chapter 3 and 4 definitions

• ecosystem

  ecological system that includes organisms in an area (biotic factors), their physical environment (abiotic factors) and the interactions of these factors
• biosphere

  sum of all ecosystems
• biomes

  regions of the world with similar climate, animals and plants
• each biome consists of several different ecosystems
• ecosystem

  interactions between the environment and its community
• community

  biotic factors (living components) and abiotic factors (non-living factors)
• population

  group of individuals in the same species
• habitat

  area where an organism lives
• intraspecific interactions

  relationships between members of the same species
• interspecific interactions

  relationships between members of different species
• parasitism

  parasite benefits at the expense of host
• endoparasites

  live and feed within the host
• ectoparasites

  live and feed on the external surface of host
• mutualism

  where both organisms benefit
• commensalism

  one species benefits while the other neither benefits nor harmed
• energy

  capacity to cause change, it can exist in many forms and can be transformed from one form to another
• energy cant be recyled
• energy can be transformed from one type to another
• energy can be transferred from an organism to another
• light energy

  enters ecosystems via autotrophic producers who transform light energy into chemical food energy during photosynthesis
• chemical energy

  energy stored in chemical bonds in the carbohydrate food is transferred to consumers upon consumption
• heterotrophs

  depend on autotrophs because they cant perform photosynthesis
• biomass

  total mass of biological matter in an area
• productivity

  percentage of energy entering an ecosystem
• photosynthetic energy

  how well producers convert light energy into carbohydrates during photosynthesis
• gross primary productivity

  total amount of energy that flows through producers
• net primary productivity

  amount of energy available to consumers
• trophic level

  position in the food chain/web
• food chains/webs

  models that allow ecologists to monitor the sustainability of feeding relationships
• producers

  make their own food by transforming light energy into chemical energy
• primary consumers (herbivores)


  feed on producers
• secondary consumers (omnivores/carnivores )

  feed on primary consumer, or omnivores feed on producers
• top consumer (apex predator)


  feed on secondary consumer (not preyed on)
• scavengers


  animals that feed on dead animals, helping speed up the decaying process
• detrivores


  feed on decaying plant and animal tissue
• decomposers


  continue process of detrivores by breaking down the complex organic material into smaller pieces