Wild fisheries geological record of human activities of the last century. Some specific examples are Eutrophication is an increase in chemical nutrients, typically compounds containing nitrogen or phosphorus, in an ecosystem. It can result in an increase in the ecosystem's primary productivity (excessive plant growth and decay), and further effects including lack of oxygen and severe reductions in water quality, fish, and other animal populations. The biggest culprit are rivers that empty into the ocean, and with it the many chemicals used as fertilizers in agriculture as well as waste from livestock and humans. An excess of oxygen depleting chemicals in the
Artificial reproduction Artificial reproduction Artificial reproduction/propagation is the creation of new life by other than the natural means available to an organism. Examples include artificial insemination, in vitro fertilization, cloning and embryonic splitting, or cleavage. Cutting plants' stems and placing them in compost is also a form of artificial reproduction. We can grow many plants from one plant by using the man-made methods. The process of growing many plants from one plant by man-made methods is called artificial propagation of plants. A number of methods of artificial propagation of plants are used in agriculture (for raising crops), and horticulture (cultivation of vegetables,