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
- 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.
Extinct Species
- 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
Endangered Species
- 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.