An Overview of the Animal Kingdom and the Development of Its Members

This paper examines growth and development patterns in the lives of humans and animals, both in the course of individual lifetimes and over the longer period of species evolution.

Animals and humans undergo several distinct transformations during their lives. The first, the growth of a fetus into a child, establishes the essential structures, functions, and forms of the body and equips it with the physical capacity to exist autonomously. Puberty, the transformation of a child into an adult, results in a reproductively mature entity whose brain, at the end of the process, has reached its peak level of information capacity and processing. Afterward, the body and mind, in terms of their capacities and functions exist in a fairly constant (though slightly declining) state during the majority of adulthood. The final stage, senescence, is the atrophy of bodily functions, the beginnings of the brain's and heart's loss of ability to coordinate all aspects of an organism's life with full competence. The body begins to become frail as the mind's cognitive capacities weaken, eventually resulting in death.

Life forms can change over generations by the accumulation of subtle mutations in the gene pool that, cumulatively, can lead to a trait that ensures greater reproductive success to those who exhibit it. This trait, subsequently, is passed on and amplified. Multicellularity, the development of internal fertilization, the backbone, the ability to walk upright, and man's capacity to reason were all advantages that ensured greater viability within an organism's environment and thus assisted in its survival to reproductive maturity. Human beings' rational faculty, especially, proved to be such a vast and unprecedented asset that, within mere millennia, man has achieved virtual dominance over the entire planet.