

Deforestation - Deforestation is clearing Earth's forests on a massive scale, often resulting in damage to the quality of the land. - This decreases Biodiversity by destroying the ecosystems organism live in. - This occurs due to over-logging and in some situations forest fires. - The loss of habitat for millions of species occurs due to deforestation. - 70% of Earth’s land animals and plants live in forests, and many of these species cannot survive the deforestation that destroys their homes.

Overfishing - Overfishing is described as catching too much fish for the ecosystem to support which leads to an overall decrease in the number of fish and the diversity of fish in an ecosystem. - Overfishing is a non-sustainable use of the oceans. - 80% of the world's fisheries are fully over-exploited, depleted, or in a state of collapse. - Worldwide about 90% of the stocks of large predatory fish stocks are already gone.

Climate Change - Climate change and global warming are huge threats to biodiversity around the world. - If the Earth’s temperature continues to increase at the alarming rate which it has been in the recent past, many coral reefs will not be able to properly function, resulting in the death of said reefs, and the devastating loss of a rich and biologically diverse ecosystem. - In addition to the loss of coral reefs around the world, climate change affects all major ecosystems, namely those in polar regions.

Introduction of Invasive Species - The introduction of invasive species is a serious threat to biodiversity. - When invasive species are introduced, they can wipe out one or several existing, indigenous species, causing a loss of many different kinds of animals. - Examples of threatening invasive species are the kudzu vine and the zebra mussel. - In addition to causing a loss of biodiversity, invasive species cost the U.S. over 138 million dollars a year.

Overpopulation - Though overpopulation does tie in with deforestation, it is very much its own, severe issue. - The world’s population is growing at an alarming, exponential rate. Estimates suggest that the population in the year 2020 will be close to 7 ½ billion. - The Earth is not designed to sustain such an incredible amount of humans, nor is the environment. - As the population grows, there becomes a need for more land in order to provide everyone with a place to live. As the human population numbers go up, the amount of natural habitat, and therefore species, goes dramatically down.