In the past week, scientists have published findings of a study which concluded that there are approximately 8.7 million species on the planet. The paper which was published in the journal Public Library of Science Biology comes at a time where the number was previously thought to be anything between three and one hundred million.
To come up with the most accurate species estimate to date, the team adopted a new approach by studying the relationships between individual species and the wider assemblages to which they belong.
The research found that there are 6.5 million species living on the land and 2.2 million in the world’s oceans and rivers. However exciting, this figure represents only a promising start in our bid to understand our place on the planet, with around 86% of all terrestrial species and 91% of marine species yet to be discovered, described and catalogued.
Study leader, Dr Camilo Mora of the University of Hawaii said "The question of how many species exist has intrigued scientists for centuries and understanding the variety of life around us was important because human activities were accelerating the rate of extinctions."
‘‘Many species may vanish before we even know of their existence, and of their potential contribution to improved human well-being,’’ he said in a commentary in the journal.
The impact of humans on the environment has also been assessed in a separate study. Scientists used mathematical models in nature to calculate the effect of human existence on our surrounding habitat. By scaling Earth's age to 46 years, the study estimated that human existence is equivalent to approximately four hours. When analysed in the model, the impact of human activities on species was shown to be at a rate 1000 times faster than is considered normal in evolutionary terms.
The dependence of humans on natural resources for food, water, health and livelihoods has increased significantly in recent years and it is unclear just how many species have suffered as a direct result. Consequently, it is not known what impacts this may have on habitats that humans rely so heavily upon for resources.
Albert Einstein once said "If bees disappeared, man would only have a few years to live. No more pollinisation, no more grass, no more animals, no more men".
The new estimate has naturally come under criticism, with error bars of plus or minus 1.3 million. However, the figure is by no means definitive and the calculations simply mark the beginning of an assessment of all life on Earth.