Herbivory

• Community


  An assemblage of populations interacting with one another within the same environment
• Species composition/ species richness


  A listing of various species in the community
• Species diversity


  Includes both species richness and the abundance of different species
• Habitat


  The area where an organism lives and reproduces
• Ecological niche


  The role a species plays in its community, including its habitat and interactions with other organisms
• Fundamental niche


  All conditions under which the organism can survive
• Realized niche


  Set of conditions under which it exists in nature
• Abiotic components of an ecosystem


  • Atmosphere
  • Water
  • Soil
• Biotic components of an ecosystem


  • Autotrophs
  • Heterotrophs
• Autotrophs


  Require only energy and inorganic nutrients to generate the food necessary for the ecosystem
• Photoautotrophs


  Land plants and algae

  
• Chemoautotrophs


  Some bacteria
• Heterotrophs


  Need a preformed source of organic nutrients as they acquire food
• Heterotrophs


  • Consumers (Herbivores, Carnivores, Omnivores)
  • Detritivores
  • Decomposers
• Herbivores


  Feed on plants
• Carnivores


  Feed on other animals
• Omnivores


  Feed on plants and animals
• Detritivores


  Feed on decomposing organic matter
• Decomposers


  Break down dead organic matter
• Energy flow in an ecosystem


  • Begins when producers absorb solar energy
  • Producers make organic nutrients via photosynthesis
  • Organic nutrients are used by producers and others
  • Energy eventually dissipates into the environment as heat
• Chemical cycling in an ecosystem


  • Begins when producers take in inorganic nutrients from the physical environment
• Only a portion (10%) of the organic nutrients made by producers is passed on to consumers</b>
• Food web


  • Represents interconnecting paths of energy flow within ecosystems
  • Describes trophic (feeding) relationships
• Grazing food web


  1. Begins with a producer (oak tree)

  2. Insects, rabbits, and deer feed on leaves

  3. Birds, chipmunks, and mice feed on fruits and nuts
• Detrital food web


  1. Begins with detritus

  2. Detritus is food for soil organisms such as earthworms

  3. Earthworms are in turn fed on by carnivorous invertebrates

  4. Invertebrates may be eaten by shrews or salamanders
• Food chain


  A diagram showing a single path of energy flow in an ecosystem
• Trophic level


  A level of nourishment within a food web or chain, composed of all the organisms that feed at the same level
• Ecological pyramids


  • Depict the flow of energy with large losses between successive trophic levels
  • May be based on the number of organisms or the amount of biomass at each trophic level
• Only about 10% of the energy of one trophic level is available to the next trophic level
• Biomass


  Number of organisms x dry weight of the organic matter within one organism
• In aquatic ecosystems, the herbivores may have a greater biomass than the producers due to the high consumption rate of aquatic algae
• Herbivory affects primary productivity (GPP and NPP), secondary productivity, trophic structure, and ecological pyramids
• Terrestrial herbivory is affected by temperature and moisture, while aquatic herbivory is affected by nutrients
• Species richness


  The number of different species present in a community
• Species evenness


  The relative abundance of different species
• Simpson's Index (D)


  A measure of species diversity
• Simpson's Diversity Index (1-D)


  a measure of diversity which takes into account the number of species present, as well as the relative abundance of each species
• The Philippines has high levels of species endemism and threat across major taxonomic groups