Regents Prep: Living Environment: Human Impact:

The Earth has limited to resources to support populations of humans and other organisms.   Our ever increasing human numbers is depleting many of our planet's resources and placing severe stress on the natural processes that renew many of our resources.    

Ecosystem Processes
Natural ecosystems are involved in a wide variety of natural processes influencing humans and other organisms.    The activities of humans in the environment are changing many of these natural processes in a harmful fashion.    Some of these natural processes and a brief description of a human influence on these processes is indicated in the table which follows.

Human Influence on Some Ecosystem Processes

Ecosystem Process

Human Influence

 Generation of Soils Agricultural practices have exposed soil to the weather resulting in great loss of topsoil.
Control of the Water Cycle The cutting of forests and other human activities have allowed increased uncontrolled runoff leading to increased erosion and flooding.
Removal of Wastes Untreated sewage wastes and runoff from farms and feedlots have led to increased water pollution. 
Energy Flow Some industries and nuclear plants have added thermal pollution to the environment.   The release of some gases from the burning of fossil fuels may be slowly increasing the Earth's temperature. 
(Greenhouse Effect).
Nutrient Recycling The use of packaging material which does not break down, burning of refuse, and the placing of materials in landfills prevents the return of some useful materials to the environment.

Some Detrimental Human Activities
Humans are part of the Earth's ecosystem.   Human activities can either deliberately or inadvertently alter the balance of an ecosystem.   This destruction of habitat, whether accidental or intentional, is threatening the stability of the planet's ecosystems.    If these human influences are not addressed, the stability of many ecosystems may be irreversibly affected.   Some of the ways that humans damage and destroy ecosystems are indicated in the table below.

Some Ways Humans Adversely Influence Ecosystems

Human Influence

Effect on Ecosystems

Population growth Our increasing numbers are using excessive amounts of the Earth's limited resources.
Overconsumption Industrialized societies are using more resources per person from our planet than people from poor nations.
Advancing Technologies Often we introduce technology without knowing how it will influence the environment
Direct Harvesting This has resulted in a large loss of rainforest and the many products associated with its biodiversity.
Pollution Land, air, water, and nuclear pollution have had many adverse influences on ecosystems.
Atmospheric Changes These include the addition of Greenhouse gases mostly due to the burning of fossil fuels and depletion of our stratospheric ozone layer.
Other pollutants also have negative effects on living things.



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