Directions: Before you start listen to part of a talk in a biology class.
*Vocabulary is sometimes provided in written form when it may be unfamiliar to the student, but essential for understanding the lecture
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Question 1 of 2
1. What is the lecture mainly about?CorrectIncorrect
Question 2 of 2
2. Based on the information from the listening, indicate which characteristic on the left belongs to either primary succession or secondary succession by marking the correct cell with an X.
Primary Succession Secondary Succession An ecosystem is disturbed but part of the community remains Newly formed rock is colonized by living organisms Has a sequential change in species until a permanent community develops
Community dynamics are the changes in community structure and composition over time, often following environmental disturbances such as volcanoes, earthquakes, storms, fires, and climate change. Communities with a relatively constant number of species are said to be at equilibrium. The equilibrium between species identities and relationships changes over time, but maintains a relatively constant number. Following a disturbance, the community may or may not return to the equilibrium state.
Succession describes the sequential appearance and disappearance of species in a community over time after a severe disturbance. In primary succession, newly exposed or newly formed rock is colonized by living organisms; in secondary succession, a part of an ecosystem is disturbed and remnants of the previous community remain. In both cases, there is a sequential change in species until a more or less permanent community develops.