Climate change results in evolutionary changes
IT is a fact that all parts of the world experience climate change in terms of rain, storms, cyclones and drought. When we say climate change, it means a change from the normal climate we experience during the year at certain times, the frequency of it happening and the severity of it.
As we learn the theory of evolution, we realize the climate effect on human evolution. Evolution is the change in heritable characteristics of biological populations over successive generations.
Evolution occurs when an evolutionary process such as natural selection (including sexual selection) and generic drift act on genetic variation, resulting in certain characteristics more or less common with a population over successive generations.
In other words, evolution happens over a period of several generations through natural selection to adapt to the changing living conditions which is influenced by the changes on earth, which is also impacted by climate change.
What is the theory of natural selection, living things to change over generations? Living things have variations in traits that are determined by their genes like hair color, eye color, foot length, etc. The changes in the traits give them an advantage in surviving and even finding mates. The process of natural selection causes living things to change over generations.
Today we take for granted that we live among diverse communities of animals that feed each other. Our ecosystems are structured by feeding relationships like killer whales eating seals, which eat squid, which feed on krill. These and other animals require oxygen to extract energy from their food. With an environment devoid of oxygen and high in methane, for much of its history, the Earth would not have been a welcoming place for animals.
The earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old. Cyanobacteria evolved about 2.4 billion years ago, which was the first transformation, they survived through photosynthesis, making food using water and Sun’s energy and releasing oxygen as a result.
An increase in oxygen level in the environment made it less hospitable for microbes that could not tolerate oxygen and evolved bacteria that need oxygen. Then DNA evolved resulting in the evolution of animals about 800 million years ago, the earliest ones were the Sponges. Evolution continued to create new species and animals.
Microorganisms evolved into small reptiles, animals, fishes and birds through natural adaptation to changing situations over the earth and ocean. It is believed that small animals evolved about 250 million years ago. Dinosaurs lived on Earth 150 to 60 million years ago. It is believed that big asteroids struck the earth and the Dinosaurs died.
The land was one mass on Earth, which later split away into several continents. Major evolutionary changes happened when environmental conditions on Earth changed. After the Dinosaurs' extinction, smaller animals and birds evolved and human evolution happened about a million to 500,000 years ago.
Diverse species have emerged over the course of human evolution and a suite of adaptations have accumulated over time, including upright walking, the capacity to think, make tools, enlargement of the brain, prolonged maturation, the emergence of complex mental and social behavior and dependence on technology.
The period of human evolution has concluded with environmental changes including cooling, drying and wider climate fluctuations over time.
How did environment change shape the evolution of new adaptations?
We may not notice these changes in new adaptations, over generations, we will notice the change in human body shape, longer hands or shorter legs, better eyesight, the shape of the nose and even the face.
A recent change in babies’ growth I notice is that, once they sit, instead of crawling on leg and hand, they push on their legs while sitting and standing up, the crawling stage is bypassed. After a few generations, you may notice major changes in the baby’s development in walking and talking. Adaptation to a changed environment through natural adaptation is what evolution is. You can see changes in the way animals behave, even plants and trees grow or fishes multiply.
Climate changes will eventually make environmental changes which result in living creatures adapting to the new situations resulting in evolutionary changes.
There was a report in the Malayala Manorama on October 8 that climate change and environmental disasters have affected 430,000 children around the world and that it has threatened human life on Earth. It was reported on CNN a few days ago that billions of snow crabs have disappeared from the ocean around Alaska.
Until three years ago, hundreds of birds used to come to our area during October, stay for a few days and fly away during their migration from North America to South America to avoid the cold weather. We don’t see them anymore. We read stories of changes in animal life in the western United States, Amazon forest, Africa and elsewhere due to changing weather patterns.
How can we avoid or reduce these climate and environmental changes?
If we can reduce the emission of carbon dioxide and methane in the atmosphere, it will help. If we can do more reforestation, it will increase the intake of carbon dioxide by the plants and emit oxygen into the atmosphere.
Industrialization and fossil fuel burning resulted in more emissions of carbon dioxide and methane. In the next 1000 to 10,000 generations, human beings, animals and every living creature on earth shall go through evolutionary changes.
Changes are so slow that we will not see them in our lifetime.