One of the most controversial subjects in religion today is evolution. While some enlightened religions (Buddhism, Judaism, Hinduism, and some liberal Protestant religions) have little difficulty accepting the scientific consensus on human evolution, most religions either reject evolution out-right, or else qualify their acceptance of evolution as being directed by God. However, this is not evolution; it's Intelligent Design or creationism pseudoscience.
Mormons have an especially difficult time accepting evolution: only 22% of Mormons agree that "evolution is best explanation for the origins of human life on earth." Mormons are even more skeptical than Evangelicals who believe the Bible is inerrant and literal.
Why are Mormons so skeptical of evolution?
1. Evolution contradicts LDS scriptures and official (and unofficial) statements by LDS leaders:
See the Church's official website for an broad overview of the current LDS position. What becomes clear by reading official LDS scriptures, First Presidency declarations, General Conference talks, Ensign articles, and LDS lesson manuals - is that Mormons believe the creation was an event caused and controlled by God, that humans are the offspring of God, and that we were literally created in God's image.
However, Darwin's theory of evolution by natural selection explains the origin of man in natural terms; no God required. Therefore invoking a God is unnecessary and superfluous. Using God to try and explain human origins is like trying to explain the theory of gravity in theistic terms. Gravity, like evolution, has no need to invoke God as a causal agent since it operates all by itself. We don't need to invoke a supernatural explanation when a purely natural one will do - even if it leaves God with nothing to do. Mormonism - through scripture and prophetic leaders - has repeatedly invoked God as our creator. Now, after scientists have explained the one-time-mystery of human origins, it's hard for Mormons to leave God out of the picture. Doing so would challenge the very core of Mormon authority: revelation. Also, if God didn't create us, then what obligation do we have to Him? The myth of creation is weaved into the fabric of our doctrine so intimately and so literally, that pulling out that thread would destroy it.
2. Evolution contradicts core LDS doctrine:
The "three-pillars" of Mormon doctrine are the Creation, the Fall, and the Atonement. Mormon faith rests on the validity of each of these doctrines. Without one of these pillars of belief, the entire Mormon worldview collapses. Joseph Fielding Smith said:
... the doctrine [of evolution] is so incompatible, so utterly out of harmony, with the revelations of the Lord that a man just cannot believe in both ... I say most emphatically, you cannot believe in this theory of the origin of man, and at the same time accept the plan of salvation . . . You must choose the one and reject the other, for they are in direct conflict and there is a gulf separating them which is so great that it cannot be bridged. . . for, according to this theory, death had always been in the world. If, therefore, there was no fall, there was no need of an atonement, hence the coming into the world of the Son of God as the Savior of the world is a contradiction, a thing impossible. Are you prepared to believe such a thing as that? (Joseph Fielding Smith, Doctrines of Salvation 1:141-142, quoted in Old Testament Student Manual for Genesis - 2 Samuel, page 34.)Therefore, evolution not only destroys the doctrine of the Creation, but also the doctrine of the Fall and the Atonement. If there was no need for Adam to "fall" in order to introduce reproduction and death into the world (since birth and death had been going on for billions of years prior to Adam), then there would be no need for Jesus to redeem mankind from the fall. No creation - no Adam; no Adam - no Jesus; no Jesus - no true Church of Jesus Christ.
3. Evolution contradicts Mormon belief in the nature of God:
Mormons believe God is an evolved man; an advanced superhuman from another planet. In his King Follett Sermon, Joseph Smith said "What sort of a being was God in the beginning? . . . God himself was once as we are now, and is an exalted man, and sits enthroned in yonder heavens! That is the great secret." It was President Lorenzo Snow who coined the famous couplet "As man now is, God once was; as God is now man may become."
So, according to LDS doctrine, God is clearly a human male. However, evolution shows how Homo sapiens shared a common ancestor with both common chimpanzees and bonobo chimpanzees only 7 million years ago. Given our recent common ancestry, we share an amazing 98.4% of our DNA in common with chimps. The genetic difference between humans and chimpanzees (1.6% of our DNA) is barely double that separating bonobo chimps with common chimps (0.7%). In fact, our genetic difference from chimps is less than that separating chimps from gorillas! Put another way, chimpanzees closest relative is not gorillas, but humans. Human DNA differs from gorilla DNA by only 2.3% (with whom we shared a common evolutionary ancestor 10 million years ago), and we differ from orangutans in only 3.6% of our DNA (since we diverged from orangutans between twelve and sixteen million years ago). To further put our similarities with chimps in perspective, consider that the human hemoglobin molecule - a protein that transports oxygen to every cell in our bodies - is absolutely identical in all of its 287 units with chimpanzee hemoglobin. What is good enough for chimps is good enough for humans.
The remaining 1.6% of human DNA, that differs from chimpanzees, accounts for all the obvious differences between our closest primate relatives. And much of that small 1.6% difference is accounted by "junk DNA." Junk DNA - what the majority of our DNA is actually composed of - is noncoding "garbage" segments of DNA, leftover from our evolutionary past, that don't really do anything at all other than tag along for the ride. Junk DNA just gets copied along with the rest of our genes, but doesn't get translated into proteins.
Even more similar to humans are the now extinct hominid species. In fact, leading up to the origin of modern day Homo sapiens about 500,000 years ago in Africa, there were about 25 different human prototype species (like Australopithecus robustus, Australopithecus africanus, Homo habilis, and Homo erectus). Now, our human-like relatives are all extinct. But about 400,000 years ago, we shared a common ancestor with Neanderthals. And between 80,000 and 40,000 years ago, modern looking humans even lived alongside and even interbred with Neanderthals. Sounds shocking, but scientists discovered in 2010 that 1 - 4% of our DNA comes from Neanderthals. In fact, Neanderthal DNA and human DNA is 99.7% similar. Our DNA is so similar that they could apparently even interbred with each other (which is what defines what a species is).
What are the implications of these biological facts on LDS theology? Well, if man is created in God's image, and God is the same species as we are (a Homo sapien who literally reproduced with Mary to sire Jesus - his only begotten son) then does God also share 98.6% of his genome with chimps? Does God also share 99.7% of his DNA with Neanderthals? Does God also have all the same "junk DNA" in his chromosome as well - mutations and all? Did he also evolve from 25 different prototype hominid species like we did? Is God a hairless ape like we are?
Does He have all the imperfections and faulty designs in His supposedly perfect body that humans do? For example, does God have a blind spot in his vision because there is a big optical nerve in the middle of his retina, are his eyes built inside out and backwards like ours, or does he have a right recurrent laryngeal nerve that (like all mammals with this design flaw) loops worthlessly and wastefully around our aortic arch? Does God have vestigial features (leftover, but now worthless, organs from our evolutionary past) like an appendix, nipples, body hair, and toenails? Does God have a limited brain like we do? Although slightly crude, we shouldn't hesitate to ask if God has an anatomically complete reproductive system? Does he have an entire digestive system; mouth, esophagus, stomach, duodenum, and anus? If so, does it work - end products and all? If not, then what is in God's abdomen? Does God's skeletal system share the same limb homology with other mammals, birds, frogs and lizards?
The story of evolution is told by our physical bodies - from our DNA to our anatomic appearance so similar to the other great apes. As Jared Diamond argues so eloquently in his book, we are "the third chimpanzee." But according to LDS theology, that would make God an ape, which is an absurd notion for God. I really like apes, but feel no need to worship one.
4. Evolution contradicts the doctrine that God is all-loving, all-powerful, and all-knowing:
In order for species to evolve they have to outproduce other species. This always involves the production of more offspring than will survive long enough to reproduce. Only the animals that don’t die of disease, starvation, or being eaten alive while young can survive long enough to pass on their genes. Random mutations that assist in passing on genes more successfully will be passed on. Genetic changes that decrease evolutionary fitness do not. And the genetic changes that improve evolutionary fitness are usually things that help help one carnivorous species kill and eat another, or things that help the hunted animal avoid being eaten. Over 99% of all species that have ever lived were so unsuccessful at living that they all died out. Not a single one of them is left alive today. Extinction is never a pretty picture for the species involved. What kind of loving parent would use such method of creation?
Why would God go to all the work to create a species if He is going to eventually annihilate it? If God was all knowing, why would he employ so much suffering and waste in the process of creating man? An all-loving God would not choose to hash out so much death, cruelty, and suffering on his creations. Would any kind of moral human create life simply to kill it in the most cruel ways? An all-knowing God would have known how inefficient and cruel the process of evolution was, and refused to employ it like some kind of mad-scientist sowing suffering and destruction all around him. And an all-powerful God could have chosen to create life in another way - perhaps with the snap of his almighty fingers if He wanted to, or in a way that was not so wasteful and cruel to his creations.
Mormons are skeptical of evolution because their scriptures and leaders have said repeatedly that it is incompatible with a Creator-God, evolution nullifies the need for Adam's fall and Christ's atonement, evolution implies that God is an evolved ape like humans, and evolution is a cruel and inefficient process that is incompatible with an all-loving, omniscient, and omnipotent God. In short, accepting evolution fully (which is the only way to accept it) threatens to destroy a literalist view of Mormon doctrine and theology. Therefore, it's an extremely dangerous idea to Mormonism. That, to answer the original question, is why Mormons are so skeptical of evolution.
When Napoleon asked Pierre-Simon Laplace why he had not included God in his explanation of the variations in the orbits of Saturn and Jupiter, Laplace is purported to have said "I have no need of that hypothesis." Just as physicists like Laplace don't need to invoke God to explain the orbits of planets, biologists today don't need to invoke God to explain the origin of humans. A natural explanation of our origins does the job more parsimoniously without the need to invent a capricious, cruel, human-like God (evolutionary warts and all) who did it. Today, we simply have no need of the creator God-hypothesis.