Diversity of Organisms Living organisms are found almost everywhere on earth. They vary widely with respect to size, shape, behavior and other features. It is impossible for anyone to study this immense number of living organism individually. To deal with the great variety of life forms, it is necessary to have some system of putting them into groups.

Diversity of Organisms Characteristics of life : Nutrition Respiration Excretion Locomotion Irritability Growth Reproduction

Order of Classification all the living organism will be classified into different kingdoms on the basis of their level of organization, complexity and their mode of nutrition. The four kingdoms are the bacteria kingdom; the protist kingdom, the plant kingdom and the animal kingdom.

Order of Classification Each kingdom is split into smaller groups called phyla (or called division in plants). Each phylum is further split into calluses, and so on. Such gradual division are listed below: Kingdom Phylum or Division Class Order Family Genus Species

Dichotomous key The simplest way to identifying organism is to construct a dichotomous key. Such keys consist of a lost of structural features about the specimen to be identified. There are two alternatives for each features, and each of these two alternatives will lead to other features until the desired group of the specimen is reached.

Dichotomous key Example of the use of dichotomous key

Dichotomous key the dichotomous key can also be expressed in a diagrammatic form

Nomenclature of organism Each kind of living organism has a specific scientification name which composed of two parts. Scientist use binomial system for naming the organisms. This scientific name is different from the common name. The first part of the scientific name is the name of the genus it belongs to and is known as the generic name.

Nomenclature of organism The generic name always begins with a capital letter and the specific name always begins with a small letter. When handwritten or typed, the scientific name should always be underlined. In print, they are in italics.

Nomenclature of organism Example:

Plant Kingdom Almost all plants contain the green pigment chlorophyll which they use for photosynthesis. The plant kingdom is divided into two major groups: the non-flowering plants and the flowering plants Non-flowering plants do not produce flowers. Non-flowering plants are subdivided into algae, fungi, mosses, ferns and gymnosperms

Plant Kingdom diagram of plant kingdom

Plant Kingdom (Non-flowering plants) Algae Simple plants without roots, stems or leaves. All contain chlorophyll and other pigments for photosynthesis. Most of them are green, while some are red or brown. Mainly live in water (aquatic).

Plant Kingdom (Non-flowering plants) Algae

Plant Kingdom (Non-flowering plants) Fungi Do not have roots, stems or leaves. No chlorophyll present, so they cannot carry out photosynthesis. They are saprophytic (腐生), feed on dead organic matter or parasitic (寄生) on other living organism. They are made up of a network of fine filaments called hyphea (菌絲).

Plant Kingdom (Non-flowering plants) Fungi

Plant Kingdom (Non-flowering plants) Mosses Small green plants that have simple stems and leaves but no true roots and vascular tissues. Found mainly in damp places. Anchored to ground by some hair-like structures called rhizoid.

Plant Kingdom (Non-flowering plants) Mosses

Plant Kingdom (Non-flowering plants) Ferns Have roots, stems or leaves. Found mainly in damp and shady places.places. Have vascular tissues for transporting water, minerals salts and food substances. Reproduce and disperse by forming spores

Plant Kingdom (Non-flowering plants) Ferns

Plant Kingdom (Non-flowering plants) Gymnosperm Large evergreen trees with roots, stems and needle-shaped leaves but no real flowers. Have vascular tissues for transporting various substances. With seeds growing inside cones for reproduction. When mature, the seeds in the cone become exposed and are dispersed by wind.

Plant Kingdom (Non-flowering plants) Gymnosperm

Plant Kingdom (flowering plants) Green plants with roots, stems and leaves. Have vascular tissues for transporting various substances. Produce flowers and develop into fruits, with the seeds enclosed inside after fertilization.

Animal Kingdom The invertebrates (無脊椎動物) are the animals that do not posses a backbone or vertebral column (脊柱). The vertebrates (脊椎動物) are the animals that posses a backbone, or vertebral column. They are usually larger than the invertebrates and have a more complex body organization and structure. Vertebrates include mainly five classes: fish, amphibians, reptiles, birds, mammals.

Animal Kingdom Diagram of animal kingdom

Animal Kingdom (vertebrate) Fish Live in water, have a moist skin covered with scales. Use gills for breathing. Have fins for swimming and maintaining balance. Cold-blooded (poikilothermic), their body temperatures changes with that of the surrounding.

Animal Kingdom (vertebrate) Fish

Animal Kingdom (vertebrate) Amphibians Have a smooth (scales-less) and moist skin. In larva stage, lives in water and use gills for breathing. In adult stage, lives on land and use lungs for breathing. Paired limbs are present. (This feature distinguishes the amphibians from the fish) Cold-blooded.

Animal Kingdom (vertebrate) Amphibians

Animal Kingdom (vertebrate) Reptiles (爬行動物) Have a hard, dry scaly skin. Use lungs for breathing. Lay eggs enclosed in hard shells on land. Cold-blooded.

Animal Kingdom (vertebrate) Amphibians

Animal Kingdom (vertebrate) Birds Body is covered with feathers. Use lungs for breathing. Fore-limbs are modified to wings for flying. Have no teeth, mouth is modified to a beak. Lay eggs enclosed in hard shells. Warm-blooded (homoiothermic), their body temperatures are constant and are independent of the surrounding temperature.

Animal Kingdom (vertebrate) Birds

Animal Kingdom (vertebrate) Mammals Body is covered with hairs. Use lungs for breathing. Young develop inside the body of the mother and are born alive (viviparous reproduction). Have mammary glands, which produce milk to nourish the youngs. The cerebrum (大腦) is more well-developed than other vertebrate. Have a diaphragm (橫隔膜) Warm-blooded.

Animal Kingdom (vertebrate) Mammals

Difference between plants and animals

Difference between plants and animals

Difference between plants and animals