After spain and portugal took over land in the new world why did other countries such as france and england do the same thing?

Reports of riches and resources--The Spanish and Portuguese reported of resources, riches, and land available for the taking. Competition for wealth motivated other countries to colonize. 

Mercantilism was the economic idea of the 15th century in which Europeans believed that there was only a set amount of wealth and for a country to "win" they had to grab up land and/or resources.