biology ecology

• organism

  a living thing
• habitat

  an environment that provides the things an organism needs to live, grow and reproduce
• biotic factor

  a living part of an organisms habitat
• abiotic factor

  a nonliving part of an organisms habitat
• species

  a group of organisms that are physically similar and can mate with eachover and produce offspring that can also mate and reproduce
• population

  all the members of one species in a particular area
• community

  all the different populations that live together in a area
• ecosystem

  the community of organisms that live in a particular area along with their non living surroundings
• ecology

  the study of how living things interact with eachover and their environment
• environment

  the surroundings or conditions in which a person, animal or plant lives or operates
• roles of bacteria in the environment

  decomposers- recycle nutrients like nitrogen and phosphorus-help plants fix nitriven-help animals digest food-some cause desease
• autotroph

  an organism that makes its own food also called a producer
• heterotroph

  organism that obtains energy from the food it consumes also called a consumer
• primary consumer

  consumer that feeds directly on producers also called a herbivore
• secondary consumer

  an organism that eats primary consumers
• food chain

  a series of steps in which organisms transfer energy by eating and being eaten
• food web

  a community of organisms where there are several interrelated food chains
• herbivore

  a consumer that only eats plants
• carnivore

  a consumer that eats only animals
• omnivore

  a consumer that eats both plants and animals
• detritivore(scavenger)

  organism that eats dead organic matter
• water cycle

  the continuous process by which water moves from earths surface to the atmosphere and back
• nitrogen fixation

  process of converting nitrogen gas into nitrogen compounds that plants can also absorb and use
• commensalalism

  a relationship between two organisms in which the organis benifits and the other is unaffected
• mutualism

  a relationship between two species in which both benifit
• parasitism

  a relationship between two organisms of different species where one benifits and one is harmed
• predation

  an interaction in which one organism kills another for food
• carrying capacity

  the largest population that an environment can support at any given time
• exponential growth

  population growth that is unhindered because of the abundance of resources for an ever increasing population
• logistic growth

  growth pattern in which a populations growth rate slows or stops following a period of exponential growth
• parasitism

  mistletoe and tree
• density dependant factor

  limiting factor that depends on population size
• density independent factor

  limiting factor that affects all populations in similar ways regardless of population size
• keystone species

  a species that has an unusual large effect on its ecosystem
• examples of density independent factors

  temperatur, weather, natural disaster, human activity
• examples of density dependent factors

  competition, predation, parasitism,disease
• habitat

  place where an organism lives
• niche

  an organisms particula role in a ecosytem, its job