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Published byStella Goodman Modified over 9 years ago
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Today we are covering from the specification:
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What is an agricultural ecosystem? Animals and plants used to produce food for humans. Aims to increase productivity – how?
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What is productivity? Rate at which useful biomass is produced. Plants produce new biomass using… light energy. Animals produce new biomass using… chemical energy from plants/animals
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What is productivity? The rate at which organisms assimilate energy taken in is called gross production. Units – energy/area/time (kJm -2 year -1 ) Organisms use some of the new biomass in respiration – what’s left is the net production. Net Productivity = Gross productivity – Respiratory loss
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5 Agricultural Productivity Net Productivity = Gross productivity – Respiratory loss Similar to a business… Net profit = Gross Profit – Operating Costs How can agricultural productivity be increased?
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6 Task – Agricultural Productivity Create a 10-15 minute presentation on one of the topics below. For each one, include: What it is; How it increases productivity; What ethical/environmental issues can it lead to? Produce a handout for the rest of the class – it could include notes, fill-in-the-gaps, questions etc.. The use of natural and artificial fertilisers. Intensive rearing of livestock. The use of pesticides (chemical and biological) and integrated pest control. Email/give me a copy of the handout by the end of the lesson on Tuesday. Presentations will be on Thursday 16 th October.
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7 Agricultural Ecosystem Q. What is the ideal Agricultural “ecosystem” for the farmer? A. Monocultures of domesticated plants or animals. Q. Why do some argue that being a vegetarian is ecologically better. A. Less energy is lost.
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Agricultural Vs. Natural Ecosystems 8 NaturalAgricultural Solar energy onlySolar + labour + fuels Lower productivityHigher productivity Higher species diversityLess species diversity More genetic diversity within a species Less genetic diversity within a species Nutrients cycle within ecosystem Nutrients added e.g. fertiliser Natural population limitsPopulations managed e.g. planting, pesticides Climax communityInterrupted/managed community
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Agricultural Ecosystems About how agricultural ecosystems differ from natural ones WAL: All Most Some What is an agricultural ecosystem? How do natural and agricultural ecosystems differ? What is meant by productivity? How is net productivity calculated?
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What is the difference between a natural and agricultural ecosystem? Energy input, productivity, diversity, population, solar, food, climax community, limiting factor, yield, ecosystem
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