Two weeks ago I highlighted a few species of plants and animals that are considered to be recovering from near extinction. In that post, I briefly alluded to the fact that many scientists in the biological realm believe the Earth has entered its sixth mass extinction event. Today I want to explore this matter with you in more detail.
Earth has gone through five previous mass extinction events before. The last, and possibly most well-known, was the extinction event that took out the dinosaurs. While extinctions have occurred regularly throughout history - made evident by the fossil records - what distinguishes a mass extinction event is the fact that large groups of species are lost in a relatively short time frame and that loss outpaces the formation of new species. Plants and animals face a great deal of stress coming at them from multiple sources on a daily basis. When those stresses drastically inhibit the species' ability to reproduce over a long enough period of time, eventually that species will become extinct. Mother Nature can be quite tough, and success really is measured in the ability to survive long enough to reproduce. In the case of many animals that do not reproduce the next generation on a massive scale (think frogs or insects laying their eggs), the parents also must be able to ensure that enough of their offspring survive to maturity so that reproduction by the new generation is more likely.
Today, biologists are seeing the rate of species able to successfully reproduce over successive generations in steep decline. This is due to a variety of reasons, but unfortunately they are either directly or indirectly linked to our activities. In the past, mass extinction events occurred after extreme and sustained shifts in biological parameters were achieved through natural means. The first and greatest extinction, the Permian, where 96% of all species went extinct came about because of a prolonged and intense series of volcanic eruptions that altered the atmosphere. The dinosaurs and other plants and animals from that same era are believed to have gone extinct after a meteor hit the planet, altering both ground and atmospheric conditions.
So how is it that humans are causing the sixth mass extinction? Our activities, whether directly or indirectly, are putting such stresses on biological life that they are unable to survive. Some examples of direct causation is the hunting of animals for food or other purposes. Steller's Sea Cow and the Passenger Pigeon are two instances of this cause. Other direct causations can be the competition for resources. We have all heard on some nature program at some point that a plant or animal is threatened because of habitat encroachment. This is because humans are much more successful at competing for resources. So much so that we don't leave a lot for other species to survive off of.
Humans are also indirectly causing the next mass extinction. Climate change and invasive species, among other factors, are drastically changing habitat structure, resource availability, and ecosystem dominance. We are not purposefully trying to cause a species harm, but our activities have introduced stress factors that burden these species even more. Coral reefs are an example of this, as rising sea-levels, warmer sea temperatures, and higher carbonic acid concentrations (all related to carbon emissions from human activities and subsequent climate change) are making it more difficult for the actual corals to survive. Not only would we lose the hard corals if they succumbed, we would lose an entire ecosystem and much of the marine life that depends on the reefs for their own survival.
This is another one those environmental topics that can be quite depressing. However, we needn't take a defeatist or there's-nothing-I-can-do position. As I previously posted, we have come to our senses before and saved a species from collapsing into extinction. We have prevented several species from dying out. There are those who work hard every day to raise awareness and funds to protect as many plants and animals as possible. By supporting measures such as the Endangered Species Act and consuming items that are clearly marked with an "eco-friendly" stamp (such as the Rainforest Alliance stamp), as well as continuing to push our leaders to enact meaningful emissions legislation, we can reduce the stresses that are being heaped up on the rest of our biological "family". These issues are raised - with clear warnings sent out - not to depress us, but to spurn us into action. We are the only species that has such a wide impact on the natural world and we are the only species with the ability to recognize it and alter our behavior. It requires all of us, but we can stop this mass extinction before it gets worse.
Earth has gone through five previous mass extinction events before. The last, and possibly most well-known, was the extinction event that took out the dinosaurs. While extinctions have occurred regularly throughout history - made evident by the fossil records - what distinguishes a mass extinction event is the fact that large groups of species are lost in a relatively short time frame and that loss outpaces the formation of new species. Plants and animals face a great deal of stress coming at them from multiple sources on a daily basis. When those stresses drastically inhibit the species' ability to reproduce over a long enough period of time, eventually that species will become extinct. Mother Nature can be quite tough, and success really is measured in the ability to survive long enough to reproduce. In the case of many animals that do not reproduce the next generation on a massive scale (think frogs or insects laying their eggs), the parents also must be able to ensure that enough of their offspring survive to maturity so that reproduction by the new generation is more likely.
Today, biologists are seeing the rate of species able to successfully reproduce over successive generations in steep decline. This is due to a variety of reasons, but unfortunately they are either directly or indirectly linked to our activities. In the past, mass extinction events occurred after extreme and sustained shifts in biological parameters were achieved through natural means. The first and greatest extinction, the Permian, where 96% of all species went extinct came about because of a prolonged and intense series of volcanic eruptions that altered the atmosphere. The dinosaurs and other plants and animals from that same era are believed to have gone extinct after a meteor hit the planet, altering both ground and atmospheric conditions.
So how is it that humans are causing the sixth mass extinction? Our activities, whether directly or indirectly, are putting such stresses on biological life that they are unable to survive. Some examples of direct causation is the hunting of animals for food or other purposes. Steller's Sea Cow and the Passenger Pigeon are two instances of this cause. Other direct causations can be the competition for resources. We have all heard on some nature program at some point that a plant or animal is threatened because of habitat encroachment. This is because humans are much more successful at competing for resources. So much so that we don't leave a lot for other species to survive off of.
Humans are also indirectly causing the next mass extinction. Climate change and invasive species, among other factors, are drastically changing habitat structure, resource availability, and ecosystem dominance. We are not purposefully trying to cause a species harm, but our activities have introduced stress factors that burden these species even more. Coral reefs are an example of this, as rising sea-levels, warmer sea temperatures, and higher carbonic acid concentrations (all related to carbon emissions from human activities and subsequent climate change) are making it more difficult for the actual corals to survive. Not only would we lose the hard corals if they succumbed, we would lose an entire ecosystem and much of the marine life that depends on the reefs for their own survival.
This is another one those environmental topics that can be quite depressing. However, we needn't take a defeatist or there's-nothing-I-can-do position. As I previously posted, we have come to our senses before and saved a species from collapsing into extinction. We have prevented several species from dying out. There are those who work hard every day to raise awareness and funds to protect as many plants and animals as possible. By supporting measures such as the Endangered Species Act and consuming items that are clearly marked with an "eco-friendly" stamp (such as the Rainforest Alliance stamp), as well as continuing to push our leaders to enact meaningful emissions legislation, we can reduce the stresses that are being heaped up on the rest of our biological "family". These issues are raised - with clear warnings sent out - not to depress us, but to spurn us into action. We are the only species that has such a wide impact on the natural world and we are the only species with the ability to recognize it and alter our behavior. It requires all of us, but we can stop this mass extinction before it gets worse.
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