Obviously, the scientists in my family go WAY back. This newspaper ad, (circa late 1800s), features my great-great- grandfather, Stephen Kellogg. Professor Kellogg, that is: a “scientific masseur” and “suggestive therapeutist”. Family lore is that his wife subsequently left him, not keen on the idea of her husband seeing the local townswomen in various stages of massage-necessitated undress (not to mention the wide possibilities of suggestions in “suggestive therapy”).
The “professor” is an interesting bud on my family tree. And branching off all around him are greats and greats of aunts, uncles, and cousins. My family tree tells me that I descended from the illustrious Professor Kellogg – he is my ancestor, I am his direct descendant. All the aunts, uncles, and cousins many times removed are my relatives, some more closely related than others. They are my relatives, but not my ancestors.
Our Common Ancestor
“If we came from monkeys, why are there still monkeys?”
A Twitter feed I follow called “Take That Darwin” trolls the twitterverse daily and retweets all the variations of the “why are there still monkeys” meme along with snarky responses (“Wow! Have scientists never thought of that??”). Irritainment, I know.
Short answer – people did not “come from” monkeys. Monkeys are still around because monkeys did not “change into” humans.
However, humans share a common ancestor with the great apes, specifically chimpanzees and bonobos. Genetic analysis estimates that the last common ancestor of humans and chimpanzees lived between eight million and five million years ago. After that, the family tree branched off in different directions – modern apes preceded by their (now extinct) ancestors as well as great aunts and uncles and cousins; modern humans preceded by their (now extinct) ancestors as well as great aunts and uncles and cousins.
Family Tree or Family Bush?
Until the late 1990s, the record of human history was fairly straightforward. The human family tree was scraggly – basically just a trunk and one or two branches. Here’s what we thought: about 4.4 million years ago, the very first hominins (the science word for humans and their ancestors) appeared in east Africa. The most famous early hominin is “Lucy” (her science name is Australopithecus).
About 2.2 million years ago, our genus, Homo, appeared. About one million years ago, members of Homo left Africa and moved into Asia. Separated from their kin in Africa, a new species of Homo arose in Asia called Homo erectus. Homo erectus moved into Europe and became Homo neanderthalensis (the Neanderthals).
These two Homo species thrived for hundreds of thousands of years until a new species of Homo charged out of Africa and took the planet by storm. The new kids on the block were us – modern humans – Homo sapiens. We were so good and smart and talented and verbal we out-competed or killed off all other Homo species until we were the last group standing, approximately 30,000 years ago.
Or so we thought.
Turns out, the human family tree is a bit bushier – not quite the straight shot we once thought from Lucy to Homo erectus to Neanderthals to us. Over the last several decades, a wealth of new fossil finds has changed the picture.
In addition, evidence from genetic studies has fine-tuned it all. (Side note: it is hard to overstate the impact of modern genetics on evolutionary biology – it is the smoking gun of evidence predicted by the fossil record.)
Evidence now indicates that some of the early hominins left Africa thousands of years before Homo, but died out.
There is also evidence that for several thousand years, our direct ancestors shared the planet with some of our close relatives (other hominins) who were not in our direct lineage – hominin aunts, uncles, and cousins, so to speak. These hominin aunts, uncles, and cousins eventually went extinct, with modern humans the lone survivors.
Recent discoveries also indicate that modern humans were emerging, filling Africa, and migrating out of Africa during a time of climate changes, specifically the waxing and waning of ice ages. The superior brains, dexterity, and language of modern humans probably allowed them to survive while earlier humans went extinct.
And it appears there was another reason for the replacement of the Neanderthals by modern humans in Europe: modern humans and Neanderthals interbred. In fact, the genomes of non-African people today are up to 3 percent Neanderthal.
The human family tree is evidently full of branches, all of which eventually came to a dead end except one: Homo sapiens – us.
What Makes Us Special?
Our Skeletons. The human skeleton, unlike the skeleton of the chimp, allows upright posture, walking on two feet, and fine motor coordination. Two characteristics that initially allow scientists to distinguish early human fossils from chimp fossils are found in the skull. In humans, the opening for the spinal cord is forwardly placed, allowing for upright posture.
Teeth are also telling – the canine teeth are small in humans and large in chimps; human teeth are arranged in an arch, chimp teeth are in a rectangular configuration.
Skull and teeth traits emerged early in the hominins, but other traits that are hallmarks of the human body emerged in our forebears piecemeal over millions of years: a large brain, a long flexible thumb, long legs, a short and broad pelvis, a long flexible waist, and low shoulders.
Human femurs (thigh bone) point inward, allowing upright walking; chimp femurs are splayed outward – a sign of a knuckle-walking chimp.
When scientists find fossils with some or all of these traits, they know they’ve found a human or a human relative, not an ape.
Tools: Tool use really took off with the appearance of the genus Homo, but there is evidence that tools were used at least a half a million years before Homo arrived. The Homo groups used fire, clothing, and built shelters. The more sophisticated tools of Homo allowed more efficient hunting and butchering of animals, fueling the growth of a large brain with a protein-rich diet.
But even the large brain in the earlier members of Homo did not result in the success achieved by modern humans.
Symbols. What really made us who we are happened relatively quickly (in evolutionary time). About 100,000 years ago, a Homo group in Africa acquired the ability to use and understand symbols. This unique cognitive ability distinguished Homo sapiens from all other groups. Humans could engage in shared tasks such as hunting big game and building complex societies. They developed language and communicated abstract ideas. Humans are alone in the ability to discern what another person is thinking in order to work toward a shared goal.
So Where’s the Missing Link?
“Scientists have never found the missing link!” is often a throw-down argument used to topple claims of human evolution.
Actually, there isn’t a missing link between apes and humans.
There are multitudes of links. There is a wealth of missing links. The bushy tree of human evolution is full of them.
“Lucy” and her close cousins are excellent examples of the transition from ape to modern human. Lucy’s skull is small and chimp-like, so she had a small brain. But her teeth were more human – small canines with arched tooth rows. In her middle, she was a mixture of ape and human traits. But her lower body was almost modern human.
The fossils that date from the time of Lucy and her cousins to the early Homo groups become less and less ape-like and more and more human-like as they progress to anatomically modern humans.
Answers in Genesis, Ken Ham’s creationist organization and the most prolific producer of young earth, literal seven-day-creation writings, rejects all evidence of human evolution and the existence of any “missing links”. The proof, they say, is not in the fossils, but rather in the “Biblical Worldview”:
Therefore, a now-extinct ape with a unique pelvic anatomical design should not even be considered as a possible missing link. There were none. Anatomical variations do nothing to threaten biblical authority or to support evolution. …Adopting a biblical worldview means accepting God at His word.
A Creating Creation
Accepting the natural history of human beings does not have to threaten faith.
The real threat to faith is equating a “biblical world view” with a 6,000 year-old earth and a literal, historical, and scientific interpretation of the Genesis creation stories.
There is absolutely nothing in evolutionary biology that dismisses God or devalues faith. Charles Darwin recognized that his ideas would be perceived by some to be irreligious and he addressed the religious objections head-on. Why would someone hold religious objections to the origin of man, over time, using natural processes, Darwin asked, but not object to the natural processes that, over time, bring about the birth of a baby?
And God said, “Let the earth bring forth living creatures of each kind, cattle and crawling things and wild beasts of each kind.” And it was so. God made wild beasts of each kind and cattle of every kind and all crawling things on the ground of each kind, and God saw that it was good (Gen. 1:24-25).
In 24, the earth is commanded to “create”. But in 25, it is God who creates. Inconsistent?
Not at all.
Here’s Robert C. Bishop, writing at BioLogos:
…these verses are telling us that God and creation are both at work fulfilling God’s purposes in bringing forth and sustaining living creatures.
In other words, God created a creation capable of creating.
Biologically, we are related to all living things – we are part of one big family tree.
Chemically, we are made of the same stuff as the universe.
Truly, we are creatures of the dust and clay.
And none of that contradicts faith in God. None of it demeans or devalues God – a God who loved his creation so much that he stepped down and became part of his creation, part of the family tree, a creature of the dust and clay. God with us.
The heavens declare the glory of God;
the skies proclaim the work of his hands.
Day after day they pour forth speech;
night after night they reveal knowledge.