When asking the question, "When does human life begin?" one first needs to define the properties that are characteristic of any living organism. A scientific and factual answer to this controversial question will separate the characteristics of living and nonliving organisms and then determine what category the fertilized egg falls into. An answer to the aforementioned question will answer the following question: Does the fertilized egg possess the same properties of all living organisms?
Cleveland Hickman, Jr., Larry Roberts, and Allan Larson (1997) begin to provide answers to these questions. "Although we do not force life into a simple definition, we can readily identify the living world and separate it from the nonliving. Many remarkable properties have arisen during life's history and are observed in living forms in various combinations. They clearly identify their possessors as part of the unified historical entity that we call life."
According to Hickman, Roberts, and Larson (1997), any living organism will meet the following seven basic properties of life:
1) Chemical uniqueness.
Living systems demonstrate a unique and
complex molecular organization.
2) Complexity and hierarchical organization. Living systems
demonstrate a unique and complex hierarchical organization.
3) Reproduction. Living systems can reproduce themselves.
4) Possession of a genetic program. A genetic program provides fidelity
5) Metabolism. Living organisms maintain themselves by obtaining
nutrients from their environments.
6) Development. All organisms pass through a characteristic life cycle.
7) Environmental reaction. All animals interact with their environment.
An analysis of the fertilized egg must be made to determine if the fertilized egg and the resulting zygote, embryo, and fetus can all be classified as living organisms. Do these entities meet the properties seen in all living organisms?
1) Chemical Uniqueness.
Fertilized eggs possess their own unique DNA
2) Complexity and hierarchical organization. Hickman, Roberts, and
Larson (1997) explain that the most basic unit in the biological
hierarchy is the cell. The cell holds the properties of living organisms,
and cells can be manipulated in the laboratory and can be reproduced,
whereas nonliving elements cannot. Therefore, the fertilized egg would
meet this criteria, although it would be a more basic unit of the
3) Reproduction. Francis Beckwith (1994) observes that the zygote
possesses two different methods of reproduction: cell reproduction and
twinning. According to Beckwith (1994), twinning is "a form of asexual
reproduction, which can occur after conception."
4) Possession of a genetic program. Francis Beckwith (1994) confirms
that from conception, the fertilized egg has "its own unique genetic
code." The 46 chromosomes present at conception provide all of the
genetic information that will ever be needed.
5) Metabolism. Francis Beckwith (1994) confirms that from conception,
the fertilized egg meets the requirement of metabolism.
6) Development. Hickman, Roberts, and Larson (1997) state,
"Development describes the characteristic changes that an organism
undergoes from its origin (usually the fertilization of the egg by sperm)
to its final adult form." Thus, although the fertilized egg will take on
different forms throughout its life cycle, the development of life begins
7) Environmental interaction. The entity in the womb interacts with its
environment in many ways. Kicking and jumping are both examples.
In addition, research has shown that the fetus can be soothed by music
and can recognize the voice of its mother.
The fertilized egg,
from the moment of conception, meets each of the properties that have been
found to determine if an organism can be classified as living. Based on
this definition, life begins at conception.
Return to the Biological Facts.
This page was made by
Christina Rutten, a student at Wayne State College,
on April 20, 1999. If you
have any questions or comments, please e-mail me at firstname.lastname@example.org.