Food and Agriculture ( Holt Environmental Science) – Flashcards

!. domestic animals are allowed to overgraze the land 2. too many crops are grown on the land and the land gradually loses its fertility 3. As a result of erosion, there is no fertile soil left to grow plants.

land where it is possible to grow crops

Food production is not increasing at the same rate as human population.

plant

Seeds are planted among the roots of the previous crop. The remnants of the previous crops are left to slowly decay providing nutrients to the soil.

We can raise aquatic organisms for human consumption (aquaculture)

1. It does not break down quickly into harmless chemicals. 2. It concentrates in the bodies of animals high in the food chain (biomagnification). 3. It causes some birds to lay eggs so thin thay they break when the birds sit on them.

Essential amino acids are the amino acids that humans must have in their diet. There are 8 of them. These are the amino acids that our bodies can not synthesize from other materials.

1. the failure of food production to keep pace with population growth 2. distribution problems caused by political turmoil 3. crop failure brought on by sustained / long-term drought.

The use of persticides and fertilizer increase the risk of pollution.

Erosion can be reduced by incorporating strips of vegetation into plowed land.

Rivers and groundwater

The pests can become resistant to pesticides via natural selection.

Persistent pesticides become concentrated in organisms high on the food chain. These pesticides undergo biomagnification.

leather, wool, eggs, meat, manure

It is being reduced by fast -growing human populations, soil erosion, and desertification.

It is most likely to happen when to soil is bare and exposed to wind and rain.

1. plowing with machines 2. irrigatin with drip systems applying chemical fertilizers

Integrated pest management used both chemical and biological means to control pests (unwanted animals in farming).

Carbohydrates supply energy; proteins supply the amino acids needed to help build and maintain the body; and lipids (fats and oils) help form membranes and hormones. Lipids may also be stored and used later for energy.

If some members of a pest population happen to have a gene that allows them to survive contact with a pesticide, they are more likely to survive and reproduce. The pests that are killed by pesticides will leave no descendants. Over time, a larger percentage of the surviving pests will be those that are not harmed by the pesticide. The quicker the pests breed, the sooner the resistance is noticed.

Biological insecticides include bacteria and reproductive-interfering agents that target the problem insects but do not harm other unintended species. Chemical insecticides can persist or build up and then harm other species which feed on the insects.

For most of the 10,000 years, farmers did not leave bare soil exposed in huge fields. Small fields and gardens meant less runoff. Crop residue was returned to the fields. Farmers also widely practiced crop rotation, and they let the land recover by letting fields lie fallow every few seasons. Erosion has become a serious problem with the widespread use of modern, efficient machinery and farming practices.

When there is a war between countries or within a country, transportation is disrupted. Without transportation, food may sit in storage rather than being distributed to the people who need it. Also, political struggles are power struggles, and members of one side often withhold food from members of the other side simply to gain an advantage in the power struggle.

Most common examples include cattle, sheep, goats, pigs, chickens, horses, donkeys, and mules; also ducks and geese. Livestock are raised for meat, leather, wool, milk, and eggs; these are the primary uses provided in developed countries. People in developing countries are much less likely to use livestock for meat. Livestock in developing countries (and sometimes in developed ones) are also raised to serve as draft animals, and to provide manure for fertilizer or to be used as a source of fuel. In Africa, Masai herders drink blood from cattle.

Integrated pest management (IPM) does not set out to eliminate pest populations completely, but rather to reduce them to a level that reduces their damage to crops. A management program is designed for each step of the process: assessing crop and pest ecology to determine actions, identifying and monitoring pests, preventing pests, and later controlling pests when necessary. IPM incorporates, as needed, farming methods, biological pest control, and chemical pest control.

Brad consumed 880 Calories, 20% (180 Cal) of which were fats (also accept 20.45%). Jenny consumed 690 Calories, 13% (90 Cal) of which were fats.

Advantage: Crops have higher yields, so more people can be fed from the same amount of farmland. Disadvantage: High-yield crops require more pesticides, fertilizer, and farm machinery than traditional crops.

Scientists use genetic engineering to transfer genes for desirable traits, such as pest resistance, into crop plants from other organisms. Its benefits continue to be debated.