Ecology of lifeEcosystem

Biogeochemical Cycle

The term ecology was coined by German biologist Ernst Haeckel, but the discipline of ecology was created about 100 years ago

Greek word “oikos” meaning “house” or “place to live”

“logos” meaning “is study of”

Ecology is the study of how organisms interact with one another and with their non living environment including such factors as sunlight, temperature, moisture and vital nutrients

Ecologist focus on trying to understand the interactions among organisms, populations, communities, ecosystem and ecosphere

It can be classified into species – groups of organisms that resemble one another in appearance, behavior, chemistry and genetic endowment.

Population consists of all members of the same species occupying a specific area at the same time

◦ Eg: sunfish in the pond◦ White oak trees in the forest

Populations are dynamic groups that change in size, age, distribution, density and genetic composition as a result of changes in environmental conditions

Community or biological community –

Populations of all different species occupying and interacting in a particular place

Ecosystem – It is a community of different species interacting with one another and with their nonliving environment of matter and energy.

Ecosystem can be natural of artificial (human created) .

Examples of human created ecosystems are cropfield, farm ponds and reservoirs and artificial lakes created behind dams.

To be sustainable for some specified period of time, an ecosystem must contain the energy and nutrients resources needed to support its resident organisms and to dispose of and recycle their wastes.

All of the earth’s ecosystems together make up what we call the biosphere or ecosphere.

NUTRIENT CYCLE OR BIOGEOCHEMICAL CYCLE

Any atom, ions or molecule an organism needs to live, grow or reproduce is called nutrient.

These nutrient atoms, ions and molecules are continuously cycled from the nonliving organisms (air water soil rock) to living organisms (biota) and then back again in what are called nutrient cycles or biogeochemical cycles (literally life earth chemical cycles)

There are three general types of biogeochemical cycles:

1. atmospheric 2. sedimentary and 3. hydrologic

In atmospheric cycle, a large portion of a given element exists in gaseous form in the atmosphere.

Examples are nitrogen gas (N2) and carbon dioxide (CO2) gas, which cycle fairly rapidly from the atmosphere, through soil and organisms, and back into the atmosphere.

In sedimentary cycle, an element either does not have a gaseous phase or its gaseous compounds don’t make up a significant portion of its supply.

In this case, the earth’s crust is the main storehouse.

Such element cycle quite slowly , moving mostly from the land to sediments in the seas and then back to land through long term geological uplifting of the earth’s crust over millions to hundreds of millions of years.

Phosphorus and most nonrenewable solid minerals are circulated in such cycles.

In the hydrologic cycle or water cycle, water in the form of ice, liquid water and water vapor cycles through the ecosphere.

In this case the hydrosphere is the main storehouse. This cycle operates at the local regional and global levels.