Why do I believe in Evolution?

	Quote:
	If you believe you haven't evolved. Then perhaps your are right. You haven´t evolved yet.

I Am Evolution /Written by Holly Dunsworth (Paleoanthropologist)

I believe evolution. It's easy. It's my life. I'm a paleoanthropologist. I study fossils of humans, apes and monkeys, and I teach college students about their place in nature.

Of course I believe evolution.

But that is different from believing in evolution.

To believe in something takes faith, trust, effort, strength. I need none of these things to believe evolution. It just is. My health is better because of medical research based on evolution. My genetic code is practically the same as a chimpanzee's. My bipedal feet walk on an earth full of fossil missing links. And when my feet tire, those fossils fuel my car.

To believe in something also implies hope. Hope of happiness, reward, forgiveness, eternal life. There is no hope wrapped up in my belief. Unless you count the hope that one day I'll discover the most beautifully complete fossil human skeleton ever found, with a label attached saying exactly what species it belonged to, what food it ate, how much it hunted, if it could speak, if it could laugh, if it could love and if it could throw a curveball. But this fantasy is not why I believe evolution — as if evolution is something I hope comes true.

After all the backyard bone collecting I did as a child, I managed to carve out a career where I get to ask the ultimate question on a daily basis: "Where did I come from and how?"

If our beliefs are important enough, we live our lives in service to them. That's how I feel about evolution. My role as a female Homo sapiens is to return each summer to Kenya, dig up fossils, and piece together our evolutionary history. Scanning the ground for weeks, hoping to find a single molar, or gouging out the side of a hill, one bucket of dirt at a time, I'm always in search of answers to questions shared by the whole human species. The experience deepens my understanding not just about what drives my life, but all our lives, where we came from. And the deeper I go, the more I understand that everything is connected. A bullfrog to a gorilla, a hummingbird to me, to you.

My belief is not immutable. It is constantly evolving with accumulating evidence, new knowledge and breakthrough discoveries. For example, within my lifetime, our history has expanded from being rooted 3 million years ago with the famous Lucy skeleton, to actually beginning over 6 million years ago with a cranium from Chad. The metamorphic nature of my belief is not at all like a traditional religious one; it's more like seeing is believing.

So I believe evolution.

I feel it. I breathe it. I listen to evolution, I observe it and I do evolution. I write, study, analyze, scrutinize and collect evolution. I am evolution.
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How do genes tell the story of our ancient ancestors' migrations?
When DNA is passed from one generation to the next, most of it is mixed by the processes that make each person unique from his or her parents. Some special pieces of DNA, however, remain virtually unaltered as they pass from parent to child. One of these pieces is carried by the Y chromosome, which is passed only from father to son. The other, mitochondrial DNA (mtDNA), is passed (with few exceptions) only from mother to child. Since the DNA in the Y chromosome does not mix with other DNA, it is like a genetic surname that allows men to trace their paternal lineages back through time. Similarly, mtDNA allows both men and women to trace their maternal lineages.

Both the Y chromosome DNA and mtDNA are subject to occasional harmless mutations that become inheritable genetic markers. After several generations, a particular genetic marker is carried by almost all male and female inhabitants of the region in which it arose. When people leave that region, they carry the marker with them. By studying the genes of many different indigenous populations, scientists can trace when and where a particular marker arose. Each marker contained in a person’s DNA represents a location and migration pattern of that person’s ancient ancestors.

For example, roughly 70% of English men, 95% of Spanish men, and 95% of Irish men have a distinctive Y-chromosome mutation known as M173. The distribution of people with this mutation, in conjunction with other DNA analysis, indicates that they moved north out of Spain into England and Ireland at the end of the last ice age.

Are Neanderthals part of modern human ancestry?
Neanderthals inhabited Europe and parts of western Asia starting about 230,000 years ago. They cohabited with modern humans for thousands of years before becoming extinct about 29,000 years ago. Since 1999, several DNA samples have been extracted from Neanderthal fossils and sequenced, allowing scientists to compare large sections of the Neanderthal genome with that of modern humans. This is possible because DNA fragments can survive for 50,000 to 100,000 years.

Neanderthal DNA sequences were found to be about 99.5% similar to the modern human genome, indicating that modern humans and Neanderthals had a common ancestor about 700,000 years ago. The genetic difference between Neanderthals and modern humans, however, was on average about three times greater than the genetic difference between any two modern humans. Studies of the mtDNA of nearly 80,000 people found no traces of mutations known to be common in Neanderthal mtDNA. These differences indicate no significant interbreeding between Neanderthals and modern humans after the two species diverged.
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Hominid Species
Sahelanthropus tchadensis
Orrorin tugenensis
Ardipithecus ramidus
Australopithecus anamensis
Australopithecus afarensis
Kenyanthropus platyops
Australopithecus africanus
Australopithecus garhi
Australopithecus aethiopicus
Australopithecus robustus
Australopithecus boisei
Homo habilis
Homo georgicus
Homo erectus
Homo ergaster
Homo antecessor
Homo heidelbergensis
Homo neanderthalensis
Homo floresiensis (New)
Homo sapiens sapiens