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> What is biodiversity?
> Exploring biodiversity
WHAT IS BIODIVERSITY?
Biological diversity or biodiversity refers to the variety of life forms; including plants, animals, microorganisms, the genes they contain, and the ecosystems they form. This living wealth is the product of hundreds of millions of years of evolutionary history. Biological diversity is usually considered at three different levels: genetic diversity, species diversity and ecosystem diversity.
- Genetic diversity refers to the variety of genetic information contained in all of the individual plants, animals and microorganisms. Genetic diversity occurs within and between populations of species as well as between species.
- Species diversity refers to the variety of living species.
- Ecosystem diversity relates to the variety of habitats, biotic communities, and ecological processes, as well as the tremendous diversity present within ecosystems in terms of habitat differences and the variety of ecological processes.
Biodiversity in the natural world can be considered at every scale from the microscopic to the global. Organisms are described according to their species and varieties and occur in populations. Populations occurring together form ecological communities. Ecological communities occurring together make up ecological systems, or ecosystems. Ecosystems that occur together in a region with similar climate and geography are often referred to as a bioregion. All the bioregions of all the continents and all the oceans collectively make up the biosphere.
Biodiversity in Australia
As a 'developed' nation, Australia has a special responsibility for biodiversity conservation and management.
It is estimated that there are 13.6 million species of plants, animals and micro-organisms on earth. Australia has about one million of these, which represents more than 7% of the world's total and is more than twice the number of species in Europe and North America combined. Megadiversity describes countries with very high levels of biodiversity. Twelve of the megadiverse countries, including Australia, contain about 75% of Earth's total biodiversity. As a 'developed' nation, Australia has a special responsibility for biodiversity conservation and management. Other megadiverse countries include Brazil, Colombia, Ecuador, Peru, Mexico, Democratic Republic of the Congo, Madagascar, China, India, Indonesia and Malaysia.
EXPLORING BIODIVERSITY
Where does biodiversity come from?
The Earth's biodiversity is the product of three and a half billion years of evolution. Evolution is the process by which, over many generations, living things change and diversify into different forms. Through evolution, species tend to split into separate populations that evolve into distinct varieties, which in time may evolve into distinct species. For example, all the marsupials in Australia today evolved from a single common ancestor species that lived many millions of years ago.
The counterpart to evolution is extinction, which reduces biodiversity. Extinction can occur for many reasons, including natural events and processes. Some natural causes are climate change, competition with other species as they evolve, global disasters such as asteroids striking the earth, and local disasters such as volcanic eruptions or major landscape change. The extinction rate attributable to people is however many times greater than that attributable to natural causes.
Over the history of life, both evolution and extinction rates have fluctuated. When the extinction rate is the higher of the two, biodiversity decreases. Otherwise the total biodiversity tends to creep up as new varieties and species evolve. Because of the way people today use and alter the natural world, current extinction rates are many times higher than would otherwise occur naturally and the total amount of biodiversity in the world is being reduced. The extent of this reduction is likely to be on the scale of that which occurred during ancient catastrophes such as the one that caused the extinction of the dinosaurs (unless we humans change our ways).
Why should we preserve biodiversity?
Biodiversity and its conservation are vital to our quality of life. The benefits and services it supplies underpin our social, economic and environmental well being.
Biodiversity makes natural ecosystems strong and stable, and thereby protects all the values they provide
The natural world is incredibly complex, and all parts of it are interlinked and interdependent in ways that we are only beginning to understand. Due to this complexity, it is generally very difficult to predict beforehand the effects of introducing, removing or altering the abundance of species in an ecosystem.
However, we do know that each such change increases the odds of causing species to go extinct, or of losing some other value (such as clean water). When many changes occur a cascade of effects can happen wherein each species lost increases the probability that others are lost and the loss of these in turn causes still others to disappear.
Biogeographic regions (bioregions) capture the patterns of ecological characteristics in the landscape, providing a natural framework for recognising and responding to biodiversity values. Bioregions reflect underlying environmental features, can be related to patterns of land use and can be used to identify the relationship between many natural resource based activities and biodiversity assets.
Biodiversity is critical to the economy
Our economy is utterly dependant on the wealth of biodiversity on this planet. It is the source of all our current and future crop and stock species. And it is the repository of all those wild varieties that allow us to breed new, more productive and disease resistant strains of these. Most of our medicines are derived from otherwise obscure plants, bacteria or micro-organisms that have lived on this planet since before the dawn of man. Our fisheries are based around species that are utterly dependant on the biodiverse ecosystems of which they are but a tiny part. Even the quality of our air and water are dependant on healthy, well functioning ecosystems.
The biodiverse natural world has no need for the human economy, and in fact is today deeply threatened by it. By contrast, our economy is utterly dependant on the resources and services that it gains for free from that same world.
Biodiversity makes life a more pleasant and fulfilling experience
Consider the places you most appreciate; those areas where you go with your friends or family for holidays; or where you like to spend time alone recuperating from the stresses of life. It is very likely that biodiversity is one of, if not the key feature that make these places so important to you.
The human species has evolved in and as part of the natural world. We therefore, instinctively value the beauty of a forest, the smells of the ocean, the sight and sounds of living things. Even the very knowledge that there are wild places in the world that are unspoiled and safe from exploitation is deeply important to most people.
All living things have an intrinsic right to exist
The human species is but one of the tens of millions of species that inhabit earth today. We have the capacity to significantly impact most of the others and will do so if we do not now take steps to reduce the pressure that we exert on the natural world.
You may ask: If we have no direct use for them or can replace them with other species of our choice, then who cares? What is the big deal if most of the native species of fish disappear from Australia when we can restock with trout? Who will miss a few obscure species of possum? Why get concerned about losing all those native grassland species that can be replaced with introduced pasture anyway?
In response, it can be argued that we do not have the right to allow or cause other species to become extinct. They have as much right to live and prosper as we do. After all, they have been here as long as us, and most of them have been here a lot longer.
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