Transcript Succession
Warm-up 9-22-2009 Producers • Using complete sentences answer the question below in your Composition Notebook. • What is the role of producers in the environment? What do they do for other organisms? Answer • • • • Provide food source Provide medicines Provide Oxygen Prevent erosion Today’s Objective: • Identify positive and negative conditions in an ecosystem Can be found in the book: Pg. 65 - 69 Life In an Ecosystem • Conditions in one part of the world are suitable for supporting certain forms of life, but not others. Ranges in Tolerance • The ability of an organism to withstand fluctuations in biotic and abiotic environmental factors is known as tolerance. For example, some crops may survive a long drought periodThey may not produce as as well, but they’re able survive. This makes me think of “Children of the Corn” • A limiting factor is any biotic or abiotic factor that can affect the existence of an organism. Common Limiting Factors Sunlight Climate Atmospheric gases Temperature Nutrients/Food Fire Soil chemistry Amount of Space Other organisms Water Limiting Factors • Factors that limit one population in a community may also have an indirect effect on another population. For instance, what if a drought caused grass to reduce the number of seeds it produces… What would happen to the mice that feed on those seeds? What would happen to the hawks that feed on those mice? • The maximum amount of organisms that can survive in an ecosystem is the carrying capacity. – It is determined by the amount of resources available, such as: • Habitat • Water • Food No population can live beyond the environment’s carrying capacity for very long. ● The “J” shape shows growth at a constant rate (exponential growth). ● When the “J” becomes an “S” shape…it means the population has reached carrying capacity. Warm-up 9-23-2009 Ecological Pyramid • Using complete sentences answer the question below in your Composition Notebook. • What is the purpose of an ecological pyramid? How much energy is passed on to each level? What happens to the rest of the energy that is not passed? Succession: Changes over Time • Ecologists refer to the natural changes and species replacements that take place in an ecosystem as succession. • Succession occurs in stages. • At each stage, different species of plants and animals may be present. Succession: Changes over Time • As succession progresses, new organisms move in. • Others may die out or move out. There are two types of succession— • primary • secondary. Succession: Changes over Time PRIMARY SUCCESSION • The colonization of organisms in a completely barren land is called primary succession. • Primary succession takes place on land where there are no living organisms. PRIMARY SUCCESSION • The first species to take hold in an area like this are called pioneer species. PRIMARY SUCCESSION • As these organisms die, more soil builds- and it has more nutrients in it. Moss Lichen Exposed rock Pioneer species Primary succession SECONDARY SUCCESSION • Secondary succession is the sequence of changes that takes place after an existing community is severely disrupted in some way. • Secondary succession, however, occurs in areas that previously contained life, and on land that still contains soil. Succession: Changes over Time SECONDARY SUCCESSION • Because soil already exists, secondary succession takes less time than primary succession to become a rich ecosystem again. Question 1 A(n) _____ is something that restricts the existence, numbers, reproduction or distribution of organisms. A. abiotic factor B. biotic factor C. tolerance factor D. limiting factor The answer is D. A limiting factor may be a abiotic factor. Tolerance refers to an organism’s ability to withstand fluctuations of environmental factors. Common Limiting Factors Sunlight Climate Atmospheric gases Temperature Water Nutrients/Food Fire Soil chemistry Space Other organisms Discuss with the person next to you: The difference between primary and secondary succession. Question 2 Which of the following best illustrates primary succession? A. moss growing on a lava bed B. wildflowers growing where forest fires had burned C. pine seedlings sprouting D. mature trees growing The answer is A. Primary succession is the colonization of barren land by pioneer species, such as moss or lichens. Question 3 What is required in order for secondary succession to occur? Secondary succession occurs in areas that previously contained life. Soil must be present on this land, and the species that grow will differ from pioneer species.