How do scientists distinguish between life and non-life?
A scientific textbook called “Basics of Biology”1 gives five characteristics of living things; these five criteria are found in all modern elementary scientific textbooks:
- Living things are highly organized.
- All living things have the ability to acquire materials and energy.
- All living things have the ability to respond to their environment.
- All living things have the ability to reproduce.
- All living things have the ability to adapt.
According to this elementary definition of life, life begins at fertilization, when a sperm unites with an oocyte. From this moment, the being is highly organized, has the ability to acquire materials and energy, has the ability to respond to his or her environment, has the ability to adapt, and has the ability to reproduce (the cells divide, then divide again, etc., and barring pathology and pending reproductive maturity has the potential to reproduce other members of the species). Non-living things do not do these things. Even before the mother is aware that she is pregnant, a distinct, unique life has begun his or her existence inside her.
- Basics of Biology, Carol Leth Stone, Greenwood Publishing Group, January 1, 2004, ISBN: 0-313-31786-0
- American Life League, Retrieved: July 31, 2013, http://www.all.org