotrs that resulted
  in the characteristics of observed systems
• addressed by evolutionary sciences using
  comparative method, not experimentation
• characteristics are compared among related sp.
• patterns of similarity and dissimilarity used to
  test relatedness
• subfields
• comparative biochemistry, molecular evolution,
  comparative cell biology, comparative anatomy,
  comparative physiology, phylogenetic systematics