Your Inner Fish - Neil Shubin

A Journey into the 3.5 Billion History of the Human Body

My post of Jan.14, 2008 is an excerpt from the final chapter and it was this passage that whetted my appetite to read the entire book.

Science buffs up on their paleontology will recognize author Shubin as one of a team that, investigating a quarry of 375 million old rocks on Canada’s Ellesmere Island, discovered the famous fossil Tiktaalik, an intermediate species between fish and land mammals

Like a fish, Tiktaalik has scales on its back and fins with webbing, but like the early land living mammals, has a flat head and a neck. Inside the webbed fin are bones that correspond to the upper arm, the forearm and parts of the wrist. Further study of the joints revealed an extraordinary function – it was capable of doing push-ups.

Thus, Shubin introduces us to the remarkable origins of the human body.

Combining DNA studies with genetics and paleontology reveals the connections between human anatomy and that of early, very early, life on earth.

The findings are remarkable.

All appendages, fins or limbs, are built by similar kinds of genes. The evolutionary transition from fin to limb did not require new DNA but rather used ancient genes in new ways to make limbs with fingers and toes.

The biological processes that make all the structures that develop within the skin: scales, hair, feathers, teeth, sweat glands, even mammary glands are all versions of the same thing, the interaction of two layers of tissue in the developing skin.

The basic structures of our head can be traced back to worms, organisms that do not even have a head.

Shubin goes on to describe the development of our eyes and ears and the gradual loss of our sense of smell.

“All animals are the same but different. Like a cake recipe passed down from generation to generation – with enhancements to the cake in each – the recipe that builds our bodies has been passed down, and modified, for eons. We may not look much like sea anemones and jellyfish, but the recipe that builds us is a more intricate version of the one that builds them.”

As an added attraction he explains a simple way to extract DNA from plant or animal bodies, peas, steak or chicken, in the kitchen.

Shubin is one of those rare species, an academic who can write for the rest of the world. His humour and obvious enthusiasm for his subject are infectious, making this book a pleasure to read although a little work is required to grasp some of the science.