Homo rapiens, species extinction and the meaning of life

By: Lykke E. Andersen*

The impacts of Homo sapiens on this planet are enormous.  We have turned about a fifth of the total land area of this planet into agricultural fields and pasture to feed ourselves; we are burning massive amounts of fossil fuels, thus altering the composition of the atmosphere and causing climate change; we are extracting at least 150 million tons of fish from the oceans every year; and we area leaving our trash everywhere. This predatory behavior has prompted John Gray, professor emeritus of London School of Economics, to call us Homo rapiens (1). Guilt over our adverse impacts is widespread, and the Voluntary Human Extinction Movement goes as far as suggesting that humans should stop breeding in order to save the planet (2).

It is true that we are a rather successful and aggressive species, at least so far. But we have only been here for a few hundred thousand years and the 4.5 billion year old planet has been through a lot worse than humans. More than 99% of all the species that have ever lived on this planet went extinct before humans arrived on the scene. Most disappeared simply because they were not adaptive and competitive enough to survive over a long period of time (background extinction), while others disappeared in mass extinction events, such as the one that wiped out the dinosaurs and most other land-based species 65 million years ago. Still, the level of biodiversity is probably higher than it has ever been (see figure 1).

Figure 1: Genus diversity during the last 542 million years according to the fossil record

Extinction is an integral part of life and evolution. If the dinosaurs hadn’t gone extinct due to an unfortunate encounter with a meteor about 65 million years ago (the 5^th mass extinction in Figure 1), humans almost certainly wouldn’t be here today. Every species in existence today is due to a long series of random events and accidents, and every single species, including us, are going to go extinct someday – it is just a question of time.

There are many other species on Earth that are at least as aggressive as humans. Sharks, for example, are extremely well adapted to a constantly changing climate, they have been around for at least 450 million years, and they have no natural enemies, except now humans. There are probably at least 1 billion sharks in the World, each of them consuming a lot more fish than humans (roughly 10% of their bodyweight per week), so in the oceans they are much bigger predators than we are (3).

On land, one could argue that certain angiosperms (such as corn, wheat, rice, potatoes, oranges and other flowering plants) are among the most successful and aggressive. They have taken over large parts of the world, and they have even made humans work as slaves for them – clearing land for their expansion, spreading their seeds, feeding them with fertilizer and water, fighting their enemies with pesticides, and even improving their domination of the Earth through GMO technology.

Bacteria are perhaps the most aggressive and most successful species on Earth so far.  They have been around for perhaps 3.5 billion years, and not only have they decimated human and animal populations repeatedly (being an important cause of many background extinctions), but they have also changed the composition of the atmosphere much more dramatically than humans. While humans so far have increased the amounts of CO₂ in the atmosphere by about 100 parts per million (0.01%), cyanobacteria changed the amount of O₂ from almost cero to 21%. That is a change several thousand times as big as ours, and an impact that caused the extinction of almost all other species on earth, as they were naturally oxygen intolerant.

In addition, large parts of what you consider you, is not even human. About 90% of all the cells in and on your body are non-human, mostly bacterial cells (4). Thus, from the viewpoint of many types of bacteria, humans are just a convenient habitat in which to feed and multiply.

Perhaps the only way humans are different from all the other species on Earth is that we feel bad about our impacts on other species. We like to think of ourselves as important – either as the pinnacle of billions of years of evolution, or as a plague that is going to destroy the planet. Few consider us simply to be an integral part of nature, equal to all the other species on the planet. One notable exception is George Carlin, who makes an excellent case of the insignificance of humans in this entertaining talk: George Carlin on the Environment.

If we climb down from the pedestal that we have placed ourselves on and recognize that, in the grand scheme of time and space, we are really quite insignificant, then we don’t have to feel bad about breathing, eating a steak, taking a nice warm shower, or leaving our cell-phone charger in the power outlet. We should enjoy our brief presence on this planet, and try to make the best of it. That includes being nice to our fellow beings, using our impressive brains to understand how the world works at all levels, and using that understanding to maximize human well being while minimizing environmental impacts.

For your reference: 

(1)    John Gray (2003) Straw Dogs. London: Granta Books.

(2)    See http://www.vhemt.org/ .

(3)    http://wonderopolis.org/wonder/how-many-sharks-are-in-the-ocean/ .

(4)    Glauciusz, J. (2007) “Your Body Is a Planet.” Discover Magazine. June 19.

* Dr. Lykke E. Andersen is the Director of the Center for Economic and Environmental Modeling and Analysis (CEEMA) at the Institute of Advanced Development Studies (INESAD), La Paz, Bolivia.