Living things are amazingly complex and refined organisms. Contained within our skin are muscles, organs, a nervous system, a circulatory system, an immune system, a digestive system, a reproductive system, a repair system, a growth system, and perhaps the most complex of all, a brain.
We are amazed and baffled by the latest smartphones and tablets, yet they are incredibly primitive compared with the brain. Research has shown that there are more switches in a single brain than in the entire internet! (http://www.cnet.com/news/human-brain-has-more-switches-than-all-computers-on-earth/ )
Yet all the complexity of the human body grows from a single cell.
One cell divides into two, then four, then eight. On and on, dividing, specialising, growing and dying in a precise order to gradually construct the fully grown human being. And the developing body self-programs the control systems and brain in a robust and repeatable process.
How can such a robust process happen? Where are the instructions to tell the cells what to do? Is it in the DNA?
There are 3 billion base pairs in human DNA. Is it really possible that all the information necessary to grow and operate fifty trillion different cells over the entire lifespan of a human is fully encoded in the DNA of the original single cell? Even if we used one base pair to define the position of each cell we are 10,000 times too short of information carrying capacity in the DNA.
But it’s worse than that. In the DNA base pair system of numbering the letters CAGT are equivalent to numbers in base 4. In base 10, the number fifty trillion (50,000,000,000,000) uses eleven characters, but in base 4 we would need 23 characters. Our 3,000,000,000 DNA base pairs can only now specify 150,000,000 positions – 300,000 times less than we need just to define the position of each cell.
In addition to the position and type of cell, we are asking the DNA to carry the information to define the construction sequence and to program all of our behaviour patterns, our “operating system.”
What are the chances of that? Yet it happens. Humans grow from a single cell every day. Billions of us.
This sort of mathematics is often applied to the beginning of life, and show that the odds of forming even the simplest protein by chance are like looking for a single molecule in the whole mass of the earth. Yet it happened.
And how likely is the evolutionary process? In their book The Origins of Life the authors John Maynard Smith and Eörs Szathmáry identify a number of what they call “Major Transitions” without which we would not exist such as:
- From replicating molecules to populations of molecules in compartments
- From independent replicators to chromosomes
- From RNA as gene and enzyme to DNA as gene and protein as enzyme
- From bacterial cells (prokaryotes) to cells with nuclei and organelles (eukaryotes)
- From asexual clones to sexual populations
- From single-celled organisms to animals, plants and fungi
What are the chances of that? Yet it happened.
Here is a summary of the history of the earth and life on earth:
13.8 billion years ago: universe created
13.5 billion years ago: first stars form
5 billion years ago: the Sun forms, perhaps as a second or third generation star.
4.5 billion years ago: The earth formed as a molten mass. For the next 700 million years it was probably bombarded by large objects, and the energy of the collisions probably kept the earth molten up until…
3.8 billion years ago: earth crust solidified. Manufacture of pre-biotic chemicals needed for the life to exist
3.5 billion years ago: fossil evidence of cellular cyanobacteria. .
1.5 billion years ago: first eukaryotic cells (cells with a nucleus) evident
1 billion years ago: first metaphytes (multicellular algae and higher plants)
500 million years ago: first metazoans (invertebrate and vertebrate animals)
1/4 million years ago: first homo-sapiens
Let’s put the evolutionary timeline into perspective of number of generations:
Bacteria typically reproduce every hour, so in the 3.5 billion years since cyanobacteria first emerged there have been about 35 trillion generations, although there seems to have been little evolutionary change in the 2 billion years before the first cells with a nucleus appeared.
Animals first emerged around 500 million years ago, and with a typical generation of 2 years implying around 250 million generations to move from the first animals to one with all of the complexity that we see in a human.
Against this backdrop, the evolutionary process has been incredibly fast; remember the extremely complex product that it has developed. Yet it happened.
There are those who claim that all this happened as a result of sheer luck.
There are others for whom the following text seems to better describe things:
You made all the delicate, inner parts of my body and knit me together in my mother’s womb. Thank you for making me so wonderfully complex! Your workmanship is marvellous—how well I know it. You watched me as I was being formed in utter seclusion, as I was woven together in the dark of the womb.
For me, the findings of science hint strongly at a God who is continuously engaged in sustaining and interacting with the universe and life that he brought into being. I find this fully consistent with the God that is revealed through a reasoned understanding of the Bible and demonstrated through the life of Christ. I accept that it is not indisputably demonstrated, but I find the evidence sufficiently convincing to give my life as a result.
These issues are explored more fully in The Big Picture