Transcript Pisaster
Ecology: Communities Organizational Hierarchy of Life Most Complex biosphere ecosystem community population organism organ system organ Living tissue cell organelle macromolecule Non-living molecule Least atom Complex sub-atomic particles Term Population Community Ecosystem Biosphere Definition Individuals of one species that occupy a given environment All populations in a common environment Organisms in community plus nonliving factors Zones of air, land and water at earth’s surface occupied by living things Interactions in Communities -Competition -Predation -Symbiosis Competition Relates to Niche Overlap Degree of competition is proportional to the overlap in ecological niches of competing species Ecological niche = total way of life of all members of a species --Habitat --Physiological needs such as temperature, moisture, nutrients --Behavior --Interactions with other species Outcomes of Competition Competitive Exclusion = One species eliminates the other Grown in Separate Flasks Grown in the Same Flask Outcomes of Competition Resource Partitioning: Use of small differences in environment to fulfill needs Outcomes of Competition Character Displacement: Through natural selection, two species diverge in characteristics that overlap Theoretical vs. Actual Niche Theoretical Niche Defined by Physiological Limits: needs for food, water, temperature Actual Niche Portion of Theoretical Niche that is used, limited by competition Barnacle B, theoretical and actual niche Barnacle C, Actual niche Barnacle C, theoretical niche Competition Between Two Species of Barnacles for Region Near the Ocean Surface Applying Your Knowledge 1. Character Displacement 2. Competitive Exclusion 3. Resource Partitioning A. Which one involves the use of different features of the environment so that two species can coexist in the same area? B. Which one involves physical changes in two separate species? C. Which one involves the elimination of one of the competing species? Effects of Predation Predation = eating of live organisms • Eliminates old and weak individuals • Regulates numbers of both predators and prey • Coevolution of predator and prey • Regulates diversity of populations in community The sea star Pisaster is a keystone species in aquatic communities in the Pacific Northwest. Population Cycles in Predators and Prey Coevolution of Predator and Prey Camouflage hides prey Symbiosis Close Interaction Between Species Parasitism One helped , other harmed Symbiosis Mutualism Both helped Symbiosis Commensalism One helped, other neither helped nor harmed Applying Your Knowledge 1. Mutualism 2. Commensalism 3. Parasitism Which type of symbiosis is operative if • A barnacle attaches to a whale so it can feed on organisms encountered as the whale swims but the whale is unaffected by the barnacle? • Athlete’s foot fungus starts growing between your toes? Will the Monarch Butterfly be affected by the development of herbicide resistant crops?