Name : Liew Chen Feng
Form : 4 Kensett
Subject: Biology
Chapter: 8
Topic: 8.4 Biodiversity
Biodiversity refers to the diverse species of plants and
animals in different Ecosystems on Earth. Biodiversity is the
foundation of life on Earth. It is crucial for the functioning of
ecosystems which provide us with products and services without
which we couldn’t live. Oxygen, food, fresh water, fertile soil,
medicines, shelter, protection from storms and floods, stable
climate and recreation - all have their source in nature and
healthy ecosystems. But biodiversity gives us much more than
this. We depend on it for our security and health; it strongly
affects our social relations and gives us freedom and choice.
Biodiversity boosts ecosystem productivity where each species,
no matter how small, all have an important role to play. For
example, a larger number of plant species means a greater
variety of crops; greater species diversity ensures natural
sustainability for all life forms; and healthy ecosystems can
better withstand and recover from a variety of disasters.
And so, while we dominate this planet, we still need to
preserve the diversity in wildlife.
Approximately 1.5 million species of living organisms
have been discovered and there are millions of living organisms
that are yet to be discovered. Since there are many organisms in
this world, it is important to classify them.
1. Classification of Organisms…………………………….1-4
2. Hierarchy in the classification of organisms……4-5
3. The importance of biodiversity……………………….5-6
4. Source……………………………………………………………….6
Taxonomy is a branch of Biology concerned with identifying, describing
and naming organisms. It is a systematic method of classifying plants and animals
based on their characteristics and similarities. Classification is necessary so that
organisms can be easily and accurately identified. It enables scientists to
communicate accurately and precisely with one another.
All organisms on Earth are divided into five kingdoms:
a) Monera
Bacteria
Cyanobacteria
Monera is the only kingdom composed of prokaryotic organisms. They are
unicellular and have cell walls but lack both membrane-bound organelles and
nucleus. Because these organisms do not have a nuclear membrane, their genetic
material is scattered in the cytoplasm. Cyanobacteria and certain bacteria can
carry out photosynthesis. Most bacteria have three typical shapes: rod-shaped,
round or spiral.
b) Protista
Amoeba
Trypanasoma
Paramecium
Protista is the kingdom which includes a variety of unicellular and a few
multicellular eukaryotes such as algae and protozoa. Their cells have nucleius and
numerous organelles that are surrounded by membranes. Plant-like protists, such
as green algae, have chloroplasts which allow them to photosynthesis. They can
either be heterotrophic or autotrophic, or both. The cells of multicellular protists
are not specialized to perform specific functions within the organisms.
c) Fungi
Mushroom
Yeast
Pin mould(growing on tomato)
Fungi are heterotrophic multicellular eukaryotes. Fungi are mostly
multicellular organisms but some fungi are unicellular microorganisms. The cell
walls of fungi contain a material called chitin. Their main bodies consist of a
network of thread-like hyphae called mycelium. All fungi are saprophytic. They
have no cholorophy ll and obtain their energy by decomposing decaying
organisms and absorbing the resulting nutrients from the organic remains.
Examples of fungi are moulds ( Mucor sp.), mushrooms and yeasts.
d) Plantae
Fern
Hibiscus
Palm tree
Plantae is the kingdom which includes all land plants. Plants are immobile,
multicellular organisms with cholorophy ll. Plant cells are enclosed in cellulose cell
walls. Plant cells are organized into specialized tissues such as phloem and xylem.
Some examples of Plantae include various types of moss, ferns, conifers and
flowering plants.
e)Animalia
Goat
Fish
Birds
Animalia are multicellular heterotrophic organisms with welldeveloped tissues. Animal cells do not have rigid cell walls and choloroplasts that
characterise plant cells. Most members of this kingdom are mobile. Some, such as
sponges and barnacles, are permanently attached to surfaces. Some examples of
Animalia include mammals, reptiles, fishes, amphibians and birds. Unlike fungi
which rely on external digestion, animals usually digest their food internally.
Hierarchy in the classification of organisms
Living organisms are classified according to certain basic features. They
are classified into seven hierarchical levels. Each kingdom is a group of organisms
sharing certain basic features. Kingdom is the largest unit of classification and
contains the largest number of organisms. It is divided into smaller units called
phyla. Each phylum is divided into classes, each class into orders , each order into
families, each family into genera and each genus into species. The number of
organisms in each unit decreases from kingdoms to species. Therefore, each
higher unit covers a greater range of organisms. The organisms of a species are
very similar to one another. However, they still have individual differences. A
species is a group of organisms which share many common features and are
capable of interbreeding to produce fertile offspring.
Kingdom
Phylum
Class
Order
Family
Genus
Species
Each organism is given a scientific name according to an internationally
accepted system of nomenclature based on the Linnaeus binomial system. Each
organism has two names in Latin in this system. The first name which begins with
a capital letter refers to the genus while the second name which begins with a
smaller letter refers to the species.
Examples:
Common Name
Bunga raya
Oil palm
Durian
Frog
Fruit fly
Scientific Name
Hibiscus rosa-sinensis
Elaeis guineensis
Durio zibenthinus
Bufo melanostictus
Drosophila melanogaster
The importance of biodiversity
1) The variety of species and ecosystems provides many environmental services
to humans as well as to other species. These include pollination, nutrient cycling,
regulation of the water and carbon cycle and climate.
2) The diverse species and the variety of ecosystems in the biosphere provide
various biological products, many of which play important roles in the economy.
3) All the species are supported by the interactions among other species and
their ecosystems for food, shelter and other basic needs. If a species disappears,
the survival of other species which depend on it may be threatened and, as a
result, the whole ecosystem will be affected.
Source
1) http://en.wikipedia.org/wiki/Biodiversity
2) http://www.globalissues.org/issue/169/biodiversity
3) http://www.eoearth.org/article/Biodiversity?topic=49480
4) http://www.google.com.my/imghp?hl=en&tab=wi
5) Biology Form 4 textbook.