In some parts of the world, the indigenous population had very little previous contact with people from other places. This meant that they did not have immunity to the diseases brought by the colonisers. Consequently, colonisation had a disastrous demographic impact.

For example, there was a sharp decline in the indigenous population of Australia in the 19^th and early 20^th centuries as a result of disease, war and other actions by the British colonisers.

Traditional society was transformed by colonisation. The colonisers formed the elite class of colonial society: they controlled the economy and held high positions in business and government. Indigenous people were considered inferior and were marginalised.

For example, they were forced to live in separate areas, were refused entry to certain places, etc.

Western customs spread among indigenous peoples, and their elite studied in European universities and became westernised. Over time, the process of acculturation had great influence everywhere. People's clothes, beliefs and even the languages that they spoke were all transformed.

The European powers established three main types of rule in colonised territories:

• Colonies, where the colonised nation lost all sovereignty to the colonising power, which controlled every aspect of government.
• Protectorates, where the colonial power controlled the foreign policy and wealth of the colonised nation, while local authorities dealt with domestic policy.
• Spheres of influence, where colonial powers forced independent countries to cede trade advantages.

Colonialism introduced modern government and political organisation in colonised nations. Colonial borders were often drawn without taking into account the tribal, linguistic or religious differences of the local population. This caused severe conflicts, many of which have lasted until today.

The mother countries exploited the natural resources of their colonies for their own benefit. Colonial economies were based on plantation agriculture and mineral extraction (gold, diamonds, and coal), using indigenous peoples as a source of cheap labour, working in slave-like conditions.

Private companies from the mother countries took land from the indigenous population and created large plantations (rubber, coffee and tea).

The mother countries had no interest in developing industry in the colonies, and local artisans grew poor, as they could not compete with industrial European products.

The colonial powers built port and railway infrastructure for their own needs, not for the local population, who often could not use these means of transportation as they lived in isolated areas.

Colonisation had a disastrous demographic impact because indigenous populations in some parts of the world had very little previous contact with people from other places and they did not have immunity to the diseases brought by the colonisers. 

Traditional society was transformed by colonisation. The colonisers formed the elite class of colonial society: they controlled the economy and held high positions in business and government. Indigenous people were considered inferior and were marginalised.

Western customs spread among indigenous peoples, and their elite studied in European universities and became westernised. Over time, the process of acculturation (the adaptation of one culture to another) had great influence everywhere. People's clothes, beliefs and even the languages that they spoke were all transformed.