Characteristics of Biological Systems

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• Characteristics of Biological Systems
• Regulation
• Metabolic processes controlled to maintain
  homeostasis
• Feedback regulation may be
• Negative (Ex Glucose metabolism)
• Positive (Ex Blood clotting)

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Fig 1.13
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• Characteristics of Biological Systems
• Growth and Development
• Increase in cell number, size, both
• Uniform or local growth
• Determinate or indeterminate growth
• Development Changes in structure and/or function
• Reproduction
• Asexual No gametes
• Sexual
• Genetic material from multiple individuals
• Creates genetic variation important for
  adaptation and evolution

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• Characteristics of Biological Systems
• Evolutionary Adaptation
• Change over multiple generations
• Involves natural selection

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Peppered Moth
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• Cellular Basis of Life
• All organisms composed of cells
• Organisms unicellular or multicellular
• First observations of cork cells by Robert Hooke
  (1665)
• First observations of microorganisms by Anton van
  Leeuwenhoek (1665)
• Cell Theory developed in 1838-1839 by Schleiden
  and Schwann using inductive reasoning
• Later Cells come from other cells, providing
  basis for growth, reproduction, and repair

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• Cellular Basis of Life
• Cell types
• Prokaryotic
• Domains Archaea and Bacteria
• No membrane-bounded organelles or
  membrane-bounded nucleus
• DNA not separated from rest of cell
• Most with tough exterior cell walls
• Usually much smaller than eukaryotic cells
• Eukaryotic
• Domain Eukarya (Animalia, Plantae, Fungi,
  Protists)
• Membrane-bounded organelles
• DNA separated from rest of cell as chromosomes in
  nucleus
• Some have cell walls (Plantae, Fungi)

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Fig. 1.8
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• Transmission of Heritable Information
• Basis for most species on earth is DNA
  (Deoxyribonucleic Acid)
• Double-stranded backbone with four types of
  nucleotide building blocks
• Organized into functional units called genes
• Fundamental units of heredity
• Transmission of genes ? transmission of traits
• All known forms of life use same genetic code
• Genetic complement of an organism genome

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Fig. 1.11
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• Diversity of Life
• About 1.8 million described species
• 1,000,000 insects
• 290,000 plants
• 100,000 fungi
• 52,000 vertebrates
• Estimated total 10-200 million
• Classification system taxonomy
• System developed by Carolus Linnaeus
• Binomial nomenclature (Genus species)
• Shared characteristics unite members of a taxon
  (group)

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Fig. 1.14
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Fig. 1.15
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• Diversity of Life
• Unity in diversity
• Similarities among distantly-related species

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How can this happen?
Fig. 1.16
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• Evolution
• Concept underlies virtually all of modern biology
• Explains unity and diversity of life
• Involves responses by species (not organisms) to
  their environment
• Charles Darwin (1859) On the Origin of Species
  by Means of Natural Selection
• Synthesis of information from biology and geology

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• Evolution
• Descent with Modification
• Species change from generation to generation
• Contemporary species arose from ancestral species
• Natural Selection
• Mechanism for evolutionary change

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Fig. 1.20