Chapter 1 Biology As An Overview

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Chapter 1Biology As An Overview

• August 18, 2008

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Objectives

• Exploring Life on its Many Levels
• Describe the unifying themes that characterize
  the biological sciences.
• Diagram the hierarchy of biological organization.
• Distinguish btwn prokaryotic and eukaryotic
  cells.
• Describe the basic structure and function of DNA.
• Explain the importance of regulatory mechanisms
  in living things. Distinguish between positive
  and negative feedback.   
• Evolution, Unity, and Diversity
• Explain the phrase lifes dual nature of unity
  and diversity.
• Describe the observations and inferences that led
  Charles Darwin to his theory of evolution by
  natural selection
• Explain why diagrams of evolutionary
  relationships have a treelike form  

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Biology Is An Enormous Scope

• Size scales from submicroscopic molecules to
  global distribution of biological communities
• It encompasses life over huge spans of time, from
  contemporary organisms to ancestral life

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Biology Is An Ongoing Process

• New research methods have led to an information
  explosion
• Recombinant DNA Techniques
• Technological advances yield new information that
  make the conceptual framework accepted by most
  biologists
• Sequencing of the human genome

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Unifying themes
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A. Life is organized on many structural levels

• Atoms, complex biological molecules, sub-cellular
  organelles, cells, tissues, organs, organ
  systems, complex organism, population, community,
  ecosystem, biomes, biosphere

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B. Each level of organization has emergent
properties

• Emergent property Property that emerges as a
  result of interaction between components
• Order
• Reproduction (biogenesis)
• Growth and development (directions stored in
  heritable DNA)
• Energy utilization
• Response to environment
• Homeostasis
• Evolutionary adaptation

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Each level of organization has emergent
properties cont.

• Holism The principle that a high level of order
  cannot be meaningfully explained by examining
  component parts in isolation
• An organism is a living whole greater than the
  sum of its parts (a cell dismantled into its
  chemical parts is no longer a cell)
• Reductionism The principle that a complex system
  can be understood by studying its molecular
  structure
• Study genetics through first studying the
  structure and function DNA

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C. Cellular basis of life

• Basic unit of structure and function of life
• Lowest level of structure capable of life
  performing all life activities
• All organisms are composed of cells
• Unicellular/Multicellular
• Robert Hooke described cells in cork
• Anton Van Leeuwenhoek (1600s) used a microscope
  to view microorganisms, blood cells, and animal
  sperm
• Schleiden and Schwann included all things are
  made of cells basis of cell theory

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Cellular basis of life cont.

• Prokaryotic cells
• Lack membrane bound organelles
• Kingdom Monera
• Smaller than eukaryotic
• Most have tough external walls
• Bacteria

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Cellular basis of life cont.

• Eukaryotic Cells
• Membrane enclosed nucleus and organelles,
  cytoplasm, some have cell walls
• Protists, plants, fungi, animals

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D. DNA and heritable information

• Biological instructions for an organisms complex
  structure and function are encoded in DNA
• Inheritance is based on passing information
  encoded on DNA from parent to offspring
• All forms of life use essentially the same
  genetic code. Differences result from different
  nucleotide sequences

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E. Structure/Function Form fits function

• Example The nucleus of a cell
• Membrane to protect DNA
• Nuclear pores to allow mRNA to go to ribosomes
  for translation
• Example The bones in a hand
• Smaller sized bones allow for delicate and
  precise movement

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F. Organisms interact with environments

• Nutrient cycling
• Energy flow
• Food webs
• Energy conversion
• Chemical energy ? heat

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G. Unity/diversity

• Taxonomy Science of naming and classifying
  organisms (kingdom, phylum, class, order, family,
  genus, species)
• Five kingdoms Monera, Protista, Plantae, Fungi,
  Animalia
• Unity is evident in universal genetic code,
  biochemical pathways, similarities of cellular
  structure

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H. Evolution

• Life evolves
• Similar species share a common ancestry
• Darwin natural selection
• variation
• overproduction
• individuals with traits best suited to
  environment experience greater reproductive
  success

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Scientific method
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Objectives

• Distinguish between discovery science and
  hypothesis-based science. Explain why both types
  of exploration contribute to our understanding of
  nature.
• Distinguish between quantitative and qualitative
  data and inductive and deductive reasoning.
• Describe what is meant by a controlled
  experiment.
• Distinguish between the everyday meaning of the
  term theory and its meaning to scientists.
• Explain how science is influenced by social and
  cultural factors. Distinguish between science and
  technology.

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• Hypothesis Educated guess proposed as a
  tentative answer to a specific question or problem

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• Inductive Reasoning Making an inference from a
  set of specific observations to reach a general
  conclusion (cell theory)
• Deductive Reasoning Making an inference from
  general premises to specific consequences which
  logically follow the premises are true
• Ifthen logic
• Usually involves predicting experimental results
  that are expected if the hypothesis is true

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• Control Group all variables are held constant
  and provides a basis of comparison

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• Variable condition of an experiment that is
  subject to change and may influence the
  experiments outcome

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• Experimental Group The group in which one factor
  treatment is varied

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