Environmental Science Chapter 9 Notes 3

Pest Control Pests Any organism that occurs where you don’t want it, or in large enough numbers to cause damage Eat/destroy certain types of plants Need to be controlled to keep up percent yields of crops

Pest Control Pesticides Substances that kill pests Specifically – insects/small rodents Types Chlorinated hydrocarbons Persistent…Example DDT Persistent – doesn’t break down Causes biological magnification Organophosphates - degradable Carbamates - degradable

Pest Control Drawbacks Health Concerns Pollution and Persistence Chemical leaks Can cause cancer Pollution and Persistence Don’t break down, accumulate in water and soil Ex. Makes birds eggs so thin, they break when mama bird sits on them Pesticide Resistance Pests evolve resistance New chemicals must be developed

Pest Control Biological Pest Control Using living organisms or naturally produced chemicals to control pests Breeding plants with natural defenses with those that don’t have them to have the defenses transfer over Takes longer for resistance to evolve Only hurts the pest it is trying to control

Pest Control Types of Biological pest control Predators Pathogens Release natural predators to an area Pathogens Pathogens = disease causing organisms Most common – Bacillus Thuringiensis To control insect larvae and moths & butterflies Disrupting Insect Breeding Spread pheromones to confuse the males X-rays sterilize male insects

Pest Control Plant Defense Chemical compounds that repel pests and they are biodegradable Can be extracted and used as pesticides Physical barriers, for example tougher skin Breeding plants with natural defenses

Pest Control Integrated Plant defense Modern method of controlling pests on crops that seeks to reduce the number of pests, but does not completely eliminate the pest population Uses a combination of: Chemical pest controls Mix of farming methods Biological pest control

Genetic Engineering Using modern technology to allow desirable traits in crop plants to be transferred through the direct manipulation of genes for those traits A way to develop new foods Taking the gene that carries the resistance to a particular pest and putting it into another type of plant Continues to be heavily debated among scientists

Genetic Engineering Benefits Scientists who support it liken it to cross-breeding More precise and efficient, though Biotechnologists say these foods are just as safe as regular foods It can add nutrients, keep produce fresh longer, create more successful crops Possibility? Creating crops that could grow in poor soil or poor water conditions?

Genetic Engineering Risks Scientists that support this claim the foods are very different then the ones we currently consume Safety concerns Allergic reactions Safety of the “foreign” genes in the plants Religious/ethical concerns - inserting genes from foods they don’t eat into foods they do Environmental - if introduced to the wild, they could thrive over the original plant and cause extinction