Pro-Human Extremist

Extremism in the defense of humanity is no vice

Archive for September 2011

Earth as a tourist destination

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In August, the journal Acta Astronautica published some dark thoughts by scientists at The Pennsylvania State University about what intelligent extraterrestrials might want to do to us if they ever find their way to Earth. This became hot news for a few days. While one can never rule out the possibilities that extraterrestrials might come here to exploit us, I’d like to offer a sunnier alternative.

For several years now, I’ve been convinced that if extraterrestrials ever do visit our dear little planet, it won’t be for conquest but for tourism. Extraterrestrial planetary connoisseurs will, I think, be attracted by Earth’s peculiar mix of water and land masses. They will like how plate tectonics and the geological rock cycle have only very slowly remodeled the surface of our continents, allowing rain and runoff to sculpt it into the many beautiful shapes that we so often take for granted. Their tours will take in the craggy, snow-capped peaks of our high mountain ranges, the broad valleys and deep gorges cut by our rivers, and the shorelines and island chains eroded into so many unique shapes by our oceans’ waves.

Earth will likely be prized for having the right range of temperatures to support water as solid, liquid, and gas—and all three in substantial quantities. Interstellar tourists will watch the calving of icebergs near its poles and then bask in its tropical rainshowers. They will also enjoy the pace of our planet’s cycle of evaporation and condensation, and the speed of our jet streams, which together produce such a diversity of weather patterns and cloud formations. Our sunsets will, I think, be particularly acclaimed.

They will appreciate the diversity of elements in Earth’s crust—a remnant of the long-ago nova of our solar system’s first sun and the subsequent re-aggregation of the matter thrown off by it, to form Earth and the other planets. Having been to other less chemically diverse planets, they will marvel at the range of colors and textures in our planet’s rocks, thanks to the many combinations that can be formed of its various elements.

Needless to say, any extraterrestrials who are able to travel to our planet must have gained so much control over matter and energy that they could engineer other planets to achieve whatever aesthetic effects they desire. But just as we prize natural diamonds over more flawless synthetic diamonds, the more discerning extraterrestrials will prefer the rare idiosyncrasies of naturally occurring planets like Earth.

The beauty of our planet owes much to the plants that cover so much of its landmasses, and to the softening effect they have had on the landscape—turning rocks and gravel into dark, rich soil. Interstellar visitors should enjoy how many of our planet’s photosynthetic organisms are multicellular, and in so many different sizes, shapes, and colors. Even to our Earth-accustomed eyes, the beauty of a landscape so often comes of how a diversity of plants have grown over the attractive shapes of the land itself. I suppose the home planets of our interstellar visitors are likely to have multicellular photosynthetic organisms, but still ours are bound to seem exotic to beings who haven’t grown up here. And the flowers and fruits that we so often take for granted may be unique to our planet’s angiosperms.

The beauty of Earthly scenes is further enlivened by the animals that move over our land, in our waters, and through our air. Terrestrial biped though I am, I’m guessing that Earth’s birds and flying insects will be most celebrated by interstellar visitors, followed closely perhaps by our brightly colored tropical fishes. Mammals may appeal to us humans, but most of them are rather drably colored, and they seldom make themselves as conspicuous to a casual glance as birds do.

The tourism appeal of our planet should benefit from the welcoming service they will get from our species. Once we have gotten over the initial shock of contact, and as we grasp the benefits to us of interacting with so technologically advanced a civilization, I am confident that we will extend the same gracious hospitality to extraterrestrials that people all over the world already do to human tourists. Not having yet encountered any other intelligent lifeforms from other planets, I can of course only offer my own hunches, but I doubt that many others will exhibit so many of the gentle and agreeable emotions that we humans do, or be so well-suited to supporting an interstellar tourism industry. With their vastly more advanced civilization, extraterrestrials will I think be charmed by our simple ways. Those who have come to enjoy visiting Earth will presumably resist any attempts by others to exploit our planet more violently.

I suppose even as beautiful a planet as ours won’t be for everyone. We have evolved on Earth and so are adapted to its particular conditions, and so to us its gravity and air pressure feel just right. Visitors from other mid-sized rocky planets may feel at home, but other extraterrestrials will presumably need technological assistance to feel comfortable here.

The big question will be whether they can tolerate the oxygen gas in our atmosphere. Thanks to the molecular adaptations of our distant single-celled ancestors, our cells produce anti-oxidants that protect us from the toxic oxygen free radicals produced from O2, and the O2 in our atmosphere actually helps in the release of energy from organic molecules. Extraterrestrials from other planets with oxygen-rich atmospheres should have analogous adaptations and so will be fine, but how common are those I wonder? The oxygen gas in our atmosphere has been produced from water molecules through the action of electron transfer systems in photosynthetic organisms. Such biochemical adaptations may evolve often on water-rich planets, in which case interstellar visitors would likely be unharmed by our atmosphere. Otherwise, the tourism potential of Earth would be more limited, as visitors would have to be encased in protective suits and so the experience could hardly be relaxing.

To appreciate the colors of our planet, they will have to be able to sense light in the wavelengths put out by our sun. Depending on what molecules their bodies are made of, they may need to grow their own food or show us how to develop chemically isolate environments in which we can grow their food for them. These and other problems will no doubt have to be solved before our interstellar tourism industry can really take off. But if they are motivated to vacation here, our visitors should take the lead in offering solutions. I just hope I’m here to see it.

© Joel Benington, 2011.

Written by Joel Benington

September 22, 2011 at 7:43 am

The evidence for biological evolution on Earth

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I’m constantly amazed by how many people in the US either reject the idea of biological evolution or have serious reservations. By contrast, in Europe and other countries with developed economies, only a relatively small fraction do. And the mainstream Christian denominations that most Americans belong to all explicitly accept the reality of biological evolution. That includes the Catholic, Episcopalian, Presbyterian, Methodist, Lutheran, and Anglican churches

The simple fact is that there is overwhelming evidence for biological evolution. As the 20th century biologist Theodosius Dobzhansky said (when the evidence for biological evolution was not even as strong as it is today), “Nothing in biology makes sense except in the light of evolution.” If we were compelled to reject the idea of biological evolution, there would be literally thousands of unexplained biological phenomena that currently make perfect sense as consequences of the evolutionary history of life on Earth.

No credible biologist rejects the reality of biological evolution. Even the very few biologists that have signed on to the Intelligent Design movement, like Michael Behe, accept the reality of the vast majority of evolutionary thought, arguing merely that certain biological phenomena cannot be explained by a purely mechanistic process.

When asked to make a quick case for the reality of biological evolution, I like to focus on the evidence for common descent—that all animals including humans have descended from a common ancestor that lived hundreds of millions of years ago, and that animals are likewise related to other groups of living things, with a common ancestor that lived billions of years ago. The evidence for these conclusions includes the following:

All living things use DNA as their genetic material.

The genetic code, determining which three-nucleotide DNA sequences code for which of the 20 amino acids that are used to make proteins, is essentially the same in all living things.

All living things use essentially the same molecular machinery (involving over 100 proteins and other molecules) to synthesize proteins based on DNA sequences.

All living things use ATP and some of the same other molecules as energy carriers.

Many metabolic pathways are shared among all or a considerable fraction of living things. Many enzymes have essentially the same shape and catalyze the same chemical reactions in those pathways in animals, plants, fungi, and other living things.

The cells of all animals (including humans) are made of many of the same components, including their membranes, internal organelles, cytoskeleton, etc. Many of the same proteins are found in these various structures, in animals as diverse as humans and other mammals, fish, birds, worms, and flies. And those proteins interact with each other in many of the same ways in these different animals.

Mammals exist in a wide variety of shapes and sizes, but they all share substantial similarities in their bony structure, internal organs, cell types, and the organization of cells in different tissues.

In other words, though we may be accustomed to thinking of humans as distinct from other animals, on the levels of molecules, organelles, cells, tissues, and organs, there are literally thousands of ways in which our bodies function in essentially the same ways as the bodies of other animals.

Over ¾ of the approximately 22,000 genes in the human genome have specific, one-to-one equivalents in the mouse genome. Also, 90% of the mouse and human genomes can be lined up based on the occurrence of equivalent genes in more or less the same order.

96% of the over 3 billion nucleotides in the DNA sequences of the human and chimpanzee genomes are identical. This includes both functional and non-functional (“junk”) nucleotide sequences, the latter having no identifiable genetic influence on either organism. Similarities in functional DNA might be explained based on similarities in the structure and functioning of  the two species, but similarities in “junk” DNA only make sense if the two species share a recent common ancestor.

The fossil record presents a succession of forms of living things over time that is entirely consistent with evolution of life on Earth over the past 3.5 billion years or so. There are some gaps in this record, but it is far more complete and detailed than one would think after reading creationist literature. Given the thousands of fossil species that have been identified in rocks dating from just a few million years ago to billions of years ago, the chance that a succession of forms consistent with biological evolution would occur by chance is infinitesimally small. For example, even one fossil rabbit or bird in rocks from 500 million, or 1, 2, or 3 billion years ago would be completely inconsistent with an evolutionary process; and yet such inconsistencies are strikingly absent.

There are also many demonstrated cases of natural selection causing evolution among present-day living things. These include the evolution of antibiotic resistant bacteria, experiments in which model organisms like fruit flies and yeast have evolved when placed in new environments, and studies in which populations of organisms are compared in two different environments where different characteristics should be selected for. Creationists, however, discount all of this evidence by supposing that small evolutionary changes do occur as a result of natural selection, but there are limits to how much any given species can change. There is no evidence for such limits—evolutionary changes observed in the present are relatively small only because such small time periods are involved. More dramatic changes in living things typically involve millions to hundreds of millions of years.

© Joel Benington, 2011.

Written by Joel Benington

September 10, 2011 at 7:39 pm

Posted in biology, evolution