AP ENVIRONMENTAL SCIENCE 2010 SCORING GUIDELINES

Transcription

1 Questin 3 (a) Why are zebra mussels lcated primarily in areas in the eastern United States rather than in the western United States? One pint can be earned fr any acceptable explanatin: The animal was intrduced in the eastern U.S. and is still spreading acrss the cntinent. The eastern states have mre surface waters available fr clnizatin and t act as crridrs t dispersal; the western states have fewer such habitats. The western muntain ranges (e.g., the Rckies) serve as a natural barrier t dispersal. Humans spread the animal, and human ppulatin density is generally higher in the East. (b) Hw are zebra mussels intrduced int islated lakes? Describe ne viable methd fr preventing the spread f zebra mussels int islated lakes. Tw pints can be earned: 1 pint fr a mechanism by which the mussels are spread and 1 pint fr a methd t prevent mussel intrductins. The tw respnses need nt be linked. Mechanisms f zebra mussel intrductin Transprt f bats r bat trailers with mussels attached Carried in water in bats (excluding ballast, which implies ceanging vessels) Inundatin f islated lakes with fldwater cntaining mussels Building canals r ther waterways between previusly islated lakes Transprt by animal vectrs (migratry waterfwl, etc.) Brught with fish used t stck water bdies Methds t prevent spread f zebra mussels Thrugh inspectin/cleaning f bats befre transprt r launch Flushing r draining f water between water bdies Refraining frm building cnnecting waterways Educatin/infrmatin campaigns t discurage practices causing spread Prhibiting transprt f bats t unaffected lakes

2 (c) Identify and explain ne impact that zebra mussels can have n aquatic ecsystems. One pint can be earned fr naming an impact, and 1 pint can be earned fr an apprpriate explanatin. The identificatin and explanatin must be linked. Impact n Ecsystem Increased water clarity/transparency Increased light penetratin in water clumn Increased phtsynthesis/primary prductivity Increased ppulatins f ther species (certain fish, waterfwl, etc.) Cmpetitin frm zebra mussels fr available resurces Decreased ppulatins f ther species (mllusks, insects, etc.) Altered water chemistry Disrupts fd chains/trphic dynamics Explanatin Mussels are filter feeders, remving slids frm water as they feed. Remve suspended matter frm water. Results frm increased water clarity. Results either frm greater primary prductivity (base f trphic pyramid) r greater ability f fish that are visual feeders t see their prey. Decreased ppulatins f ther species (mllusks, insects, etc.). Cmpetitin frm zebra mussels fr available resurces. Mussels change bigechemistry thrugh filtering and digestin f fd; shells sequester/stre minerals. Eats fd required by ther species.

3 (d) Identify anther invasive species, either terrestrial r aquatic, and describe ne negative impact it has had. One pint can be earned fr naming a species, and 1 additinal pint can be earned fr an apprpriate explanatin f its impact. The identificatin and explanatin must be linked. Acceptable examples include: Invasive Species Cane tad Rats Purple lsestrife (Eurasian) water milfil Snakehead fish Rabbits Kudzu vine Emerald ash brer Sea lamprey Nutria (Brazilian) pepper tree Pythns, cnstrictrs Japanese/Asian beetles Pigen/rck dve (Eurpean) starlings Feral dmestic animals (e.g., bar, cat) Ice plant Africanized ( killer ) bees Bll weevil Negative Impact Txin kills native predatrs. Eat bird s eggs; spread disease. Crwds ut native plant species in wetlands. Crwds ut native plants, clgs waterways. Preys n native fish, reducing ppulatins. Clear vegetatin. Smthers ther vegetatin. Burrwing and feeding kill trees. Predatin harms ther fish. Eats marsh vegetatin, destrying wetlands. Tissues are txic; shades ut ther plants. Eat native species, lwering ppulatins. Eat native plant species. Nuisance in cities; vectrs f disease. Cmpete with native birds fr nest sites. Predatrs f native species. Cmpetes with native plant species. Attacks peple/animals; displaces hneybees. Imprtant crp pest. Nte: A crrect respnse must identify a specific rganism. General categries f bita (e.g., snakes ) are nt acceptable.

4 (e) One strategy fr cntrlling an invasive species has been t intrduce anther nnnative species t cntrl it; this strategy can ften have unintended results. Give a specific example f the use f this strategy and discuss a negative impact f intrducing a nnnative species t cntrl an invasive species. One pint can be earned fr identifying a specific example f bilgical cntrl, and 1 additinal pint can be earned fr an apprpriate explanatin f a ptential negative impact. The tw respnses need nt be linked. Acceptable examples include: Bilgical Cntrl Insects (stem brers, leaf eaters) t feed n purple lsestrife Ladybird beetles (ladybugs) t feed n pest insects Parasitid wasps t cntrl weevils Bacteria (e.g., Bt) r viruses t cntrl animal pests Mngse t hunt rats Cane tads t prey n insect pests Predatin f nntarget species Cmpetitin with native species Negative Impact Txic t native predatrs, r reduces available fd t native predatrs Alters eclgical interactins, e.g., fd webs r bigechemical cycles Nte: The specific example cannt be hypthetical r a general prescriptin, e.g., intrduce a predatr f agricultural pests.

5 (f) Discuss TWO specific characteristics f invasive species that enable them t thrive in new envirnments. Tw pints can be awarded: 1 pint fr each specific characteristic. Generalist species Excellent dispersal mechanisms, allwing it t spread R-selected r r-strategist OR any f the fllwing characteristics: Large clutch size/many ffspring prduced Early nset f reprductin/early maturatin Frequent reprductin Superir defenses against predatrs in new envirnment Superir skills as a predatr in new envirnment Nte: Listed characteristics must be specific. Generic qualities r life-histry strategies are nt acceptable.