feeds from sacw.net
print versionEvolution teaches children that change is an opportunity, erasing it from NCERT textbooks is huge disservice
To deprive students of learning evolution is to deprive them of a powerful
concept that brings great order and coherence to our understanding of life
Partha P Majumder
April 25, 2023
Some extraordinary events in understanding science and imparting science
education have taken place in the last month or so. We have known that our
eye is a complex organ and enables us to see. The quality of life of those
who cannot see is hugely compromised. How did such a complex organ come to be? On April 10, we learnt that a gene donated to us by bacteria has enabled us to see. More about that later.
On April 20, about 2,000 scientists including me, *wrote to the Government
of India to repeal some recommendations of the National Council of Educational Research and Training (NCERT) about high-school science education that have been implemented. The NCERT had recommended in May 2022 some sweeping “rationalisation” of contents of high-school science textbooks, ostensibly to “reduce content load on students” “in view of the Covid-19 pandemic.”
The NCERT had justified the recommendation stating that the National Education Policy 2020 has emphasised “reducing the content load and providing opportunities for experiential learning with a creative mindset.”
Among others, the NCERT’s recommendation included removing nearly all references to concepts and methods for the study of biological evolution, and renaming the chapter on “Heredity and Evolution” as “Heredity.” Interestingly, there were also some recommendations to remove discussions on the eye, vision and our ability to perceive colour. I believe that these recommendations were irrational, and importantly, even though the pandemic has ended, their implementation has not been repealed.
“Experiential learning” is learning based on “experience and observation”. Charles Darwin, the proponent of biological evolution, was a stellar champion of learning by experience and observation. No one can deny that he also taught us how to creatively interpret what we experience and observe. Yet, the NCERT has axed Charles Darwin and evolution.
Back to the eye. How the eye evolved attracted, not surprisingly, the attention of Charles Darwin. In a section titled “Organs of extreme perfection and complication” in his magnum opus On the Origin of Species, Darwin wrote, “To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree.” However, he later wrote in the same section “… if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection … can hardly be considered real.”
The eye collects and focuses light and converts it into an electrical signal which the brain then translates into an image. The retina — inner surface of the wall of an eye — has photoreceptors — light-sensitive cells — that detect light and send signals that carry information to the brain. Vitamin A plays a critical role in the processing of visual signals. Overlying the retina is a thin layer of cells in which a gene that produces the interphotoreceptor retinoid-binding protein, IRBP for short, is expressed. When light strikes a photoreceptor in the retina, vitamin A complexes become shrivelled. The IRBP then helps the complexes to be straightened or shrivelled, restoring normal function.
Without the IRBP, the vertebrate eye would not have vision. On April 10, we learnt that a gene called pepsidase found in bacteria was transferred over 500 million years ago into an ancestor of all living vertebrates. The pepsidase gene underwent some molecular changes resulting in the gene that produces IRBP, a specialised protein that binds to light-sensing molecules.
Thus, we owe to bacteria our ability to see.
Appreciation and unravelling of such interesting facts about development of our abilities, organs and the continuity of life would not be possible if the teaching of evolution in schools is axed. We notice an extraordinary diversity of life forms around us. How did this diversity come about? How can we explain the similarities of organisms? To not allow young children to study evolution is tantamount to constricting their ability to ask relevant questions and to disable them from thinking under a unifying framework to seek answers to relevant questions. Enabling children to learn the concept of evolution goes beyond its power as a scientific explanation.
Today’s children are encountering conditions and facing experiences that are vastly different from those of their parents or teachers. They are finding that fluidity and change are central to the world around them. They have to see change as an agent of opportunity rather than as a threat — this is a silent message and challenge in the lesson of evolution. To deprive students of learning evolution is to deprive them of a powerful concept that brings great order and coherence to our understanding of life. The Benchmarks for Scientific Literacy has emphasised that “the educational goal should be for all children to understand the concept of evolution by natural selection, the evidence and arguments that support it, and its importance in history.” Let us not deliberately force our children to become myopic.
(The writer is National Science Chair, Science & Engineering Board, Govt of
India)
[The above article from The Indian Express is reproduced here for educational and non commercial use]
