ECO - Disruptions [LESSON]

Disruptions

Human Influence

As the human population continues to grow, activities and technological advancements have disrupted the natural flow established by trophic structure, energy flow, and biogeochemical cycling. Human influence has resulted in a loss of resources, excessive pollution, and global climate change.

Natural Resources

Natural resources are a part of the natural environment that is used by living things to sustain life. These resources can be divided into two categories, renewable and nonrenewable resources. Renewable resources are those that can be replaced or recycled by natural processes, such as plants, animals, crops, soil, wind, solar, geothermal power, and even water if carefully managed. Nonrenewable resources are those that are available in limited amounts, such as fossil fuels, and metals such as gold, silver, and copper.

Pollution

Pollution is the introduction of harmful substances into the environment, by air, land, or water. Air pollution is caused most by burning fossil fuels, which causes particulates to fill the air. This type of pollution can cause cancer and respiratory illnesses. Air pollution also leads to acid precipitation. Water mixes with carbon dioxide to form carbonic acid or with nitrous oxide compounds to make nitric acid which collects in the water in the atmosphere and falls as precipitation. Acid precipitation damages plants, affects fish, and contaminates water reservoirs.

Land pollution is created when trash is burned, buried, or discarded instead of being recycled. Non-biodegradable wastes stay in the environment for hundreds to thousands of years. Biodegradable wastes are broken down naturally by bacteria or other decomposers in a much shorter period of time. Water pollution may occur in relation to air pollution or land pollution as acid precipitation and excessive waste meet natural water reservoirs. Water pollution may also occur as a result of sewage, industrial wastes, and fertilizer runoff.

Greenhouse Gases

Human activities release a variety of gaseous waste products, particularly carbon dioxide. Normally, atmospheric gases, including CO₂, act as an insulating blanket to trap heat and keep the earth from getting too cool at night. However, scientists have found that excess CO₂ may trap too much heat, resulting in global warming. Global warming is a theory that a temperature rise caused by the combination of different greenhouse gasses such as methane and carbon dioxide will continue until the earth becomes uninhabitable.  

Another closely related problem is that of ozone depletion. The atmosphere also consists of ozone, O₃, which serves to protect the earth from ultraviolet radiation. Gases such as chlorofluorocarbons (CFCs) are responsible for the depletion of the protective layer of ozone gas.

Have you ever lost your phone? Ever wonder why something you cooked did not taste quite right? Do you try to win at video games? These are some questions you may come across in your day to day life. Did you know you can use the scientific method to help you with these questions and more?

Our choices affect ecosystems in big and small ways. The pesticides we use in gardens kill insects we consider pests, but they can also kill some reptiles and amphibians that are natural pest reducers, such as lizards and frogs. In addition, the fertilizers used by farmers can flow into local lakes and rivers with the rain, depositing nitrogen compounds that deplete oxygen levels in the water. Municipal and industrial wastewater systems, septic tanks, and discharges from car exhausts also deposit nitrates into freshwater and marine ecosystems. These pollutants cause fish kills and brown blood disease in the fish remaining. Brown blood disease disrupts oxygen transport in the cells of fish.

Try the Impact Self-Assessment below.

Invasive Species

An invasive species is a species that has been introduced to an area outside of its native range and has the potential to cause harm or has already caused harm in its new environment. It can have a large impact on the native species of the area.

Kudzu is one dramatic example of what can happen when a species gets introduced into a new ecosystem where it has abundant resources and few predators. The kudzu plant was introduced to the United States from Asia in the late 1800s as an ornamental plant, and it was planted widely in the South in the early 1900s to reduce soil erosion.  The people that introduced it didn’t know it would outcompete most of the native species and take over the way it did.

Invasive species are often so successful because they do not have any natural predators in the new area and the other lower trophic level organisms don’t have adaptations to avoid them.

[CC BY 4.0] UNLESS OTHERWISE NOTED | IMAGES: LICENSED AND USED ACCORDING TO TERMS OF SUBSCRIPTION