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u01a1 Diversity of Life Essay
Scott Macdonald

For this essay, discuss the diversity of life forms within the biosphere and the features that unify all living species. How does the human species fit into this concept? Explain how we are at a tipping point, and why this affects all life. Limit your essay to 500–600 words. The scoring guide for this essay is linked in the Resources section, below. Consult it for the criteria your instructor will use to evaluate your essay. Use the following tools from the Study section for this unit (u01s1) to prepare and write this essay:

Submit your essay to your instructor as an attachment in the Diversity of Life Essay Assignment

Scott Macdonald

Professor Ian Lyons

BIO1050: Biology and Society

October 22, 2011

The diversity of life forms on Earth, their common characteristics, and the effects to the biosphere created by the activity of the human species

The planet Earth is abundant with a variety of living organisms, of which about 1.5 million are currently classified by scientists (Volk, T, 2005), and there may be millions more that are as yet unknown (Wilson, E.O., 2007). All of the living organisms discovered to date share at least 7 common characteristics – humans among them. However, as humans have developed industry, technologies, and communities, they are increasingly stressing the ecosystems of other organisms and risking to upset the delicate balance that may assure the mutual survival and way of life for all living things.

"Biodiversity (short for biological diversity) refers to all life on earth, including humans" according to environmental ecologist Nancy E. Todd, PhD (Cambridge Educational, 2005). Wilson breaks down biodiversity into three levels, from the ecosystems such as lakes and oceans, deserts, forests, etc. at the top, to the actual species themselves, and finally down to the genetics that each species is composed of.

Aristotle was one of the first to classify organisms, by separating between plants and animals. Within the grouping of animals, he subdivided them further by land, air, or sea creatures, and differentiated plant life by their stems. Over the years, as it became increasingly inadequate to classify the diverse range of living organisms that were constantly being discovered, categories were devised to "to better describe the specific relationships between living organisms" (Cambridge Educational, 2005). Today, biologists and scientific professionals depend upon a system of taxonomy devised in the 18th century by Swedish naturalist Carl Linnaeus, one that provides a blueprint for naming, ranking, and classifying life forms into distinct groups.

Currently, there are six kingdoms consisting of Animal (multi-cellular, Heterotrophic, move voluntarily, breathe oxygen), Plant (Autotrophes that produce their own food from sunlight [photosynthesis] or other inorganic materials – and are the main source of the oxygen in the atmosphere), Fungi (Saprophytes that feed off another source), Protista, Bacteria, and Archaea, the latter two being mostly single-celled Prokaryotes that lack a true nucleus encased by a cell membrane.
Initially, organisms were classified using morphological (external and structural) features and then complete physiology. Today, scientists use genetics and molecular taxonomy (amino acids, DNA, RNA, Ribosomal RNA, or rRNA), leading to new classification systems known as systematics and cladistics (common ancestry).

According to environmental ecologist Nancy E. Todd, PhD (Cambridge Educational, 2005) common traits among living organisms are that "we're made of the same substances", including carbon, nitrogen, and DNA. Living organisms all have cells, and "all cells have RNA and DNA" (Cambridge Educational, 2005). All living organisms grow and develop biologically, reproduce, metabolize food sources into energy, respond to stimuli within their environment (oxygen, sunlight, temperature, etc.), are animated (voluntarily or involuntarily), and are constantly evolving (Characteristics of Living Organisms, 2006). One of the traits that identifies an organism as belonging to a species is that not only can they interbreed and reproduce viable offspring, but their offspring can reproduce as well.

"There's a lot we don't know about biodiversity, but what we do know is that"... "preserving biodiversity is preserving the planet." – environmental ecologist Nancy E. Todd, PhD (Cambridge Educational, 2005). In accepting his TED award in 2007, Edward Wilson made one of his most passionate public pleas about the importance preserving biological diversity, and the interdependencies among living organisms, and that just "wiping out insects alone" would lead to the demise of all of humanity in just a few short months. He goes on to say that we understand very little about the diversity of life and the links among them, and "how pressing a danger that our activities have created for it".

According to Lester R. Brown in Plan B 3.0: Mobilizing to Save Civilization, there is concern by scientists that the world is at the precipice, or threshold of several points of no return, referred to as social tipping points – all with global consequences. These include shrinking populations of endangered species, rapid growth of human populations in developing countries that are unable to support them, failing underground water tables and water shortages, overfishing and the collapse of fisheries, soil erosion, excessive carbon emissions, and the failure of nation states to name just a few.

Brown describes how these create severe stress on governments, which in turn increases the danger of reaching such tipping points globally. These stresses are due to the decline of oil production and lack of plans to effectively cope with the shrinking supply, alternative fuels produced from commodities such as corn and wheat that are driving up the costs of food production, the increase in disease such as HIV/AIDS and malaria among developing countries, and the breakdown in societies that spills over into neighboring states – all of which may be more than civilization will be able to handle if not brought under control.

The planet is comprised of millions of forms of living organisms, most of which are yet to be discovered, which creates a severe lack of understanding about how they are all related. Human activity is encroaching upon the habitats of many of these organisms with effects we also don't understand, much less see. If we continue to disregard our responsibility of stewardship as the most intelligent life form on the planet – capable of advanced communication and tool-making, then we may not only create a very different ecosystem of other living organisms, but a very different way of life for ourselves, one with unknown and potentially irreversible consequences.

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Brown, L. R. (2008). Plan b 3.0: Mobilizing to save civilization. (1st ed.). New York, NY: W. W. Norton & Company.

Capella University, (2006). Characteristics of living organisms. [Web Map]. Retrieved October 12, 2011 from

Cambridge Educational. (Producer). (2005). Organization and diversity. [Web Video]. Retrieved October 12, 2011 from

Wilson, E. O. (2002). The future of life. (1st ed.). New York, NY: Vintage Books.

Wilson, E.O. (2007, March). TED: E.O. Wilson on saving life on Earth. [Web Video]. Retrieved October 15, 2011 from

© 2011. Scott Macdonald