Genesis of Eden
Biodiversity Pages:
Lead Articles on Values:
Biodiversity is not just some benign backdrop for hiking holidays, but the very substance and foundation of our survival, whether we realize it or not. We are entirely dependent upon the plants, animals, fungi, and micro-organisms that share the world with us. Individually, they alone feed us, and without them we would starve. Yet we frequently act to undermine these very species essential to our welfare. In addition to food, they provide many of the drugs and other medicinal and industrial products on which the quality of our lives increasingly depends. They offer the promise of sustainable economy - productivity that the Earth can support on a continuing basis, so our children and, in turn, their children will survive and be able to live peaceful lives of abundant splendour..
We live in an age driven by the apparently insatiable desire of industrialized nations to go on getting richer, and of free-market economics driven by equally insatiable multi-national corporate organizations, competing to exploit the remaining resources of the planet. Though we are now beginning to consider atmospheric changes such as the ozone hole and global warming as significant international problems, we have yet to demonstrate we can hold good to effective action. However at the same time the threats to biodiversity, which are much more long-lasting are not being taken seriously politically. The fact is that up to a quarter of the species on Earth may be lost in the course of the next three decades - within the lives of the majority of us alive today, and a majority of biodiversity is likely to have perished by the middle of next century.
"Each year, we are cutting and burning 1.5 to 2 per cent of the world's remaining tropical rainforests; losing an estimated 24,000 million tonnes of topsoil; and adding some 93 million people to a world that is already far too full, judging from the extent of human misery, and starvation, let alone from the depletion of every conceivable resource." (Peter Raven "Porritt 71"). Since Rio, the rate of felling of the Amazon has increased some 30%, finally exacerbated by drying from accentuated El Nino, a possible consequence of global warming. Every, point on the Earth's surface, from the frozen wastes of Antarctica to the most remote stretches of the oceans, receives a steady shower of man-made chemicals. We are clearly "managing" the entire planet now, for better or for worse, whether we acknowledge this responsibility or not. In this sense, there is no longer any region that can be said to be truly "natural". The future impact of genetic engineering technologies is likely to be vast and has barely even been considered in the midst of runaway technological initiative.
Stewardship of Planet Earth
"Will we act as responsible stewards of the many organisms that share the Earth with us? We have certainly not given much evidence so far of our commitment; having given names to only 1.4 million of them, we don't know whether the total number may be 10 or 100 million. We understand even less - often nothing at all - about their individual properties, or the ways in which they interact with one another. Moving beyond our growth-orientated mentality which assumes that every, productive system on the planet can be expanded indefinitely to meet our needs, regardless of its biological basis, is an essential ingredient of stewardship. Every nation must work to develop its own base of information on biodiversity, and strive to understand, to use, and to save it, both for its own purposes and for future generations. For rich nations, this means understanding that we cannot continue to ravage our strictly limited home planet as if its productivity and stability were simply inexhaustible. For poorer nations, the challenge will be even greater, and will not be met without reversing the tragic flow of many millions of dollars from poor, starving countries to the rich industrialized North. Environmental stewardship and social justice go hand in hand"(Peter Raven "Porritt 71").
Multifarious Insects
There are more insects in the world than any other group of organisms. Until recently, virtually all the natural medicines we have developed have come from plants and fungi, but there is no reason why a sector which produces both cochineel and potent stinging toxins cannot have diverse biochemicals, especially to resist predators and to give protection against diverse plant toxins. "Currently only about 20% of all insect species have been identified, let alone chemically characterized. Bioprospecting in the insect species has only begun and is barely explored, yet the diverse insect species could be rapidly reduced in number with the destruction of habitats" (Peter Raven "Porritt 71"). There are currently some efforts under way to develop cooperative relationships with the governments of some developing countries in which wide assays of insect species are carried out.
A Case: Cone Snails
Just as arrow poison
frogs are famed for their toxins, so are cone snails.
Typical cone snails contain between 200 (chemical analysis)
and 2000 (genetic analysis) types of polypeptide toxin of between
10 and 30 amino acid units. By contrast, snake toxins frequently
contain 80 peptides and spider toxins up to 1000 units.
Left: Detail of the shell pattern of Olivia
porphyria and wave-like cellular automaton with long-range and
local autocatalytic interactions (Schroeder: Chaos, Fractals and
Power Laws).
The cone snail toxins represent both acetylcholine blockers similar to cobra venom toxin and ion blockers, which instead of the stopping flow of sodium ions like puffer fish, block one of the seven types of calcium channel. They also contain glutamate NMDA receptor blockers. No two species have the same toxins and many change their output over time. Their extremely varied shells, which mimic know cellular automata have fetched more than a Vermeer painting (New Scientist 19 Oct 1996 26).
Scientific American Feb 96 reported their use in a new pain-killing drug SNX-111 which proved effective in 5 out of 7 cases of intractable pain which had become tolerant to opiates. It thus represents the first of an entirely new class of compounds to treat severe pain.
A second case of medicinal toxins: The Platypus New Scientist Jan 3 98
The poison from the spurs of the duck-billed platypus could point to ways of designing new types of painkiller, physiologists say. They believe that a toxin in the poison acts directly on our pain receptors. The male of this strange Australian species has spurs on its hind legs that contain at least four different toxins. They are thought to help the animals defend their breeding territory. "It's an unusual venom that's not designed to kill or paralyse its victims," says Rosemary Martin of the Australian National University in Canberra. Humans that are pricked by the platypus experience intense pain that can sometimes last for several weeks, she adds. "it seems designed as a deterrent to induce pain." Martin and her colleagues, led by Greg de Plater, have now pinned down how at least one component of the poison of the platypus's spurs behaves. The researchers tested the effects of a protein in the toxin on the neurons of laboratory mice. lt turned out that the protein binds to a channel in the membranes of the neurons which allows positive ions to enter and leave the cells.
Snake oil and Cancer The protein contortrostatin named after the copperhead has been found to have a dual anti-cancer action stopping cells spreading and rducing blood-vessel formation. The Afican saw-scaled viper also produces a heart drug Aggrastatis. Reuter Aug 98
Case Study: The Wollemia Pines (New Scientist 6 Dec 1997 36)
In a remote stretch of national park in Australia, was accidentally discovered this stand of an exceedingly ancient pine Wollemia nobilis known only from fossil records dating back to 250 million years. The trees stand in a formation of Wollemi sandstone dating itself from around 250 million years ago. Wollemia was common in Pangea from 200 million years and existed worldwide until 65 million years ago and continued in Gondwanaland up until 30 million years ago (New Scientist 1997).
This single stand later proved to be genetically monoclonal suggesting it has survived by vegetative sprouting from the forest floor. A second stand has been found a kilometer away. Otherwise this is the only specimen of this ancient and widespread species still on Earth.
Endemic Diversity: Hot Spots and Fragile Niches
Almost every corner of the earth supports some form of life but while in some areas there are only a limited number of species, others, particularly certain tropical forest areas appear to have living diversity in superabundance. "Ecuador has many more plant species than the whole of Europe, which is more than 30 times as big. Madagascar has five times as many kinds of trees as the whole of temperate North America. The United States contains fewer woody species of plant than a single volcano, Mount Makiliang in the Philippines - and the entire 20 million square kilometers of the North American continent contain fewer bird species than a 2,000-square kilometer national park in Costa Rica" (Lean et. al. 133).
A species is called endemic to a region if it is found only in the specific locality and nowhere else in the world. Some areas have many endemic species. Indonesia has one sixth of the world's bird species, and nearly a quarter of them are endemic. Half of Papua New Guinea's birds, half of the Philippines' mammals, and about 80 per cent of Madagascar's plants are unique to them. Many islands have unique endemic species because of their evolutionary isolation, which are often exceedingly vulnerable because they have small populations easily wiped out by a single disaster.
"Tropical rainforests contain the greatest diversity of species; the US National Academy of Sciences reports that a typical patch, just 10 kilometers square, contains as many as 1,500 species of flowering plant, up to 750 species of tree, 400 different types of bird, 150 butterfly species, 100 kinds of reptile, and 60 species of amphibian. Insects are so abundant that no-one has yet been able to count them, but the Academy estimates that there may be as many as 42,000 in a single hectare" (Lean et. al. 133). The Amazonian rainforest helps to make South America the richest continent for wildlife and for biodiversity generally. It covers an eighth of the world's land surface, but harbours around a third of the world's birds diversity of species. Some local hotspots can contain comparable diversity to whole temperate habitats.
Coral reefs are the rainforests of the oceans; the Great Barrier Reef, for example, contains more than 3,000 animal species. "The rainforests' nearest rivals on land are areas with a Mediterranean climate - such as coastal California, the southern part of Western Australia, and the Mediterranean basin itself. These lack the rainforests' diversity of large animals, but have a huge number of endemic plant species" (Lean et. al. 133).
The Impact on Diversity of a Changing World
Climate and geography play a part in determining why some areas have so many more species than others. Areas with high temperatures and rainfall and little seasonal variation - like tropical rainforests and coral reefs - can support many more species than cold, dry places with distinctly different seasons. History also plays a role in determining why some habitats have more species. When areas became isolated from each other, as a result of continental drift, mountain formation, ocean inwelling or drying out of large rainforests into smaller islands, their animal and plant life evolves in different ways. The longer an area is isolated, the more distinct and different its inhabitants are likely to become. The best examples are islands and super-islands, such as Madagascar and Australia, with highly distinct fauna and flora, but a similar explanation has been proposed for the high diversity of the Amazon involving insular dry periods during ice ages and re-integration of these island forest sanctuaries during warmer wetter epochs.
The theory of continental drift suggests that all the major land areas were once joined in a single "supercontinent", Pangea. Between 200 and 80 million years ago this broke up, first into two land masses, Laurasia and Gondwanaland - and then eventually into the modern continents. Australia and Antarctica broke off relatively early, while Madagascar probably did not separate entirely until about 60 million years ago. New Zealand has been isolated so long it contains no land mammals. As these land masses separated they carried plants and animals with them. Some of the ancient forests of Gondwanaland are still detectable scattered as ancient beech forest stands.
As evolutionary paths begin to diverge, different species form, filling the available ecological niches. For example, Madagascar and Gondwanaland probably had very similar kinds of primitive primates when they separated. "However, over vast periods of time, Madagascar's primates (sheltered from the fierce competition that species still faced on the mainland) developed into lemurs, lower primates found nowhere else. Gondwanaland's primates, subjected to greater pressures, evolved into higher forms - including modern monkeys, apes and, ultimately, man. Madagascar has more than 6,000 unique flowering plants and half the world's species of chameleons are endemic to the island." (Lean et. al. 133)
Similarly in New Zealand many of the niches usually filled by mammals have been adopted by flightless birds. Australia's unique array of species evolved similarly in isolation from the rest of the world. Antarctica probably set out on a similar path, but became a snow-bound pristine wasteland with a few specialized species.
The Rich Endemism of Isolated Islands
Some islands have never been attached to the continents. Often volcanic, they start out as sterile outcrops of rocks, but later become colonised some even ending as low-lying atolls almost submerged and covered by their own biota. Their animal and plant life consists entirely of species which have colonized them from outside. Birds, bats and winged insects are obvious examples, as are fungi and plants with seeds able to blow in the air, resist the ravages of the sea, or be carried in the digestive tracts of birds or bats. Although only a small proportion of genetic 'landfalls' form other regions survive, over time, those that do evolve into species unique to their islands. "Almost 900 species of bird - 10 per cent of the world's total - have a range of only one island (Lean et. al. 133). Old, isolated islands such as the Hawaii and the Galapagos Islands in the Pacific have relatively low natural species diversity compared with continents, although their endemic species may be quite unusual. Many of those present will be endemic. Young oceanic islands, and those like coral atolls, which are small and frequently flooded by the sea, often have very limited diversity, except for their marine life
A
tropical grouper in a coral reef (New Scientist 1997)
Plundered Coral Reefs face Potential Extinction by 2050. Reef depletion is a global problem. Clive Wilkinson, the coordinator of the Global Coral Reef Monitoring Network, said about 10% of the coral reefs worldwide had disappeared. Coral mining over-fishing pollutions and damage caused by boats and anchors were ruining the reefs. 30% of the world's coral reefs are in critical shape and may die within the next 10 to 20 years and an additional 30% are coming under sustained attack (New Scientist 19 Dec 97).
Groupers and other natural predators are disappearing from Great Chargos Bank south of the Maldives because of illegal fishing from Sri Lanka. This is predicted to "cause the collapse of the reef ecosystem" (New Scientist 18 Oct 1997)
Islands on the Land
Any ecosystem or habitat surrounded by a different one is a biospheric island for the species which live there and similar mechanisms of evolution and immigration hold. "Flower-rich areas in Mediterranean climates are such ecological islands, since they have been separated from each other by enormous areas with quite different habitats for millions of years. They support very diverse flora, with a high percentage of endemic species. The same applies to isolated mountainous regions in the tropics, such as the highlands of Ethiopia, Cameroon and the eastern side of the rift valley in central Africa, which between them support a high proportion of the rare species of Africa" (Lean et. al. 133) . Similarly, the rift valley lakes in Africa are isolated from each other and each has evolved it own highly diverse kinds of fish as noted below in the Chichlids.
Chichlid Fishes (see also New Scientist 2 Aug 97)
Lakes Malawi, Victoria and Tanganyika harbour an unparalleled variety of chichlid fishes. Tankanyika supports 250 species, Victoria 500 and Malawi over 1000, 5 times as many as in the whole of Europe. These are now facing invasion of their habitats by introduced exotic species.
There have been many discussions over the causes for such diversity. The lake water levels have changed very significantly even over recent history. At least one of the lakes became dry only 12,500 years ago, in an ice-age related event which the species could not be expected to have survived. Biological remains including seeds of pasture species have been dredged from the deepest spot. This places a very short time limit on a very diverse adaptive radiation.
Many of the species have very confined habitats on the rocky shoreline and do not cross regions with different character. This may help explain how they could become separated into distinct genetic lines. Their uniquely adapted jaw may also have given them a monopoly over a variety of niches.
The biodiversity of the sea is often ignored by land-dwelling humans. The sea contains four fifth's of the photosynthetic potential and a major share of the planet's biodiversity and is sensitive to both pollution and destructive fishing practices, such as drift net fishing, and frank overfishing of the world's oceans.
Some regions are exceedingly valuable hotspots of diversity:
Most plants in many regions are endemic, with more isolated regions highest:
Small isolated ecosystems such as islands have many threatened species:
Madagascar : A precious example of endemism through isolation
There is a widely held belief that prairie potholes, many of which were drained for agricultural purposes, are easy to restore: just return the water. But the ecosystems of these ponds, originally created by the surging of glaciers, may not be so amenable to quick rehabilitation, says Susan M. Galatowitsch of the University of Minnesota. The botanist examined records of more than 1000 restorations conducted by the Fish and Wildlife Service and closely scrutinized 62 of them. She and others found that the longer the pothole had been dry, the less viable the seeds lying dormant in the soil proved to be. Certain types of plants also did not return, and as a result, few birds came back, "There is a whole suite of species that rely on sedge meadows," Galatowitsch notes. "Wrens, yellow-throats, bitterns and rails need dense vegetation. So they have not come in." She says it may be necessary to reseed areas to get the original vegetation to come in again. "The important thing is for people to be constantly improving restoration."
Part 2: The Holocaust of the Green Cathedral
Get the Genesis of Eden
AV-CD by secure internet
order >> CLICK_HERE
Windows / Mac Compatible. Includes
live video seminars, enchanting renewal songs and a thousand page
illustrated codex.
Return to Genesis of Eden?