The last time I tackled this subject was in June 2021, in the context of COVID-19. My article, “Evolution and the COVID Variants” (Balita, June 1, 2021), described the meaning of a “variant,” how it develops, and what it signifies concerning the original population. I explained what viruses, such as COVID-19, are and why they evolve and reproduce more easily than many other organisms. The simplicity of viruses favours mutation regularly, allowing them to thrive in our bodies as they enter and exit. Some of these interactions may lead to illness.
Throughout history, we have faced a litany of viral illnesses, some reaching epidemic proportions. Examples include polio, smallpox, and HIV/AIDS, which have all left significant marks on human history. When a virus mutates, its genetic code undergoes a reshuffling, which can sometimes prove harnful to the host. The disease occurs when the virus invades a host’s cells and uses its machinery to reproduce, as viruses cannot multiply independently.
Occasionally, viruses can recombine their genetic DNA or RNA with another virus, producing a variant that differs significantly from its parent virus. This newly formed virus might have more pronounced effects than its parent, although it does not necessarily lead to an epidemic on the scale of annual flu infections. Interestingly, vaccines are developed through a similar recombination process, often deactivating viruses by harnessing their physiological mechanisms.
THE ESSENTIALS OF EVOLUTION ARE SIMILAR IN ALL CASES.
Beginning a discussion on evolution with viruses can complicate matters, but the concepts align closely once we clarify the reproductive process. We will explore this further later in the article.
I have had many conversations with individuals regarding evolution, and a recurring theme is a profound misunderstanding of the process, often stemming from incorrect interpretations of various concepts. To summarize, the common contentions I have encountered include: – Big Bang Theory – Creationism – Missing Link and Natural Selection
Many books and courses have been dedicated to evolution, supporting a scientific theory that explains the diversity of life on Earth, particularly concerning human origins. I aim to avoid creating an article that reads like a textbook. The doctrine of evolution is complex, and adequately addressing it would require extensive background readings in genetics, molecular biology, and taxonomy.
To sidestep this complexity, I’ll simplify the subject so readers do not equate Biblical Genesis as a “ gold standard “ regarding our origins. Conversations often include the four aforementioned subjects, particularly among the rank and file.
THE BIG BANG THEORY
The Big Bang Theory explains the origin of the universe, describing a stellar explosion that gave rise to stars and planets, including Earth. According to this theory, the universe originated from a hot, dense point in the void of space. A massive explosion formed matter that expanded, eventually creating galaxies and stars. Over time, these celestial bodies became less dense and cooled as the universe dispersed.
This model is widely accepted in the scientific community as the origin of Earth and the planets of our solar system. Big Bang events are believed to continue to generate other universes in the infinite void of space. Scientists have determined that this cosmic event occurred approximately 13.8 billion years ago by measuring the universe’s expansion rate.
It took about 4-5 billion years for the Earth to cool sufficiently to allow the synthesis of organic compounds from inorganic molecules. The Oparin-Haldane hypothesis suggests that building blocks like amino acids gradually emerged and eventually formed complex polymers, a process that has been replicated in laboratory settings.
Another popular hypothesis posits that the earliest life forms originated in hydrothermal vents as early as 4.28 billion years ago, soon after the formation of the oceans. Whether life began deep in the oceans or evolved from complex molecules on land is a subject that science continues to refine. Out of these possibilities, a single primitive organism is believed to have emerged approximately 3.5 billion years ago. This organism has continued to evolve gradually into the diverse population of life we see today, including humans.
It is essential to note the time frame involved here: 3.5 billion years (3,500,000,000). This gradual process of evolution took an extensive amount of time to produce Homo sapiens.
CREATIONISM
( image by Wikipedia )
Creationism is a belief that describes a specific interpretation of how life began, as detailed in the Biblical book of Genesis. According to this account, the world and everything in it were created by God in six days. This process includes the creation of light, oceans, life, and, ultimately, humans on the last day. The belief holds that God created humans in His own image, resembling us as we are today. Creationism suggests that this creation occurred within the last 6,000 to 10,000 years.
It encompasses the story of Adam and Eve, their lives in the Garden of Eden, and their eventual banishment. This punishment was a consequence of their disobedience to God’s command after being tempted by a serpent (often associated with the devil) to eat the fruit from the “Tree of Knowledge.” As a result of this “original sin,” death and suffering entered the world. Genesis implies that all living things, including humans, have a divine origin.
MISSING LINK
Before the advent of molecular biology, one of the favourite arguments of anti-Darwinian forces was the absence of the so-called Missing Link or transitional forms between species. Early studies of evolution relied heavily on fossils as physical evidence. Critics were quick to point out the lack of an animal species that exhibited characteristics of both humans and monkeys, as creationists mistakenly speculated about our linear connection with apes.
No Missing Link of an ape-man has ever been found because we did not evolve from apes. Instead, as we have discovered, apes are more like distant cousins rather than our ancestors. I will provide a more thorough narrative of our origins in part II.
It’s important to note that only a small percentage of plants and animals become fossils. Rock formations and the structures of plants and animals often do not have the necessary conditions to fossilize. When fossils are found, they are typically deep within rocks and usually incomplete. However, archaeologists have made significant strides in locating notable fossil records of “missing links” within sedimentary rocks.
A fascinating array of extinct animals, including mammoths, wolves, camels, roundworms, and bison, has been discovered in the thawing permafrost from Yukon to Siberia. These complete, intact fossilized remains, some found as recently as last year, date back 50,000 years or more. These discoveries further demonstrate the evolution of animal species in response to climatic changes.
Biologists have mapped out these organisms’ locations accurately, with earlier forms found in lower sediments and later, more complex forms found in higher levels. Some prominent examples of these forms include:
Archaeopteryx: A fossil that exhibits characteristics of both reptiles and birds, providing evidence that some dinosaurs evolved into birds.
Tiktaalik: A fossil that shows a blend of characteristics between fish and tetrapods, suggesting it served as a transitional form between the two.
Pakicetus: An extinct amphibious whale that lived between land mammals and whales.
Coelacanth: Dubbed a “living fossil,” this fish was discovered alive in the waters off South Africa and displays leg-like structures instead of fins, indicating a transition towards reptiles.
( image by Wikipedia )
Today, scientists focus less on fossil evidence. Molecular biology and genetics provide a more systematic and methodical connection among all living things. For instance, cyanobacteria may represent the Last Universal Common Ancestor (LUCA) from which all life today originated, dating back between 3.5 and 3.9 billion years ago. These bacteria, discovered in Western Australia, may be our ancestors!
NATURAL SELECTION
Natural selection is the mechanism that drives evolution, first proposed by Charles Darwin and now recognized as a biological fact. Our understanding of evolution is deeply connected to our grasp of this process. Simply put, environmental pressures—such as climate, food supply, or predators—constantly challenge the survival of organisms.
The fittest, meaning the most adapted, survive and reproduce more than others in their population. Subsequent generations stem from the survivors of previous ones, ensuring that the populations in the wild remain the fittest for their current environment. Genetics (i.e., DNA) guarantees the continuity of the characteristics of these survivors.
As the environment changes, so do the living organisms within it. These changes are typically subtle, much like the habitat that remains consistent from year to year. When a significant mutation occurs in an animal, it may result in drastic changes. If an animal or plant suddenly possesses a mutation that does not suit the current environment, it will eventually die off, and its traits will not be passed on to future generations.
For example, albinism (absence of pigment ) almost never allows survival in wild populations (unless humans intervene) because the affected animals struggle to hide from predators. In plants, the lack of the green pigment (chlorophyll) hampers photosynthesis, making survival unlikely. Without human intervention, the “law of the jungle” ensures that only the fittest plants and animals thrive in their best physiological and anatomical conditions.
Human civilization has, of course, altered this dynamic. We often protect the least fit members of our population and even support organisms that benefit humanity regardless of their survivability in their environment. I will explore this topic further in part II.
Natural selection operates similarly in both land and water habitats. There are tens of thousands of variations in every population, ensuring nature’s resilience—whatever happens in the environment, there will be organisms that can adapt. Those that do will survive, reproduce, and ensure the continuation of their species.
On occasion, environmental changes can be abrupt and catastrophic. Some organisms may not adapt quickly enough to new habitats or lack sufficient time to reproduce offspring with traits that suit the altered conditions. Organisms affected by such circumstances can become extinct. The dinosaurs, the woolly mammoth, and the dodo are famous examples of species that succumbed to drastic environmental pressures.
Currently, climate change is placing over 10,000 species of plants and animals in an endangered category, alongside issues like pollution and habitat destruction.
Nothing is as thought-provoking and captivating as a discussion on human origins. The simplicity of the Biblical Genesis falls short of credibility when set beside the scientific explanation of our beginnings.
We will explore this in part II.
