Introduction
Ever since biochemical evolutionary processes caused the origin of life on Earth several billion years ago, the drivers of natural selection, heredity, and variability have resulted in a wide range of biodiversity. This diversity is the foundation for questions about what determines the properties of living matter in the first place. This raises questions about the differences in functional structures and environmental adaptations for different representatives of living things, as well as making comparisons with systems that may have some properties of living things but, in reality, are not. This essay analyzes this problem in depth with guiding questions as part of the assignment.
Defining the Characteristics of Living Things
Many biologists of past centuries have attempted to contribute to science by describing the phenomenon of life. One of the most prominent definitions was by the German philosopher Friedrich Engels, who pointed out that life is a special way of existence of protein molecules capable of self-renewal (Zwart, 2020). In this definition, Engels focused on two basic properties of life, namely the presence of protein composition and self-renewal. Extending this list to include the ability to metabolize, grow and reproduce, hereditary variability, discreteness, self-regulation, and irritability. The totality of these traits, but not each of them individually, defines life in terms of biological significance.
Of interest is the definition of the life category for the following six samples: a fertilized chicken egg, a supermarket egg, an HIV, an amoeba, a human hair, and a blood cell. The living systems listed are all but HIV, the supermarket chicken egg, and the human hair cells. The chicken egg and the human hair can be seen as once-living systems that have been put to death. For the egg, this mortification is necessary for the economic purposes of the agricultural industry, while the hair is a dead keratinized substance with no living properties except for the root follicles.
Unobservable Traits of the Living
Humans can easily observe not all of the traits listed in the last section. For example, we cannot observe metabolic processes, for they take place at the molecular level, but we can see their consequences. Self-regulation is also not consistently observable — for example, the adaptation of blood acidity or gastric juice is not observable, but thermoregulation, realized through sweating, can be easily seen.
Living vs. Dead Organism
Life is designed so that any living being will one day die. While alive, the body was filled with biochemical, metabolic, and cognitive processes that ended almost immediately with brain death. Some of these would properly include maintenance of thermoregulation, digestion of food, germ cell maturation, somatic cell mitosis processes for tissue repair, growth, and irritability to external factors. Certainly, pathology knows that a cadaver can exhibit some characteristics of the living, such as urination, erections, and muscular tremors (CC, 2022). However, these should be regarded as abnormal emissions after death since they are of short-term significance and do not recur again.
Inanimate System with Functions of the Living
It is noteworthy that a virus, regardless of the specific type, can behave like a living organism in some cases, which creates a controversial opinion about it. When it enters the body, the virus triggers replication processes, that is, it is capable of self-replication, a key characteristic of life. However, this only works in the host body; outside the body, the virus does not exhibit the properties of life, so it is correct to say that all viruses are not living systems and are only capable of exhibiting some of the properties of life. The same can be said of a stone composed of nonliving minerals but capable of exchanging substances with the water that washes it: the stone releases substances into the water and receives moisture in exchange, but the singular performance of the properties of living is insufficient.
Distinguishing Plants from Animals
Like animals, plants are living systems, which means they have all the characteristics of life, from growth to hereditary variability and irritability. However, some could be more distinguishable because of their attached way of life. For example, a plant may grow all its life but seems incapable of movement. In reality, plants, especially flowering plants, constantly move and point their leaves toward the sun to provide photosynthesis or hide them during high winds (Srivastava, 2022). The way they eat differs as well: most animals are heterotrophs, that is, they get their food by eating organic matter that has already been cooked. In contrast, plants are predominantly autotrophs: they use light energy to synthesize carbohydrates.
Dormant Organism
Living organisms can enter an anabiotic state, during which they can be considered dormant. In such a state, the basic organismal processes do not stop but are slowed down or almost stopped. This is necessary to preserve their resources long under adverse environmental pressure. Dormant organisms are not dead because, despite the slowing of metabolic processes, they do not stop completely, the properties of living systems are preserved.
Craig Venter’s Discovery
In 2010, Craig Venter stated that he had created a fully synthetic single-celled organism, Mycoplasma laboratorium, capable of performing all the functions of living systems (Venter et al., 2022). If it were not known that this organism is artificially synthesized, one would think that it is indeed a living system: the cell is capable of metabolism, division, and irritability. It is, therefore, true to say that Venter’s team’s discovery can be seen as the creation of a new form of life that satisfies the characteristics of whole living systems.
Conclusion
Living systems are highly diverse and rarely resemble each other. There would seem to be nothing in common between the perpetually attached to the soil plant, the ocean whale, and the chicken egg, but they all satisfy the properties of living systems. Such properties include the ability to respond to the environment, modify in the context of hereditary variability, reproduce, and move. This essay has examined various aspects of the problem of defining life and has shown how one can determine whether a system is living, dead, or nonliving.
References
CC. (2022). What happens when you die. Cleveland Clinic. Web.
Zwart, H. A. E. (2020). Friedrich Engels and the technoscientific reproducibility of life. Science and Society: A Journal of Marxist Thought and Analysis, 84(3), 369-400.
Srivastava, R. (2022). Plant movements – definition, types & examples. Embibe. Web.
Venter, J. C., Glass, J. I., Hutchison III, C. A., & Vashee, S. (2022). Synthetic chromosomes, genomes, viruses, and cells. Cell, 185(15), 2708-2724. Web.