Biodiversity

Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or
an entire planet. Biodiversity is one measure of the health of ecosystems. Life on Earth
today consists of many millions of distinct biological species. The United Nations
declared the year 2010 as the International Year of
Biodiversity.

Biodiversity is not uniform across the Earth. In

terrestrial habitats, for example, tropical regions are
typically rich whereas polar regions support fewer
species.

apid environmental changes typically cause

extinctions.[1] 99.9 percent of species that have existed
on Earth are now extinct.[2] Since life began on Earth,
five major mass extinctions have led to large and
sudden drops in Earthly biodiversity. The Phanerozoic
eon (the last 540 million years) marked a rapid growth
in biodiversity in the Cambrian explosion—a period
during which nearly every phylum of multicellular
organisms first appeared. The next 400 million years
was distinguished by periodic, massive biodiversity
losses classified as mass extinction events. The
Permo-Triassic Extinction, 251 million years ago was
the worst, devastating life in the sea and on land;
vertebrate recovery took 30M years.[3]. The most recent, the Cretaceous–Tertiary
extinction event, occurred 65 million years ago, and has attracted more attention than all
others because it killed the nonavian dinosaurs.[4]

The period since the emergence of humans has

displayed an ongoing reduction in biodiversity.
Named the Holocene extinction, the reduction is
caused primarily by human impacts, particularly
the destruction of plant and animal habitat. In
addition, human practices have caused a loss of
genetic diversity. Biodiversity's impact on human
health is a major international issue
Etymology

The term was used first by wildlife scientist and conservationist Raymond F. Dasman in
the 1968 lay book A Different Kind of Country[5] advocating conservation. The term was
widely adopted only after more than a decade, when in the 1980s it came into common
usage in science and environmental policy. Use of the term by Thomas Lovejoy, in the
foreword to the book Conservation Biology,[6] introduced the term to the scientific
community. Until then the term "natural diversity" was common, introduced by The
Science Division of The Nature Conservancy in an important 1975 study, "The
Preservation of Natural Diversity." By the early 1980s TNC's Science program and its
head, Robert E. Jenkins,[7] Lovejoy and other leading conservation scientists at the time in
America advocated the use of "biological diversity".

The term's contracted form biodiversity may have been coined by W.G. Rosen in 1985
while planning the National Forum on Biological Diversity organized by the National
Research Council (NRC) which was to be held in 1986, and first appeared in a
publication in 1988 when entomologist E. O. Wilson used it as the title of the
proceedings[8] of that forum.[9]

Since this period both the term and the concept have achieved widespread use among
biologists, environmentalists, political leaders, and concerned citizens. The term is
sometimes used to reflect concern for the natural environment and nature conservation.
This use has coincided with the expansion of concern over extinction observed in the last
decades of the 20th century.

A similar concept in use in the United States is "natural heritage." Less scientific, it
predates the others and is more accepted by the wider audience interested in conservation.
Unlike biodiversity, it includes geology and landforms (geodiversity).
Definitions

"Biological diversity" or "biodiversity" can have

many interpretations and it is most commonly
used to replace the more clearly defined and long
established terms, species diversity and species
richness. Biologists most often define
biodiversity as the "totality of genes, species, and
ecosystems of a region". An advantage of this
definition is that it seems to describe most
circumstances and presents a unified view of the
traditional three levels at which biological
variety has been identified:

 species diversity
 ecosystem diversity
 genetic diversity

But Professor Anthony Campbell at Cardiff

University, UK and the Darwin Centre,
Pembrokeshire, has defined a fourth, and critical
one: Molecular Diversity[10]

This multilevel conception is consistent with the

early use of "biological diversity" in Washington, D.C. and international conservation
organizations in the late 1960s through 1970s, by Raymond F. Dasmann who apparently
coined the term and Thomas E. Lovejoy who introduced it to the wider conservation and
science communities. An explicit definition consistent with this interpretation was first
given in a paper by Bruce A. Wilcox commissioned by the International Union for the
Conservation of Nature and Natural Resources (IUCN) for the 1982 World National
Parks Conference in Bali[11] Wilcox's definition was "Biological diversity is the variety of
life forms...at all levels of biological systems (i.e., molecular, organismic, population,
species and ecosystem)..." Subsequently, the 1992 United Nations Earth Summit in Rio
de Janeiro defined "biological diversity" as "the variability among living organisms from
all sources, including, 'inter alia', 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". This definition is used in the United Nations
Convention on Biological Diversity.

One textbook's definition is "variation of life at all levels of biological organization".[12][13]

For geneticists, biodiversity is the diversity of genes and organisms. They study processes
such as mutations, gene transfer, and genome dynamics that generate evolution.
Consistent with this, Wilcox also stated "genes are the ultimate source of biological
organization at all levels of biological systems..."[11
Linking biodiversity levels

A complex relationship exists among the different diversity levels. Identifying one level
of diversity in a group of organisms does not necessarily indicate its relationship with
other types of diversities. All types of diversity are broadly linked and a numerical study
investigating the link between tetrapod (terrestrial vertebrates) taxonomic and ecological
diversity shows a very close correlation between the two.[

Distribution

Selection bias amongst researchers may contribute to biased empirical research for
modern estimates of biodiversity. In 1768 Rev.
Gilbert White succinctly observed of his
Selborne, Hampshire "all nature is so full, that
that district produces the most variety which is
the most examined."[15]

Biodiversity is not evenly distributed. Flora

and fauna diversity depends on climate,
altitude, soils and the presence of other species.
Diversity consistently measures higher in the
tropics and in other localized regions such as
Cape Floristic Province and lower in polar
regions generally. In 2006 many species were formally classified as rare or endangered or
threatened species; moreover, many scientists have estimated that millions more species
are at risk which have not been formally recognized. About 40 percent of the 40,177
species assessed using the IUCN Red List criteria are now listed as threatened with
extinction—a total of 16,119.[16]

Even though biodiversity on land declines from the equator to the poles, this trend is
unverified in aquatic ecosystems, especially in marine ecosystems.[17] In addition, several
cases demonstrate tremendous diversity in higher latitudes.[citation needed] Generally land
biodiversity is up to 25 times greater than ocean biodiversity.[18]

A biodiversity hotspot is a region with a high level of endemic species. Hotspots were
first named in 1988 by Dr. Norman Myers.[19][20] Dense human habitation tends to occur
near hotspots. Most hotspots are located in the tropics and most of them are forests.[citation
needed]

Brazil's Atlantic Forest is considered one such hotspot, containing roughly 20,000 plant
species, 1,350 vertebrates, and millions of insects, about half of which occur nowhere
else. The island of Madagascar, particularly the unique Madagascar dry deciduous forests
and lowland rainforests, possess a high ratio of endemism. Since the island separated
from mainland Africa 65 million years ago, many species and ecosystems have evolved
independently.
Many regions of high biodiversity and/or endemism arise from specialized habitats which
require unusual adaptations, for example alpine environments in high mountains, or
Northern European peat bogs.

Evolution

Biodiversity is the result of 3.5 billion years of evolution. The origin of life has not been
definitely established by science, however some evidence suggests that life may already
have been well-established only a few
hundred million years after the formation of
the Earth. Until approximately 600 million
years ago, all life consisted of archaea,
bacteria, protozoans and similar single-celled
organisms.

The history of biodiversity during the

Phanerozoic (the last 540 million years),
starts with rapid growth during the Cambrian
explosion—a period during which nearly
every phylum of multicellular organisms first appeared. Over the next 400 million years
or so, global diversity showed little overall trend, but was marked by periodic, massive
losses of diversity classified as mass extinction events. The worst was the Permo-Triassic
extinction, 251 million years ago. Vertebrates took 30 million years to recover from this
event.[3]

The fossil record suggests that the last few million years featured the greatest biodiversity
in history. However, not all scientists support this view, since there is considerable
uncertainty as to how strongly the fossil record is biased by the greater availability and
preservation of recent geologic sections. Corrected for sampling artifacts, modern
biodiversity may not be much different from biodiversity 300 million years ago.[22]
Estimates of the present global macroscopic species diversity vary from 2 million to 100
million, with a best estimate of somewhere near 13–14 million, the vast majority
arthropods.[23] Diversity appears to increase continually in the absence of natural
selection.[24]
Evolutionary diversification

The existence of a "global carrying capacity", limiting the amount of life that can live at
once, is debated, as is the question of whether such a limit would also cap the number of
species. While records of life in the sea shows a logistic pattern of growth, life on land
(insects, plants and tetrapods)shows an exponential rise in diversity. As one author states,
"Tetrapods have not yet invaded 64 per cent of potentially habitable modes, and it could
be that without human influence the ecological and taxonomic diversity of tetrapods
would continue to increase in an exponential fashion until most or all of the available
ecospace is filled."[14]

On the other hand, changes through the Phanerozoic correlate much better with the
hyperbolic model (widely used in population biology, demography and macrosociology,
as well as fossil biodiversity) than with exponential and logistic models. The latter
models imply that changes in diversity are guided by a first-order positive feedback
(more ancestors, more descendants) and/or a negative feedback arising from resource
limitation. Hyperbolic model implies a second-order positive feedback. The hyperbolic
pattern of the world population growth arises from a second-order positive feedback
between the population size and the rate of technological growth.[25] The hyperbolic
character of biodiversity growth can be similarly accounted for by a feedback between
diversity and community structure complexity. The similarity between the curves of
biodiversity and human population probably comes from the fact that both are derived
from the interference of the hyperbolic trend with cyclical and stochastic dynamics.[26]

Most biologists agree however that the period since human emergence is part of a new
mass extinction, named the Holocene extinction event, caused primarily by the impact
humans are having on the environment.[27] It has been argued that the present rate of
extinction is sufficient to eliminate most species on the planet Earth within 100 years.[28]

New species are regularly discovered (on average between 5–10,000 new species each
year, most of them insects) and many, though discovered, are not yet classified (estimates
are that nearly 90% of all arthropods are not yet classified).[23] Most of the terrestrial
diversity is found in tropical forests.
Human benefits

Biodiversity supports a number of natural ecosystem

processes and services.[29] Some ecosystem services that
benefit society are air quality,[30] climate (e.g., CO2
sequestration), water purification, pollination, and prevention
of erosion.[30]

Since the stone age, species loss has accelerated above the
prior rate, driven by human activity. The exact rate is
uncertain, but it has been estimated that species are now being
lost at a rate approximately 100 times as fast as is typical in
the fossil record, or perhaps as high as 10,000 times as fast.[31]
Land is being transformed from wilderness into agricultural,
mining, lumbering and urban areas for humans.

Non-material benefits include spiritual and aesthetic values, knowledge systems and the
value of education.

Agriculture

The reservoir of genetic traits present in wild varieties and traditionally grown landraces
is extremely important in improving crop
performance.[citation needed] Important crops,
such as the potato, banana and coffee, are
often derived from only a few genetic
strains.[citation needed] Improvements in crop
species over the last 250 years have been
largely due to harnessing genes from wild
varieties and species.[citation needed]
Interbreeding crops strains with different
beneficial traits has resulted in more than
doubling crop production in the last 50
years as a result of the Green Revolution.

Crop diversity is also necessary to help the system recover when the dominant cultivar is
attacked by a disease or predator:

 The Irish potato blight of 1846 was a major factor in the deaths of one million
people and the emigration of another million. It was the result of planting only
two potato varieties, both of which proved to be vulnerable.
 When rice grassy stunt virus struck rice fields from Indonesia to India in the
1970s, 6,273 varieties were tested for resistance.[32] Only one was resistant, an
Indian variety, and known to science only since 1966.[32] This variety formed a
hybrid with other varieties and is now widely grown.[32]
  Coffee rust attacked coffee plantations in Sri Lanka, Brazil, and Central America
in 1970. A resistant variety was found in Ethiopia.[33] Although the diseases are
themselves a form of biodiversity.

Monoculture was a contributing factor to several agricultural disasters, including the

European wine industry collapse in the late 19th century, and the US Southern Corn Leaf
Blight epidemic of 1970.[34]

Higher biodiversity also limits the spread of certain diseases, because pathogens may
have to adapt to infect different species.[citation needed]

Although about 80 percent of humans' food supply comes from just 20 kinds of plants,
[citation needed]
humans use at least 40,000 species.[citation needed] Many people depend on these
species for their food, shelter, and clothing.[citation needed] Earth's surviving biodiversity
provides as little-tapped resources for increasing the range of food and other products
suitable for human use, although the present extinction rate shrinks that potential.

Human health

The diverse forest canopy on Barro Colorado Island,

Panama, yielded this display of different fruit

Biodiversity's relevance to human health is becoming an

international political issue, as scientific evidence builds
on the global health implications of biodiversity loss.[35][36]
[37]
This issue is closely linked with the issue of climate
change,[38] as many of the anticipated health risks of
climate change are associated with changes in biodiversity
(e.g. changes in populations and distribution of disease
vectors, scarcity of fresh water, impacts on agricultural
biodiversity and food resources etc.) Some of the health
issues influenced by biodiversity include dietary health
and nutrition security, infectious diseases, medical science
and medicinal resources, social and psychological health.
[39]
Biodiversity is also known to have an important role in
reducing disaster risk, and in post-disaster relief and
recovery efforts.[40][41]

One of the key health issues associated with biodiversity is that of drug discovery and the
availability of medicinal resources.[42] A significant proportion of drugs are derived,
directly or indirectly, from biological sources; At least 50% of the pharmaceutical
compounds on the US market are derived from compounds found in plants, animals, and
microorganisms, while about 80% of the world population depends on medicines from
nature (used in either modern or traditional medical practice) for primary healthcare.[36]
Moreover, only a tiny proportion of the total diversity of wild species has been
investigated for medical potential. Through the field of bionics, considerable
advancement has occurred which would not have occurred without rich biodiversity. It
has been argued, based on evidence from market analysis and biodiversity science, that
the decline in output from the pharmaceutical sector since the mid-1980s can be
attributed to a move away from natural product exploration ("bioprospecting") in favor of
genomics and synthetic chemistry; meanwhile, natural products have a long history of
supporting significant economic and health innovation.[43][44] Marine ecosystems are of
particular interest in this regard,[45] although inappropriate bioprospecting has the
potential to degrade ecosystems and increase biodiversity loss, as well as impacting the
rights of the communities and states from which the resources are taken

Business and Industry

A wide range of industrial materials derive

directly from biological resources. These include
building materials, fibers, dyes, rubber and oil.
Further research into employing materials from
other organisms is likely to improve product cost
and quality. Biodiversity is also important to the
security of resources such as water quantity and
quality, timber, paper and fibre, food and medical
resources.[49][50][51] As a result, biodiversity loss is
increasingly recognized as a significant risk factor in business development and a threat
to long term economic sustainability. Case studies recently compiled by the World
Resources Institute demonstrate some of these risks for specific industries.[52]

Other services

Biodiversity provides many ecosystem services that are often not readily visible. It plays
a part in regulating the chemistry of our atmosphere and water supply. Biodiversity is
directly involved in water purification, recycling nutrients and providing fertile soils.
Experiments with controlled environments have shown that humans cannot easily build
ecosystems to support human needs; for example insect pollination cannot be mimicked,
and that activity alone represents tens of billions of dollars in ecosystem services per year
to humankind.

Ecosystem stability is also positively related to biodiversity, protecting them ecosystem

services from disruption by extreme weather or human exploitation.
Leisure, cultural and aesthetic value

Many people derive value from

biodiversity through leisure activities
such as hiking, birdwatching or
natural history study. Biodiversity has
inspired musicians, painters,
sculptors, writers and other artists.
Many culture groups view themselves
as an integral part of the natural
world and show respect for other
living organisms.

Popular activities such as gardening,

fishkeeping and specimen collecting
strongly depend on biodiversity. The
number of species involved in such pursuits is in the tens of thousands, though the
majority do not enter mainstream commerce.

The relationships between the original natural areas of these often exotic animals and
plants and commercial collectors, suppliers, breeders, propagators and those who
promote their understanding and enjoyment are complex and poorly understood. It seems
clear, however, that the general public responds well to exposure to rare and unusual
organisms—they recognize their inherent value at some level. A family outing to the
botanical garden or zoo is as much an aesthetic and cultural experience as an educational
one.

Philosophically it could be argued that biodiversity has intrinsic aesthetic and spiritual
value to mankind in and of itself. This idea can be used as a counterweight to the notion
that tropical forests and other ecological realms are only worthy of conservation because
of the services they provide

Number of species

According to the Global Taxonomy Initiative[53]

and the European Distributed Institute of
Taxonomy, the total number of species for some
phyla may be much higher as what we know
currently:

 10–30 million insects;[54] (of some 0,9 we

know today [55])
 5–10 million bacteria;[56]
 1.5 million fungi;[57] (of some 0,4 million
we know today [55])
 ~1 million mites[58]
  The number of microbial species is not reliably known, but the Global Ocean
Sampling Expedition dramatically increased the estimates of genetic diversity by
identifying an enormous number of new genes from near-surface plankton
samples at various marine locations, initially over the 2004-2006 period.[59] The
findings may eventually cause a significant change in the way science defines
species and other taxonomic categories.[60][61]

Due to the fact that we know but a portion of the organisms in the biosphere, we do not
have a complete understanding of the workings of our environment. To make matters
worse, we are wiping out these species at an unprecedented rate.[62] This means that even
before a species has had the chance of being discovered, studied and classified, it may
already be extinct.

Species loss rates

During the last century, decreases in biodiversity have been increasingly observed. 30%
of all natural species will be extinct by 2050.[63] Of these, about one eighth of known
plant species are threatened with extinction.[64] Some estimates put the loss at up to
140,000 species per year (based on Species-area theory) and subject to discussion.[65] This
figure indicates unsustainable ecological practices, because only a small number of
species evolve each year. Almost all scientists acknowledge [64] that the rate of species
loss is greater now than at any time in human history, with extinctions occurring at rates
hundreds of times higher than background extinction rates.

Threats

Jared Diamond describes an "Evil Quartet" of habitat

destruction, overkill, introduced species, and secondary
extensions.[citation needed] Edward O. Wilson prefers the
acronym HIPPO, standing for Habitat destruction,
Invasive species, Pollution, Human Over Population,
and Overharvesting.[66][67] The most authoritative
classification in use today is IUCN’s Classification of
Direct Threats[68] which has been adopted by most major
international conservation organizations such as the US
Nature Conservancy, the World Wildlife Fund,
Conservation International, and Birdlife International. The massive growth in the human
population through the 20th century has had more impact on biodiversity than any other
single factor.[69] From 1950 to 2005, world population increased from 2.5 billion to 6.5
billion.[70]

Habitat destruction

Most of the species extinctions from 1000 AD to 2000 AD are due to human activities, in
particular destruction of plant and animal habitats. Extinction is being driven by human
consumption of organic resources, especially related to tropical forest destruction.[71]
While most threatened species are not food species, their biomass is converted into
human food when their habitat is transformed into pasture, cropland, and orchards.[72] It is
estimated that more than a third of biomass[73] is tied up in humans, livestock and crop
species. Factors contributing to habitat loss are: overpopulation, deforestation,[74]
pollution (air pollution, water pollution, soil
contamination) and global warming or climate
change.

The size of a habitat and the number of species it

can support are systematically related. Physically
larger species and those living at lower latitudes
or in forests or oceans are more sensitive to
reduction in habitat area.[75] Conversion to trivial
standardized ecosystems (e.g., monoculture
following deforestation) effectively destroys
habitat for the more diverse species that preceded
the conversion. In some countries lack of property rights or access regulation to biotic
resources necessarily leads to biodiversity loss (degradation costs having to be supported
by the community).[citation needed]

A 2007 study conducted by the National Science Foundation found that biodiversity and
genetic diversity are codependent—that diversity within a species is necessary to
maintain diversity among species, and vice versa. "If any one type is removed from the
system, the cycle can break down, and the community becomes dominated by a single
species."[76]

At present, the most threathened ecosystems are found in fresh water, according to the
Millennium Ecosystem Assessment 2005, which was confirmed by the "Freshwater
Animal Diversity Assessment", organised by the biodiversity platform, and the French
Institut de recherche pour le développement (MNHNP).[77]

Introduced invasive species

Barriers such as large rivers, seas, oceans, mountains

and deserts encourage diversity by enabling
independent evolution on either side of the barrier.
So-called "super-species" have evolved to fill many
habitat niches. Without the barriers such species
would occupy those niches on a global basis,
substantially reducing diversity. Humans have
helped these species circumvent these barriers,
valuing them for food and other purpose. This has
occurred on a radically compressed time scale, unlike the eons that historically have been
required for a species to extend its range.
Some species introduced by humans to new areas are potentially invasive, and some are
proved invasive. In cases such as the zebra mussel, the invasion is inadvertent. In other
cases, such as mongooses in Hawaii, the introduction is deliberate but ineffective (the rats
the diurnal mongoose were supposed to kill are nocturnal!). In other cases, such as oil
palms in Indonesia and Malaysia, the introduction produces substantial economic
benefits, but the benefits are accompanied by costly unintended consequences. Finally, an
introduced species may unintentionally injure a species that depends on the species it
replaces. In Belgium, Prunus spinosa from Eastern Europe leafs much sooner than its
West European counterparts, disrupting the feeding habits of the Thecla betulae butterfly
(which feeds on the leaves).Introducing new species often leaves endemic and other local
species unable to compete with the exotic species and unable to survive. The exotic
organisms may be either predators, parasites, or may simply outcompete indigenous
species for nutrients, water and light.

At present, several countries have already imported so many exotic species, that the own
indigenous fauna/flora is greatly outnumbered. For example, in Belgium, only 5% of the
indigenous trees remain.[78][79]

In 2004, an international team of scientists estimated that 10 percent of species would

become extinct by 2050 because of global warming.[80] “We need to limit climate change
or we wind up with a lot of species in trouble, possibly extinct,” said Dr. Lee Hannah, a
co-author of the paper and chief climate change biologist at the Center for Applied
Biodiversity Science at Conservation International.

Genetic pollution

Endemic species can be threatened with extinction[81] through the process of genetic
pollution i.e. uncontrolled hybridization, introgression and genetic swamping which leads
to homogenization or replacement of local genotypes as a result of either a numerical
and/or fitness advantage of introduced plant or animal.[82] Nonnative species can
hybridize and introgress either through purposeful introduction by humans or through
habitat modification, mixing previously isolated species. These phenomena can be
especially detrimental for rare species coming into contact with more abundant ones. The
abundant species can interbreed with the rare species, swamping its gene pool and
creating hybrids, destroying native stock. This problem is not always apparent from
morphological (outward appearance) observations alone. Some degree of gene flowis a
normal adaptation process, and not all gene and genotype constellations can be preserved.
However, hybridization with or without introgression may, nevertheless, threaten a rare
species' existence.[83][84]

Overexploitation

There is a whole history of overexploitation in the form of overhunting. The overkill

hypothesis explains why the megafaunal extinctions occurred within a relatively short
period of time. This can be traced with human migration.[85] About 25% of world fisheries
are now overexploited to the point where their current biomass is less than the level that
maximizes their sustainable yield.[86]

Joe Walston, director of the Wildlife Conservation Society’s Asian programs, called the
illegal wildlife trade the “single largest threat” to biodiversity in Asia.[87] The international
trade of endangered species is second only to drug trafficking.[88]

Hybridization, genetic pollution/erosion and food security

In agriculture and animal husbandry, the green

revolution popularized the use of conventional
hybridization to increase yield. Often
hybridized breeds originated in developed
countries and were further hybridized with
local varieties in the developing world to create
high yield strains resistant to local climate and
diseases. Local governments and industry have
been pushing hybridization. Formerly huge gene pools of various wild and indigenous
breeds have collapsed causing widespread genetic erosion and genetic pollution. This has
resulted in loss of genetic diversity and biodiversity as a whole.[89]

(GM organisms) have genetic material altered by genetic engineering procedures such as
recombinant DNA technology. GM crops have become a common source for genetic
pollution, not only of wild varieties but also of domesticated varieties derived from
classical hybridization.[90][91][92][93][94]

Genetic erosion coupled with genetic pollution may be destroying unique genotypes,
thereby creating a hidden crisis which could result in a severe threat to our food security.
Diverse genetic material could cease to exist which would impact our ability to further
hybridize food crops and livestock against more resistant diseases and climatic changes.
[89]

Climate Change

The recent phenomenon of global warming is also considered to be a major threat to

global biodiversity.[citation needed] For example coral reefs -which are biodiversity hotspots-
will be lost in 20 to 40 years if global warming continues at the current trend.[

The Holocene extinction

Rates of decline in biodiversity in this sixth mass extinction match or exceed rates of loss
in the five previous mass extinction events recorded in the fossil record.[96][97][98][99][100]
Loss of biodiversity results in the loss of natural capital that supplies ecosystem goods
and services. The economic value of 17 ecosystem services for the entire biosphere
(calculated in 1997) has an estimated average value of US$ 33 trillion (1012) per year.[101]
Conservation

Conservation biology matured in the mid-20th century

as ecologists, naturalists, and other scientists began to
collectively research and address issues pertaining to
global declines in biodiversity.[103][104][105] The
conservation ethic differs from the preservationist
ethic, originally led by John Muir, that seeks protected
areas devoid of human exploitation or interference for
profit.[104]

The conservation ethic advocates management of

natural resources for the purpose of sustaining
biodiversity in species, ecosystems, the evolutionary
process, and human culture and society.[96][103][105][106][107]

Conservation biology is reforming around strategic plans that include principles,

guidelines, and tools for the purpose of protecting biodiversity.[103][108][109] Conservation
biology is crisis-oriented and multi-disciplinary, including ecology, social organization,
education, and other disciplines outside of biology.[103][105] Preserving biodiversity is a
global priority in strategic conservation plans that are designed to engage public policy
and concerns affecting local, regional and global scales of communities, ecosystems, and
cultures.[110] Action plans identify ways of sustaining human well-being, employing
natural capital, market capital, and ecosystem services

Means

Biodiversity banking involves placing a

monetary value on biodiversity. One
example is the Australian Native
Vegetation Management Framework.
Gene banks are collections of
specimens and genetic material.
Some banks intend to reintroduce
banked species to the ecosystem (e.g.
via tree nurseries)[113]

Exotic species removal is another approach. Exotic species that have become a pest can
be identified taxonomically (e.g. with Digital Automated Identification SYstem (DAISY),
the barcode of life.[114][115] Removal is practical only against large groups of individuals
due to the econimic cost.

Reducing total pesticide use and/or more precisely targeting harmful pests is another
technique.
However, these techniques are of less importance than preserving habitat and
reintroducing eliminated indigenous species. Once the preservation of the remaining
native species in an area is assured, reintroduction can be attempted. "Missing" species
can be identified from databases such as the Encyclopedia of Life and the Global
Biodiversity Information Facility.

Strategies

Strategically, focusing on areas of higher potential biodiversity promises greater return on

investment than spreading conservation resources evenly or in areas of little diversity but
greater interest in the conservation. A second strategy focuses on areas that retain most of
their original diversity. These are typically non-urbanized, non-agricultural areas.
Tropical areas often fit both sets of criteria, given their natively high diversity and
relative lack of development.[116]

However, many animal species are migratory, meaning that focusing only on specific
locations is insufficient. Wildlife corridors can help support migration, and is
considerably cheaper and easier than clearing/preserving entirely new areas.[citation needed]

Some habitats may require restoration before standard conservation techniques can be
effective.[citation needed]

Legal status

Biodiversity is beginning to be taken into account in

political and judicial decisions:

 The relationship between law and ecosystems

is very ancient and has consequences for
biodiversity. It is related to private and public
property rights. It can define protection for
threatened ecosystems, but also some rights
and duties (for example, fishing and hunting
rights).
 Law regarding species is more recent. It defines species that must be protected
because they may be threatened by extinction. The U.S. Endangered Species Act
is an example of an attempt to address the "law and species" issue.
 Laws regarding gene pools are only about a century old.[citation needed] While the
genetic approach is not new (domestication, plant traditional selection methods),
progress made in the genetic field in the past 20 years has led to tighter laws. With
the new genetic engineering technologies, gene patenting, processes patenting,
and a totally new concept of genetic resources are emerging.[117] A very hot debate
today seeks to define whether the resource is the gene, the organism, or the DNA.
[citation needed]
The 1972 UNESCO World Heritage convention established that biological resources,
such as plants, were the common heritage of mankind.

New global agreements (e.g., the Convention on Biological Diversity), now give
sovereign national rights over biological resources (not property). Dynamic
conservation is replacing static conservation, through the notion of resource and
innovation.

The new agreements commit countries to conserve biodiversity, develop resources for
sustainability and share the benefits resulting from their use. Under new rules, it is
expected that biodiversity-rich countries allow bioprospecting or collection of natural
products, in exchange for a share of the benefits.

Sovereignty principles can rely upon what is better known as Access and Benefit Sharing
Agreements (ABAs). The Convention on Biodiversity implies informed consent between
the source country and the collector, to establish which resource will be used and for
what, and to settle on a fair agreement on benefit sharing. Bioprospecting can become a
type of biopiracy when such principles are not respected.

Uniform approval for use of biodiversity as a legal standard has not been achieved,
however. Bosselman argues that biodiversity should not be used as a legal standard,
claiming that the multiple layers of scientific uncertainty inherent in the concept of
biodiversity will cause administrative waste and increase litigation without promoting
preservation goals.[118]

Analytical limits
Taxonomic and size bias

Less than 1% of all species that have been described have been studied beyond simply
noting their existence.[119] Biodiversity researcher Sean Nee points out that the vast
majority of Earth's biodiversity is microbial, and that contemporary biodiversity physics
is "firmly fixated on the visible world" (Nee uses "visible" as a synonym for
macroscopic).[120] For example, microbial life is very much more metabolically and
environmentally diverse than multicellular life (see extremophile). Nee has stated: "On
the tree of life, based on analyses of small-subunit ribosomal RNA, visible life consists of
barely noticeable twigs.

The size bias is not restricted to consideration of microbes. Entomologist Nigel Stork
states, "to a first approximation, all multicellular species on Earth are insects".[121] The
extinction rate insects is high and indicative of the general trend of this great extinction
period.[122][123] Moreover, there are species co-extinctions, such as plants and beetles,
where the extinction or decline in one accompanies the other.[124]
Ecosystems
Every functioning ecosystem is composed of both biotic and abiotic
factors which work together as a system -- the ecosystem. The biotic
factors combine to form a community. Each community is a collection of
populations composed of each species. The ecosystem therefore is the
intimate fusion of a community with its environment.

The environment for an individual species may be described in terms of

two ecological states. The organisms:

• Habitat: the environment in which an organism or biological

population lives or grows: and its
• Niche: (pronounced NITSH) the role a species plays in its community
which depends on both where it lives and well as what it does.

We will investigate only the larger ecosystems but an ecosystem has no

size limitations -- it can be as large as the worlds oceans; the marine
ecosystem or as small as a pool of water in the cup of a tropical leaf.

A stable ecosystem has reached a state of equilibrium. In order to remain

stable three conditions must be satisfied:

1. it must have a constant source of energy

2. the energy must be available in a usable form
3. organic and inorganic materials must be recycled constantly

Biotic Relationships

Symbiotic Relationships involve close physical contact between two different

species. These interactions can be classified in terms of who is benefited,
harmed or unaffected in each case. We will look at the 4 most common
symbiotic relationships which are:

• Mutualism -- both organisms are benefited

• Commensalism -- one organism is benefited the other is relatively
unaffected
• Parasitism -- one organism is benefited while the other is harmed.

Some examples of mutualism are:

• Bees and Flowers
 • Termites and intestinal protozoan

Some examples of Parasitism include:

• Fleas and Mammals (dogs, cats, etc.)

• Viruses and probably every form of life
• Pathogenic bacteria and their hosts

Possible examples of commensalism are:

• Barnacles attached to whales

• Epiphytic plants on larger branches of a tree
• Remora hitching a ride on sharks or other large fish
Feeding Relationships follows the path nutrients take through an
ecosystem. These relationships can be described in three ways.

o What individual organisms use for food

o How nutrients are transferred through the community
o Trophic (energy) levels

Organisms may be classified by the type of food they use or obtain into
tree groups:

Producers (plants an algae) obtain their food from sunlight -- they are
sometimes referred to as autotrophs
Consumers (all other organisms) get their food by eating other organisms.
For example: 1. herbivores are primary consumers -- eating only plants or
other producers 2. carnivores are secondary consumers -- they eat only
other animals 3. some carnivores -- especially fish -- can be tertiary
consumers -- animals that eat animals that eat animals
Decomposers (mostly bacteria and fungi) help breakdown complex
organic molecules produced by other living things.

How nutrients are transferred from one organism to another is outlined in

one of two ways:

Food chains -- each organism, starting with plants and other producers,
that eats, absorbs, or decomposes another is part of a linear sequence
called a food chain. This represents only a single thread in a larger more
complex set of relationships called a food web.
Food webs -- represents a network of food chains. The more extensive the
food web found in a community the more stable that community should
be.
 Food chains and food webs have three common
threads:

Nutrients are transferred from producers to consumers Organisms feed on

several different tropic levels Both end with decomposers.

Trophic (energy) levels

Trophic levels in a community are limited to no more than 5, but may

often be less. Each trophic level represents the amount of energy
available to levels above it. Because energy is always lost from one level
to the next the trophic levels in any ecosystem can be represented as a
pyramid -- widest at the bottom -- and narrow at the top.

Notice that the amount of energy transferred to the next higher level is
only about one-tenth of the original amount. This is due to several factors
including:

• Energy is lost as waste

• Friction and inefficiencies occur during the transfer process

• Some parts of the original organism can not be recycled

This is called the 10% rule -- as energy moves through trophic levels in an
ecosystem, only about 10% of the total energy at one level is stored in the
tissues of organisms in the next level.

Pyramid models emphasize 4 important ecological principles which

include:

All food chains begin with producers Consumers depend, directly or

indirectly on producers for their energy The amount of energy available at
each trophic level is directly related to the number of links in a food chain
Solar energy is required as the ultimate energy source (for nearly every
living thing on earth)

Remember that energy does not cycle but rather it flows through ecosystems