How do we classify 'life', and are there any instances where it's a grey area?

Question

How do we classify 'life', and are there any instances where it's a grey area?

Answer 1

From Wikipedia "Life":

Conventional definition: Often scientists say that life is a characteristic of organisms that exhibit the following phenomena:

   1. Homeostasis: Regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature.

   2. Organization: Being composed of one or more cells, which are the basic units of life.

   3. Metabolism: Consumption of energy by converting nonliving material into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.

   4. Growth: Maintenance of a higher rate of synthesis than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter. The particular species begins to multiply and expand as the evolution continues to flourish.

   5. Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.

   6. Response to stimuli: A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun or an animal chasing its prey.

   7. Reproduction: The ability to produce new organisms. Reproduction can be the division of one cell to form two new cells. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from at least two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.

Answer 2

The "gray area" would be software-based life.  With a properly programmed virtual environment, a software-based life form can exhibit all the properties of life, but does it with "data" rather than "matter."

Answer 3

no gray, its all life, even death is apart of life.  Something that has life can be classified into some kind of biological classification.

Answer 4

The classifications are not to be argued with, but there are a number of grey areas, such as crystals, and wonderfully, "clay", this grows is self regulating , reacts to its environment, and reproduces, ( please check this, before you pour scorn on it, people, it is quite correct, I assure you ), it may sound silly, but it is true, it really does all of this, and more....

Answer 5

Conventional definition: Often scientists say that life is a characteristic of organisms that exhibit the following phenomena:

Homeostasis: Regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature.

Organization: Being composed of one or more cells, which are the basic units of life.

Metabolism: Consumption of energy by converting nonliving material into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.

Growth: Maintenance of a higher rate of synthesis than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter. The particular species begins to multiply and expand as the evolution continues to flourish.

Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.

Response to stimuli: A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun or an animal chasing its prey.

Reproduction: The ability to produce new organisms. Reproduction can be the division of one cell to form two new cells. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from at least two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.

The above was taken from the Wikipedia entry on Life.

There are definitely grey areas.  A couple examples are the unborn and the brain dead - the whole abortion debate stems on whether or not the fetus is alive.  If it is alive, abortion is tantamount to murder, while if it is not alive aboriton should be a woman's choice.  As for the brain dead, there is debate as to whether or not these individuals should be kept "alive" and whether or not their state of living can actually be described as life as there is no brain activity, just working organs.  One can argue that a brain dead person fails on the "Adaptation" criteria listed above, as well as "Response to Stimuli."  

Answer 6

A livinng being has got to:

Move

Respire

Sensitivity

.

Nutrients (as in intake)

Excrete

Reproduce

Grow

Hmm... I think that's right. Its from my year 6 biology.

I think viruses are in the "grey area" as they don't do certain things which make up MRS. NERG

Answer 7

Living, breathing,healthy,God! that sums it up eh?

Answer 8

for something to be considered alive it must:

-reproduce (this can be on a cellular level as well as sexual/asexual   reproduction)

-it must react to it's surroundings

-it must have DNA

i think there's one more, i just forget what it is.

as far as grey areas go, there theoretically could be, but i'm almost certain there aren't any that we know of.

Answer 9

Viruses are a grey area. It's not clear whether they are alive, or just self-replicating crystals.