Reflection 2: What is Life?

Here are my reflections about "What is Life?" after the "Is it Alive?" experiment and reading 3 articles on What is Life.

What are some of the definitions of life used by scientists?
Trifonov said that life is self-reproduction with variables.
In his paper one of the possibilities he put forth to combine all the key terms he found was: Life is metabolizing material informational system with ability of self-reproduction with changes (evolution), which requires energy and suitable environment.
Koonin suggested that life requires replications with an error rate below the sustainability threshold.
Foong May Yeong suggested that life is an entity or property that is amenable to (natural) selection without a purpose (direction).
Some definitions by various scientists studied by Radu Popa include life is something capable of metabolism, and life has the capacity to evolve.

Why do multiple definitions of life exist?
Different scientists express the definition of life in different ways, and each definition is partially correct or has a point. It is very difficult to come up with a universally accepted definition of life, because life comes in various forms and people have different perspectives on this issue.

How difficult is it, in your opinion, to define life? What makes it so difficult?
I think it is extremely difficult to define life. As I said earlier, people have different definitions of life so it is difficult to come up with a universally accepted definition of life. In addition, there is always the possibility that somewhere in our universe, not on Earth, there are life forms that do not fit our typical descriptions of life. Therefore we will never really know if our definitions of life fit all life forms or not.

How were “living things” defined for you in Primary 3? What is good about that definition? Is it inadequate in any way? How so?

In Primary 3, "living things" were defined as things that needed air, water and food to survive. This definition is simple and easy to remember, and it is also true and relevant enough for Primary 3s. However, it is inadequate in the sense that it has exceptions and may be ambiguous. For example, the term "air" actually refers to oxygen. Furthermore not all creatures require oxygen to respire, for example yeast which uses anaerobic respiration.

 

What is your definition of life now?

After reading the articles, my definition of life is: Life is an entity that can evolve and reproduce, and requires energy to survive. (It may also require certain things to fuel the life processes that allow it to produce energy, like water).