DO NOW Objective: identify the interactions that occur within a community and describe how communities recover from disturbances. List four types of community interactions and give examples. Take out your homework.
Community Interactions • Competition • Predation • Symbiosis • Mutualism • Commensalism • Parasitism
Ecological Succession • Ecosystems that seem unchanged during a human life are often misleading. • An ecosystem can change in response to an abrupt disturbance or gradual response to natural fluctuations. • Respond to human disturbances as well as natural disturbances
Ecological Succession (continued) • Older organisms may die out and new organisms move in which creates a chain reaction of change. • Definition: series of predictable changes that occurs in a community over time.
Primary Succession • When succession occurs on land where no soil exists ( glaciers, lava rock, volcanic ash, etc) • The first species to arrive on the rock are called pioneer species. These organisms are growing where no other organism has grown before!!!
Secondary Succession • Disturbances within a community may be natural or caused by humans and include fires, farming, and floods. • Following the disturbance, community interactions attempt to restore the community back to its original condition though secondary succession. • Even though the organisms seemed destroyed the interactions of the community following the disturbance may or may not assist in getting the community back to its original state.
Succession in Marine ecosystems • There are 3 stages in a whale-fall community. • 1: a large whale dies and sinks to the bottom of the usually barren ocean floor. Scavengers are attracted to the body. • 2: within a year most tissue is gone so fewer fish can live off it, but the sediments around have now been enriched with nutrients so sediment dwellers move in. • 3: When only bones remain, heterotrophic bacteria move in and feed on the oils inside the whale bone.
Recap • Objective: identify the interactions that occur within a community and describe how communities recover from disturbances. • What are some of the community interactions we discussed? • Define ecological succession. • What is the difference between primary and secondary succession?
Homework • Page 97 questions 1-6