Ecosystems Niche The played by a species in its community o o Refers to the way that organisms respond to the resources and other species found within the habitat o Determines by abiotic physical parameters and biotic biological factors based on interactions with other species o o Resource Partitioning Fundamental Niche o Realized Niche Smaller than the fundamental niche because of competition and other biotic factors Symbioses o Associations are not fixed they can change over time o Antagonisms Competition Increase in competition and population density population growth decreases Promotes niche divergence Competitive Exclusion Can compete directly or indirectly o Mutualisms Subject to natural selection May evolve increasing independence Obligation Facultative Commensalism o o Amensalism Community Populations tied together by the various interactions that secure their spot in the food web and physical location The acts of different populations also vary in time ex seasons o o o Keystone Species Affects a community in disproportionate much larger ways o Disturbances Allow species to enter or remain in the community as long as they can establish their young in the newly opened habitat patch Intense disturbances only a species can tolerate the physical conditions of the habitat and diversity will be Rare or weak disturbances may take over and only a few stronger species may remain Species diversity tends to be highest when disturbance is or intense enough to competition but not so strong as to limit the number of species that can tolerate the environment o Succession In new habitats or following a disturbance species and transform the habitat in a predictable sequence that reflects the adaptions of a particular species o Climax Community Ecosystem Species interactions result in food webs that cycle carbon and other elements through ecosystems o o Trophic Pyramids Food Web o Trophic Level 1st primary producers 2nd primary consumers o Primary Producers Consumers o o Decomposers o Detritivores Light water nutrients and diversity all influence rates of primary production o Liebig s Law of the Minimum Biomes o Recognized by their characteristic vegetation reflects the evolutionary adaption o Reflect the interaction of Earth and life Distribution of biomes corresponds to climate o Tundra o Alpine o Taiga o Temperate Forest o Deciduous Forest o Temperate Grassland o Desert o o Chaparral Savanna o Rain Forest Evaporation Transpiration Ration between these tells us what type of can be supported in a given region Low precipitation high evaporation o Plants must limit transpiration High precipitation low evaporation Transpiration is unlimited o