Biodiversity

Biodiversity
n., plural: biodiversities
[ˌbaɪoʊdɑɪˈvɚsəti]
Definition: the diversity of life in a particular habitat or ecosystem

The biological world or life on earth is a marvel that has amazed us since time immemorial. The rich natural diversity of biological forms whether it be plants, animals, insects or fungi have all of us mesmerized at the first sight besides the basic role to sustain life on the planet Earth.

The ecological and environmental significance of this beauty is something that we don’t even need to mention or explain. The variety of forms, structures, shapes, and types in which life exists in most habitable to inhabitable ecosystems on Earth is spellbinding. In order to explain every living species (living organisms encompassed in this brief introduction, a word called “biodiversity” or “biological diversity” has been coined.

In this article, we will try to cover all the major aspects of biodiversity from all points of view. Read on to learn more about the meaning of biodiversity, how to define biodiversity how much biodiversity contributes to different aspects of human life, tools used for measuring biodiversity, how many species or diversity of plants, diversity of life and animals inhabit the planet, how new species come into existence, why is biodiversity important for the continuation of human life on earth, different biodiversity examples, what biodiversity refers to in scientific terms, the splendid values of biodiversity, different types of biodiversity (desert biodiversity, tundra biodiversity, etc).

Biodiversity Definition

To begin with, let’s find out what is biodiversity in the environment or what does biodiversity mean?

Biodiversity definition (biology): Biodiversity can be defined as the broader term that circumvents all the types of biological forms that exist on this planet. The biodiversity science definition and biodiversity ecology definition are the same as above. This covers species diversity, genetic diversity, and ecosystem diversity. So, the three types of biodiversity are:

• Species diversity: Total number of different species (diverse species that form a part of a community. (Now we can explain what is species diversity)
• Genetic diversity: Total number of different genotypes (genetic variation) existing in the population of a community.
• Ecosystem diversity: Total number of variations that exist in a biodiverse ecosystem that’s defined by a given geographical location. (biodiversity in ecosystems)

Watch this vid about biodiversity – a video that explains biodiversity, created by The Society for Experimental Biology (SEB).:

Why Is Biodiversity Important?

We often are misled by the notion that it’s us humans who are the most important for the Earth to go around its normal course of life and death. Nature is self-sustainable and what makes it so is its rich biodiversity. Each member of biodiversity whether microscopic (soil biodiversity, bacterial or viral life form) or humongous (whale or elephant) has its own essence that is often undermined by us (humans).

Some of the crudest examples of why biodiversity is important are:

• Biodiversity is the source of our food, shelter, and source of living.
• Biodiversity is what keeps us safe from different natural world disasters and pandemics.
• Biodiversity is what provides us with insights about art and literature.
• Biodiversity is the source of human being’s motivation to explore space.

These are just some of the most basic examples why biodiversity is so crucial for human survival.

Distribution

Contrary to the common notion, biodiversity is quite heterogeneously distributed across the Earth. As we are well aware of the different temperature zones of Earth, there’s a higher affinity of biodiversity towards the warmer, more humid zones (near the Equator with high biodiversity) as compared to temperate regions (low biodiversity).

These regions of Earth are highly dense with high primary productivity rates. Tropical rainforest biodiversity is richer than that of any other geographical location on Earth.

To read more about primary productivity and understand the difference between gross and net primary productivity, click here and learn more with BiologyOnline.com.

Though the tropics cover only 10% of Earth’s total surface, they account for a magnanimous 90% of the Earth’s biodiversity. South America is one of the most biodiverse countries in the world. This disproportionate distribution is what makes the conditions of tropical ecosystems so special.

The increasing deforestation, destruction of natural habitats, and retreating forest covers of tropics and forest biodiversity is thus a serious issue over which the countries should unite and take a leap forward for restoration.

The major factors that determine the distribution of biodiversity are:

1. Temperature
2. Latitudinal gradient
3. Altitude
4. Precipitation
5. Soil type
6. Geography
7. Biological interaction with other organisms

• Latitudinal gradients

Latitudes are the parallel lines to the equator; while the equator is 0°, the latitudes range till 90°, the farthest one being 90°. The lower latitudes (closer to the equator) witness richer biodiversity. The higher latitudes (closer to the pole) witness lower biodiversity. This concept in biodiversity explains that most species distribution is in accordance with latitude and its associated environmental conditions (temperature, nutrients, competition, etc).

• Biodiversity Hotspot

Biodiversity hotspots are (also known as biological hotspots) defined as a region with a very high distribution of endemic species or native species. Endemic species are those individual species that are found only in a restricted geographical zone with defined (specific) ecological factors. A very abundant presence of endemic species in an area could be due to:

• Plentiful resources
• Favorable abiotic conditions
• Availability of specific factors for each species’ growth

Evolution

The biodiversity that we see through our eyes and cameras today is a product of several years of evolution. Not all life forms that we see today have always existed on this Earth. Some forms might not exist even today and would have disappeared before we were born.

• History

Evidence suggests that evolving forces of nature have acted upon different facets of life for over 3.5 billion years. And this entire process has brought to us what we see today and describe as the “current biodiversity of Earth”. Early life forms like bacteria, protozoa, protists, and archaea are believed to have witnessed different seasons of Earth’s evolution. The other more complex life forms like floral and faunal have evolved only recently (a few million years ago)!! ☺

Yes, that’s recent when seen from an evolutionary point of view! So, one can estimate how many humans have ever lived.

• Diversification

Majorly, the diversity of life forms in terrestrial ecosystems which are a part of bigger ecological complexes has been studied as compared to aquatic (specifically marine biodiversity) ecosystems. The diversification patterns across terrestrial ecosystems are believed to have followed exponential scales after the mass extinction. Although we could possibly be undermining marine diversity till now it’s believed to have followed logistic diversification patterns.

Ecosystem Services

Usually, we fail to acknowledge and credit the biotic support that we get from nature. The various types of services that the ecosystem and its rich biodiversity provide to us for our survival, growth, luxury, and recreation are called ecosystem services. Biodiversity and ecosystem services go hand in hand. As long as we are taking care of biodiversity, we are being served different ecological functions and services as biodiversity supports it till its threshold.

• General ecosystem services

Under the heading of general ecosystem services, we classify those services which are provided to us at no cost yet with plentiful benefits. Some of those are:

1. Renewable resources (provisioning service) {example: climate regulation}
2. Maintenance resources (regulating service)
3. Recreation resources (cultural service/cultural processes)

• • Services enhanced

Under services enhanced, we study:

1. Provisioning service and how greater diversity of plant species on the planet increases the available resource of fodder or crop yield or timber production (by increased plant growth)
2. Regulating service and how greater diversity of a few species (specifically plant species) on the planet reduces the prevalence of certain types of pests and pathogens.

   • Services with mixed evidence

Under services with mixed evidence, we study:

1. No provisioning service
2. Regulating service and how the diversity of pollen can or can’t determine the pollination rate.

   • Services hindered

Under services hindered, we study:

1. Provisioning service and how higher plant species diversity leads to a reduction in primary productivity.
2. Regulating service and how higher species diversity might link to lesser rates of water purification.

• Agriculture

We study agricultural diversity (agrobiodiversity) under 2 sub-headings:

1. Intraspecific diversity (between individuals of the same biodiversity species)
2. Interspecific diversity (between individuals of different species)

Biodiversity aids pollination, nutrient cycling, and pathogen and pest control in agriculture.

• Human health

While the world becomes more and more industrialized, commercialized, and ignorant of the fact that nature must not be threatened beyond its threshold (threatened biodiversity), we also lose track of how human health is intrinsically dependent or closely linked with the ecosystem’s health and the world’s biodiversity.

An ecosystem is not just about our commercially important plants and animals but the entire biodiversity that the planet nurtures. This issue is now escalating on the political battlegrounds but only a conscious and real effort and lessons from human history can help mankind in developing a mutual relationship with biodiversity.

• Business and industry

Almost all businesses and industries across the globe thrive on some or the other form of biodiversity. Some examples are the timber industry, rubber industry, food, and spices business (for human consumption), etc.

• Leisure, cultural and aesthetic value

The recreational service offered by biodiversity is one of the most pleasing experiences of one’s life. Whether it be bird watching or seeing fishes while kayaking in a backwater or natural history, the biodiversity never fails to amaze.

• Ecological services

For a smooth and undisrupted continuum of ecological processes, biodiversity plays an indispensable role. Some of the ecological services where biodiversity is integral are:

1. Nutrient cycling
2. Water purification
3. Maintenance of life cycles of species
4. Maintenance of fertility of the soil

Number of Species

There are only estimates of the species number. No one can vouch for an exact figure here. So, some of the more speculated and believed numbers are:

• Terrestrial species= 8.7 million
• Oceanic species= 2.2 million
  (Source of information: see Reference-4)

Measuring Biodiversity

We measure biodiversity using a diverse set of tools or terminologies. Let’s discuss them one by one.

1. Species evenness: It is an approximate measure of species that inhabit a particular geographical location.
2. Species richness: It is the total number of species that inhabit a geographical location.
3. Species diversity: It is the relationship between species’ evenness and richness.

Species Loss Rates

It has been estimated that nearly 30% of the species will be risked of species extinction (already in the category of endangered species) by the year 2050. According to the Species-Area theory, approximately 140,000 species will be extinct per year, and losing biodiversity in such numbers should be worrisome. This overwhelming figure can’t be justified as more and more species face the threat to their basic survival.

According to the world wildlife fund, Earth has already lost nearly 50% of the biodiversity that inhabited the planet in the 1970s. Scientific studies have shown that anthropogenic/human activities have converted more lands into inhospitable places and Earth is right now running on the course of ecological armageddon.

Threats to Biodiversity

Some of the major threats to biodiversity are:

1. Prioritized industrialization (contributor to greenhouse gasses like carbon dioxide, etc)
2. Increasing commercialization
3. Expanding residential spaces
4. Deforestation
5. Unscrupulous usage of natural resources
6. Ignorance towards sustainability
7. Increasing demand for food and resources
8. Pollution
9. Climate change
10. Issue of invasive species

• Habitat destruction

The escalated rates of biodiversity loss are interrelated with habitat destruction. The increasing human population, human activity, and the ever-increasing demand for limited resources have pushed the environment beyond its carrying capacity. This is something that makes everything unsustainable in the ecological systems.

• Introduced and invasive species

Invasive species are those which break natural barriers and start growing on foreign lands. They often threaten the growth and distribution patterns of natural, wild, and endemic species.

• • Genetic pollution

Genetic pollution encompasses phenomena like:

1. Hybridization
2. Introgression
3. Genetic swamping

• Overexploitation

Overexploitation of both abiotic and biotic resources has brought ecosystems to the brink of breakdown. Mindless tree logging, dumping of sewage in water bodies, and burdening of soil systems with chemicals like herbicides, fertilizers, etc have extremely degraded the quality of ecosystems.

• Hybridization, genetic pollution/erosion, and food security

Hybridization as a phenomenon was highly lauded during the Green Revolution for the production of crops that have higher yields. But as time passed, it somehow led to genetic erosion. This topic might be highly debatable. For the sake of developing crops resistant to various pests, abiotic factors, etc, plants are being genetically modified (containing the genetic material of other species) and this again brings a lot of change at the genetic level.

• Climate change

Let’s take a quick sneak peek at biodiversity and climate change. Challenges like global warming are also a great threat to biodiversity. The retreating oceans, increased incidences of forest wildfires, etc which are a result of global climate changes have swept away many species of life forms in the past few years, thereby taking a toll on global biodiversity. An alarming example of the same is the coral reefs which are biodiversity hotspots (abundant in coral reef biodiversity) and are predicted to be lost in the next 100 years if the current trend of Earth’s degradation continues.

• Human overpopulation

According to a census in 2017, the total world population is estimated to be 7.6 billion. The increasing population calls for increased biological resources which the planet is currently not able to. This increase beyond the planet’s intrinsic bio-capacity or intrinsic value has served as a major threat to biodiversity.

The Holocene Extinction

Holocene extinction is defined as the current running extinction phase during this Holocene epoch.

Conservation

What is conservation? When the masses are ignorant and abusive toward nature’s health, they fail to recognize that ecosystems are self-healing. In such scenarios, anthropogenic conservation efforts by a few sensitive fellows become crucial. Conservation biologists, naturalists, etc have started making humongous efforts for the conservation of biodiversity that we can still save.

• Protection and restoration techniques

Some of the techniques for protecting biodiversity are:

1. Removal of exotic species
2. Biodiversity banking
3. Creation of gene banks
4. Reduction in usage of fertilizers, herbicides, and other chemicals
5. Introduction of wildlife corridors

Protected Areas

Protected areas have become the need of the hour. Defining reserve forests, taking stringent actions against smugglers and poachers, etc could be some of the efforts that can help in the manifestation of protected areas.

• National parks

IUCN recognizes national parks as “category II type” protected areas that could be natural or semi-natural. These areas are demarcated in order to protect not just the plant and animal species but also the ecological framework in which these organisms thrive and function as a part of nature. While preserving biodiversity, it is also important that spiritual, cultural, and traditional aspects related to biodiversity are taken care of.

• Wildlife sanctuary

Wildlife sanctuaries are recognized to protect biodiversity (only the species). These protected areas can be government or privately controlled. Also, their boundaries are not defined by state boundaries.

• Forest reserves

Forest reserves are defined to focus on the conservation of endemic species of forests. Ethnic tribal or local communities that have lived for several years in harmony with the forests are usually allowed to stay inside or on the fringes of the forest. Some limited hunting and grazing rights are also provided to them by the state in the forest reserves.

• • Steps to conserve the forest cover

Some important steps to conserve forest cover are:

1. Prevention of hunting, grazing, smuggling, and poaching activities
2. Boost for reforestation and afforestation
3. Prevention of tree logging for large-scale industries from forests
4. Modern-day interventions to prevent forest wildfires
5. Regulated entry of scientists and visitors (only after forest permissions)
6. Inclusion in national and international policy-making

• Zoological parks

Zoological parks, often referred to as zoos are established majorly for human recreation and to spread awareness among the masses about biodiversity in terms of faunal species, i.e. types of animals (different animals). This helps the masses in knowing how many animals in the world (animal biodiversity) are found in their country.

• Botanical gardens

Botanical gardens are established for human recreation as well as to spread awareness among the masses about biodiversity in terms of floral species (plant biodiversity).

Resource Allocation

Resource allocation is a very crucial step in biodiversity conservation. There could 2 types of strategies when allocating resources:

1. Focusing on smaller areas with more biodiversity (richer areas) than larger areas with less biodiversity.
2. Focusing on non-urbanized areas with original biodiversity than urbanized areas with replaced biodiversity.

• In society

In the present scenario where the human population is skyrocketing, it is important that we head towards sustainability. Some aspects to keep in consideration are:

1. Change in current land use patterns
2. Maximizing conservation efforts while meeting the population’s demands
3. Making agriculture and meat industry more sustainable
4. Spreading awareness about different aspects of personal life that contribute to more sustainable living

Citizen Science

Citizen science is an initiative to involve the common people in fuelling science research. It can prove highly useful as it helps scientists and researchers in gathering public knowledge and insights about conservation and biodiversity among common people. The convention on biological diversity is a United Nations body that takes care of all the legal issues related to biodiversity worldwide. Similarly, there is another center for biological diversity (an NGO in the USA).

Analytical Limits

No matter how much science has progressed over the years and decades, the studies of the rich biodiversity of Earth have been limited due to the humongous size of the dataset.

• Taxonomic and size relationships

The biodiversity of Earth is both microscopic and macroscopic (primarily, microscopic) . This is one of the reasons that less than 1% of the Earth’s biodiversity has been properly described and studied in detail.

Arogyapacha – “The green that gives strength”

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There is an endemic plant that grows in the southern western ghats of India known as Trichopus zeylanicus. It is a perennial herb with a rhizomatous stem and berries. It belongs to the family Dioscoreaceae. It is commonly known as “Arogyapacha” meaning ‘the green that gives strength’ by an ethnic tribal group called the “Kaani tribe” in Agastya Koodam ranges, Kerala, India.

The tribe has long consumed the fruit (berries) of this plant for the health benefits like immunomodulatory, adaptogenic, anti-fatigue, stimulant, stamina-boosting, and aphrodisiac properties.

In an attempt to bring the medicinal resources to use, an Indian scientist P. Pushpangadan and his team at Tropical Botanical Garden and Research Institute (TBGRI) designed a wonder drug called “Jeevanika/ Jeevani” from this plant which has been licensed to Kottakkal Arya Vaidya Sala. This is the world’s first product to exemplify “benefit-sharing system”!! It was a brilliant example of translating traditional knowledge systems to commercial value as it:

• benefits the tribal community (in form of license fees and royalties)
• effectively overcomes bottlenecks of bioprospecting via industry-academia-community network
• Potential to earn a large share of the foreign exchange if scientific evidence is provided!!

Remember, when we preserve the ethnic communities along with the biodiversity, we preserve the mediators who have studied the local flora and fauna for years and generations. The knowledge system they can share is immense.

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Further Reading

• Biology Tutorial: Ecology & Biodiversity: New Zealand Flora & Fauna

References

• Aigeo, T. J., Scheckler, S. E., & Scott, A. C. (1998). Terrestrial marine téléconnexions in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events. Phil. Trans. R. Soc. Lond. B, 353, 113-130.
• Sahney, S., Benton, M.J., Ferry, Paul (2010). Links between global taxonomic diversity, ecological diversity and the expansion of vertebrates on land. Biology Letters. 6 (4): 544–547. doi:10.1098/rsbl.2009.1024. PMC 2936204. PMID 20106856
  Business and Biodiversity webpage of the U.N. Convention on Biological Diversity. Cbd.int. 21 June 2009.
• Mora, C., Tittensor, D. P., Adl, S., Simpson, A. G., & Worm, B. (2011). How many species are there on Earth and in the ocean?. PLoS biology, 9(8), e1001127.
• Mulongoy, K., & Chape, S. (2004). Protected areas and biodiversity: an overview of key issues.

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