Understanding Richness, Evenness, and Their Importance
If an alien from a foreign galaxy where to go to our planet Earth, the primary thing that might amaze and baffle him would most likely be the big diversity of life that he would encounter. The rich diversity of organisms sometimes even astonishes human beings. Biodiversity is inherent within the occurrence of varied sorts of environmental conditions in several parts of a neighborhood also as earth and therefore the presence of varied sorts of life adapted to those different environmental regimes. These further contribute to the components of species diversity.
It is hard to believe that there are quite 21000 species of ants, 310000 species of beetles, 29000 species of fishes, and nearly 21000 species of orchids. Biodiversity isn't uniform. it's tremendous in some places, moderate in others, and low in certain regions. Ecologists and evolutionary biologists try to know the importance of such tremendous species diversity, species richness and relative abundance.
Biodiversity
Biodiversity plays a major role in components of species diversity. This term was given by Edward Wilson. It describes the combined diversity in the least levels of the biological right from macromolecules to within the cells, genes, species, ecosystem, and biomes. it's taken many years of evolution to accumulate this diversity in nature, but we could lose all that wealth in two centuries if this rate of species losses continues. Biodiversity and its conservation are now vital environmental problems with international concern as more and more people around the world begin to understand the critical importance of biodiversity for our survival and well-being on this planet. It is responsible for enhancing the species diversity, species richness and relative abundance. There are three main components of species diversity, species richness and relative abundance. We will learn about them below.
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Figure: Different species of Hawaiian fishes in a single ecosystem.
Genetic Diversity
It is the first and one of the very important components of species diversity, species richness and relative abundance. Sometimes a single species can show a high level of diversity at the genetic level. It means it's a measure of variation in genetic information within the organisms. Within a species, genetic diversity occurs within the differences of alleles, entire genes, and chromosomal structures. Genetic diversity enables a population to adapt to its environment and therefore the changes occurring within the environment. It leads to variation in potency and concentration of the active chemical which is reserpine being present in medicinal plant Rauwolfia vomitoria that grow in several Himalayan ranges. It helps within the formation of ecotype and plays a key role in the process of speciation. quite 50000 genetically different strains of rice and 1000 sorts of mango occur in India thanks to genetic variations.
Species Diversity
It refers to the variability of species within a neighborhood, for instance, Western ghats have greater amphibian species as compared to Eastern ghats. Species diversity may be a product of species richness and species evenness. So species diversity, species richness and relative abundance are all responsible for forming the species diversity. It's a variety of species present during a unit area. Species evenness and species equitability is that the proportionate number of people of various species and taxonomic groups. Others where one or more species have more individuals than others show dominance and unevenness. Maximum toxic diversity occurs where species of taxonomically different groups occur in almost equal abundance.
Ecological Diversity
It is one of the last components of species diversity, species richness and relative abundance.
It is also referred to as community diversity. it's a spread of ecosystems that indicate the range within the number of niches, trophic levels, food webs, nutrient cycles, and ecological processes sustaining energy flow. for instance, ecosystem diversity is high in India due to the occurrence of an outsized number of ecosystems like deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows. it's quite low in small countries like Scandinavian countries like Norway.
Species Diversity in India
India is split into 10 bio-geographical regions. India with only 2.4% of the world’s acreage possesses 8.1% species diversity of the planet thanks to varying physical conditions and species grouping. It's because India is one of the 12 mega diversity countries on the planet. There are nearly 46000 species of plants and almost double of this number of animal species. Still, quite 300000 animal species and 1000000 plant species are yet to be discovered. However, a really sizable amount of species that are yet to be discovered face the threat of becoming extinct even before we discover them.
Importance of Species Diversity to the Ecosystem
The number of species during a community really matters to the functioning of the ecosystem because rich biodiversity is vital for stability, productivity, resilience, alternative pathways, and health of ecosystems. The importance of species diversity and of the components of species diversity is listed below.
Stability: Communities with more species are more stable than communities with fewer species. A stable community shouldn't show an excessive amount of variation in productivity from year to year. It must be resistant or resilient to sometimes natural also as man-made disturbances. It must be immune to invasion by alien species.
Ecosystem Health: It's often believed that tiny harm to the ecosystem will occur to the ecosystem if a couple of species become extinct. There shouldn't be much difference if one among the tree frog species is lost forever from the Western ghats ecosystem or the number of ant species is reduced from 20000 to 15000. Apparently, there won't appear any difference for a few times. However, rich biodiversity isn't only essential for ecosystem health but, also for the survival of humanity on earth. it's because an outsized number of species have a better number of niches, more interactions, and more inter-relationships.
FAQs on Components of Species Diversity: What You Need to Know
1. What are the two primary components used to measure the species diversity of an ecosystem?
The two primary components used to measure species diversity are species richness and species evenness. Species richness refers to the total number of different species in an area, while species evenness refers to the relative abundance or proportion of individuals among those different species.
2. How do species richness and species evenness differ in describing a community's diversity? Provide an example.
Species richness is a simple count of species, whereas species evenness describes how balanced the population sizes of each species are. For example, consider two forests, A and B, each with 100 trees and 10 different species. Forest A has 10 trees of each species (high evenness). Forest B has 91 trees of one species and 1 tree for each of the other nine species (low evenness). Both forests have the same species richness (10 species), but Forest A has much higher species evenness and is considered more diverse overall.
3. Can you provide an example of high vs. low species diversity in a real-world ecosystem?
A classic example of high species diversity is a tropical rainforest, which has a vast number of different species (high richness) with relatively balanced populations (high evenness). In contrast, an example of low species diversity is a monoculture agricultural field, like a wheat farm. It has extremely low richness (only one dominant species) and low evenness, making it highly vulnerable to pests and diseases.
4. Why is maintaining high species diversity considered crucial for the stability of an ecosystem?
High species diversity is crucial for ecosystem stability for several reasons:
Increased Productivity: Diverse ecosystems are generally more productive as a wider range of species can utilize resources more efficiently.
Greater Resilience: A diverse ecosystem is better able to withstand and recover from environmental stresses like droughts, floods, or disease outbreaks. If one species is affected, others may be able to perform its function.
Ecosystem Health: It ensures the continuation of essential ecosystem services such as pollination, nutrient cycling, and pest control.
5. How did Paul Ehrlich's 'Rivet Popper Hypothesis' explain the importance of every single species?
Paul Ehrlich's 'Rivet Popper Hypothesis' uses an analogy to explain the importance of each species. He compared an ecosystem to an airplane and species to the rivets holding it together. Losing one or two rivets (species extinction) might not immediately cause a crash. However, as more rivets are lost, especially key ones (keystone species), the airplane (ecosystem) becomes progressively weaker and eventually falls apart. This illustrates that every species, no matter how small, contributes to the overall integrity and stability of the ecosystem.
6. In what way does genetic diversity within a species contribute to the overall species diversity of a region?
Genetic diversity is the variation of genes within a single species. This variation provides the raw material for adaptation. When a species has high genetic diversity, it is more likely to have individuals with traits that allow them to survive environmental changes, diseases, or new predators. By preventing the local extinction of that species, high genetic diversity directly helps maintain the region's overall count of species (species richness), thus upholding the broader species diversity.
7. What is a common misconception about measuring species diversity?
A common misconception is that a high number of species (species richness) is the only factor that matters for a healthy ecosystem. However, an ecosystem might have many species, but if one or two species overwhelmingly dominate, the functional diversity and resilience are actually low. Therefore, species evenness, which measures the relative abundance of different species, is an equally critical component for assessing the true health and stability of an ecosystem.
