Learning Outcomes
- What is biodiversity
- Origin of biodiversity
- Nature of biodiversity
- Interrelationships of organisms
- How to measure biodiversity
- Biodiversity of Bangladesh
- Risks and remedies of biodiversity
What is Biodiversity?
The term biodiversity describes the great variety of life on Earth.
Biodiversity refers to the variety of living things, including plants,
animals, and microorganisms. We don’t know for sure exactly how many different
organisms there are on Earth. However, scientists estimate that there are
about 8-14 million (80 to 140 lakh) different species of organisms on this
Earth. Some believe that the number is higher. But whatever the number, most
of these organisms are unknown to us. Only 1.2 million (12 lakh) species have
been identified and described so far, most of which are insects. This means
that billions of other organisms are still mysterious and unknown to us.
Origin of Biodiversity
The unique characteristics of all species alive today have evolved over
generations over thousands of years. The strategies and methods followed by an
organism to adapt itself to its environment are called adaptation.
On the other hand, without any specific reason, some changes occur during the
transition of an organism from one generation to the next. That’s why we don’t
look exactly like our parents and are a bit different siblings! Siblings do
not look exactly alike unless they are twins, even though they are children of
the same parents! From parent to child, this difference in appearance is a
minimal change in one generation. But as these small changes occur over
millions of years from generation to generation, at some point, new organisms
appear with characteristics that are very different from their original
ancestors. Thus, the change process in organisms over a long period is called
evolution.
The characteristics acquired through the process of evolution and adaption
distinguish the members of the organism from one another. Any animal keeps its
species alive by creating its copy during its lifetime. This process is known
as reproduction. Organisms are there that have evolved and adapted over time
and become so different from each other that they can no longer breed with one
another. They are considered separate species. Organisms that can interbreed
are usually included in the same species.
Nature of Biodiversity
Scientists have an endless interest in knowing how much biodiversity there is
worldwide because they still have so much left to discover. different
organisms in different regions of the world are adapted to the environment of
that region. The system formed by combining these regional organisms and the
non-living elements of their environment is called an ecosystem. This
ecosystem is also called a biome.
Different ecosystems develop in different regions of the world. For example,
the types of covered Tundra regions, or under the water of a pond, lake, or
ocean. Species whose characteristics are best adapted to the environment of a
particular area survive and reproduce successfully there.
Simply speaking, a biome is a large area marked by the area’s vegetation,
soil, climate, and wildlife. There are five main types of biomes: aquatic,
grassland, forest, desert, and tundra. However, some of these biomes can be
divided into more specific categories, such as freshwater, marine, rainforest,
which is tropical or temperature, and swamp pine forest or the taiga.
Walking by a pond, you will see fish, frogs, kingfishers, grasshoppers, and
other insects. There may be species such as rats, snakes, earthworms, and
insects in grasslands. Again, if you compare grassland in Bangladesh with
grassland in Canada, you will see that their biodiversity is different.
Ecosystems that contain the most biodiversity have ideal environmental
conditions for the growth of animals, plants, and microorganisms.
Some regions of the world, such as Mexico, South Africa, Brazil, the
southwestern United States, and Madagascar, have more biodiversity than
others. These parts of the world have a large number of endemic species.
Endemic species are those that exist only in a particular place.
For example, about 6200 plant species in the Cape Floristic region of South
Africa are not found anywhere else in the world. Areas with high numbers of
endemic species are called hotspots of biodiversity.
Interrelationships of Organisms
All species on Earth work together to survive and maintain the balance of
their ecosystems. For example, the grass of pasture is consumed by cattle. The
dung left by the cattle creates manure. This manure returns nutrients to the
soil, which helps grow more grass. This fertilizer can also be applied in
croplands. Many species on Earth play essential roles for humans providing
various materials, including food, clothing, and medicine.
Ways to measure Biodiversity
A common way to measure biodiversity is to count the total number of species
living within a given area.
Tropical regions, which are warm all year round, have the highest
biodiversity. Temperate regions, with hot summers and cold winters, have low
biodiversity. Areas with dry conditions, such as mountaintops and deserts,
have even less biodiversity.
Generally, the closer a region is to the equator, the greater the
biodiversity. The Amazon rainforest of South America is home to at least
40,000 different plant species. It is one of the most biologically diverse
regions on our planet Earth.
The warm waters of the western Pacific and Indian oceans have the most diverse
marine environments with many species of fish, corals, etc. Many corals
combine to form coral reefs, which are home to hundreds of other species of
organisms. These coral reefs are home to many things, from tiny seaweeds to
big sharks.
Another way to measure biodiversity is genetic diversity. In the following
chapters, we will know more in detail, but for now, let’s know that the gene
resides inside the nucleus of the living cell.
Whether you are a two-legged human or a four-legged cat, whether your hair is
curly or straight – all this information is stored in some gene hidden within
your cells. Some species have as many as 400,000 genes. Humans have about
25,000 genes. Some of these genes are the same for all members of a species.
These genes determine a rose to be a rose and a dog to be a dog. But among a
species of genes, some genes are different. This genetic variation causes some
roses to be pink while others are white. In humans, such genetic differences
cause some people to have brown eyes and some to have blue eyes.
Greater genetic diversity in species can make plants and animals more
resistant to disease. Genetic diversity allows species to adapt better to
changing environments.
Biodiversity of Bangladesh
As a part of the Indus-Gangetic Plain, Bangladesh is a beautiful land of
biodiversity. Bangladesh is surrounded by greenery, where the soil, water,
forests, and natural environment are suitable for the living of various types
of organisms. The rich biota of the Sundarbans and the underwater fauna of
Cox’s Bazar and Saint Martin’s are all bio-resources of this country.
[The Indus-Gangetic Plain is a large fertile plain that covers part of
Pakistan, most of northern and eastern India, and almost all of Bangladesh.
The region is named after the rivers Indus and Ganges that flow through the
region.]
Bangladesh has a rich collection of flowering plants, fishes, amphibians,
reptiles, birds, and mammals. The natural forest areas of the country are rich
in biodiversity due to their location. For example, more than 5000 flowering
plant species are found in the forests of Bangladesh. Forest regions of
Chattogram alone have about 2,260 plant species. These plants include
wood-producing plants, fiber-producing plants, and medical plants.
So far, 132 species of mammals, 578 species of birds, 154 species of reptiles,
and 19 species of amphibians have been identified in Bangladesh.
Risks and Remedies of Biodiversity
Much of the world’s biodiversity is threatened by humans’ use and other
activities, which disrupt and sometimes destroy ecosystems. Pollution, climate
change, and population growth are all threats to biodiversity. These threats
play a role in the extinction of species. Some scientists estimate that half
of all species on Earth will be extinct within the next century.
Even though Bangladesh is rich in biodiversity, many species are under threat.
According to information from the International Union for Conservation of
Nature (IUCN), the existence of 23 species of wildlife in Bangladesh is under
threat of extinction. Moreover, about 29 wild animals in this country are
endangered. The safe habitats of organisms are being destroyed mainly due to
urbanization, the arrangement of food and shelter, and the collection of
medicinal and clothing materials.
Human beings are reducing all the natural resources like water bodies, oceans,
and forests for their own interests. Animals and fauna, such as the Royal
Bengal Tiger, spotted deer, reptile, python, wild duck, black duck, Belgian
Blue (nilgai), king vulture, wild buffalo, freshwater crocodile, and Gharial
in different forest areas, including Sundarbans, Madhupur, and BhawalGarh, are
almost extinct and living under threat today. About 39 species of animals in
Bangladesh are in danger. According to forestry scientists, about 125 tree
species are endangered in Bangladesh.
We need our collective efforts to conserve biodiversity and protect the same
endangered species and their habitats. Countries worldwide, including
Bangladesh, should take appropriate steps to conserve biodiversity. The need
for wildlife conservation has been widely felt due to the problems of
environmental pollution, killing wildlife to make products from their skin or
bones animal trafficking, etc. Various international and regional
organizations, government and non-government organizations, and renowned
organizations outside the country, including the United Nations, play an
important role in conserving this attempt.
Realizing the importance of biodiversity, we should encourage the conservation
and enhancement of biodiversity. In different countries, natural forests have
been developed as safe sanctuaries for the native flora and fauna, where human
movement is restricted if necessary, prioritizing biodiversity. To conserve
biodiversity in Bangladesh, the government has declared some parts of the
country’s forests as protected areas. In addition, collecting trees from
protected natural forest areas and collecting old trees from man-made forests
have been stopped with the aim of the conservation of biodiversity.
A new law enforcement agency has been created to combat poaching and
trafficking wildlife. By taking such integrated initiatives, many countries
have given new hope for protecting the diversity of life.
However, scientists and environmental organizations call for greater measures.
Only government initiatives are not enough in this regard; mass awareness is
also needed. Species that have already become extinct over time may not be
brought back, but if everyone is careful, it may be possible to preserve the
current world’s biodiversity. Everyone needs to pay attention to that. Then
maybe the diversity of life in the beautiful world will become rich and
colorful again.
