Human Evolution

No other area of evolution has more denial than that of human beings. Most people don't like the idea that we came from 'monkeys' which happens to be a very large misconception. We did not evolve from monkeys, we merely had a common ancestor when our species diverged millions of years ago. No longer is the notion of ape-man. The evidence being brought these days is stagering that indeed we did come out of central Africa.

Lucy just isn't the lone fossil anymore. There are now over 4,000 hominid fossils that have been found (Lubenow 1992). Of those, about 150 are Homo Erectus, 90 Australopithecus robustus, 150 Australopithecus afarensis, and 500 Neanderthals. That is as of 1999, if anyone has a more updated count please let me know. Then, just recently in 2009, Ardi Ardipithecus ramidus was found, a hominid species from 4.4 milllion years ago.

I was originally going to lay out all the evidence in this post but I figured people like visual evidence, not something that's explained out to them. It needs to be real in their eyes. Also, the videos at the bottom in my opinion did such a wonderful job at showing the transitions of hominid species. Make no mistake about it. Human evolution is alive.

Here is a figure showing many of the hominid skull fossils that have been found. There has been many many more fossils found recently along with complete skeletons that are not shown in the diagram. The first skull is that of a chimpanzee (A), our closest living relative, for comparison. Notice how as time goes on, the frontal lobe starts to increase in size, giving rise to a larger pre-frontal cortex which is responsible for planning, decision making, and higher order thoughts.

(A) Pan troglodytes, chimpanzee, modern
(B) Australopithecus africanus, 2.6 Million Years
(C) Australopithecus africanus, 2.5 Million Years

(D) Homo habilis, 1.9 Million Years

(E) Homo habilis, 1.8 Million Years

(F) Homo rudolfensis, 1.8 Million Years

(G) Homo erectus, 1.75 Million Years

(H) Homo ergaster, 1.75 Million Years

(I) Homo heidelbergensis, 300,000 - 125,000 Years

(J) Homo neanderthalensis, 70,000 Years

(K) Homo neanderthalensis, 60,000 Years

(L) Homo neanderthalensis, 45,000 Years

(M) Homo sapiens, Cro-Magnon I, 30,000 Years

(N) Homo sapiens, modern

This diagram illustrates which species lived during the same. Whether or not any of these species ever came into contact with each other is still highly debatable and unknown. However there is some minor evidence suggesting that homo sapiens may have made contact with neanderthals. The neanderthals died out about 30,000 years ago from unknown causes.

Here are two very good videos (with lousy music) walking you through each of the many known hominid fossils and showing the transitions. Please watch and enjoy your family history:

Missing Links?

Genetics shows that microevolution is true but it is hard for us to appreciate the whole picture because of our fraction of time spent on this planet in relation to the time needed for large macroevolution changes. Sure we can look at speciation in the lab with bacteria and such but people want to see larger animals, mammals, and humans to be convinced. So, do we have evidence for macroevolution? You betcha! Museums around the world are filled with thousands upon thousand of fossils showing transitional changes. Here is a select few examples showing some of the transitions we understand deeply, including the transition from water to land and from reptiles to mammals.

One of the key points to remember about fossils is that you can make predictions of where in the strata layer you can find a species. For the most part you find oldest layers being at the bottom and younger layers being at the top. And again as a point, no species has ever been found in the wrong strata layer. One way to completely debunk evolution is to find a species in the wrong order. Dawkins says the creationists should be out frantically digging up fossils to find one out of place if they want to hold to their creation and flood myth.

One of the reasons people have a hard time accepting evolution is the transition of species from water onto land. It is now well documented and understood as we now have a good amount of fossils showing the transition. In 2004, Neil Shubin made the critical discovery of the Tiktaalik, being the main transition species between water and land. Shubin was able to make predictions of what strata layer he might find this transitional species based on what layers more fish like species and more tetrapod like species lay in. And anybody could have guessed it, right smack dab in the middle! Tiktaalik's fins had more shoulder, elbow, wrist like features suggesting that it was able to lift it self up out of the water like a push-up. So here is our current understanding of great transition from water to land:

Next up we have the transitional fossils that fill in the gaps between reptiles and mammals. This fossil sequence shows how the reptilian jaw developed into the mammalian ear. Additional evidence has even shown that the same embryonic structures in the reptile also develop into the ear of mammals:

A bit of odd evolutionary history is that modern dolphins porpoises, and whales evolved from land mammals. Another clue was looking at the swimming biomechanics compared to other fish. Most fish have a side to side swimming stroke where as most land animals like otters that enter the water have an up and down swimming stroke. It goes to show that dolphins, porpoises, and whales have an up and down swimming stroke. Even further evidence is the vestigial hind limbs in whales. They still have the genetic code to build hind limbs but the gene is switched off early on leaving small femur like bones that can be seen on any whale fossil.

Was Darwin Wrong?

NO. THE EVIDENCE FOR EVOLUTION IS OVERWHELMING. That was the first line in large print I remember reading in the National Geographic article. Evolution is one of the most solid theories in science. Wait you said theory? Yes that's right, a scientific theory. Creationists love to play the 'just a theory card' when not knowing exactly what theory means. In science, theories are a term and model used to explain a set of facts in their relation to one another. In evolution we have thousands upon thousands of facts that have been observable over history as well as in real time. Evolutionary theory is the term used to describe the vast amount of facts and how the process works. If a college student wanted to study physics, they may have to take an atomic theory class. And just as well, Einstein's general relativity is the theory of gravitation that improved on Newton's theory of gravitation.

"Let me try to make crystal clear what is established beyond reasonable doubt, and what needs further study, about evolution. Evolution as a process that has always gone on in the history of the earth can be doubted only by those who are ignorant of the evidence or are resistant to evidence, owing to emotional blocks or to plain bigotry. By contrast, the mechanisms that bring evolution about certainly need study and clarification. There are no alternatives to evolution as history that can withstand critical examination. Yet we are constantly learning new and important facts about evolutionary mechanisms." - Theodosius Dobzhansky, Biologist. He made this quote in 1973, before the understanding of genetics, hence 'mechanisms that bring evolution about certainly need study and clarification.'

Evolution has stood up in every facet of science including archaeology, biogeography, biology, chemistry, comparative anatomy, embryology, genetics, geology, neuroscience, paleontology, pharmacology, and physics. The key is that many fields came to the same conclusion independently. Here is a brief preview of some of the fields that make up evolution:

• Fossil Record- The weight of the fossil record is twofold. First, you can make predictions on when the species lived and in what strata layer they will show up based on dating techniques. For the record, no fossil has ever been found in the wrong strata layer. Oh and also, the fossils found in the dated strata layer also matches the estimated dating techniques in genetics.
  
• Geographical Distribution- Looks at species distribution and the relationships among species themselves and in relation to geography. So sorry Noah's Ark, your ship didn't sail. Unless you want to claim that when the flood went down, penguins waddled their way to Antarctica.
  
• Domestic Selection- Man has their hand in evolution which has been demonstrated and documented in dog and pigeon breeding as well in the lab with everything from bacteria to flies.
  
• Genetics- Every creationists nightmare. Genetics essentially put the proof in the pudding for the evidence of evolution. Even showing that natural selection does indeed work. Dawkins claimed that the one observation to refute creationism was the pattern of resemblances you see when you compare the genes, using modern DNA techniques, of any pair of animals and form a perfect family tree.
• Development & Embryology- The study of the similarities between species during embryo development. Darwin originally made observations of this field in his 1859 publication, On the Origin of Species. It has gained recent popularity and is now dubbed Evolutionary Development or Evo-Devo.

In the coming posts I will lay out the evidence supporting each of these claims.

"Even as the evolution wars rage, on school boards and in courtrooms, biologists continue to accumulate empirical data supporting Darwinian theory."

- Wall Street Journal, April 7, 2006