People control some characteristics of plants and animals they raise by selective breeding and by preserving varieties of seeds (old and new) to use if growing conditions change.
Learning Goal 3ac
In agriculture, as in all technologies, there are always trade-offs to be made. Specializing in one crop may risk disaster if changes in weather or increases in pest populations wipe out that crop. Also, the soil may be exhausted of some nutrients, which can be replenished by rotating the right crops.
For Grades: 9-12
Learning Goal 1
New varieties of farm plants and animals have been engineered by manipulating their genetic instructions to produce new characteristics.