Living Environment                              Name___________________________ 
                                                              Period _____ 
               
                                                    Ecology Notes 
               
              Ecology – the study of how organisms interact with the living and nonliving things that 
              surround them. 
               
              Organisms are interacting with their environment all of the time, and their environment 
              impacts them as well. 
               
              Environment – every living and nonliving thing that surrounds an organism 
               
              Abiotic Factors – nonliving factors in the environment 
              Examples: temperature, humidity, precipitation, pH, composition of air (gases) 
               
              Biotic Factors – living factors in the environment 
              Examples: plants, animals, single-celled life forms 
               
              There are several levels of organisms within the environment.  Listed from largest to 
              smallest they are: 
                    Biosphere (this is the biologically inhabited portions of the planet) 
                    Ecosystem (all of the living and non-living things that interact with one another in a 
                     particular place) 
                    Community (all of the different populations of organisms living in an area) 
                    Population (all of the members of one species that live in the same area) 
                    Organism (an individual animal, plant, or single-celled life form) 
                                                
       The growth of an ecosystem depends on the physical conditions and on the resources 
       available to the organism. 
        
       Carrying Capacity – the number of organisms of any single species that an ecosystem can 
       support 
        
       Competition helps keep the size of a species population under control. 
       Competition – the struggle for resources among organisms 
        
       Another thing that limits the size of populations in an ecosystem are called limiting 
       factors. 
        
       Limiting Factors – any factor in the environment that limits the size of populations 
       Examples: amount of oxygen, amount of sunlight, temperature, predator/prey interactions 
       Predator – an organism that kills and eats other organisms 
       Prey – an organism that is killed for food 
        
        
       All organisms interact and have roles they play in an ecosystem. 
       Ecological Niche – the role that each species plays in an ecosystem 
          A niche includes: 
            o  The range of conditions that the species can tolerate 
            o  The methods by which it obtains the needed resources 
            o  The number of offspring it has 
            o  Its time of reproduction 
            o  All of its other interactions with its environment 
       In every ecosystem populations of all different species are linked together.  Sometimes 
       these relationships are competitive, other times they are cooperative. 
       Food Chains – illustrate the relationships between the prey and predator (it shows what 
       eats what) 
                                                
       Some food chain vocabulary: 
       Autotroph (or Producer) – organisms that make their own food (they provide a source of 
       food energy for almost all other living things 
       Heterotroph (or Consumer) – organisms that must acquire food by consuming other 
       organisms 
            o  Carnivore – heterotrophs that eat other animals 
            o  Herbivore – heterotrophs that eat plants only 
            o  Omnivore – heterotrophs that eat both plants and animals 
           
            o  Decomposer – an organisms that consumes the wastes and dead bodies of all  
              organisms, they recycle materials that can be reused by producers 
            o  Scavenger – animals that consume the carcasses of other organisms that 
              have been killed by predators or have died of other causes 
            o  Parasite – organisms that attack other live organisms (called host organisms) 
            o  Detritivore – chew or grind on detritus particles into smaller pieces, they 
              commonly digest decomposers that live on and in detritus particles (parts of 
              dead organisms converted by decomposers) 
       Food Web: overlapping food chains