Over years, Chinese were evolved and developed in following different ways:Pictographs
The original written format were found on markings scratched onto tortoise shells and animal bones, so-called "oracle bones". These ancient writings were pictures or Pictographs.
Many people tend to think that Chinese characters are all pictographs. Actually, pictographic characters are only one kind of Chinese character, there are only about 600 pictograph characters.
Pictographic Chinese characters are pictures of concrete objects, they are basic units for forming other Chinese characters.
These are a few examples showing pictographic characters:
山 Mountain ; 羊 sheep ; 月 moon
Ideographs
As time went on and people needed to express more complex ideas or concepts, pictographs were extended or combined to form ideographs. Ideographs are graphical representations of abstract ideas.
For example:
a sun 日 and a moon 月 together means 'bright' 明
a woman 女 and with a child 子 beside means 'good' 好
The single character ? stands for a tree, two trees together ? refers to a group of trees-grove character made up of three trees ? means a place full of trees - a forest Phonetic-Semantic Compounds
Over 90% of current Chinese characters are semantic-phonetic compounds.
There are many objects, abstract and ideas that are difficult to express through Pictographs or Ideographs.
For example, 鸟 is general term for birds, but there are thousands of types of birds in world, and it is impossible to differentiate each of them by way of pictography or ideography. But this is easily achieved in phonetic-semantic compounds by adding different phonetics to radical 鸟, e.g. 鸽 ( pigeon ), 鹊 ( crane ), 鸡 ( chicken ) or 鹅 ( goose ).