Zoo2

• Zoology


  The study of animal life
• Zoologists strive to understand

  • The origin of animal diversity
  • How animals perform basic life processes
  • How they are able to inhabit various ecosystems
• Principles of modern zoology are derived from

  • Laws of physics and chemistry
  • Scientific method
• Because life shares a common evolutionary origin, principles learned from the study of one group often pertain to other groups as well
• Life


  No simple definition
• The history of life shows extensive and ongoing change called evolution
• Answer must be based on the common history of life on earth
• Chemical uniqueness


  Living systems demonstrate a unique and complex molecular organization
• Living organisms assemble large molecules - macromolecules - that are more complex than breakdown molecules found in nonliving matter
• Four categories of biological macromolecules

  • Nucleic acids
  • Carbohydrates
  • Proteins
  • Lipids
• Water is the most common and basic nutrient
• Protein


  Amino acids are the building blocks
• Small animals need more protein than adults
• High-protein intake can cause kidney problems
• Low-protein intake can lead to kwasiorkor
• Lipids are oils, fats, and tallows
• These 4 macromolecule groups differ in their components, types of bonds holding them together, and functions
• Macromolecules evolved early in the history of life and are found in every form of life today
• Proteins


  Made up of 20 different amino acid subunits, allowing for enormous variability and diversity of living forms
• Nucleic acids, carbohydrates, and lipids are also organized in a way that gives living systems a large potential for diversity
• Complexity and hierarchical organization

  Molecules are organized into patterns in the living world that do not exist in the nonliving world
• New characteristics can appear at any level of organization - emergent properties
• Emergent properties depend upon the characteristics found at lower hierarchical levels to some extent
• Reproduction


  Living systems can reproduce themselves and multiply
• Mitosis


  Cell duplication, in which one cell divides into two genetically identical daughter cells
• Stages of mitosis


  • Interphase
  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Sexual reproduction


  Reproduction involving male and female
• Asexual reproduction


  Reproduction without male
• Genes replicate themselves forming new genes, cells divide to produce new cells, organisms reproduce to produce new organisms, and populations can split to form new populations
• Even species may split to produce new species - speciation
• Heredity and variation are present at all levels of reproduction
• Heredity


  Faithful transmission of traits from one generation to the next
• Variation


  Production of differences among the traits of individuals
• Result: offspring are similar to - but not exactly like - parents
• Genetic program


  Provides fidelity of inheritance
• DNA


  Deoxyribonucleic acid, a long chain of nucleotides (sugar, phosphate, and nitrogenous base)
• The sequence of nucleotides codes for the order of amino acids in the specified protein
• Chemical bases in DNA and RNA

  • Adenine (A)
  • Cytosine (C)
  • Guanine (G)
  • Thymine (T) in DNA
  • Uracil (U) in RNA
• The genetic code is universal among living organisms from bacteria through humans, supporting the concept of a single origin of life
• Metabolism


  Living organisms maintain themselves by acquiring nutrients from their environments