There are currently 1.4 million described species on earth, but estimates of as many as 5 to 50 million total species have been projected to exist (Becher, 1998, 60). Tropical entomologist Terry Erwin’s research supports that there may be as many as 30 million insect species alone in the tropical rainforests (Shiva et al, 1991, 14). One of the true challenges to biodiversity is that there are so many species that we may be obliterating that we are not even aware exist yet. We are destroying species faster than we can identify them.
Extinction and evolution are a normal part of the life cycle on Earth. Of all the species that ever have lived on the earth only between one and six percent exist today (Shiva et al, 1991, 15). Many mass extinctions have previously occurred killing of as much as 90% of life on earth in one fell swoop. In 1995 there were 26,106 species of mammals, birds, reptiles, amphibians, fishes invertebrates and plant that were considered endangered, vulnerable rare or indeterminate, (Watson, 1995, 26), that figure is certainly higher today. Conservation biologists warn that 25 percent of all species could become extinct during the next twenty to thirty years (Shiva et al, 1991, 15).
The difference between the previous extinctions and the ones currently taking place are the time line and the cause. Where as in the past as one species fell out of existence another had sufficient space on the geological timeline to replace and therefore replenish the biological diversity. Fossils show that the birth and death of a species occur on a million year timescale-called a background rate ( Pimm et al, 2005). Currently the extinction rate is 40,000 times higher than this “background” rate (Shiva et al, 1991,16). Though humans evolved along side the millions of others we are now the force that rules over the existence or demise of our fellow inhabitants. We are replacing the natural delicately balanced ecosystem with our own habitat....
What does biodiversity mean? It is a word used to describe the variety of all life in an ecosystem in addition to the specific habitats and communities in which they live (Convention on Biological Diversity). For years, people have been going back and forth on whether the environment is overprotected or underprotected. I believe that both sides of the debate go to unnecessary extremes, but agree with those who say that biodiversity is underprotected. The movement to really start caring about the environment began back in the later 1900s, when acts and policies such as the Endangered Species Preservation Act of 1966 was created, which provided lists of species that could be endangered and some means of protection for them (U.S. Fish & Wildlife Service). Even with movements such as that, as well as groups lobbying to “go green” and save what natural resources we have left, biodiversity is only continuing to decrease.
Species go extinct all the time—some estimates suggest that over 99.9% of all species to ever live on the planet have gone extinct, which goes to show that it is a natural process (GeoWords). Since in reality extinction is inevitable for all organisms at some point or another, it is our job as humans to do everything in our power to slow this process down as much as possible, especially for those species already considered...
...Biodiversity is comprised of the totality of genes, species and ecosystems of a region. The occurrence of various kinds of flora and fauna in a region reflects its biological diversity or biodiversity. In most parts of the world which are habitable, the living world abounds in biodiversity. In a patch of forest, there is a wide variety of insects, animals, plants and trees.
All plant and animal species cannot occur at one place. Whether or not a species can occur on a site is determined by environmental conditions of site and range of tolerance of species. Biologically rich and unique habitats are being perished, fragmented and degraded due to increasing human activities, resource consumption and pollution. Biodiversity loss is now one of the most pressing crises. How to check the loss of species and erosion of gene pool is one of the major challenges to science.
Systemic work on identifying and naming species has been in progress for the last two centuries. But still, the numbers of species collected, described and named so far are much less than the actual number of species present. The known and described number of species of all organisms on earth is between 1.7 and 1.8 million, which is fewer than the 15 per cent of the actual number. The predicted number of total species varies from 5 to 50 million and averages at 14 million. There are many more species that have not yet been described, especially in the...
...Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Greater biodiversity implies greater health. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions support fewer species.
Rapid environmental changes typically cause extinctions. One estimate is that less than 1% of the species that have existed on Earth are extant.
Since life began on Earth, five major mass extinctions and several minor events have led to large and sudden drops in biodiversity. The Phanerozoic eon (the last 540 million years) marked a rapid growth in biodiversity via the Cambrian explosion—a period during which nearly every phylum of multicellular organisms first appeared. The next 400 million years included repeated, massive biodiversity losses classified as mass extinction events. In the Carboniferous, rainforest collapse led to a great loss of plant and animal life. The Permian–Triassic extinction event, 251 million years ago, was the worst; vertebrate recovery took 30 million years. The most recent, the Cretaceous–Tertiary extinction event, occurred 65 million years ago, and has often attracted more attention than others because it resulted in the extinction of the dinosaurs.
The period since the emergence...
...Threats to Biodiversity
Extinction is a natural event and, from a geological perspective, routine. We now know that most species that have ever lived have gone extinct. The average rate over the past 200 million years is 1-2 species per million species present per year. The average duration of a species is 1-10 million years (based on the last 200 million years). There have also been several episodes of mass extinction, when many taxa representing a wide array of life forms have gone extinct in the same blink of geological time.In the modern era, due to human actions, species and ecosystems are threatened with destruction to an extent rarely seen in Earth history. Probably only during the handful of mass extinction events have so many species been threatened, in so short a time.What are these human actions that threaten biodiversity? There are many ways to conceive of these; let's consider two.First, we can attribute the loss of species and ecosystems to the accelerating transformation of the Earth by a growing human population. As the human population passes the 6 billion mark, we have transformed, degraded or destroyed roughly half of the word's forests. We appropriate roughly half of the world's net primary productivity for human use. We appropriate most available fresh water, and we harvest virtually all of the available productivity of the oceans. It is little wonder that species are disappearing and ecosystems are being destroyed....
...Hand out : Biodiversity
Biological Diversity or Biodiversity - is the variety (diversity) of all life forms on earth, encompassing all plants, animals, microorganisms and the intricate ecosystems they form.
- the totality of ecosystems, species, and genes within the area.
Levels of Biodiversity
1. Species Diversity (Different Life Forms)
2. Genetic Diversity (Different characteristics of plants, animals & other living organisms)
3. Ecosystem Diversity (Different types of Ecosystem)
Species: Two individuals are named to be of the same species if they can reproduce and their offspring is fertile. Species are the units of biodiversity.
a group of related or similar organisms capable of breeding freely to produce fertile offspring. It is the basic unit of biological classification and hence, its use as a measure of biodiversity.
Species Diversity - refers to the variety of species found within a discrete geographical boundary. It is usually measured in terms of the total number of species found within a particular area.
Importance of Biodiversity
To maintain or restore healthy ecosystem functioning
To maintain photosynthetic fixation of solar energy, the energy input for the world
To maintain water cycles and protect watersheds
To avoid climatic change
To maintain storage and cycling of nutrients
To maintain soil production and avoid soil erosion
...Biodiversity: Who Cares?
Biodiversity is important for many reasons. One reason it is important is for biological reasons. If biodiversity is affected in a biological community it can cause species to overpopulate or become extinct. These changes can cause issues with the goods and services that an ecosystem provides to humanity. Species’ functional characteristics influence the ecosystem properties. Every species depends on each other. If one is wiped out then another species will lose their food source and could be wiped out, too. Another species will overpopulate because they aren’t being hunted by the other species. Because of that species overpopulating they will eat too much of their food source and then they will start to die. Without all the different characteristics of a biological community it cannot survive.
In terms of aesthetic reasons biodiversity can be important to create beautiful scenery with all of the plants. The animals are also a part of the beauty. The plants and the animals rely on each other of course. So they work together to create beauty in the wilderness. What is more beautiful than seeing a deer grazing in a meadow, or hearing the birdsong in the trees? The variety of trees makes beautiful views up in the mountains. Out in a desert the cacti make it seem a little less barren and boring.
Then there are ethical points about biodiversity. Most people would think that...
...We can no longer see the continued loss of biodiversity as an issue separate from the core concerns of society: to tackle poverty, to improve the health, prosperity and security of present and future generations, and to deal with climate change. Each of those objectives is undermined by current trends in the state of our ecosystems, and each will be greatly strengthened if we finally give biodiversity the priority it deserves.
The Majesty of Life
When we say we want to save the planet, we use the word "biodiversity" to encompass this entire concept - which, granted, is a big one.
Biodiversity: Life, the world, the variation of life for the entire globe.
It’s a big idea with a long history.
Biodiversity found on Earth today consists of many millions of distinct biological species, the product of four billion years of evolution.
But the word “Biodiversity” itself is actually quite new.
"Biodiversity" was coined as a contraction of "biological diversity" in 1985.
And as politicians, scientists, and conservationists became more interested in the state of the planet and the amazing complexity of life we became quite attached to this new word.
And why were we talking so much about Biodiversity?
The world has begun, relatively recently, to lose species and habitats at an ever-increasing and alarming rate.
Quote : Biodiversity is Life!
Biodiversity is the greatest treasure we have... Its diminishment is to be prevented at all cost. - Thomas Eisner
Planet Earth is so diverse! There is diversity of Life, Biodiversity!
• Full variety of life on Earth • The study of the processes that create and maintain variation • Variety of individuals within populations • Diversity of species within communities • Range of ecological roles within ecosystems • Genetic diversity • Species diversity • Diversity of environment & habitat
Three Major Areas
LEVELS OF BIODIVERSITY Genetic diversity
• Variety of genetic information in all individuals ( plants, animals and microorganisms). • Genetic diversity occurs w/n and between populations of species as well as between species. • New genetic variation is produced in populations of organisms that can reproduce sexually by recombination and in individuals by gene and chromosome mutations.
Levels of Biodiversity
• Pool of genetic variation in an inter-breeding population is shaped by selection. o Selection leads to a certain preferred genetic attributes being preferred & results in frequency changes of genes within this pool. • There are about 10B different genes.
o Genes which control fundamental biochemical processes are strongly conserved across different...