Though a relatively new term, Biodiversity echoes the timeless pursuit of naming and classifying organisms. In the Genesis, Adam names everything. In his “History of Animals,” Aristotle invents the first taxonomic hierarchy. During the 1700s, Carl Linneaus publishes his “Systema Naturae,” inventing a new system for classifying plants. And of course, a century later, we all came to know our favourite naturalist, Charles Darwin, who wrote “The Origin of Species,” in which the final page refers to biodiversity as “…all forms most beautiful and wonderful.” And don’t forget the old Chinese proverb, stating  that“the beginning of wisdom is calling things by their right name.”

When scientists began linking species extinction to climate change, biodiversity became a hot topic. The term was first coined in 1985 when National Forum on Biological Diversity was first created and was later introduced in conservation literature by E.O. Wilson prior to his publication of “The Diversity of Life.”

In 1993, United Nations Environment Programme (UNEP), stressed the importance of biodiversity, formally stating a need to: 1) Conserve biological diversity, 2) Use biological diversity in a sustainable fashion and 3) Share the benefits of biological diversity fairly and equitably while “achieving a significant reduction of the current rate of biodiversity loss” by 2010.

Obviously, this didn’t happen.

So what did the ecologist do? Make it part of their science. Hence, Biodiversity today is formally known as the sum of all variation, over all levels of biological organization.

Biodiversity Hierarchy

Biodiversity begins on the individual level, which focuses on the individual variation within a given population. Phenotypic (i.e. observable) variation occurs due to genetics, the environment and the interactions a particular set of genes has with the given environment. The focus here is on identifying heritable genetic traits that establishes the kind of variation occurring among individuals.

At the species level, the focus is on phenotypic variation between populations. A species consist of populations of organisms that interbreed. So populations within a species may show phenotypic variation in genetically inherited traits due to gene pool differences. A gene pool is a collection of alleles in a group of individuals available for the next generation. Thus, studying at the species level requires looking at differences among the gene pool, which are generally caused by different selective pressures.

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A level up and we have communities, which differ in the KINDS and the ABUNDANCES of species. Different communities have different rates of abundances. For example, a cloud forest has a high abundance and high species richness of epiphytes and hummingbirds. Whereas, a different community such as dry forests have low abundance and low species richness of epiphytes and hummingbirds. Furthermore, community compositions are influenced by a number of factors such as predation, competition, mutualism, dispersal, and biotic interactions. To illustrate, in regions that have warmer climates, there is higher abundance and species richness of ants, which effects those communities compositionally as their presence results in higher species richness of plants that have mutualistic relationships with the ants.

At the next level, we have the ecosystem, which is made of the organisms that live in a particular location (biotic), in an area functioning together with all their physical (abiotic) surroundings. This is also known as Functional diversity. An ecosystem is also considered a unit of interdependent organisms sharing the same habitat and the interdependencies form a number of food webs. The geographic range in ecosystems are huge, ranging from a tadpoles in a puddle to the Great Barrier Reef.

Food Web

Lastly, at the highest level, is the landscape, which is a composite of multiple ecosystems. Since variation is compounded with each additional level, the biodiversity estimate at the landscape level is usually the greatest.

From a macro view,there are three things to consider when analyzing the a region’s biodiversity:

  1. Composition: who is there
  2. Structure: how it looks
  3. Function: what happens

The highest biodiversity occurs in the tropics, where there is high species richness and endemism. The three most biodiverse regions in the world are Madagascar & the Indian Ocean Island, the Philippines and Indonesia.

Overall, biodiversity is an important topic in understanding how to maximize our resources (such as food, medicine, even genes) from nature while simultaneously minimize our impact on the environment. Ecosystem services provided by areas with high biodiversity, such as erosion prevention, water purification, C02 and climate regulation and nutrient cycling through decomposition are to be further investigated as well.

Today, the focus of biodiversity is to be able to identify all of the Earth’s species, which are still largely undiscovered. Only by knowing what’s out there can we then understand the functionality of the diversity available to us.

References

Chaves, Johel. “Concepts of Diversity.” CIEE Tropical Diversity Lecture. September 2014.