Lecture # 4: Biodiversity

Objectives:1.To Define Biodiversity2.To Discuss the Types of Biodiversity3. To Discuss the Significance and Conservation of Biodiversity

Presented by Abul Kalam Azad

Senior Lecturer, GEDNorthern University Bangladesh

E-mail: kalamadd@gmail.com

Biodiversity is fundamental to the existence of life on Earth, and its importance cannot be underestimated. The fundamental property of ecological systems is a certain mixture or diversity of living things. It is not only the variety of living organisms on our planet, but also the interdependence of all these living things, including humans. Let’s define and classify the concept, and then explore its importance.

Introduction

The word biodiversity was first used in 1980.It first got the publicity on world media in 1992 summit on Environment in Rio De Rio de Janeiro in Brazil. Now a days it indicates the number, variety and variability of bios in an area.

Brief History of Biodiversity

Definition of Biodiversity

Biodiversity, a contraction of the phrase "biological diversity," is a complex topic, covering many aspects of biological variation. In biodiversity “bio” means life and “diversity” means variety. In essence, biodiversity means variety of life.

Simply stated, biodiversity refers to the variety of species, of genes of each species, and of ecosystems that they form.

According to D.B. Jensen, M. Torn, and J. Harte (1990) and US Congressional Biodiversity Act, HR1268 (1990):

“Biological diversity means the full range of variety and variability within and among living organisms and the ecological complexes in which they occur, and encompasses ecosystem or community diversity, species diversity, and genetic diversity.” [In Our Own Hands: A Strategy for Conserving Biological Diversity in California]

Now, it is understood from the above definitions that biodiversity is the part of nature which includes the difference in genes among the individuals of a species, the variety of all the plant and animal species and various types of ecosystems.

Three Types of biodiversity

1. Genetic diversity

Genetic diversity is the combination of different genes found within a population of a single species, and the pattern of variation found within different populations of the same species. Coastal populations of Douglas fir are genetically different from Sierran populations. Genetic adaptations to local conditions such as the summer fog along the coast or hot summer days in the Sierra result in genetic differences between the two populations of the same species.

If you think of a group of people in your street, or within your own family, no two will be exactly alike. All are humans, but all are different. These differences are due to genetic diversity, that is, the variety of genes within a species.

Each species consists of individuals with their own particular genetic composition. When the individuals interbreed, their offspring have new combinations of the genes, resulting in new mixtures of the characteristics of the species.

2. Species diversity A species can be defined as a group or

population of similar organisms that reproduce by interbreeding within the group.

Species diversity refers to the variety of different types of living things on Earth, such as bacteria, fungi, insects, mammals, plants, human etc. Different species have different roles to play within ecosystems. Human beings, for example, belong in a single species — Homo sapiens. Although there are different populations of humans, with different characteristics in different parts of the Earth, they can all successfully interbreed with each

other and produce normal offspring. So, even though no two human beings are exactly alike, humans make up a single species because they reproduce among themselves.

All the different breeds of dogs, from Great Danes to Chihuahuas, belong in a single species, because they can interbreed and produce fertile offspring. Dogs and foxes, however, are different species because they can't interbreed.

3. Ecosystem Diversity Ecosystems are the combination of

communities of living things with the physical environment in which they live. There are many different kinds of ecosystems, from deserts to mountain slopes, the ocean floor to the Antarctic, with coral reefs and rainforests being amongst the richest of these systems.

Each ecosystem provides many different kinds of habitats or living places. The living things and the non-living environment (earth forms, soil, rocks and water) interact constantly and in complex ways that change over time, with no two ecosystems being the same.

Significance of Biodiversity

"The fundamental property of ecological systems is a certain mixture, or diversity of living things. Biodiversity, or the variety of living things that exist, is fundamental to the existence of life on Earth, and the importance of it cannot be underestimated. Biodiversity is an extremely important part of life on Earth. It is not only the variety of living organisms on our planet, but also the interdependence of all these living things, including humans.

Biodiversity, besides its ecological significance provides a socioeconomic asset to the nation. Human society depends on biological resources, their diversity and the ecosystem that sustain them provide essential goods and services.

The significance of biodiversity may be discussed under the following heads:

I. Productive use (Fuel, timber, fish, skin, fruits, and medicinal plants)

II. Consumptive use: Goods that we use directly.

III. Indirect use: Balance of Ecosystem, conservation of natural resources and prevention of soil erosion.

Awareness of Biodiversity Issues

United Nations Organization proclaimed May 22 as the International Day for Biological Diversity to increase understanding and awareness of biodiversity issues. In 2000 Un General Assembly adopted 22 May as IBD. The secretariat on convention on Biological Diversity is pleased to continue the focus of the 2007 for International Day Biological Diversity (IDB), May 22 – Biodiversity and Climate change.

During the last century, erosion of biodiversity has been increasingly observed. Some studies show that about of eight known plant species is threatened with extinction. Some estimate put the loss up to 140,000 species per year. This figure indicates unsustainable practices. Almost all scientists acknowledged that the rate of species loss is greater now than at any time in human history. So this loss of biodiversity is a serious threatened to the environment.

Threats to Biodiversity

Conservation and Protection

Action can be taken to reduce human impact and therefore reduce the rate of biodiversity loss in dry and subhumidland. Among others these include:i. Reducing overgrazing in ecosystem.ii. Reducing pollutants produced by

intensive agriculture.iii. Slowing the conversion of grassland and

natural land to agriculture and urban settlement.

iv. Taking steps to control invasive alien species within ecosystems.

v. Helping build institutions that will alleviate poverty and allow the poor to realize sustainable livelihood.

vi. Mobilizing sufficient financial and technical resource particularly for developing countries to achieve Millennium Development Goals and the 2010 biodiversity forget.

In taking this action we will achieve concrete results. If we act now, it is within our power to achieve the 2010 biodiversity.