BIODIVERSITY AND ITS CONSERVATION
- Rapidly expanding human population and activities, amplified by the power of technology, threaten to eliminate much of the diversity of the biosphere.
- Humans have become a natural force, levelling mountains, diverting rivers into new channels and causing soil erosion on the order of 25 billion metric tons worldwide per year.
- Humans destroy wildlife directly by over-harvesting animals and plants for food and commerce.
- These impacts initiate species extinction and the unique and complex characteristics of the biosphere may be permanently lost.
- Extinction is neither a new phenomenon nor a process caused only by humans.
- The geological record shows that a number of widespread biological catastrophes have caused mass extinctions from the Earth.
- The best known of these occurred 65 million years ago when “dinosaurs” disappeared, along with at least 50 percent of existing genera and 15 percent of marine animal families.
- An even greater disaster occurred at about 250 million years ago when two – thirds of all marine species and nearly half of all plant and animal families died out over a period of about 10,000 years.
Current Extinction Rates
- The rate at which species have been lost appears to have increased dramatically over the last one hundred years.
- Before humans became a major factor, extinction rates from natural causes appear to have been one species lost every five to ten years.
- Between 1600 and 1900 A.D., human activities seem to have been responsible for the extermination of about one species per year.
- During this century, especially since World War II, the rate of extinction appears to have accelerated to dozens or even hundreds of species per year.
- Destruction of tropical forests; coral reefs, estuaries, marshes, and other biologically rich ecosystems threaten to eliminate millions of species in a human-caused mass extinction that could rival those of geologic history.
- It has been suggested that millions of species could be lost in the next few years if this destruction continues.
- The first population increase was about a million years ago and the discovery of fire and the invention of tools that enabled our ancestors to be a more effective society.
- Expansion of growth, of which we are a part, was stimulated by the scientific and industrial revolution.
- If the present trend continues, the world in 2100 will be more crowded, more polluted, less stable ecologically and more vulnerable to disruption.
- There are three points worth making about the capacity which is fundamental to our understanding of current dilemmas in managing the Earth system.
- We are animals, with the same basic biological limitations of birth, growth, reproduction and death of other animals and with the same basic competitive drives towards the acquisition of material resources.
- Passenger Pigeon: The last member of this species died in Cincinnati zoo in 1947.
- Overhunting and habitat disruption caused their extinction.
- Green pitcher Plant – Insectivorous plants: Only about 1000 plants remain because of habitat destruction.
- African violet these familiar house plants have almost totally disappeared from their native habitat in South Africa
- Siberian Tiger: These Siberian large cats are endangered in the world
- Black rhinoceros originally there were about one million rhinoceros in Africa and now there are fewer than 4000 Poachers kill them for their horns.
Wonders of nature
- Chimpanzee This Chimpanzee is using a strict to trick tasty termites out of their nest.
- If it used its fingers instead, the termites would bite them.
- Aya – Aye During the day, the rare aya – aye sleeps in a nest in the trees.
- It spends the night digging insects out of tree bark with its long third finger.
- To find out where the insects are, it has to listen carefully with its big ears.
- Leopards They are covered with black spots, which help to hide them when they sit up in the shady jungle trees.