Environmental Science
Name: ______________________________
Food and Agriculture
Goal: The student will explain how overharvesting affects the supply of aquatic organisms used for food,
describe the current role of aquaculture in providing seafood and describe the importance of livestock in
providing food and other products.
Vocabulary:
1. Domesticated –
2. Overharvesting –
3. Aquaculture –
4. Livestock –
5. Ruminant Chapter 9.5: Animals and Agriculture
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We have seen that the total energy needed to grow plants for food is much less than the energy needed to raise
animals as food.
Most people will include some animal proteins in their diets because they contain more essential amino acids than
proteins found in plants; animal proteins have been the basis of life for centuries; many populations have
traditionally obtained most of their proteins from fish and seafood.
Ancestors hunted and fished; today, animal proteins are obtained from domesticated species (about 50 species are
domesticated – bred and managed for human use) ex: chicken, sheep, cattle, honey bees, silkworms, fish,
shellfish, goats, pigs, water buffalo
Food from Water
 Fish are an important food source for humans
 Harvesting fish has become an important industry worldwide
 Damage to ecological systems can occur when too many fish are harvested over a long period of time.
Overharvesting
 Catching or removing too many of any one organism from a population without giving them time to be
replenished is called overharvesting.
 Governments are now attempting to stop overharvesting by creating no-fishing zones so the fish populations can
recover; surrounding areas have seen improvements after a few years
 These areas are necessary if fish markets throughout the world are to prosper
Aquaculture
 Fish and other aquatic organisms provide up to 20% of the animal protein consumed worldwide; however,
overharvesting is reducing the number of fish and other organisms in the oceans
 Aquaculture (raising of aquatic organisms for human use and consumption) is rapidly increasing and will continue
to be an important source of protein in the human diet
 Not a new idea; began in China about 4000 years ago; they lead the world in using aquaculture
 Different methods of aquaculture include: oyster farms and fish farms-ponds that contain fish at specific stages of
development by using clean water to bring in oxygen and remove CO2 and fecal matter, grow until maturity and
then are harvested
 Another type of aquaculture is known as ranch. Fish, like salmon, as raised until they reach a certain age, then are
released into the wild. Salmon return to their birthplace to reproduce, when they return, they are captured and
harvested.
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Most of the catfish, oysters, salmon, crayfish and rainbow trout eaten in the US are products of aquaculture;
worldwide, about 23% of seafood comes from aquaculture
This method can cause environmental damage is not managed properly (ex: aquatic organisms can create a large
amount of waste, can deplete local water supplies, wetland areas can be destroyed when aquaculture operations
are located within them)
Livestock
 Domesticated animals that are raised to be used on a farm or ranch or to be sold for profit are called livestock
 Global livestock populations have changed dramatically in the last 40 years; meat production per person has
increased worldwide since 1950
 Pig farming produces most of the meat consumed in developed countries; in developing countries. Livestock also
provided leather, wool, eggs, meat and many other functions
 Some livestock are used as draft animals (to pull carts and plows), while others provide manure as the main
source of plant fertilizer or as a fuel for cooking
Ruminants
 Cattle, sheep and goats are ruminants (cud-chewing mammals that have three or four chambered stomachs
 Cud is the food these animals regurgitate from the first chamber of their stomachs and chew again to aid
digestion; also have microorganisms in their intestines which allow them to digest plant material
 Humans have created hundreds of breeds of cattle suited for specific environments; they are most common in
North America, India and Africa; not always slaughtered for meat
 In Africa, herders drink milk and blood from their cattle, rarely kill them for meat; India has almost 1/5 of the
world’s cattle, they are sacred to Hindus and are not killed or eaten, they are used for milk, dung and as draft
animals
Poultry
 Chicken populations worldwide have increased by a greater percentage than any other population of livestock
since 1961.
 In more-developed countries, chickens and turkeys are usually raised in factory farms; these farms have been
criticized because of the cramped, artificial environments these animals live in
 Fewer ducks and geese are raised worldwide than chickens but in some areas ducks and geese are economically
important. Chinese use ducks for meat and for their waste; waste is used to fertilize rice paddies
Lesson Reflection:
Compare the nutritional value of some products made with meat to products made with a meat
substitute. Create a summary of your findings and include your own conclusion about the nutritional value of
the products.
Assessment:
1. Explain why the percentage of seafood produced by aquaculture is increasing so rapidly.
2. Explain how overharvesting affects the supply of fish such as salmon.
3. Describe the importance of livestock to cultures that consume no meat.
Active Reading: Animals and Agriculture
Lesson Extension (Technology/Application/Connection to Real World):
PBS Video: Salmon: Running the Gauntlet (50 min)