Option G Ecology and Conservation G 2 Ecosystems

Option G: Ecology and Conservation G. 2 Ecosystems and Biomes

F. 2. 1 Define gross production, net production and biomass Units: k. J m-2 yr-1 Gross production = net production + respiration OR total amount of organic matter produced by plants in an ecosystem Net production = gross production - respiration Biomass = dry weight of an organism measured in g m-2 yr-1

F. 2. 2 Calculate values for gross production and net production using the equation: gross production – respiration = net production Example: Construct an pyramid of energy using the following information: Tropic level Producers Primary consumers Secondary consumers Tertiary consumers Energy flow (k. J m-2 yr-1) 20 810 3368 383 21

F. 2. 3 Discuss the difficulties of classifying organisms into trophic levels

F. 2. 4 Explain the small biomass and low numbers of organisms in higher trophic levels • Biomass is lost during respiration at each trophic level • Predators at the top of the pyramid must be large enough to catch prey; there can only be a few of them

F. 2. 5 Construct a pyramid of energy giving appropriate formation The total solar energy received by a grassland is 5 x 105 k. J m-2 y 1. The net production of the grassland is 6 x 102 k. J m-2 y-1. The total energy passed onto the primary consumers is 60 k. J m-2 y-1. Only 10% of this energy is passed onto its secondary consumers. • Calculate energy lost by plant respiration • Construct a pyramid of energy for this grassland.

F. 2. 5 Construct a pyramid of energy giving appropriate formation The total solar energy received by a grassland is 5 x 105 k. J m-2 y 1. The net production of the grassland is 6 x 102 k. J m-2 y-1. The total energy passed onto the primary consumers is 60 k. J m-2 y-1. Only 10% of this energy is passed onto its secondary consumers. • Construct a pyramid of energy for this grassland.

F. 2. 6 Distinguish between primary and secondary succession, using an example of each Ecological succession: change in species composition in a community over time. Primary Succession • Plants begin growing on previously lifeless area • Lacks organic soil • Example: • New volcanic island (lichen moss) Secondary succession • After primary succession • Upheaval of primary succession (plants) but has organic component (seeds/roots) • Example: • Recolonisation after forest fire

F. 2. 7 Outline the changes in species diversity and production during primary succession Example: Coastal sand dunes Foredune Yellow dune Grey dune Mature dune • thin soil layer • • Sedge and sand bindweed; • no soil dandelion and thistles • Pioneer plants: lyme and marram • Rabbits (droppings) • • Diversity increases grass • Limited diversity Humus develops (holds water) Thick shrubs • Thick humus • Supports forest • High diversity

F. 2. 8 Explain the effects of living organisms on the abiotic environment with reference to the changes occurring during primary succession • • Few species No soil New area Lichen and mosses are pioneer plants • Low biomass • Low production • • Many species Soil present Old area Seeds and roots already present • Higher biomass • Higher production

F. 2. 9 Explain how rainfall and temperature affect the distribution of biomes • Climograph plots temperature and rainfall in a particular region

F. 2. 10 Outline the characteristics of the major biomes