In these pages we'll learn:
All living things we know of are a part of the Earth's biodiversity, the diversity of life. The concept of biodiversity can be divided up in levels such as:
An important aspect of this is that these are all interconnected. As we know, several species are only found in specific areas, or ecosystems. We do not find many rainforest trees in the desert for example. Some species are adapted to specific temperature ranges or need a minimum amount of rainfall every year to survive [Rainforests]. Other species may live their whole lives on land except when it is time to mate. Frogs and toads, for example, lay eggs that need water to develop, [Frog Video]. Species may also be restricted to an environment because of other species, either because of competition that allows the stronger competitor to occupy the space [for example Mangroves] or by intricate relationships where one or more species are dependent on the presence of another species, [ie. See Symbiotic Shrimp-Goby Relationships]. So it is important to realize that in nature there is often a reason why things are found where they are and that every habitat is a network of species. These species have generally, in turn, evolved to be dependent on each other but also on the specific conditions found in that environment for survival.
If an area is suddenly destroyed or even disturbed, the chance is often very small that all species will have time to find a refuge within reasonable distance to survive. Another very important aspect of this that the biological diversity also includes things we may not necessarily like such as wasps, venomous snakes, sharks, poison ivy and ticks. Some may say, "I can do without those things but I agree that we should help the Pandas and dolphins". Well, it is just not that simple since in nature, fundamentally, everything plays a role.
Why should we strive to conserve habitats and species? Why should we care? The most striking answer to this question would probably be, "to survive as a species ourselves". The only way the human species is going to survive is a careful and sustainable use of the Earth's resources.
Estimates have varied greatly of how many species there are alive on earth today. [See 'How many species']. Different scientists have estimated between 2 million and 100 million species, where only about 1.4 million species have actually been described. New species are being discovered and described every year, especially in the tropics. I was not long ago that whole new ecosystems on the deep-sea floor were discovered. An environment that was thought to be relatively empty was found to hold a diverse community of organisms living together around deep-sea vents, thousands of meters away from sunlight.
Unfortunately for nature, biodiversity is facing a great challenge due almost entirely to one strong competitor - humans. The rapid increase in global human population, has resulted in major threats to our natural environment and many of its species. Humans have applied skills to alter nature in such abrupt ways that many species have had no chance to adapt to the new conditions. Since no one knows exactly how many species there are, it is difficult to say how fast the extinction rate is. It has on the other hand, been estimated that between 5-10 species may disappear every DAY. (Some even say that this number is an understatement). This would add up to several thousand species every year.
Extinctions have been occurring naturally for as long as earth has existed. The most commonly mentioned mass extinction was, of course, when the dinosaurs died out approximately 65 million years ago. The difference nowadays is that the extinction rate during the 20th century seems to have gone several thousands of times faster than before. It is obvious that we do need land to grow crops on, and we do need construction material to build houses for people to live in and, of course, we need to find ways to feed all people of the world. The problem is just how we could do this without causing more disturbance on nature, and what the results may be if we ignore the conservation of nature trying to solve these problems.
Some of the reasons why we should care for the Earth's resources and biodiversity can be divided up in three main categories:
1) Ethical and moral reasons
Several and even most of the species on Earth are older than us humans and it is our duty to help preserve as much of this diversity as we can. We also have a responsibility for generations to come. By removing habitats and species for short-term economical reasons we are overall reducing the value of what we leave behind to future generations.
2) Aesthetic and cultural reasons
Surely we have all been out in nature many times to return home revitalized, happy and filled with new energy. Maybe we have been on a vacation to a coral reef, a skiing trip or just taken a hike through a national park. All these beautiful natural experiences give us memories that we tell our friends about. Nature has also, for as long as humans have existed, been an inspiration to composers, artists and poets. The beauty of nature adds a level to our lives that I am sure no one could seriously say they could do without.
3) Material and economical reasons:
Decreasing the genetic diversity could ultimately also lead to a decreased ability of species to adapt to future environmental and pollution problems. Already several animal and plant species are used as bio-indicators of pollution. The conservation of species and genetic variation today may help us to keep a better eye on environmental health tomorrow.
Another more prominent economical reason to care for biodiversity
is to ensure a sustainable food source in the future.
The clearing of land to give space to agriculture or cattle removes
large habitats and with them species of both plants and animals.
The use of mangroves, for example, as
building material, removes a necessary nursery ground for marine
fish and thus, the food source for a local community. The mangroves
Many of our most important drugs and medications also come from nature. Every year researchers find new natural compounds that can help us treat diseases or be used as pesticides etc.
So please, give this a little thought when you hear about threatened species of animals and plants. Don't just ignore these facts. It does not take much effort to make a little difference, but the little difference could eventually help so much. Extinction does not give a second chance.
Text by Jonas Stenstrom
Biodiversity Lesson PlansRob Nelson