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 well-developed 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.

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 Scientific NameBunga raya Hibiscus rosa-sinensisOil palm Elaeis guineensisDurian Durio zibenthinusFrog Bufo melanostictusFruit fly Drosophila melanogaster

The importance of biodiversity1) 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.

Kingdom PhylumClassOrder FamilyGenusSpecies

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.

Source1) 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.