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biodiversity (L: bios=life; diversitas= variety) the variety that exists among organisms and their environments.  The term, short for biological diversity, is used mainly by scientists, conservationists, and others interested in the study, protection, and sustainable use of living things.  Protecting biodiversity is one of the greatest challenges facing humankind.  The scientists who specialize in ways to preserve it are called conservation biologists. (World Book 2000)
Biodiversity is a better word than biological diversity, which literally means variety in the knowledge of life.

The Convention on Biological Diversity (1992) defines biodiversity as: the variability among living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.

• biological resources: food (plant and animal), forest products, fuel, timber, pharmaceuticals, fish,
• unknown resources: pharmaceuticals, biocides,
• genetic resources: enabling us to cross wild species with food or flower species to obtain improved varieties and hybrids.
• ecosystem services: providing fresh air, cleansing the water, recycling our wastes, etc. See chapter below.
• tourism and recreation: people like to visit natural places as these become rarer. Seeing rare species can bring in money.

• keeping a species DNA data bank: by keeping some tissue samples containing an organism's DNA, the organism may be reconstructed at some later date, when the technology for doing so, is ready. However, no living organism has been resuscitated this way yet, and it remains doubtful if it can be done at all. Even if this were possible, the reconstructed organism must be raised in an environment which is suitable for its survival, complete with the right food and shelter and so on. Thus all the organisms around it need to be reconstructed similarly, and in the right numbers; then released in the right physical environment. Clearly, this option cannot be given any credence.
• keeping seed banks: seed banks are already being kept successfully of cultivars which have not been brought to production. Also the seeds of various wild plants are maintained this way. These systems work, because the species concerned are all crops for cultivation, not for preserving or creating wild environments.
• planting parks full of different species: although this may be pleasant to the eye, it does not constitute a natural environment, where species depend on one another, being grazed and predated upon by others, while maintaining their own populations. Parks need maintenance by humans such as trimming the trees and mowing the grass and culling deer. Most parks contain exotic species, which do not really belong there.
• zoos with varied animals: although a large variation in animals may assist in education, the numbers a zoo maintains, has no bearing to those found in nature. All animals live in separate pens, and do not maintain natural habitats. Zoos specialise only in spectacular and large animals, not in those essential to natural environments, like insects, worms, bacteria and so on.
• captive breeding: it is claimed that zoos are playing an important role in captive breeding of endangered species, and indeed they pay much attention to the genetic variability in the animals they rear. However, captive breeding is very expensive and does not lead to lasting solutions. It also focuses on only a few large species. Their numbers will never add up to a functionally living community, and releasing them back into the wild is questionable.
• reintroducing native species: by reintroducing native species into protected areas, it is hoped that their survival is enhanced. Indeed some successes have been scored, but all too often, the effort does not in any way affect a species' precarious state. Often the habitat or climate of the protected area proves to be unsuitable, and introduced species do not breed. However, almost-extinct plant species have been cultivated and spread all over the world, where they now live successfully in home gardens and parks.
• introducing alien species: by introducing alien species, one enhances biodiversity, it is thought. However, these species are competing with the native ones, displacing these and causing extinctions in others through predation and competition. In the end, every garden variety is a potential invading species. Many plant and animal species, once thought harmless, have turned into aggressive invaders.
• creating new species: new species can be created by breeding, cross-pollination, hybridisation, and genetic engineering. However, such species need a long period of testing whether they are suitable for the environment in which they are introduced. Most likely, they will upset an existing balance, or die. However, GE for crops is more predictable in its outcomes.
• habitat restoration: by planting shrubs and trees, people hope to restore habitats that were once lost. However, such plantings have very little chance of being in the right place, quantities, species and timing. As a result, unbalanced communities are made, not resembling a wild environment at all. They remain man-made parks.
• feeding wildlife: by feeding wildlife, it is hoped that more will survive. However, it causes wild animals to congregate to feed lots, causing unnatural tracks and erosion. It draws them to the places where diseases originate from human domesticated animals. Occurring in dense concentrations, the wildlife is more likely to spread contagious diseases. It is above all, an unnatural situation.

species (L: specere= to look; species= appearance, beauty, kind) a class of things having some common characteristics. A category in the classification of living organisms consisting of single individuals capable of exchanging genes or capable of inbreeding.

Although the above definition appears simple enough, in practice, it is difficult to tell species apart.
morphological species concept (MSC): species differ if they have different form. However, some species have richly varied forms. In some species, males and females look entirely different. Other species have many colour forms (like flowers).
biological species concept (BSC): species differ if they cannot interbreed. However, many distinct species do interbreed, but their offspring is less successful, sometimes sterile. Often species who could interbreed, are prevented from doing so, because they are isolated from one another.
DNA species concept (DSC): species are distinguished by the differences in their DNA. However, some very distinct species have only very small differences in their DNA. (Human and bonobo chimpansee DNA differ only by 0.013). This method is also used to quantify genetic diversity within a species. However, many invertebrate species and plants reproduce mainly asexually.
sibling species: even though species look alike, they do not interbreed and are truly separate species.
hybrid species: species can be crossed to produce a new species, which is often sterile. If hybrids between two similar species cannot be found in the wild, they must be biologically separate species. But when similar species are geographically separated, this becomes difficult to establish. All breeds of domestic dog can interbreed to produce fertile offspring. It is estimated that up to 10% of all species hybridise in nature.
bacteria: single-celled organisms have different means of reproduction. Viruses play an important role, being able to transmit genetic material from one organism to another. When examining a soil sample, one may visually distinguish a hundred different bacterium species, but DNA techniques applied to the entire sample, find a hundred times more. Are these truly different species? If so, the species diversity of bacteria alone eclipses all others, estimated at 70 million species.

• chance: breeding and (sexual) multiplication causes an exchange of genes, by which offspring are not identical to their parents. As a result, variety is created, as individuals have different properties. If their properties are more suitable, they will survive better.
• competition: every organisms has the capacity of producing more offspring than strictly needed. Survival is dictated by competition for food, for space, for partners and so on, which is in effect a daily test of suitability.
• functionality: nutrients and energy are the most precious commodities (tradable items) of an ecosystem. Those species able to recycle these commodities, while living frugally from them, have a better chance of surviving. It appears as if species co-operate as groups, while competing as individuals.
• habitat change: every species has an influence on its habitat, by the simple reason that it lives from what the habitat provides. As species or their numbers change, so does their habitat, including physical qualities such as soil, slope and landscape.
• isolation: when one group of a species is isolated from another (and with it many other species, like on an island), its gene pool develops in its own direction (and so do all other species, interacting together). The slightest difference in environmental conditions will then lead to a community of new species.
• time: genetic changes happen slowly from generation to generation, sometimes accelerated by sudden environmental changes. Evolution takes an enormous amount of time.

There are three kinds of species, judging by the way their numbers are increasing or decreasing:

• those on the way in: new species with improved traits (characteristics), moving to out-compete old species, upsetting the balance of nature until a large number of other species have adapted to the new situation. The number of species of this kind are very few, but where humans have disturbed an original habitat, while at the same time introducing new species from other places of the world, a major shift in biodiversity occurs.
• those in stable relationships: the majority of species is in a stable and functional relationship with the other species of the same ecosystem. Generalist species live over a wide range and may have various functions. Specialist species have a narrow range and function; they also have less genetic variation.
• common species: the main players in the functionality of ecosystems, forming the main guilds of producers, grazers, predators, scavengers and decomposers. Many other species depend on them, reason why they are also called keystone species. A drastic change in the number of a keystone species ripples through the fabric of the ecosystem, causing drastic changes everywhere. In the sea, many keystone species are overfished by us, leading to unforeseen change.
• rare species: species which maintain themselves in small numbers, using the existing ecosystems and their services, while not depending for their food on any specific species. They could also be on the way out to extinction.
• commensal species: species living on or with another species but not affecting that species.
• mutual species: species living together while benefiting each other.
• parasitic species: species living from a host species.
• those on the way out: species which have been displaced by new species, which are 'fitter' for their environment. Few species fall in this category, although the spread and multiplication of humans, has displaced many species, which have proved to be 'unfit' to live in a smaller space, together with humans. The loss of species which have already declined to small numbers, is usually insignificant.

(A separate section on this web site will be devoted to evolution)

f003929: a pregnant male seahorse (Hippocampus abdominalis) hangs on to a branch in the tidal current of an estuary in New Zealand. Seahorses have evolved a peculiar way of reproduction. The female lays her eggs into the male's pouch after an affectionate courtship. Inside the pouch they are fertilised. Each egg then attaches to the pouch's lining, drawing food from the father and developing into a tiny seahorse. At 20mm length, the 50-200 young detach and escape to live entirely on their own resources.

f023214: A male long-tailed stingray (Dasyatis thetidis) tolerates a diver touching his wings. Poor Knights Islands, New Zealand. Stingrays and sharks, considered primitive cartilagious fishes, have evolved a system of internal fertilisation. Males have two penises (claspers), as seen trailing behind the animal above. Females give live birth to two baby stingrays, which are entirely functional and capable of looking after themselves, after birth. These are two examples of nature's way of reinventing the wheel in different ways.

• genetic diversity: the variety in the genome.
• individual diversity: the variety of genes present in the members of a species, as visible in size, shape and colour, but also by invisible differences, like enzymes capable of metabolising specific substances.
• species diversity, the most familiar type of biodiversity, refers to the variety of species in a specific place or among a specific group of organisms.
• bodyplan diversity (taxonomic diversity): the variety in phyla, offering various body plans, particularly in the oceans.
• size diversity: the right size for the right job.
• ecological diversity: the variety of ways organisms live together, producing visibly different habitats.
• ecosystem diversity refers to the variety of physical settings on earth, such as forests, deserts, lakes, and coral reefs, and their populations of plants and animals.
• habitat diversity: the variety of biological communities within larger ecosystems and biomes.
• functional diversity: the variety of functions, trophic levels, guilds and others to make an ecosystem work. Size diversity is an important aspect of this too.
• physical diversity: the variety in climatic areas, biomes, geology and so on. Although not directly part of the living stock, these factors have nonetheless a profound influence on biodiversity. In general, the higher the temperature and the more moisture, the more productive and diverse life is (biodiversity).
• global ecoregions (biome types): a number of physical factors determine the type and quality of the world's major ecosystems (tundra, taiga, boreal forest, prairie, desert, rainforest, etc.). Going from pole to pole (changing latitude), the temperature changes, and with it a number of other factors. All continents have mountain ranges with wet and dry sides, and they have dry central areas. (See also oceanography/circulation)
• temperature: the surface of the earth curves away from the equator. Less sunlight reaches the surface as one travels to the poles. It makes the poles cold and the equator warm. The amount of radiation changes gradually, but temperature depends also on moisture.
• seasons: the earth rotates on a 23.5º angle with the sun, causing the seasons. Over the equator, seasons do not change in temperature, but over the poles they do so most. Seasons affect the delivery of light, warmth and moisture.
• rainfall: due to the rotation of the Earth, rain does not fall equitably everywhere. Most rain falls over the tropics. Two desert bands extend north and south of it. From there to the poles, rain increases, then decreases again. In the centres of large continents, exist desert areas where the rain, originating from the oceans, does not penetrate.
• evaporation: (potential) evaporation increases rapidly with temperature. At the poles it is very low, but over the equator it is high, and it changes gradually between these extremes. The amount of evaporation powers plant metabolism but the amount of water available depends on the difference between rainfall and evaporation. Their combined effect is crucial to plant life.
• soil: the quality of soil affects the plants that grow there, but plants in turn affect the quality of the soil. In the end, soil quality is determined entirely by the factors mentioned above, and to some extent by the local geology.
• local conditions: within the global ecosystems, an enormous variety of conditions prevails, affecting biodiversity. The local physical conditions mentioned below, affect one another locally. For instance, moisture and temperature promote plant growth, which affects shelter, which affects temperature and moisture, and so on. The local topology (land form) is also of enormous importance. Mountains become cooler and windier at height. Behind mountains shelter is found and desert conditions. Before mountains rainfall and wet forests. River valleys and wetlands create their own microclimates.
• temperature: the local temperature.
• moisture: moisture is collected on leaves, in the soil, in the subsoil and aquifers.
• wind: wind can damage plants, lower the temperature, and reduce moisture.
• slope: the slope of the land makes soil erode more quickly, resulting in poor soils uphill, and it causes water to drain more quickly, causing drier conditions uphill. The slope is decisive on what lives where.
• aspect (angle facing the sun): the aspect of a slope is also important. Shaded slopes are moist, promoting ferns and shade loving plants, whereas sunlit slopes are dry, promoting drought resistant plants.
• substrate: the local geology can change in rapid ways. Volcanoes can interrupt the landscape, and with their fertile soils introduce different species. Geological faults may thrust sedimentary layers upward, changing the way water drains. The sub soil may consist of sediments or hard rock. Minerals may enrich or pollute the environment. The substrate may provide niches for shelter for animals, and so on.

The path of succession to climax vegetation is marked by the following changes:

1. Soil development: progressive development of the soil, with increasing depth and organic content, and differentiation of layers or horizons.
2. Increasing biomass: increasing height and massiveness of the plants, while also differentiating the strata or tiers of vegetation.
3. Storing nutrients & energy: the pool of nutrients and energy held in plant tissues, animals and soil, increases.
4. Increased productivity: productivity, the rate of formation of organic matter increases.
5. Microclimate: the microclimate under the canopy becomes determined by the forest, and increases in importance.
6. Increased biodiversity: species diversity increases from simple succession communities to mature climax communities.
7. Equilibrium: populations rise and fall, replacing one another until an equilibrium is reached.
8. Long-lived species: long-lived species begin to dominate.
9. Stability: the relative stability of the communities increases. Biodiversity climaxes.

Hot spots are places in nature where one notices a remarkable increase in species, often accompanied by an increase in numbers as well. They appear as oases or slices of paradise, even to the untrained eye. Why would this be? Remember that just as a species stores a record of its evolutionary past, an environment does so too. Hot spots therefore, may give clues of a distant past, interesting to be studied, and also valuable to be preserved. Here are some possible causes:

• moisture: since moisture is the most important need for life, the reliable availability of moisture, causes local hot spots. Such moisture may be provided by a small lake, a spring or water resurgence, a wetland. A groundwater forest may arise in an arid climate where groundwater seeps upward from an impregnable layer of angled rock (artesian water).
• shelter: valleys surrounded by hills or mountains, may enjoy year-round shelter, promoting tall trees, which trap moisture, thus creating a hot spot. Under water, a hot spot forms near underwater caves, which give protection to many species, and which are a safe place to sleep. When such a place is found near currents, which bring food, the hot spot becomes very rich indeed.
• fire: some spots have systematically been missed by burns and natural fires. As a result, the old climax vegetation still stands, and around it a gradient of succession species, inviting a large number of species in a small area. In other places, sporadic fires are able to cull fast-growing species, which may suppress all others. In doing so, fires can enhance biodiversity.
• ice age: during an ice age, the land becomes covered with a moving ice sheet, which destroys all life by its sheer pressure and because it moves. It removes the soil too. But some places remain exempt for various reasons, retaining their soils and some vegetation. After the ice sheet has retreated, such spots have a lasting advantage over others, becoming rich hot spots.
• multiple habitats: where different habitats intersect, the species associated with each, meet and interact. It is a place with all the species of all the habitats.
• local disturbance: a local disturbance like a soil slip may introduce succession in the heart of a climax forest, introducing with it succession species. A soil slip also loosens the earth, while making nutrients available. Some slips are very large (slumps).

• water cycle: water evaporates mainly as a function of temperature, and mainly above the oceans because these are so large. Winds transport water vapour. Rains fall and water returns to the oceans. Our crops need reliable supplies of water.
• precipitation: planktonic organisms produce the condensation nuclei (dimethylsulfide, CH3.S.CH3) which promote cloud formation. Cool areas (forests, mountains) invite clouds to precipitate as rains.
• watershed regulation: forests, with their enormous surface area and spongy soils, buffer vast amounts of water, to be evaporated gradually or seeped down-hill to springs and creeks. Plants, particularly trees, play an important role in regulating the water supply.
• water purification: the process of evaporation is like distillation, lifting pure water from the land or oceans, while leaving salts behind. The water cycle acts like a gigantic (and free) water purifier. Rainwater is perfect for drinking and irrigating.
• irrigation: water from the sky is the best irrigation one can get. Even when cropland is irrigated with river, lake or ground water, natural rain must always exceed the artificial quantities applied, for it to be sustainable, thus avoiding salinisation (salting up).
• recycling/ cleansing: the clean rain water cleanses the soil from excessive salts, thereby increasing its fertility. Myriad small organisms work together to break down wastes and dead organisms, so that their nutrients are recycled.
• CO2: carbondioxide is reassimilated by plants and turned into food for animals.
• natural wastes: are broken down and their energy used in the process. The resulting nutrients become available to plants.
• industrial wastes: nature can neutralise and detoxify some industrial wastes, converting them to harmless components.
• mineral wastes: waste from mining can be poisonous, but nature is capable of stabilising it so that its release becomes slow and gradual.
• stabilisation: the many creatures forming ecosystems, stabilise their environment. The Earth, acting like a single creature, regulates its overall temperature by cloud formation and greenhouse gases.
• climate: the world's climate is stabilised by cloud formation, and local climate is stabilised by the presence of water, since evaporation absorbs enormous quantities of heat, while keeping temperature constant.
• rainfall: plants create a porous soil, storing rain water. As they grow, plants evaporate moisture, which rises, condenses into clouds, only to rain down again further inland. They influence rainfall elsewhere, and by cooling the surface, also attract rainfall.
• soil fertility: the fertility of soils is maintained by thousands of soil species, living in balance with the plants and animals above ground.
• pests: in a balanced environment, pests are unlikely to grow out of proportion, as they do on monoculture cropland. Every pest animal has its natural predator. Pest plants have their natural grazers.
• protection: the natural environment protects us from various kind of harm.
• radiation: radiation from the sun is shielded by gases produced by organisms. Ozone is formed from oxygen by ultraviolet radiation, and protects life this way. Water vapour forms an effective filter too.
• soil: plant roots bind the soil, preventing erosion, while their leaves prevent rain drops from hitting the soil and eroding it. Trees and shrubs shelter the soil from winds that could blow it away.
• coastal zone: living organisms growing over the rocks in the coastal zone protect it from erosion by waves.
• nursing grounds: trees and shrubs provide shelter to many organisms and their young. In the coastal zone mangrove roots provide sheltering habitat for juvenile fish.
• barrier reefs: coral reefs function as barriers against storm waves, thus protecting islands and settlements.
• supporting variety: by supporting a vast variety of species, the environment adapts slowly to new situations. By accommodating a vast number of individuals, environments can adapt quickly. Both are cases of overcapacity.
• adapting to environmental changes: fortunately for us and other species, the environment has the ability to adapt to new situations such as global climate change, although many a species may be lost in the process. The changes humans have brought about are of global magnitude: greenhouse gases, ozone depletion, acid rain, droughts and more.
• adapting to times of adversity: all species tolerate a range of living conditions. They don't die immediately in case of drought or food shortage or natural disaster, and when they do, they can quickly rebound from aestivation or hibernation, or reproduce from spores and seeds.
• adapting to new pests: whenever disease strikes human crops, some plants appear resistant. These can then be bred to form new pest-resistant varieties.
• products and services: products we use direct from the source.
• forest foods: meat, food, nuts,
• building products: timber, rattan,
• pollination of plants: pollination of fruit-bearing plants like tomatoes, kiwifruit, apples, pears, etc.
• pharmaceuticals: natural farmaceuticals for natural healing, but also toxins, quinine, agar (from seaweed), etc.
• genetic database: the individuals, species and ecosystems store a vast wealth of genetic information, which defines planet Earth. It is also a main source for plant breeding, particularly for our crop species. The crop varieties found in the wild do not produce large crops, but they may contain genes that give them protection from leaf eating insects, root rot and other diseases. Such genes can be transferred to productive crop species to make them even more productive. Because such genes have been 'tested' by nature, the risk of using them, is minimal.

This map shows the genetic hot spots where our major crop species come from, and where their wild varieties are found. These wild species and varieties are important for sustaining the crops' genetic resource base, because our main crops have the tendency to be monocultures of the most successful hybrid varieties only. Unfortunately, these hot spots are also good for cropping, which displaces the wild varieties. A concerted effort must be made to retain the genetic database and their natural habitats. When living in an artificial environment like a city, with piped water, waste and energy, it is easy to forget that we depend on the part of the planet we have not changed. That part, already less than 50%, is shrinking rapidly.