GENETICS

 "Ask the plants of the earth, and they will teach you" 

—Job 12:8

 

Around two billion years ago, Earth was teeming with cells, simple bacterial cells and from this vast ocean of microbes, arose a single, complex cell with an intricate internal structure. How or why, this happened remains a mystery—one that nature has never repeated. Everything on Earth—plants, animals, and humans—share the same father. From this celestial cell, came all life on Earth. 

Scientists have long sought to unravel this mystery, attempting to recreate Earth's early atmosphere—the primordial soup—in laboratory experiments. By combining chemicals, gases, and electric sparks, they have only managed to produce simple organic molecules, but no life. Billions of years of evolution, the right environment and one life giving cell was chosen from a sea of cells and the eureka moment in nature had arrived, the cell synthesized, and life had found a way. 

The Role of Plants in Earth's Transformation 

Around a billion years ago, Earth became a planet of plants. In plant cells, chloroplasts function as energy factories, enabling photosynthesis. Plants absorb carbon dioxide, convert sunlight, water, and carbon into carbohydrates, and release oxygen. This process transformed Earth's atmosphere, filling the sky with life-sustaining oxygen. 

Approximately 600 million years ago, an explosion of diverse life forms emerged—the Cambrian Explosion. The oceans produced a rapid succession of new species. By 65 million years ago, Earth was dominated by reptiles—dinosaurs that walked, swam, and flew. However, they did not survive the catastrophic Cretaceous-Tertiary (K-T) extinction event, which wiped out most species on Earth. 

The Mystery of the Dinosaur Extinction 

In 1956, Russian astronomer Joseph Shklovsky suggested that a supernova—the explosion of a dying star—had bathed Earth in lethal radiation, exterminating the dinosaurs. However, no traces of radiation were found to support this theory. 

In 1980, father and son scientists Luis and Walter Alvarez proposed the impact hypothesis, based on their discovery of high levels of iridium—a rare element common in asteroids—at various sites worldwide. This theory gained strong support in 1990, when scientists located the massive Chicxulub Crater at the tip of Mexico’s Yucatán Peninsula. 

According to this hypothesis, an asteroid 10 kilometers wide, traveling at 40,000 miles per hour, struck Earth 65 million years ago. The impact released energy equivalent to 100 million megatons of TNT—more than a million of the most powerful hydrogen bombs ever tested. The explosion sent debris, including iridium, across the planet. Day turned to night, temperatures plummeted, and a mass extinction followed—marking the beginning of the Ice Age. 

A Million-Year Story of Evolution 

The history of Earth's recovery from this cataclysm was revealed at Corral Bluffs, where sediment layers preserved a million-year timeline of post-impact evolution. The asteroid wiped out 75% of all living creatures and half of Earth's plant population. Temperatures plunged to 5°C, and the planet was dominated by ferns and small mammals—such as shrews—that had once lived in the shadows of dinosaurs. 

Over time, three major warming periods reshaped the planet. Volcanic eruptions released vast amounts of carbon dioxide into the atmosphere, warming Earth and triggering evolutionary surges. With each warming period, new species emerged—larger, more diverse, and better adapted to their transformed world.