1.1 Diversity of Organisms
Biodiversity is the diversity of living organisms, including animals, plants, fungi, and microorganisms, inhabiting a specific habitat or the Earth as a whole.
Importance of Biodiversity
- Sources of Food: Animals and plants provide raw food materials for human consumption.
- Balance in Nature: Ensures natural cycles (such as carbon and oxygen cycles) and food chains remain stable.
- Recreation and Tourism: Rich biodiversity creates natural eco-tourism sites.
- Medical: Plants and microorganisms provide essential ingredients for traditional and modern medicines.
- Raw Materials for Industry: Timber, rattan, and natural rubber supply construction and manufacturing sectors.
- Education: Provides opportunities for scientific research and ecological studies.
Effective Biodiversity Management
- In-situ Conservation: Preserves species within their natural habitats (e.g., National Parks, Marine Parks, Forest Reserves).
- Ex-situ Conservation: Preserves species outside their natural habitats (e.g., Botanical Gardens, Zoos, Seed Banks).
- Endemic Species: Species that live exclusively in a specific, localized geographic area (e.g., Rafflesia, Malayan Tiger, Hornbill, Proboscis Monkey).
1.2 Classification of Organisms
Organisms are classified systematically based on shared characteristics into two main kingdoms: Animals and Plants.
Classification of Animals
Animals are categorized into Invertebrates (without a backbone) and Vertebrates (with a backbone).
1. Invertebrates
- Without Legs:
- Without segmented body: Sponge, Sea anemone, Planaria, Roundworm.
- With segmented body: Tapeworm, Earthworm, Leech.
- With Legs: Classified by the number of jointed legs:
- 3 pairs of legs: Ants, Butterflies, Grasshoppers (Insects).
- 4 pairs of legs: Spiders, Scorpions, Ticks (Arachnids).
- More than 4 pairs of legs: Centipedes, Millipedes, Crabs, Prawns.
2. Vertebrates
Vertebrates are divided into five major groups:
| Group |
Body Covering |
Respiration |
Body Temp. |
Reproduction |
Fertilisation |
| Fish |
Slimy scales |
Gills |
Poikilothermic |
Lays eggs |
External |
| Amphibians |
Moist skin |
Gills (young), Lungs & skin (adult) |
Poikilothermic |
Lays eggs (jelly-like) |
External |
| Reptiles |
Hard, dry scales |
Lungs |
Poikilothermic |
Lays eggs (leathery shell) |
Internal |
| Birds |
Feathers |
Lungs |
Homeothermic |
Lays eggs (hard shell) |
Internal |
| Mammals |
Hair or fur |
Lungs |
Homeothermic |
Gives birth (live young) |
Internal |
Note: Poikilothermic organisms have body temperatures that change according to their surrounding environment. Homeothermic organisms maintain a constant body temperature regardless of external surroundings.
Classification of Plants
Plants are classified into Non-flowering plants and Flowering plants.
1. Non-flowering Plants
- Mosses: Reproduce by producing spores; non-vascular (no vascular bundle).
- Ferns: Reproduce by producing spores; vascular plants.
- Conifers: Reproduce by producing cones; vascular plants.
2. Flowering Plants
Flowering plants produce seeds enclosed in fruits and are divided into two categories:
| Feature |
Monocotyledons |
Dicotyledons |
| Number of Cotyledons |
One cotyledon |
Two cotyledons |
| Root System |
Fibrous root system |
Taproot system |
| Leaf Venation |
Parallel venation |
Netted / Network venation |
| Stem |
Non-woody stem |
Woody stem |
| Examples |
Maize, Paddy, Coconut tree |
Balsam plant, Durian tree, Hibiscus |
Dichotomous Keys
A dichotomous key is a scientific tool used by biologists to identify and classify organisms based on paired, contrasting physical characteristics.