Evolution myths You probably believe in — Part 1
Travelling back to approximately 13.5 billion , our universe came into existence as a ‘singularity’ as a result of Big Bang. In the next 8.3 billion years, earth had witnessed some of the most dramatic changes in the ‘reducing atmosphere’ being transformed to the ‘oxidising environment’, the aquatic life and the formation of the prebiotic soup (The Hot Dilute Soup) giving rise to the single celled organisms with the emergence of the first genetic components, the purine and pyrimidine bases in interaction with the sugar, phosphate residues and thereafter, with the emergence of what we call the present day “Life” came the dominance of Homo sapiens on this planet, a meagre 2.5 million years ago.
The Latin word for ‘wise men’ being the only living representative of the genus Homo, faces numerous speculations and probably the most debated issue, regarding how we evolved from our first ancestral Australopithecus (Southern Apes) to what we are today.
Historically there has been two key models that exemplify the evolution of Homo sapiens. These are :
- The Out-of-Africa model — most widely accepted that suggests Africa the hub of human origin, before they migrated to other regions
- The Multi-regional model — it says, human beings evolved along different lines from different parts of the world ; hence different sources of origin and the intermingling of various population, races and genes eventually led to present day human beings as we see them.
The multi-regional hypothesis
However, even though the theories are supported by the mass, there has been a never ending debate on “Human Evolution” which continues to be under the radar since decades. As an intrinsic aspect of human behaviour and culture is to be in groups, that lodges people with the same pattern of thinking and the similarities in action and perceptions, naturally a large section of us despite scientific advancements and acquired knowledge, in “groups” do have certain misconceptions and myths on Human Evolution.
Popularised among them are:
1. Natural Selection and Evolution are the same
Natural Selection is a process whereas evolution is the phenomenon. Nature selects the species with a high turn over rate(here it refers to Reproductive Potential of one species with respect to another according to Darwin). Hence the existence of a race largely depends on its ability to leave more progeny(parental genes)that have features, either the same or more suited, attributed to face competition for food, shelter and sustenance. Evolution is the result of this act that Nature facilitates. It can be called as the end product of processing Natural Selection which again is also the raw material.
2. Evolution is merely an adaptation
Imagine this the next time when you shut your eyes while sneezing or the next time you deeply inhale the fragrance of a rose or the scent of your favourite perfume. These are classified as reflex actions in biology but are these the mere results of your evolution? People vary greatly when it comes to smell due to mutations in certain OR genes (olfactory receptor genes) that codes for these receptors and consecutive ligand binding and not for adaptive reasons. Adaptation is the ability (acquired or innate) to get accustomed with the changing climatic, topographical or geological changes. Evolution is a game of numbers that surpassed various degrees of adaptations in each species.
3. The only means of Evolution is Natural Selection
Evolution happens by a chance factor too. Allele frequency may change over one generation to the next, when a few members of one colony suddenly abandon their community and invade and thereby reside in a different colony, splitting up the former population — Founder Effect.
The Galapagos finches are a classical example to stand in support where the original seed eating birds shifted to separate islands and developed different feeding habits leading to various degrees of beak modifications. Similarly another way of evolution is Bottleneck Phenomenon — drastically reduced number of species due to genetic drift not accurately represented in the new population.
4. Mutations can not create information, they only destroy
Do you know about “Retinoblastoma”?
It’s an inherent tumour in the retina of the eyes, commonly observed in children, that occurs due to a mutation in chromosome 13.
It is lethal, it is dangerous, but despite it being harmful, nature and life has permitted the existence of these genes. They can be sporadic or hereditary and evolution successfully has kept them. Why? In spite of treating cancers and tumorigenesis, nothing has been able to wipe out their population. This is because, once nature supports a gene, it occupies a niche in the ecology just as we do.. (organism, population, community, biome, biosphere)
Also think of the infamous, “Sickle Cell Anaemia”. The replacement of GAG to GUG codons plays the game. And the ones with this mutation are the successful survivors of malaria in Africa, where the sickle nature of the RBC prevents the further proliferation of the malarial parasites in the blood corpuscles, thereby helping the population to thrive despite the odds.
Then how can we say that mutation always wipes out important genes? They never kill. How can they be so selfish?
Rather they work to sustain the good ones and eliminate the ones that are no longer of any good use to human life and those that pose a threat to the laws of Nature.
From the religious point-of-view
The biggest blow that the science of evolution face are the misconceptions, the supernatural alternatives people harbour under the banner of “Creationism”. The common myths and misconceptions that have gained ground by contradicting logic and science are :
5. Evolution violates the 2nd Law of Thermodynamics
According to the second law, the entropy (degree of randomness) cannot decrease in an isolated system and our planet is an open system with respect to energy changes. There is a constant influx of solar radiations and a part of which (nearly one fourth) gets reflected back
6. Evolution equals unlimited creativity
Nature has always been one of the biggest creators and inventors because of which we have a vast array of flora and fauna, each with strikingly different features.However there are certain features that cannot evolve and their significance of existing does not have a clear cut distinction. In a paper Stephen Jay Gould and Richard Lewontin (1979) contrasted natural selection driven adaptations with phylogenetic, architectural and developmental constraints. The presence of long tailed salamanders that rolls up on perceiving danger or the black and white contrasted skin of zebra are the creative aspects of nature which has not seen further evolution or modification in due course of time.
7. Evolution leads to Perfectly Adapted beings
The distinction between “perfectly adapted” and “well adapted” needs a deeper look into. A species need not have to be perfectly adapted but well adapted with respect to its other competitors is crucial for existence. Take for instance, the five digits of our toes and palms. Necessarily we do not require 5, or 4 would have been sufficient..perhaps 6 too.. So nature promotes what works in favour of it not something that has to be 100% effective in terms of utility.
8. Evolution always promotes the Survival of the species
Is it so?
Not always.
9. Evolution can often lead to Elimination
In a few cases, where nature does not support the presence of a trait or gene, causes the depletion of the species leading to extinction of that feature. This is possible by reducing the overall fitness of the species or population or individual. In 1932, J. B. S. Haldane suggested this could even lead to the extinction of populations — a phenomenon called evolutionary suicide. Models and some experimental evidence suggest he was right. Another evidence is when nutrients run low, individual myxobacteria (slime bacteria) may come together to form a fruiting body to produce spores. Lab studies have shown that cheating mycobacteria that only produce spores and never help form the non-spore producing parts of the fruiting body can drive populations to extinction.
Evolution is after all, “Best known, worst understood”
Myths debunked? Somewhat. There are still quite a few misconceptions that need to be cleared out. And cleared out they have been! Take a look:
Evolution is not a force, but a process.
It’s not a Cause, but a Law.“We are the representatives of the cosmos; we are an example of what hydrogen atoms can do, given 15 billion years of cosmic evolution.”
- Carl Sagan
And yet, there are thousands of people who still harbour doubts regarding evolution and are skeptical. Many downright reject it. But that can not and will not change the fact that it is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring.
Thank you for reading!
