Evolution - in general, and human intelligence

The pain having subsided, I can get back to re-reading Carl Sagan's The Dragons of Eden. This book was, in the late 1970's, America's most entertaining and acclaimed best seller. The Chicago Tribune hailed it as "A powerful and compelling voyage to the inner space between your ears, it will leave the reader exhilarated and tingling.... a masterpiece.", while the New York Times heralded it as "A history of the human brain from the Big Bang, 15 billion years ago, to the day before yesterday." By today's standards, it is "Old news", yet it still remains a tribute to Sagan's brilliance and skill, even after all these decades. It continues to be an interesting look into the evolution of our brains.

Sagan and I disagree on certain things, mainly that certain theropods were still limited in cognitive functioning and reasoning. I do understand that this book was written during a time before we had gained much insight into dinosaur intelligence, as species such as the Velociraptor had not been unearthed yet (and notable paleontologists such as Dr. Robert Bakker, were just beginning to undertake the seemingly impossible task of changing the way dinosaurs were viewed by the scientific community.) Sagan is spot on with his graphs and charts, and he did leave an opening by which we could apply his theories to recent dinosaur findings.

Many people argue over the possibility of evolution, concentrating upon Darwin as the root of all evil. I find this irksome. While they accept the basis of DNA, they seem to almost fear the possibilities of the earth being more than a few thousand years old. Some people refuse to accept that we belong to any taxa at all; man is not a species related to primates. I have encountered some people who refuse to believe we are even mammals. This leads me to wonder, of course, if they are capable of appreciating the fact that the Creator (God) is not a dumbass. Seriously. It would be all too easy to "poof" something into being, were you a powerful being yourself. To create something (from nothing)that is sound within the ecology you provide for it, you must put a great amount of thought into how that creature will function within its environment. In the words of Michael Crichton, noted author of Congo and Jurassic Park, "Life finds a way."

Life on this planet changes (or adapts) as the environment changes (or adapts). Evolution of a species occurs when a life form changes significantly enough to be unique to its species. A tiger and a lion are of the same line, yet a tiger evolved stripes while a lion's coat is brown; both evolutionary adaptations which help conceal these carnivores as they hunt prey - an example of microevolution (adaptation.) Animals that become extinct are ones that fail to adapt. The Smilodon, for example, did not evolve into our modern puma, although there are many similarities. Darwin's studies of species of finch, and his notations on their beaks and plumage, is simply a means of discussing progression of species isolated by locality. Microevolution is nothing more than changes on a small level between species.

In evolutionary biology today, macroevolution is used to refer to any evolutionary change at or above the level of species. It means the splitting of a species into two (speciation, or cladogenesis, from the Greek meaning "the origin of a branch") or the change of a species over time into another (anagenesis, not nowadays generally used). Any changes that occur at higher levels, such as the evolution of new families, phyla or genera, is also therefore macroevolution, but the term is not restricted to the origin of those higher taxa.

Microevolution refers to any evolutionary change below the level of species, and refers to changes in the frequency within a population or a species of its alleles (alternative genes) and their effects on the form, or phenotype, of organisms that make up that population or species.

Another way to state the difference is that macroevolution is between-species evolution of genes and microevolution is within-species evolution of genes.
There are various kinds of dynamics of macroevolution. Punctuated equilibrium theory proposes that once species have originated, and adapted to the new ecological niches in which they find themselves, they tend to stay pretty much as they are for the rest of their existence. Phyletic gradualism suggests that species continue to adapt to new challenges over the course of their history. Species selection and species sorting theories claim that there are macroevolutionary processes going on that make it more or less likely that certain species will exist for very long before becoming extinct, in a kind of parallel to what happens to genes in microevolution.

I hope this helps clear up the misunderstands of what evolution is. Back to Sagan...

Sagan puts forth his speculation on the evolution of human intelligence. He delves into the brain mass to body weight ratios, as well as known brain mapping at the time. You see, we are at a constant state of adaptation. It is plausible to consider that most evolution occurs because of select breeding. For example, giraffes (a tried and true standby in these debates.) Giraffes with longer necks could perform better courtship displays. The length of the neck also aided in reaching food. Females began to choose males based on not only their health, but on their ability to display. The gene for the long neck became dominant, while the gene for the shorter neck became recessive. Over time, giraffes were being born with longer and longer necks, until they are the creatures we know and love today. Now, I won't go into all that Sagan covers as far as human beings go, but his theories as to how our own intelligence developed still, to this day, stand out as being not only plausible but also practical. Over time, we traded our instincts for intellect, sacrificing our parental freedom for a more lengthy period where we raise our young. We are hardwired for certain behaviors, being primates, but we also put forth great efforts into teaching our young. We have a strong language based form of communication, and we are tool users. These things are not instinctual.

I do not presume Adam (the first man, according to the bible) to have been a blithering idiot, for that would make God a blithering idiot. I do put forth that Adam may have been the 'unknown' ancestor who "did it all". Have you ever read Watership Down by Richard Adams? It contains small stories that the rabbits tell each other to pass the time. All of these tales center around the first rabbit, El-ahrairah, who is the equivalent of our "Adam". El-ahrairah has done it all, been the most clever, and his knowledge is what made rabbits so strong today. At the end of Watership Down, a doe is telling her kits a story about El-ahrairah, yet her tale is not of the "Adam" of their distant past; it is the tale of Hazel, the rabbit hero of the book Watership Down, who leads this doe's mother and other rabbits out of does out of Effrafa - only it is not Hazel the doe tells about, but El-ahrairah substituted in Hazel's place.

The same may have been true of our own Adam. Adam may have been the star of the beginning of Genesis simply because all the people after him looked upon him as their leader, the first man to have lead them out of the Garden of Eden. (Put down your pitchforks; I am simply tossing out thoughts about Adam in general, with no attempt being made to discredit the story of Genesis.) Actually were it not for evolution, we would all still look like Adam, right down to our eye color and nose shape.

At any rate, intelligence in life forms began to evolve long before Adam ever set foot on a blade of grass in Eden. I do not believe the earth was created in a period of seven 24-hour days. Would God have chosen that method, life on the planet would have self-destructed after the first five. To believe in a pure 24-hour day time table, we would need to discount all dinosaurs, all plants which became extinct prior to Adam's first day, and all record of prehistoric time. Gone also would be the belief in DNA (deoxyribonucleic acid), which is the building block of life - it is the very thing which ties us (all life on earth) together in an evolutionary fashion. We are certainly more intelligent than an amoeba or tapeworm. Sagan, in his book, explains how our intelligence evolved, but more importantly, he explains why our intelligence evolved.

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