Biodiversity – the number of different life forms on planet Earth – is vitality important to understand if we’re to survive in the 21st century.
Scientists estimate that there are between 10 and 110 million species on Earth. So far, we have catalogued about 1.7 million of them. The awesome diversity that exists on our planet today represents only about one percent of all species that have ever lived here.
Life began on Earth 3.5 billion years ago. Ultraviolet radiation relentlessly bombarded the planet. Our thin atmosphere was a toxic mixture of hydrogen, ammonia, methane and carbon monoxide with very little or no free oxygen.
Lightning was a major force in that world of very active volcanic upheavals. Bolts of lightning hit the ocean and from one of those reactions came the beginning of life, with the formation of DNA (deoxyribonucleic acids, the main constituent of chromosomes, which carry the genetic code).
DNA is the fundamental building block of life, with power to replicate itself as the blueprint for the formation of amino acids (the building blocks of proteins). The oldest forms of life (and first fossils), bacteria, fed on carbon compounds that had accumulated in the seas. Over time, they made their own food from free hydrogen released from volcanic activity.
Miraculously, there eventually came a time when this blue-green algae developed the ability to harvest the sun’s energy and use carbon dioxide in primitive green (or chloro) cells, thus making its own food. One major byproduct of this activity was the release of oxygen.
So much oxygen was released by the algae that some oxygen floated to the upper atmosphere and formed the ozone layer. That remarkable oxygen-rich layer filters and prevents almost all ultra-violet radiation from reaching the Earth’s surface. Once this layer was in place, life on our planet took off. First in the ocean, and then from the ocean to the land, life proliferated.
Today, off the coast of east Africa and Western Australia there are what looks like worn-out old stumps called stromatolites that contain evidence of the first ancient aquatic bacteria dating back 3.5 billion years.
Life has amazingly adapted to many different environments. It has developed mechanisms for surveying extreme heat or cold, wetness or drought, high mountain altitude or deep ocean depths. Each habitat, or set of environmental conditions, is home to different life that has developed mechanisms to successfully survive.
There are certain traits which each living thing possesses specially adapted to its unique environment. For example, the northern-most species of rattlesnakes living in the desert of the Kamloops (interior of British Columbia) region could not exist on the wet outer coast rain forests of the Queen Charlottes, British Columbia.
Species of organisms sharing a habitat live in a community, also called an ecosystem. How organisms interact in each ecosystem is important and that’s why scientists study them.
In order for 7.1 billion people (and growing to 8 billion by 2023) to exist on Earth, we require old growth forests and tropical jungles to provide fresh water, white clouds to reflect incoming solar radiation at the tropics, oxygen and habitats for all the critters. Scientists must be allowed to study these magnificent ancient forests to understand how they work. Accordingly, a moratorium on logging any ancient forests on Earth is requisite. Wild forests contain untold cancer fighting and pain-relieving medicines. In addition, big trees are the most remarkable carbon warehouses to have ever evolved on our planet!
If we deprive a species of what it needs to live, it becomes extinct. Globally, over the past 50 years, thousands of species have gone extinct due to human population pressures and destruction of habitat from mining and logging.
Conservation biology is a relatively new, exciting and challenging branch of science. The discipline is charged with the responsibility of maintaining biological diversity or the tapestry of life on our planet.
Protecting all remaining wild ecosystems brimming with biodiversity — in face of rapid human-induced climate change — is our salvation.
Earth Dr Reese Halter is a broadcaster, biologist, educator and co-author of Life, The Wonder of It All.