Changes to the Biosphere

The biosphere, as indicated by its name, is a ball of life. It is the term that encompasses every living thing on Earth. All life, from primitive organisms to current ones, have been able to obtain energy, build organic molecules, acquire nutrients, and reproduce. As the earth's spheres have changed over the years, the means of achieving these life requirements have changed as well. Organisms have adapted their structures and functions to match the changing Earth around them.

biosphere timeline

The amount of life varies greatly to the area of Earth you are looking at, but overall 8.7 million species have been named that exist today. It is estimated that there are 5 to 20 million species that have yet to be named. Many unidentified species are tiny and live in extreme places such as the Antarctic Ocean or thermal vents in the ocean floors. The total mass of the biosphere is estimated to be more than one trillion tons of carbon and consists of plants, fungi, bacteria, and animals which are all interdependent on one another.

The biodiversity of life on Earth is changing at any given time and moment. Over time more species have gone extinct than are alive today. Paleontologists have pieced together five mass extinctions over the past 4.6 billion years - each time reducing the biodiversity on Earth by over half. Abrupt changes in physical and chemical factors are key components to mass extinctions. After an extinction event, life slowly adapts and evolves to fill in the niches available in the Earth's environment.

Many scientists feel that we are in the midst of our 6^th mass extinction of plants and animals. We are experiencing a rate of species die-off second only to the loss of the dinosaurs 65 million years ago. While extinction is a way for biodiversity to evolve, our current extinction rate is 1,000 to 10,000 times faster than natural phenomena. In the past 500 years, 1,000 known species have gone extinct. Past mass extinctions have been caused by natural events - while this one is human made. Ninety-nine percent of all organisms at risk of extinction are at risk from human activity - including habitat loss, global warming, and introduction of invasive species. Loss of one species can have profound effects to other species in an ecosystem - as organisms die off there is likely to be more extinctions as ecosystems unravel.

Biodiversity ensures the survival of an ecosystem. It allows ecological communities the scope that is needed to withstand stress (changes) to an area. Conserving local populations is one of the only ways to ensure the success of the Earth's biosphere.

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