Ecological System

Question 1

Ecological system

Answer 1

The term ecological system is used to describe the organization and interactions of communities of living things, including humans, together with the chemical and physical factors that are part of their environment.

Ecological systems are characterized by:

1. a nesting of systems
2. Interdependence
3. change
4. cycling

Question 2

A nesting of systems

Answer 2

Nature is made up of systems that are nested within systems. Each individual system is an integrated whole and—at the same time — part of larger systems. Changes within a system can affect the sustainability of the systems that are nested within it as well as the larger systems in which it exists. For example: Cells are nested within organs within organisms within ecosystems.

Question 3

Levels of organization in nature

Answer 3

Atom - fundamental units of all substances
Molecule - two or more atoms joined in chemical bonds
Cell - smallest unit that can live and reproduce on its own
Tissue - organized array of cells and substances interacting in some task
Organ - structural unit of two or more tissues that interact in one or more tasks
Organ system - organs that interact in one or more tasks
Multi-celled organism - individual composed of different types of cells
Population - group of individuals of a species in a given area
Community - all populations of all species in a given area
Ecosystem - a community that is interacting with its physical environment through inputs and outputs of energy and matter.
Biosphere - all regions of Earth’s waters, crust, and atmosphere that hold organisms

Question 4

Interdependence

Answer 4

Everything in ecological systems is connected in space ad time. Ultimately the Earth is one ecological system embodying all the smaller subsystems into one interconnected system.

Question 5

Complexity

Answer 5

Because all living and non-living components of ecological systems are interconnected and interdependent, there is enormous complexity. A change in any part ripples through the system similar to the domino effect. An ecological system is a dynamic continuum with complex cause and effect interrelations.

Question 6

Change

Answer 6

Ecological systems are dynamic and therefore always changing. Population abundance, species composition, intra- and interspecific relations change in time (seasonally but also in process of succession). The species present and the physical environment control the patterns, rates, and limits of this change. Changes to one small ecological system can have impacts on larger ecological systems.

Question 7

Cycle

Answer 7

Matter cycles through the ecological systems. For example: carbon is captured by growing plants from carbon dioxide in the air through the process of photosynthesis. The carbon in plant material may later be partly decomposed by soil microbes and remain in the soil as humus. Or, if eaten by an animal, it might be fully oxydised during respiration and exhaled back into the air as carbon dioxide. Other elements have different cycles.