PARASITISM
parasitism-relationship bet 2 organisms; parasite -lives in or one other (host) , benefits and harms host
plasmodium- pathogen of malaria disease, unicellular protozoan, vectors of malaria = man + female Anopheles mosq

Life cycle of plasmodium
(male A.mosq. -suck plant juices, dont carry parasite, female A.mosq. - suck vertebrates blood for strength & proteins to lay eggs) infected female A.mosq. bites suck blood from individual by piercing skin w/ stylets. Mosq injects saliva, containing anti-coagulant subs (prevent blood clot) & 100s of tiny sporozoites. Sporozoites > blood > liver > multiply > attack erythrocytes > asexual reprod. in RBC > merozoites > RBC bursts > merozoites released in blood > anemia, shivering, intermittent fever (toxins released when RBC bursts), pain in limbs, vomiting, profuse sweating. merozoites > gametocytes [(fe)male] (further development only in mosq) > female A.mosq sucks blood of infected person > gametocytes > mosq stomach > sexually reprod. > zygote > divides repeatedly > 100's of sprozoites > salivary glands for future blood sucking

Life cycle of female anopheles mosquito (biological vector)
Mosq > complete metamorphosis > 4 stages > eggs > larva > pupa > adult
Female A.mosq lay eggs on stagnant H₂O to obtain oxygen for resp., in ~2 days eggs hatch > larvae > larvae elongated w/ head, thorax and abdomen (end of abdomen - spiracles), the high surface tension of H₂O enables larvae to stay near surface. Larvae eat microscopic plants and animals in H₂O > grow rapidly > store food material in body for pupa stage (they wriggle in H₂O as they swim), in ~1 week; larvae > pupae > each pupa has a large round cephalothorax (head and thorax fused together) and curved abdomen, pupae eat stored food accumulated in body from larvae stage, after 5-10 days > adult emerges from pupa, spreads wings > flies, adult A.mosq abdomen tilted at an angle to horizontal surface when resting on a surface

Control of mosquitoes (control of vectors) (chemically & biologically)
mosq can be prevented from breeding by draining swamps, spraying lakes and ponds (stagnant H₂O) w/ insecticides & kerosene (thin film over H₂O > reduces O₂ supply to larvae and pupae > suffocate)
mosqs breed in stagnant H₂O > breeding places should be destroyed (drains > treated w/ insecticides)
chemical: insecticides- pyrethrum and some synthetic insecticides (DDT- dichlorodiphenoltrichloroethane, Dieldrin, etc)
residual spraying: on walls, under roofs > spray consists of small particles of chemicals > mosq land on surface > die
biological: uses living orgs to control pests > best method, few damaging effects & doesnt cause health problems
-fish introduced into lakes and ponds > feed on wrigglers (larvae) > less future adults
-bacterium, Bacillus thuringienisis, used in H₂O > produces protein which is poisonous to larvae > less future adults

Control of malaria
Controlled by preventing female A.mosq from sucking blood of malarial patients > use mosq nets + repellants
Drugs can also be used; quinine (causes abortion) - 1st anti- malarial drug, effective against parasite in RBC only, chloroquine- acts on diff stages of parasite in RBC, controls severe malaria, primaquine- kills parasite in liver and RBC, anti- malarial drug for long-term treatment and cure
Prophylatic drugs; taken by healthy ppl to prevent parasite from developing when it enters blood, paludrine for malaria
Parasite can develop resistance > immunization not possible

The Human Impact on the Environment
Reproduction in plants
Sexual reproduction in animals
Genetics
Cell Strcuture and Organisation
Enzymes
Animal and Plant Nutrition
Transport in Plants and Transpiration
Support, Movement and Locomotion
Transport in Man
Respiration
Excretion
Homeostasis
The Eye
Nervous System
Chemical Control of Plant Growth
The Use and Abuse of Drugs
Diversity of Organisms
Nutrient cycles and Ecology

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