Endangered Species Essay Sample and Writing Guide

What Are the Natural Reasons for Endangered Species Disappearing?

The Earth has already witnessed five mass extinctions and is about to experience one more. More than 99 percent of total species, amounting to over five billion species that ever existed on Earth are estimated to be extinct (Gaston and Kunin). But why does it happen? What are natural reasons for the species to disappear? Usually, it is linked to habitat fragmentation and climate change. But there also are other hidden reasons underneath them.

There is one latent reason that lies in the bottom of animal and plant extinction and poses the single greatest threat to the biological diversity of our planet. Habitat fragmentation is destructive change to landscapes and environment that is caused either by natural phenomena, such as floods, hurricanes, and volcanic eruptions, or human activities, such as deforestation, construction, artificial land drainage, and changing land use for agriculture. Despite the process, the natural environment of a species becomes diminished in total area size, broken up into several smaller patches or destroyed (Suzán et al.). If the habitat is reduced in size or divided into smaller pieces, it tends to support smaller populations of species, which poses an increased risk of a genetic diversity that influences long-term survival of the species. If the environment is demolished it forces inhabitants to flee from the territory, they adapted to for hundreds of years and migrated to a different environment. Such an intrusion into other species’ habitat often has disastrous consequences for local biota and leads to the arising of conflicts between local and migratory species (Suzán et al.). If they are not able to adapt to changes, one of them will be pushed towards extinction.planet.

Another cause of the extinction is climate change, which is the change in the distribution of average weather patterns, which can last for an extended period of time, like millions of years. Basically, the climate is the equilibrium of the energy our planet receives from the Sun, the density of the ozone layer which protects us from Sun’s ultraviolet radiation and concentration of greenhouse gases in the atmosphere. Greenhouse gases, such as carbon dioxide, methane, and nitrous oxide, absorb and emit solar radiation within thermal infrared range, thus keeping the Earth warmer (“Climate Change Indicators: Greenhouse Gases”). In the last 650,000 years, Earth’s climate changed for seven times with the sudden end of the last ice age about 7,000 years ago, that marked the modern climate era. Most of the factors that can change climate are variation in solar radiation, change in Earth’s orbit, depletion of the ozone layer and changes in greenhouse gas concentrations. While the energy output of the Sun and rotation of our planet are unabated, the density of the ozone shield and greenhouse gas concentration are in limits of reach and humanity fails to maintain it. The depletion of the ozone layer is only caused by human-made chemicals, such as chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances and enables more UV to come through. The power of UV radiation affects the way plants form, timing the growth and development, metabolism, and distribution of plant nutrient, which important implications for plant competitive balance, animals that feed on these plants, plant diseases, and biogeochemical cycles. The power of higher UV radiation levels affects the natural balance of gases and greenhouse gases in the biosphere, like carbon monoxide, carbon dioxide, and carbonyl sulfide (“Climate Change Indicators: Greenhouse Gases”). What is more, certain human activities, such as combustion of fossil fuels, oil, natural gas, and principally coal, along with animal agriculture, deforestation, and soil erosion produce an enormous amount of carbon dioxide (“Climate Change Indicators: Greenhouse Gases”). All this cause heat of the atmosphere, resulting in global warming that causes the world’s oceans to warm, as they absorb 80 percent of the additional heat, changes the global sea level.

Rising temperatures of the oceans directly affect the metabolism, behavior and life cycle of marine species. For various species, temperature serves as a signal for reproduction. Changes in sea temperature could have an impact on their successful breeding. For instance, the number of male and female offspring is determined by temperature for marine turtles, as well as some fish and copepods (“Climate Impacts On Ecosystems”). Changing climate could, therefore, skew sex proportions and threaten population survival. Rising temperatures in the oceans will also affect the development and population of the plankton which forms the basis of marine food chains and fixes about half the carbon dioxide that gets released into the atmosphere. As the oceans become warmer, the location of the ideal water temperature may shift for many species, thus forcing them to migrate (“Climate Impacts On Ecosystems”).

Sea level has been growing over the past century, and the rate has risen in recent decades. The increase of the sea level is usually linked to two primary factors: the thermal expansion of seawater and the added water from melting ice sheets and glaciers both as a result of the global temperature rise (“Climate Impacts On Coastal Areas”).

Increasing sea levels due to climate change may have a great influence on the coral reef ecosystem. The coral reef ecosystem is evolved to thrive within specific temperature and sea level range (“Climate Impacts On Ecosystems”). They live in a symbiotic association with photosynthetic zooxanthellae. Zooxanthellae needs the sunlight to produce the nutrients necessary for the coral. Rising sea levels may cause a decrease in solar radiation at the sea surface level, impairing the ability of photosynthetic zooxanthellae to synthesize nutrients for the coral, whereas, a sudden exposure of the coral reef to the atmosphere may cause coral bleaching due to a low tide event (“Climate Impacts On Ecosystems”).

The melting of the glaciers and ice sheets contributes to increasing the levels of the world’s oceans. It is affecting certain animal species at the North pole. One such species are the polar bears. They usually rely on the ice sheets that swarm on the Arctic sea to find their prey. Global warming is making the ice sheets to melt earlier every year, affecting the survival of the polar bears (Ma). Scientists have predicted that the polar bears will not survive an entire loss of sea-ice cover during the summer. They also estimated that the population of the polar bears is of a little more than 20,000 and that this number could decrease by the year 2050 (Ma).

It has been shown that the primary natural causes of the animal extinction are habitat fragmentation and climate change which include rising of the sea levels and melting ice sheets and glaciers. Despite the reason why the endangered species become extinct, it looks like it is somehow triggered by the human activities which we need to rethink to save our planet.

Works Cited

Gaston, Kevin, and William E. Kunin. The Biology of Rarity. Chapman and Hall, 1997.
Suzán, Gerardo et al. “The Effect of Habitat Fragmentation and Species Diversity Loss on Hantavirus Prevalence in Panama.” Annals of the New York Academy of Sciences, vol. 1149, no. 1, 2008, pp. 80-83. Wiley-Blackwell, doi:10.1196/annals.1428.063.
“Climate Change Indicators: Greenhouse Gases.” US EPA, 2017, https://www.epa.gov/climate-indicators/greenhouse-gases.
“Climate Impacts on Coastal Areas.” EPA, Environmental Protection Agency, 6 Oct. 2016, www.19january2017snapshot.epa.gov/climate-impacts/climate-impacts-coastal-areas_.html.
“Climate Impacts on Ecosystems.” EPA, Environmental Protection Agency, 22 Dec. 2016, www.19january2017snapshot.epa.gov/climate-impacts/climate-impacts-ecosystems_.html.
Ma, Michelle. “Polar Bears Across the Arctic Face Shorter Sea Ice Season.” Climate Change: Vital Signs Of The Planet, 2017, www.climate.nasa.gov/news/2499/polar-bears-across-the-arctic-face-shorter-sea-ice-season/.