Letter to my Daughter
Sunday, 3 November
Good Morning Jessicca…
Nothing is static so long as there is the dimension of time involved. All things known to the human mind are in constant transition. The universe is expanding. Gas clouds deep in space condense into stars. Stars age and go cold or are consumed by black holes. The galaxies move and swirl about. Our solar system does the same about our star, the sun, which itself is a captive rider on a course set by our Milky Way. Our planet Earth, provider of all that is needed to sustain life, is in constant change. The land forms, projecting above Earth’s liquid surface, inch slowly about the globe – gathering together into new formations, eventually to be pulled apart before, once again, reforming into new configurations. Ocean currents change their flow, as does the axis of this planet’s rotation, creating new climate patterns. Every life form able to sustain itself over the span of ages must have within it the capacity to meet the challenges that change with time. Adaptation is an ever present dynamic of life. It is the merciless economics of nature.
We change – you and I. We call it growing up, early on, but then we settle for just witnessing our own body growing old. Aging is transition. We live for a time, and then expend ourselves. The resources I once called ‘me’ are freed up for new and interesting other life forms to use to sustain their own moment in the sun. We are the product of many ancestors who once dreamed as we now do. We are like them because we carry their traits. Go far enough back in time and our ancestors look less like we do now. Our own species has improved in its abilities over time. Our rise to the top of the animal kingdom has been extraordinary. You and I are living examples of a broad category of animals known as mammals. One gender of this species has the capacity to carry a forming life within it and also internally manufacture all the nourishment the new life will need once born. We call this gender ‘Mom’. She protects within her body this new person – a baby if human, a puppy if she is a dog or colt if she is a horse. In every case the new being begins as a single cell. The cell splits and these cells grow before they also divide from one into two cells. The cells take on specialized tasks and the new life begins to show different characteristics and constantly refines them until it finally, one day, emerges. Look at the baby! How wonderful it is. The baby gives us its total trust. It is powerless to do otherwise. We must not let it down. We are overwhelmed with emotion. We give the baby our devotion. We pledge it our very lives. It is that important that new life should one day replace old. The baby must grow and gain wisdom so that it, too, will one day fulfill its biological destiny and bring forth new life to replace its own. This is the manner in which life is sustained on Earth.
The necessary change that must occur to life over the generations cannot be accomplished in a manner of one individual regenerating itself as a new copy. New life, at a complexity beyond microscopic cellular existence, requires the intimate interaction of two life forms giving of their traits in order to produce one new existence exhibiting the combined characteristics of the previous two. Surprising new dimensions of an old formula may arise from this process. Variations in abilities among individuals within a population enhances the chances a species will survive dangerous new environmental challenges. The offspring of the survivors retain these adaptive characteristics and we say the species has evolved.
Climate change can be one factor in the slow drying up of a large body of water. It means extinction for most, if not all, forms of fish inhabiting their shrinking watery world. Yet, there may be hope if a fish has, for instance, the characteristics of the modern-day lung fish. Its gas bladder serves as a rudimentary lung, replacing for short periods of time, dependency on gills for gas exchange. It’s lobed, meaty fins serve as vestigial legs, poor locomotion over land but it may get the animal to the next available pond. The lung fish survives areas of drought by seeking out depressions that still retain water.
The earliest forms of amphibians may have had similar motivation and capabilities when they first ventured above the water’s surface and squirmed onto land. Unlike the lung fish, though, these vertebrates discovered a new world rich in resources. Without competition, plump insects and lush vegetation was theirs for the taking. A husky animal with thick fins, capable of moving over land, has attributes poorly suited to compete with fast, nimble fish. But its rudimentary terrestrial abilities are game-changing assets that enable it to exploit an environment teeming with new possibilities. Success on land leaves them only one powerful reason to return to water. Their young require a watery environment during the first stages of their life.
Eventually this new niche for life becomes heavily populated with individuals competing with one another for food and other resources. One obvious characteristic that improves one’s chances for survival would be improved locomotion. All else being equal, an animal that is faster and moves with less effort is more likely to enjoy a full stomach. The animal is also more likely to survive to have offspring. These young will share their parents’ adaptive characteristics. Over the generations competition among animals of the same species provides survival pressures that select for a fin’s bone structure to become one whose configuration is more suitable for walking.
Today’s amphibians are well suited for their environment but they remain tied to water for reproduction. They become scarce in arid climates. The first vertebrates free to lay its clutch of eggs in a dry location could once again exploit a rich niche free from competition. The egg shell didn't magically come about overnight. It had to be the result of long and slow refinement, much as the bone anatomy of the fish’s fin served as the basis for the terrestrial leg. Once again competition for resources provides the selective pressures that drive biological improvements. The animal best adapted to its current environment is the one most likely to live and reproduce; ensuring the characteristics that best aid survival will be represented in the next generation of individuals. This is the biological meaning of the phrase ‘survival of the fittest’.
Today’s winning asset is the human intellect. The human being has, in the space of a few short thousand years, come to be the unchallenged, dominate ruler of this planet on the basis of human reasoning alone. Like the first amphibians on land we have no competition except for ourselves. Yet, our advantage goes far beyond that of any other animal species’ success prior to our own geologically recent appearance. We are the only species to inhabit this planet Earth that can accurately claim that we are the master of our own destiny. Should our future status be imperiled we have only ourselves to look to for blame. It’s the responsibility we have taken on when we became the top of the pyramid.