Animals and AgricultureEnvironmental ScienceChapter 15 Section 3

Animals and Agriculture Remember, the total energy needed to grow plants for

food is much less than the energy needed to raise animals as food.

Most humans include some animal products in their diet.

Our ancestors obtained animal proteins by hunting and fishing.

Now, most people get animal proteins from domesticated species. Bred and managed for human use.

Food From Water Fish are an important food source.

When too many fish are harvested over a long period of time, ecological systems can be damaged.

Overharvesting Catching or removing from a population more

organisms than the population can replace. Many governments try to put an end to this. No-fishing zones – fishing will improve in areas around

these after only a few years.

Aquaculture The raising of aquatic organisms for

human use or consumption.

Not a new idea.

China leads the world in using aquaculture to produce freshwater fish.

Aquaculture Methods

Fish farm Generally consist of many individual ponds that each

contain fish at a specific stage of development. Clean water is circulated through to bring in oxygen and

remove wastes. Fish grow to maturity and are then harvested.

Ranch Fish are raised until they reach a certain age and are

then released. Ex: Salmon will be released, live downstream, then

return to reproduce, where they are captured and harvested.

Aquaculture Most of the catfish, oysters, salmon, crayfish,

and rainbow trout eaten in the U.S. are the products of aquaculture.

Worldwide, about 23% of seafood.

Problems Pollution – large amounts of waste. Water usage – require large amounts of water.

Livestock Domesticated animals that are raised to be

used on a farm or ranch or to be sold for profit. Chickens, sheep, cattle, pigs, goats, horses,

donkeys, mules.

Provide leather, wool, eggs, and meat.

Can also be used as draft animals (pull carts and plows).

Livestock Ruminants

Cattle, sheep, and goats. Cud-chewing mammals that have three-

or four- chambered stomachs. Hundreds of breeds of cattle that are

suited to life in different climates. Not always used for meat – milk, blood,

dung, draft animals.

Livestock Poultry

Domesticated birds raised for meat and eggs.

Usually raised in factory farms. Criticized because of cramped, artificial

environment. Ducks and geese.

Ducks’ droppings are used in China to fertilize rice paddies.