Final answer:
Somatic cells do not directly leave progeny but play an essential role in supporting germ cells, which are responsible for reproduction and passing on genetic information. The health and functionality of somatic cells are crucial for the reproductive success of an organism.
Step-by-step explanation:
The statement that somatic cells exist only to help create, sustain, and propagate germ cells can be considered true in an evolutionary sense. Somatic cells are the body cells that make up most of an organism and are not involved in reproductive processes. They do not pass on genetic information to the next generation directly. Instead, their primary role is to support the individual's survival and the functioning of germ cells, which are the cells responsible for reproduction.
Germ cells undergo processes such as mitosis and meiosis to perpetuate the germ line and produce haploid gametes. Through reproductive events, these gametes contribute to the genetic pool of the next generation. Hence, while somatic cells do not leave progeny themselves, they do play an essential role in the survival and reproductive success of germ cells, which in turn carry forward the genetic legacy of the organism.
It's important to note, however, that somatic cells are not valueless; they are essential for the overall fitness of an organism. While they may not contribute directly to the next generation, their health and functionality are imperatives for the reproductive cells to fulfill their evolutionary purposes.