The early chemistry of the planet and carbon’s remarkable nature provided the conditions necessary for simple and complex hydrocarbons to form. Some of these in all probability formed amino acids and resembled RNA, a carbon molecule that can reproduce itself.
Before the organic polymers actually formed cells however, they formed protobionts.
But right from the beginning of life, we see the two traits necessary for an individual organism’s successful adaptation or evolution.
So what’s life? Wikipedia definition from 2012 below or current text here:
1. Homeostasis: Regulation of the internal environment to maintain a constant state; for example, electrolyte concentration or sweating to reduce temperature.
2. Organization: Being structurally composed of one or more cells, which are the basic units of life.
3. Metabolism: Transformation of energy by converting chemicals and energy 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 anabolism than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter.
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. (Nice, the Adaptation listing is an addition that was not there when I started writing this and referencing it. Someone noticed.- Michael)
6. Response to stimuli: A response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of multicellular organisms. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun (phototropism) and by chemotaxis.
7. Reproduction: The ability to produce new individual organisms, either asexually from a single parent organism, or sexually from two parent organisms
Even given the source, a wholly endorsable definition. And one that applies to us as well as the single cell organisms we know as microorganisms. Let’s look at how interaction with the environment relates to Successful Adaptation for these remarkable forms of life.
By examining traits of these simple creatures, some of the core and unstated ideas inherent in the above definition can be further explored and related to the evolution of life on this planet.
Next Single Cell Organisms
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