21.1 Importance of Biodiversity

The Amazon rainforest has lost a significant amount of its flora and fauna.

Rates are higher in other rainforests.
Food, clean water, and the rate of development of new medicines will all be affected by the loss of biodiversity.
Human activities such as destruction of habitats, introduction of disruptive species, hunt some species to extinction, continue to warm the planet with greenhouse gases, and influence nature in other ways have increased the loss of biodiversity.
If we make dramatic changes in our behavior, we can slow the loss of biodiversity.

An example of a high habitat is the tropical lowland rainforest in Madagascar.

Half of the original coastal lowland forest has been lost, yet this location is protected within a national forest.
Measures of biodiversity at several levels of biological organization are being used by biologists to help focus efforts to preserve the biologically and technologically important elements of biodiversity.

There is no reason to care about the loss of the passenger pigeon, the dodo, or the woolly mammoth because these events happened a long time ago.

The current accelerated extinction rate means the loss of tens of thousands of species within our lifetimes, even though the loss of a particular individual species may seem unimportant.
The collapse of the ecosystems is likely to have dramatic effects on human welfare, in addition to the added costs of maintaining food production, clean air and water.

Every other species on the planet is dependent on human populations, just as they are.

Early hunter-gatherer societies first settled in one place and then heavily modified their environment to make agriculture possible.
The cultural transition has made it difficult for humans to recognize their dependence on living things other than crops and animals.
Our technology allows us to live longer, more comfortable lives, but ultimately the human species cannot exist without its surrounding environment.
Our food comes from our ecosystems.
This includes living plants that grow in soil and the animals that eat them as well as this OpenStax book is available for free.
Many of the medications that maintain our health are made from compounds found in living organisms.
Our clean water can be found in the lake and river ecosystems or through the Terrestrial ecosystems on its way to the ground.

The American Ornithologists' Union has a list of 2078 species of birds in North and Central America.

This is a measure of bird diversity.
The relative abundances of species are taken into account in more sophisticated measures of diversity.
A forest with 10 equally common species of trees is more diverse than a forest with only one of those trees making up 95 percent of the trees.
Some of the measures that are important in planning how to preserve biodiversity have been identified by biologists.

Genetic diversity is an alternate concept.

The future potential of a species depends on the genetic diversity in the populations that make up the species.
The same is true for higher categories.
A group with different types of species will have more genetic diversity than a group with the same types of species.
The most genetically diverse one of the genera is the one with the greatest potential for evolution.

metabolic processes that keep organisms alive and reproducing are carried out by most genes.

This chemical diversity is important for humans because of the potential uses for these chemicals.

The drug eptifibatide is derived from rattlesnake venom and is used to prevent heart attacks in people with certain heart conditions.

It is cheaper to discover compounds made by an organisms than it is to imagine them and make them in a laboratory.

Chemical diversity is a way to measure diversity.
Humans have domesticated animals, plants, and fungi, but they are suffering losses because of market forces and globalization.
International seed companies only produce a very few varieties of a given crop and give incentives around the world for farmers to buy these few varieties, while abandoning their traditional varieties, which are far more diverse.
Crop diversity is a stable food source for the human population and its decline is troubling to biologists and agricultural scientists.

Even if some of the species survive, whole ecosystems can disappear.

The loss of an ecosystems means the loss of interactions between species, the loss of unique features, and the loss of biological productivity.
The prairie ecosystem is an example of a largely extinct one.
Prairies once stretched from northern Canada down into Mexico.
Crop fields, pasture lands, and suburban sprawl replaced them.
Many of the species survive, but the hugely productive ecosystems that were responsible for creating our most productive agricultural soils are gone.
Unless they are maintained at a higher cost, their soils are being deplete.

The decline in soil productivity is caused by the loss of interactions in the original environment, which is more important than the extinction of a few species.

There is a great diversity of species on Earth.

Knowledge of the species that live on the planet is limited.

According to a recent estimate, less than 20% of the total number of species on the planet are known by science.
Estimates of the number of prokaryotic species are largely guesses, but biologists agree that science has only just begun to catalog their diversity.
Even with what is known, there is no centralized repository of names or samples of the described species; therefore, there is no way to be sure that the 1.5 million descriptions is an accurate number.
It is a guess based on the opinions of experts.
Science doesn't know what is being lost because Earth is losing species at a rapid pace.

The estimated number of species is shown in the table.

The internet is facilitating the effort to catalog described species in more organized ways.

It would take close to 500 years to describe all of the species currently in existence.

The other needs of humanity make naming and counting species seem unimportant, but it isn't just an accounting.

It is a complex process by which biologists determine an organisms unique characteristics and whether or not that organisms belongs to any other described species.

In May, 20, 2012

After the initial discovery to follow up questions about its biology, this OpenStax book is free.

The discoveries that come from that research will make the species valuable to humans.
Without a name and description a species cannot be studied in depth and in a coordinated way.

The diversity of the planet is not evenly distributed.

The introduction of an exotic species in the 1980s and 1990s caused a mass extinction of almost 500 species of cichlids.

All of these species were found in Lake Victoria.

The Barton Springs salamander is endemic to the mouth of one spring in Austin, Texas, while the blue jay is endemic to North America.
The Barton Springs salamander is vulnerable to extinction.
The genera and families can be endemic.

Many other lakes in North America have the same number of species of fish.

Lake Victoria is a tropical lake, while Lake Huron is a cold lake.
The present form of Lake Victoria is about 15,000 years old, while the present form of Lake Huron is about 7,000 years old.
Two of the hypotheses biogeographers have suggested are latitude and age.

The study of the distribution of the world's species is called biogeography.

Understanding our physical environment, how the environment affects species, and how changes in environment impact the distribution of a species is critical to the work of biogeographers.

There are three main fields of study under the heading of biogeography.

Ecological biogeography studies the distribution of plants and animals.
The protection and restoration of species based on historical and current ecological information is the focus of conservativism biogeography.

In almost every group of organisms, there is an increase.

The number of amphibian species across the globe is shown on the map.

The pattern is the same for most groups.

It's not clear why the tropics have more biodiversity than the other parts of the world, but there are some theories about why the tropics have more life than the other parts of the world.

There is more time for speciation when the age is greater.

It is possible that the tropics receive more energy from the sun than the polar regions.
Scientists haven't been able to explain how more energy input could translate into more species.
More opportunities for coevolution, specialization, and perhaps greater selection pressures are provided by the greater heterogeneity.
The tropics have been seen as being more stable than the other parts of the world.
The tropics have their own form of seasonality, such as rain, but they are generally assumed to be more stable environments.

It's true that the tropics have the greatest amount of biodiversity.

There are more endemic species in the tropics.
The tropics have more of the same.
The knowledge of the species living in the tropics is the lowest and the potential for loss is greatest because of recent human activity.

We don't impact other species directly because of their interconnectedness, as species disappear from an environment other species are threatened by the changes in available resources.

It is important for the survival and welfare of human populations because of the impacts on our health and ability to feed ourselves through agriculture and harvesting populations of wild animals.

Natural chemicals are used to make many medications.

Some of the secondary plant compounds are used as human medicines.
Modern societies that live close to the land have a lot of knowledge of the uses of plants.
For hundreds of years in Europe, books were written about the medical uses of plants.
Humans are not the only animals that use plants.
The other great apes have been observed self-medicating with plants.

The importance of these plant compounds is recognized by modern pharmaceutical science.

Aspirin, codeine, digoxin, atropine, and vincristine are examples of significant medicines derived from plant compounds.
Plant extracts were once used to make many medications.
At one time, 25 percent of modern drugs contained at least one plant extract.
Synthetic versions of the plant compounds are replacing natural plant ingredients, so the number has probably decreased to about 10 percent.
Antibiotics, which are responsible for extraordinary improvements in health and lifespans in developed countries, are largely derived from fungi andbacteria.

It is a source of vincristine, a drug used in the treatment of lymphomas.

Five drugs based on animal toxins were approved by the FDA in 2007.

There are at least six drugs that are being used in other countries.

There are toxins from mammals, snakes, lizards, fish, snails, and scorpions.

These medications improve people's lives and represent billions of dollars in profits.

New natural compounds that can function as medicines are being sought after by pharmaceutical companies.
35 percent of new drugs brought to market between 1981 and 2002 were from natural compounds, and one third of pharmaceutical research and development is spent on natural compounds.

Humans benefit from living in a biodiverse world.

E. O. Wilson is an entomologist.
He says that human evolution has adapted us to live in a natural environment and that built environments can cause health and well-being problems.
There is research that suggests the hypothesis may hold some truth.

Humans have been breeding and selecting crop varieties for over 10,000 years.

The crop diversity matched the cultural diversity of the population.
Around 7,000 years ago, potatoes were domesticated in the central Andes.
The people in this region used to live in settlements separated by mountains.
There are seven species of potatoes that are grown in that region.
Each variety has been bred to thrive in certain environments.
The demands of the dramatic elevation changes, the limited movement of people, and the demands created by crop rotation are some of the reasons for the diversity.

There are many examples of agricultural diversity.

The demands for food value, adaptation to growing conditions, and resistance to pests have led to the creation of diverse varieties of plants and animals.
The potato is an example of the risks of low crop diversity: during the potato famine in Ireland in the 18th century, a single potato variety became susceptible to a potato disease.
famine, death, and mass emigration were caused by the loss of the crop.

Resistance to disease and lack of diversity in contemporary crop species are both benefits to crop biodiversity.

To keep up with evolving pest organisms, seed companies must continually breed new varieties.
The decline of the number of varieties available is a result of the seed companies focusing on selling fewer varieties in more areas of the world.

The ability to create new crop varieties is dependent on the diversity of varieties available and the availability of wild forms related to the crop plant.

These wild forms are often the source of new genes that can be used to create new varieties.
The loss of wild species will affect crop improvement.

Our continued supply of food is ensured by maintaining the genetic diversity of wild species.

Seed banks of crop varieties have been maintained by the government since the 1920s.

There is no way to replace lost seed varieties in this system.

Losses can be replaced from the regional seeds if something happens to them.

The rock of the island has a seed vault.
The deep underground location of the vault in the arctic means that the vault's systems will not compromise the climatic conditions inside the vault.

The seeds of Earth's diverse crops are stored in the Global Seed Vault.

Our ability to grow crops is dependent on the diversity of the environment in which they are grown.

The conditions under which crops are able to grow are created by the diversity of the environment.
Crops are not grown in built environments.
They are grown in the soil.
Although some agricultural soils are rendered sterile using controversial pesticide treatments, most contain a huge diversity of organisms that break down organic matter into compounds that crops need for growth.
Water and oxygen dynamics in the soil are important for plant growth.
It's not possible to replace the work of these organisms in forming arable soil.
These kinds of processes are called services.
They occur as a result of the diverse metabolism of the organisms living there, but they provide benefits to human food production, drinking water availability, and breathable air.

Plant pollination and crop pest control are some of the key services related to food production.

It is estimated that honeybee pollination in the United States brings in over a billion dollars a year.

In the United States, over 150 crops require pollination.

Beekeepers rent out their services to farmers.
Colony collapse disorder, a new phenomenon with an unclear cause, has caused large losses of honeybees in North America.
Other pollinators include insects and birds.
Increasing dependence on other crops would be made impossible by the loss of these species.

Humans compete for their food with crop pests.

Pest populations adapt to pesticides and they lose their effectiveness over time.
They endanger the health of agricultural workers and consumers by killing non-pest species as well as beneficial insects.
Pesticides may migrate from the fields where they are applied and do damage to other ecosystems like streams, lakes, and even the ocean.
Ecologists believe that the majority of the work in removing pests is done by animals, but the impact has not been studied.
The effect of landscape complexity on natural enemies of pests was found to be greater in 74 percent of studies.
A study found that introducing multiple enemies of pea aphids increased the yield of alfalfa.
A diversity of pests is more effective at controlling pests.