Dive Dry with Dr. Bill

094: Why Die?

I'm preparing to board a flight to Boston tomorrow for the 35th reunion of my graduating class at Harvard, and I'm faced with not one, but two deadlines for my columns. This is a great time for "writer's block!" On top of that, visibility in the Dive Park this weekend was incredibly poor (10-15 feet) so whatever might have been there for me to write about, I couldn't even see it! I guess I'll have to reach into my bag of tricks and come up with something significant for you, my readers.

Death and dying have been topics of immediate interest given my father's current medical state. Fortunately he is facing his impending death with dignity and a sense of humor, making it much easier for him, and the rest of my family, to accept. These topics were also of interest back in my college days when I took a class on "The Psychology of Death" by noted thanatologist (look that up in your Funk & Wagnalls) Edwin Shneidman, who was featured on the front page of the Los Angeles Times this weekend. I look at these topics not only from the philosophical standpoint of someone who lives and recognizes that the ultimate consequence of life is death. I also look at them from the perspective of a biologist.

Why die? This is a very interesting question. With modern medical technology, some assume humans could ultimately live forever. One might ask why we would want to endure such an eternity, a fate my vampire "relatives" face (you have noted my fangs, haven't you?). Some species, like the bristlecone pines, may live thousands of years. But why is it that ultimately all individuals die? Here I'll speak as a biologist rather than from a philosophical or spiritual perspective.

While many evolutionarily "primitive" species reproduce asexually, most species including vertebrates reproduce sexually. The benefit of sexual reproduction is that it allows the recombination of our genetic material into new variations (a form of biodiversity). We all know we humans, like other species that reproduce sexually, receive half our genes from our mother and half from our father (or maybe the milkman... remember those days?). That means that we differ significantly from each of our parents, and most likely from our siblings as well. So each generation produces new genetic combinations, then eventually dies to avoid over-population and outstripping of their resources.

Genetic recombination is a good thing. It creates greater biodiversity within a species' gene pool. Why is this beneficial? It means there are more variants within the human (or other) population to cope with changes in the environment and other dynamics within our habitats. The more variation present in a period of changing conditions, the greater the chance that some will be adapted to adjust to those changes. Of course in the human species, we modify our environments through the construction of shelters with heating and cooling systems. Other species are not so lucky and must accommodate to outside changes or die.

Of course if we wanted the maximum diversity in a population, it might be best for all individuals to live very long lives. Yet each species appears to be genetically programmed to self-destruct within a given span. For some it is immediately after they reproduce. Humans are more fortunate- most survive well after their peak reproductive period. Perhaps this is related to our need to raise our children for a minimum of two decades, or to our ability to contribute to the next generation's survival by teaching them learned behaviors based on our own experience.

However, most evolutionarily advanced species do not survive long into "old age." If so, their populations might quickly outstrip their resources (as I fear ours is now). For many of these species, death comes not from genetic programming and "old age." Instead they are eaten and the surplus population serves as food to sustain the entire ecosystem. The lush kelp forests are beginning to die back as water temperatures increase, and become a rich food supply. The eggs, planktonic larvae and young produced by most marine life out there also become a smorgasbord to nourish other species. I'm sure glad we're at the "top" end of the food chain, aren't you?

Well, it's been 10 years since I've been back in Boston. Sure will be good to discover whatever happened to some of my classmates like Al Gore and Tommy Lee Jones. I never thought they'd amount to much back then either. Why all Al wanted to do was shake hands with classmates and Tommy Lee, if he wasn't playing football, was looking forward to his first role in "Love Story." Hopefully when I return, conditions in the park will have improved. We don't need another summer like the last one.

© 2004 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays.

Poor visibility in the dive park, or why I'm writing about philosophical questions this week.

This document maintained by Dr. Bill Bushing.
Material © 2004 Star Thrower Educational Multimedia