Here is an essay on ‘Biodiversity’ for class 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Biodiversity’ especially written for school and college students.
Essay on Biodiversity
- Essay on the Introduction to Biodiversity
- Essay on the Different Levels of Biodiversity
- Essay on the Importance of Biodiversity
- Essay on the Loss of Biodiversity
Essay # 1. Introduction to Biodiversity:
Biodiversity is scalable — that is it exists on many levels, e.g., the genes within populations, the populations within species, the species within ecosystems, the ecosystems within landscapes, the landscapes within bioregions, and so on.
Biodiversity is a key element of ecosystems — without the connections biodiversity creates, ecosystems fall apart.
The first challenge to protecting biodiversity is understanding what it means and then, why you should care about it.
Biodiversity is the variety of species, their genetic make-up, and the natural communities in which they occur. It includes all of the native plants and animals in Pennsylvania and the processes that sustain life on Earth. Pennsylvania is home to over 25,000 different species of organisms, and of this total, over 800 are considered to be rare, threatened, or endangered. For many groups of organisms, such as insects, fungi, and algae, very little is known about them — not even what species occur in Pennsylvania! The need to understand the state’s rich natural resources has never been more critical.
The term ecosystem is defined as a community of living organisms combined with their associated physical environment. It is our “home system” that makes life possible.
Ecosystems are the full tapestry of nature that support life and they also provide valuable services:
i. Wetland ecosystems filter out toxins, clean the water, and control floods.
ii. Estuaries act as marine-life nurseries.
iii. Forest ecosystems supply fresh water, provide oxygen, control erosion, and remove carbon from the atmosphere.
Many species, working together, are needed to provide these critical services. The loss of biodiversity reduces nature’s ability to perform these functions. As greater fluctuations occur, ecosystems as a whole become less stable. Instability causes ecosystems to be more vulnerable to extreme conditions and may also decrease productivity.
Essay # 2. Different Levels of Biodiversity:
i. Genetic diversity is:
i. A building block of life
ii. Responsible for the variability among individuals within any species, based on variations in genes.
Genetic variability increases the chance that a species will adapt to changing environmental conditions or impacts, since some individuals will be able to handle the change better than others. The more individuals there are, the greater the chance of genetic variation. Species with a small population of individuals have limited variability and therefore have limited ability to respond to change.
This is why populations of “species at risk” can be so difficult to recover. Once you get below a certain number of individuals, it is virtually impossible based on reproductive potential. Genetic variation is the cornerstone of all biodiversity.
While we often hear about species, what we generally see and interact with are populations — distinct groups of members of a particular species that have a limited exchange of genetic material among the groups. They can reproduce together but they don’t often do so.
As a result, the genetic differences between populations tend to increase, even though the variability within any one population may be less than across the species as a whole. Also, because of the isolation, local impacts on one population may not be felt by another. A conservative first estimate indicates that about 220 populations per species puts the total number of populations world-wide into at least the low billions.
Extreme population variability can be a double-edged sword. For example, lake trout in Ontario’s Great Lakes were once very diverse. There were at least 15 to 20 different forms of lake trout recognized by commercial fishermen before the sea lamprey appeared.
The lake trout differed in where they were found, when they spawned, and in their appearance. They were given such names as blacks, redfins, yellowfins, paper bellies, fats, humpers and sand trout. Undoubtedly, the number of genetically distinct populations was much higher.
However, even all this diversity could not withstand over-harvest, sea lamprey predation and loss of habitat, particularly inshore rubble shoals required for spawning. The catches of lake trout plunged to 10% of the original yield in Lake Superior and down to almost nothing in the other Great Lakes. When conditions improved and it came time to try and reintroduce lake trout, the results were disappointing in all but Lake Superior where enough wild populations survived to make a decent comeback.
All those discrete lake trout stocks had evolved for a reason: reproductive success of lake trout in each area. The fish were in effect “tailor-made” for the area. Now many of those stocks have disappeared forever. It will take a lot of time and effort to find stocks that might be reasonable replacements.
ii. Species diversity:
Is all of the different kinds of living things found in a certain habitat or ecosystem. World-wide more than 1.4 million species have been identified but estimates of the actual number vary from 5 million up to 100 million. Fourteen million appears to be an estimate that is commonly quoted in the literature.
In Ontario, over 30,000 species have been identified including:
i. Over 20,000 macro-invertebrates (insects, spiders, etc.)
ii. More than 4,800 plants
iii. More than 150 fish
iv. More than 1000 fungi
v. 53 reptiles and amphibians
vi. 479 birds
vii. 81 mammals
Globally the estimated numbers of species are:
i. 35,000 micro-organisms
ii. 70,000 fungi
iii. 273,000 plants
iv. 875,000 invertebrates (insects, spiders, etc.)
v. 19,000 fish
vi. 10,500 reptiles and amphibians
vii. 9,000 birds
viii. 4,000 mammals
ix. 105,000 other animals
Species diversity, however, is more than just the number of species in a given area, habitat or ecosystem. Some species’ importance can be out of line with their numbers, for example keystone species. There can also be great differences in species composition over time.
Species diversity can also be greatly affected by physical conditions in the ecosystems where they live, such as differences in temperature, light, structure and chemical composition. The point is, biodiversity cannot be reduced to a single number. Time are dimensions to diversity, many of them.
iii. Ecosystem diversity:
Is the variety of ecosystems within a landscape or region including wetlands, prairies or savannahs, lakes and rivers, forests and agricultural landscapes. The basic principles of biodiversity apply here as well but the scope is much larger.
It is at this level that the interactions and links among species and the consequences of those links are evident. Less diverse ecosystems, such as coldwater streams or small lake trout lakes, contribute to the functioning and productivity of larger areas such as bioregions.
Essay # 3. Importance of Biodiversity:
Biodiversity has contributed in many ways to the development of human culture and in turn, human communities have played a major role in shaping the diversity of nature at the genetic, species and ecological levels. Biodiversity plays the following roles: ecological, economic and scientific. Ecological Role of Biodiversity Every organism, besides extracting its needs, also contributes something useful to other organisms.
Species capture and store energy, produce and decompose organic materials, helps to cycle water and nutrients throughout the ecosystem, fix atmospheric gases and help regulate the climate. These functions are important for ecosystem function and human survival. Economic Role of Biodiversity For all humans, biodiversity is an important resource in their day-today life.
One important part of biodiversity is ‘crop diversity’, which is also called agro-biodiversity. Some of the important economic commodities that biodiversity supplies to humankind are: food crops, livestock, forestry, fish, medicinal resources, etc.
Scientific Role of Biodiversity, Biodiversity is important because each species can give us some clue as to how life evolved and will continue to evolve. Biodiversity also helps in understanding how life functions and the role of each species in sustaining ecosystems of which we are also a species.
Essay # 4. Loss of Biodiversity:
Biological wealth of our country is declining rapidly and human activities are a major reason to blame for this. The colonisation of tropical pacific island by humans has led to extinction of more than 2,000 native bird species.
IUCN Red List (2004) enlists the extinction of 784 species (including 338 vertebrates, 359 invertebrates and 87 plants) in the last 500 years.
Some examples of recent extinction are:
a. Dodo (Mauritius), quagga (Africa), thylacine (Australia), Steller’s sea cow (Russia) and three sub-species of tiger (Bali, Javan, Caspian).
b. About 27 species have disappeared in last 20 years and more than 15,500 are endangered. Though 15,500 species are facing extinction at present, but the species facing the threat of extinction include 12% of all bird species, 23% of all mammal species, 32% of all amphibian species and 31% of all gymnosperm.
c. Amphibians are more vulnerable to extinction. Study of fossil record reveals that large scale loss of species also happened earlier.
Effects of Loss of Biodiversity:
(i) Decline in plant production.
(ii) Lower resistance and resilience to environment.
(iii) Perturbations such as draught and increased variability in ecosystem processes such as plant productivity, water use, disease, etc.