THE HIERARCHY OF LIFE
Life
has a hierarchy!
Every living entity does not
occur as a whole without its pieces or component parts or portions (see Figure 1). These portions aggregate
or complicate to become higher levels of
biological organization also referred to as the hierarchy of life. The hierarchy
of life is the orderly arrangement
of complex
biological
structures
and systems
that define life. Understanding
this basis of entities helps in understanding and solving problems and
predicaments as they
arise in living systems. For example, when studying an elephant
with a disease, you can break the animal down into different parts and study the
disease at these different levels.There is no hard and fast rule as the number
of this organization that is existing, but asically, there are 11
levels of biological organization. Each of these describes a hierarchy of organisation.
 |
| Figure 1: Levels of Biological Organization |
Biosphere -This
includes all
ecosystems. An
ecosystem is a short form of ecological system.
Ecosystem - consists of all organisms living in a particular area, as well as the nonliving, physical components of the environment
Community - consists of various populations of organisms living together in a given area
Population - a group of organisms of the same species in any given area. Organisms are of the same species if they are actually or potentially interbreeding and producing viable offspring. Two horses are therefore of the same species but a horse and a donkey are not the same species even though they look alike. A donkey crossed with a horse results in a mule. But a mule is not a viable offspring as it cannot reproduce itself. Similarly a lion is not the same species as a tiger. But a cross between a Lion and a tiger results in a Liger which also is not viable.
Organism - within a population there are organisms, just one of those organisms is called an organism. For example, within a population lions, there is a lion.
Organ system - consists of different organs that work together for a specific function.
Organ - consists of different tissues that function together to do a certain job
Tissue - consists of similar cells that work together
Cell - the smallest unit of life that is able to carry out all the functions of living things
Molecule - consists of different atoms. For example, DNA, within DNA there are oxygen atoms and different proteins.
Atom - the smallest unit of matter that has the chemical properties of a particular element.
Take note that thes levels are all related to one another. For example, a biosphere contains all of the mentioned levels above. So, each level contains the level before it and they all fit into each other just as it has been earlier indicated. Knowing the difference between the levels is helpful because it makes it easier when comparing different things.
The biological organization of life is a fundamental premise for numerous areas of scientific research, particularly in the medical sciences. Without this necessary degree of organization, it would be much more difficult—and likely impossible—to apply the study of the effects of various physical and chemical phenomena to diseases and body function.
Ecosystem - consists of all organisms living in a particular area, as well as the nonliving, physical components of the environment
Community - consists of various populations of organisms living together in a given area
Population - a group of organisms of the same species in any given area. Organisms are of the same species if they are actually or potentially interbreeding and producing viable offspring. Two horses are therefore of the same species but a horse and a donkey are not the same species even though they look alike. A donkey crossed with a horse results in a mule. But a mule is not a viable offspring as it cannot reproduce itself. Similarly a lion is not the same species as a tiger. But a cross between a Lion and a tiger results in a Liger which also is not viable.
Organism - within a population there are organisms, just one of those organisms is called an organism. For example, within a population lions, there is a lion.
Organ system - consists of different organs that work together for a specific function.
Organ - consists of different tissues that function together to do a certain job
Tissue - consists of similar cells that work together
Cell - the smallest unit of life that is able to carry out all the functions of living things
Molecule - consists of different atoms. For example, DNA, within DNA there are oxygen atoms and different proteins.
Atom - the smallest unit of matter that has the chemical properties of a particular element.
Take note that thes levels are all related to one another. For example, a biosphere contains all of the mentioned levels above. So, each level contains the level before it and they all fit into each other just as it has been earlier indicated. Knowing the difference between the levels is helpful because it makes it easier when comparing different things.
The biological organization of life is a fundamental premise for numerous areas of scientific research, particularly in the medical sciences. Without this necessary degree of organization, it would be much more difficult—and likely impossible—to apply the study of the effects of various physical and chemical phenomena to diseases and body function.
Consider the following examples:
- The fields such as cognitive and behavioral neuroscience could not exist if the brain was not composed of specific types of cells.
- The basic concepts of pharcology could not exist if it was not known that a change at the cellular level can affect an entire organism.
- The direct effect of the notorious chenical named DichloroDiphenyle Trichloroethane but popularly known as DDT occurs at the subcellular level, but it affects higher levels up to and including multiple ecosystems.
- Also a change in one atom could change the entire biosphere.
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