Transcript Document
Monocultures L.O: to describe the impact of monocultures on biodiversity Starter: AS BIOL1 recap! If Mono = one, ?? = Two, ?? = Three, ?? = Six Do you know any others? (Chemists!) Definition The cultivation of a single crop in a given area. What? Why? So? Therefore? Why Monocultures are Created What? Why? So? Therefore? Why Monocultures are Created Advantages of monoculture: • Reduced plant competition for nutrients, space and solar radiation • Control of undesirable (unprofitable) organisms • Reduction of costs by limitation of specialized machinery required for arable operations • Maximize profit from the growing of high gross margin crops What? Why? So? Therefore? Impacts of Monocultures Paper simulation! Light Green is Noble Fir Red is Western Red Cedar Blue is Vine Maples Yellow is Western Hemlocks Orange for White Fir Pink is Bigleaf Maple Yellow is Western Dogwood What? Why? So? Therefore? • When a habitat is very diverse with a variety of different species, it is much healthier and more ecologically stable. • One of the reasons for this is that disease doesn't spread as easily in a diverse community. If one species gets a disease, others of its kind are far enough away (due to the variety of other organisms) that disease is often stopped at the one or two individuals. 1. What type of competition would be present in the wood? In the monoculture? 2. Which forest would have more ecological stability? Why? 3. Why didn't the disease spread as fast among the Douglas firs as it did in the first simulation? 4. Why would you need to use more insecticides in monoculture? Is this good or bad? 5. Why have farmers been told to plant hedgregrows around their fields? 6. Extension: Many species can only live/reproduce in 1 type of forest. The spotted owl is an example - it can only live and successfully reproduce in old growth forests(big, old cedars, hemlocks, etc.). If these old growth forests are cut down, it's unlikely this owl will survive. Environmentalists call it an "indicator" species." What does this mean? Why be concerned about 1 species? Northern Spotted Owl Northern Spotted Owl Have a narrow range of ecological tolerance and their presence or absence indicates the ‘health’ of an ecosystem Impacts of Monocultures http://www.bbc.co.uk/learningzone/clips/natural-balance-the-forest-andindustry/4707.html What? Why? So? Therefore? Biodiversity What is it? http://www.youtube.com/watch?v=oeQMRlbbI4Q