Hierarchy of Life

Hierarchy of Life

Biosphere

• When studying the biosphere, you're investigating the highest level of organization on the hierarchy of life. Scientists researching the biosphere examine the relationship between biotic and abiotic factors that impact the entire planet, focusing on biogeochemical processes, such as photosynthesis, the carbon cycle and the nitrogen cycle.

Ecosystems

• An ecosystem is the second level of organization. Scientists define the boundaries of ecosystems differently: the entire Amazon rainforest is an ecosystem, but a small lake is also considered an ecosystem. A unifying factor is that all ecosystems include biological processes through which energy is used and matter is cycled. A basic example of an ecosystem would be a pond where algae obtains energy through photosynthesis, small fish obtain energy through eating algae, and large fish obtain energy through eating small fish. Energy is consumed, but matter such as nutrients cycle back to the algae through excretion and decomposition.

Communities

• The third level of organization in the hierarchy of life is a community. Communities are groups of species that live together in a single ecosystem. Scientists studying communities investigate how interactions between species within a community affect both individual species and the entire community. An example would be one species hunting another species to the point of extinction.

Populations

• A population is the fourth level in the hierarchy of life. Populations consist of all the members of a single species that live in a particular area. Scientists study different trends and patterns within a given population to understand factors that impact the group. For example, the human population in the United States might be studied and compared with the human population in Asia to see the effect differences in natural resources and habitats have on the two groups.

Individuals

• Individual organisms are the fifth level of organization in...