The total number of organisms in a particular area is called a biome, and it is a large area of land that is categorised based on the climate, plants and animals that build their homes there. Biomes include many ecosystems within the same area and mainly there are two types of biomes present they are terrestrial biomes, aquatic biomes. For example tropical rain forest ecosystem.

Amensalism is a population interaction between two species in which one species gets harmed and another one remains unaffected, and it involves some type of chemicals interaction by which the organisms of one species affect the well-being and growth of individuals or the population biology of others. The chemicals released by one species that act on the growth, health, and behaviour of another species, are called allelochemicals.

The negative interaction that occurs among organisms whenever two or more organisms require the same limited resource is known as competition. All organisms need resources to grow, reproduce and persist. For example, animals need food and water, whereas plants need soil nutrients (for example, nitrogen), light, and water. Organisms, however, cannot receive a resource when other organisms consume or defend that resource. Therefore, in this type of interaction both the organisms gets harmed.