What Is Biodiversity And Why Do We Need To Conserve It?

What is Biodiversity?
    Biodiversity is a modern term
    which simply means " the variety of life on earth". This variety can be measured
    on several different levels.
    Genetic - variation
    between individuals of the same species.
    Species - species
    diversity is the variety of species in a given region or area.
    Ecosystem - Communities of plants and animals, together with the physical
    characteristics of their environment (e.g. Geology, soil and climate) interlink together
    as an ecological system, or 'ecosystem'. Ecosystem diversity is more difficult to measure
    because there are rarely clear boundaries between different ecosystems and they grade into
    one another. However, if consistent criteria are chosen to define the limits of an
    ecosystem, then their number and distribution can also be measured.

Why Conserve Biodiversity?
  
  
    Ecological Reasons Individual species and ecosystems have
    evolved over millions of years into a complex interdependence. This can be viewed as being
    akin to a vast jigsaw puzzle of inter-locking pieces. If you remove enough of the key
    pieces on which the framework is based then the whole picture may be in danger of
    collapsing. We have no idea how many key 'pieces' we can afford to lose before this might
    happen, nor even in many cases, which are the key pieces. The ecological arguments for
    conserving biodiversity are therefore based on the premise that we need to preserve
    biodiversity in order to maintain our own life support systems.  
  
  
    Economic Reasons
    Environmental disasters such as floods, forest fires
    and hurricanes indirectly or directly caused by human activities, all have dire economic
    consequences for the regions afflicted. Clean-up bills can run into the billions, not to
    mention the toll of human misery involved. Susceptible regions are often also in the
    less-developed and poorer nations to begin with. Erosion and desertification, often as a
    result of deforestation, reduce the ability of people to grow crops and to feed
    themselves. This leads to economic dependence on other nations.
    Non-sustainable extraction of resources (e.g.
    hardwood timber) will eventually lead to the collapse of the industry involved, with all
    the attendant economic losses. It should be noted that even if 'sustainable' methods are
    used, for example when harvested forest areas are replanted, these areas are in no way an
    ecological substitute for the established habitats which they have replaced.
    Large-scale habitat and
    biodiversity losses mean that species with potentially great economic importance may
    become extinct before they are even discovered. The vast, largely untapped resource of
    medicines and useful chemicals contained in wild species may disappear forever. The wealth
    of species contained in tropical rain forests may harbour untold numbers of chemically or
    medically useful species. Many marine species defend themselves chemically and this also
    represents a rich potential source of new economically important medicines. Additionally,
    the wild relatives of our cultivated crop plants provide an invaluable reservoir of
    genetic material to aid in the production of new varieties of crops. If all these are
    lost, then our crop plants also become more vulnerable to extinction.
    There is an ecological caveat here of course.
    Whenever a wild species is proved to be economically or socially useful, this
    automatically translates into further loss of natural habitat. This arises either through
    large-scale cultivation of the species concerned or its industrial production/ harvesting.
    Both require space, inevitably provided at the expense of natural habitats.
    Perhaps the rain forests and the seas should be allowed to keep
    their secrets.
    Ethical Reasons
    Do we have the right to decide which species
    should survive and which should die out?
    Do we have the right to cause a mass extinction?
    Most people would instinctively answer 'No!'. However, we have to
    realise that most biodiversity losses are now arising as a result of natural competition
    between humans and all other species for limited space and resources.
    If we want the luxury of ethics, we need to reduce our populations.
    Aesthetic Reasons
    
    Most people would agree that areas of vegetation,
    with all their attendant life forms, are inherently more attractive than burnt, scarred
    landscapes, or acres of concrete and buildings. Who wouldn't prefer to see butterflies
    dancing above coloured flowers, rather than an industrial complex belching smoke?
    Human well-being is inextricably linked to the natural
    world. In the western world, huge numbers of people confined to large urban areas derive
    great pleasure from visiting the countryside. The ability to do so is regarded not so much
    as a need, but as a right. National governments must therefore juggle the conflicting
    requirements for more housing, industry and higher standards of living with demands for
    countryside for recreational purposes.  

I really hope this helps you. Good Luck.