Module 2

• types of value placed on animals: economic, perceived, biological relationship
• agricultural economic value: jobs, agricultural and meat products
• biomedical economic value: animal research, pharmaceuticals
• what is the largest segment in pharmaceuticals?

  cancer drugs
• ecological/wildlife economic value: national parks, water management/drought prevention
• companion animal economic value: expenditures on pet health and wellness
• what animals did the Herzog reading compare for perceived value?

  cats (pets), snakes (danger/threat), and rats (pests, disease carriers)
• how are human/animal biological relationships perceived?

  compare physical commonalities, but may differ from evolutionary relatonships
• common cellular basis: all life on earth, cells developed specialized functions and adapted to the environment
• lineage: ancestor and descendant populations
• node: division of single lineage, shared characteristic
• taxon: group of species designated with a name
• clade: taxon of evolutionary descendants of a common ancestor
• what type of data is used to construct phylogenetic trees?

  molecular data (DNA)
• nuclear DNA is most used for molecular data
• chloroplast DNA is used for plants
• mitochondrial DNA comes from specialized cells that produce energy, passed down the maternal line
• the 3 domains are bacteria, archaea, and eukarya
• taxonomic rank:

  1. domain
  2. kingdom
  3. phylum
  4. class
  5. order
  6. family
  7. group
  8. species
• homologus: feature shared by 2 or more species and inherited from a common ancestor
• structural homology: same structures with different functions
• what did Darwin say about structural homology?

  it is the product of descent with modification
• example of structural homology

  fused phalanges (hooves) in horses vs. elongation (webbing) in bats
• convergent evolution: superficially similar traits that evolve independently in different lineages
• convergent evolution occurs in an environment that favors a particular adaptation
• classes of biological molecules: carbohydrates, lipids, nucleic acids and proteins
• carbohydrates are simple sugars used for energy in animals and starches used by plants
• lipids are a component of cell membranes and hormones
• nucleic acids encode and store genetic information
• proteins are linked amino acids
• what biological molecule helped form initial life on earth?

  fatty acids made membranes to separate hydrophobic cells from environment (ocean)
• 8 characteristics of living organisms:

  1. composed of common set of chemical components and similar structures
  2. contain genetic information in nucleic acids (RNA and DNA)
  3. convert molecules from environment into new biological molecules
  4. extract energy from the environment and use it to do biological work
  5. regulate internal environment (homeostasis)
  6. replicate genetic information when reproducing
  7. share sequence similarities among fundamental sets of genes
  8. evolve through gradual changes in genetic information
• why are viruses not living organisms?

  require host for energy and reproduction
• life on earth formed 4.6-4.5 bya, didn't evolve for 600 million years
• how did complex molecules evolve (miller experiment)

  • lightning (energy source) heats ocean and release water vapor that mixes with organic compounds in early environment (methane, CO2)
  • condensed water is released into environment (ocean)
  • introduced organic molecules can form large molecules from smaller ones (amino acids to peptides)
• why could early life not survive outside the ocean?

  minimal O2 in atmosphere, no protective ozone layer and only UV protection was in ocean
• photosynthesis evolved 3-3.5 bya, O2 accumulated in atmosphere and ozone layer forms
• multicellular organisms evolved 1 bya, cells became specialized
• genes: DNA that controls appearance/cell function, allows for specialization
• allele: alternative forms of same gene (same function, different forms)