As the 1800s went on and Europeans began taking over more territory in Africa and Asia these rationales became more racist. The publication of Charles Darwin’s, On the Origin of Species, had effects beyond biology. Some imperialists adopted ideas called Social Darwinism, which believed that people and countries were more or less successful based on their biological qualities (skin color). For them, this justified imperialism, because imperialists told themselves that their conquests were natural. Similarly, another idea that imperialists used to justify their idea was called phrenology. It was a racial 'science' that argued that the racial superiority of certain ethnic groups depended on the size and shape of their skull. Social Darwinism was a racist rationale for imperialism, but other rationales were more cultural. European and American imperialists sometimes justified their expansion as helping others by spreading Christianity.

Some of these imperialist states built on existing maritime empires. Britain & France both had colonies in the Americas and Asia in 1750. However, France lost its North American colonies to Britain but conquered new colonies in Africa, Asia, and Oceania. Britain, too, lost some of its North American colonies when the United States became independent, but overall, they also conquered massive new territories in Africa, Asia, and Oceania. Moreover, Belgium, Germany, and the United States are all countries that came into existence after 1750 and established colonies overseas in the 1800s. Japan had long existed, but after the Meiji Restoration in 1868, it industrialized and expanded into mainland and island East Asia. Many of these places used 'settler colonialism' which was the most extreme form of imperialism. Settlers from imperialist countries took land and resources from indigenous people with the backing of their states.

Indigenous people responded to imperialist invasions and pressures in a variety of ways. In some cases, indigenous elites cooperated with imperialists in exchange for authority and opportunities for profit. In 1857, Indian soldiers employed by the East India Company with the support of the leaders of independent Indian states rebelled against British control. This event is known by many names, including the Indian Rebellion of 1857, the Great Rebellion of 1857, the First Indian War of Independence, Indian Mutiny, and Sepoy Mutiny. The British defeated this rebellion, leading to India becoming a crown colony, as the British Parliament declared the Queen of England to also be Empress of India. In West Africa, armed groups resisted Europeans attempting to expand into the interior. In West Africa, Samory Touré led Islamist force successfully limited French expansion for several decades. Similarly, the Ashanti Empire resisted the British for most of the 1800s, including during the Yaa Asantewaa War. The Xhosa Cattle-Killing Movements was a similar religious response to displacement from British and Dutch settler colonialism in Southern Africa. While in northeast Africa the Mahdist wars combined traditional Islam with a military organization in opposition to Anglo-Egyptian control of Sudan. Other indigenous people organized armed resistance to expanding empires throughout this period. In 1780 an Indian leader from the Andes took the name Tupac Amaru II led a bloody revolt against the Spanish Viceroy of Peru that shook, but did not break imperialist control.

The expansion of empires and the growth of industrial capitalism greatly increased global exchanges. Businesses from industrialized countries benefited from imperialist power over other parts of the world, especially in pushing colonized or dependent regions to focus on exporting commodities. A commodity is a raw material or primary agricultural product that can be bought and sold in large quantities. In addition, new technology, like refrigerated shipping compartments, made the shipment of foods, like beef from Argentina, possible across large distances. So too, Guano, bird excrement, helped the production of food. In fact, guano was an excellent fertilizer that increased agricultural production in imperialist countries that supported mining. Similarly, raw materials used by industries were mass-produced and shipped globally, to the benefit of businesses in imperialist countries. British factories used cotton from colonial Egypt and India. The machines in these factories may have used belts made from rubber produced in the Belgian Congo and may have been lubricated with palm oil from the British colony of Nigeria (west Africa). In 1869, some Afrikaaners (descendants of Dutch settlers) in South Africa discovered diamonds there and that caused a rush of European settlers and investors. The result was the world’s largest open-pit mine dug by hand, forced labor from Africans who did the digging, and enormous profits for a few investors, such as Cecil Rhodes. Rhodes became so wealthy that he started his own colony in southern Africa, Rhodesia (today: Zimbabwe and Zambia).

Military and political pressure from imperialist countries created advantages for capitalists from these countries. Using political pressure to produce advantages for investors is a form of economic imperialism. One interesting example was when China outlawed the importation of opium from British-controlled India, the British government went to war with China to force them to accept these addictive drugs sold by their merchants. Despite killing Chinese people so that their businesses could sell drugs in their country, the British also continued to insist that their imperialism was a force for morality and human progress through their racist lens of Social Darwinism. This led to massive war, seeing the British not just win, but also acquire Hong Kong. In addition, investors from imperialist countries made profits from resources extracted in other countries. American and British capitalists operated copper mines in Mexico and Chile. Profits from these mines flowed out of the country where the copper was mined. Similarly, British investors controlled and profited from transportation developments including the Suez Canal in Egypt and the Port of Buenos Aires in Argentina.

Long-distance migration expanded greatly during this time period. The reasons in some ways were simple: the world population grew and transportation methods advanced. Most migrants were moving within or from Europe and Asia and many were laborers. Industrial transportation--steam!--made longer distance travel more affordable via ships and railroads. For example, some Italian migrants crossed the Atlantic twice a year from southern Europe to Argentina and back, working harvests in the northern and southern hemispheres. Laborers from Japan crossed the Pacific and worked in sugarcane fields in Hawai’i. Merchants moved, too, such as Lebanese business owners in the Americas. Some of this movement was part of global urbanization. In Ireland, due to the potato famine, rural migrants moved to cities in the United Kingdom, but many others crossed the Atlantic to relocate to Boston, Buenos Aires, or New York. In terms of labor, Coerced labor continued during this period. The late 1700s were the peak decades for the Trans-Atlantic Slave Trade. Even after the British and the US banned the slave trade in 1807, other nations continued through the 1800s. The slave trade did decline in the 1800s, but coerced labor did not. Migrants from India and China were often indentured laborers with few rights. These migrants often worked on plantations in the Caribbean or the Indian Ocean. The British also used convicts for labor in their colonies in the Indian Ocean and Australia, as did the southern states in the US, albeit in a highly racialized form.

All of this migration changed societies in both sending and receiving societies. Gender imbalances occurred at both ends of the migration process as more young males migrated than other demographic groups. Immigrants often lived near or with people from the same region in their new countries thus forming ethnic enclaves. The many “Chinatowns” in cities around the world were prominent examples of this, as were Indian communities in Africa and neighborhoods in American cities with immigrants from the same regions. Settler colonies created social hierarchies based on modern ideas of race. When migration from Asia into white settler states began, white elites in some of these states responded with racist restrictions, most prominently the Chinese Exclusion Act (US) and the White Australia Policy.