| In order for scientists to study the history of life | | | | United Nations. It has been estimated that |
| on our planet, they require a relative scale so that | | | | approximately 35% of all invertebrate species will |
| they can place important events such as the first | | | | be under extinction pressure by the end of the |
| land vertebrates, or the first evidence of | | | | 21st Century. For animals, known as the mega |
| flowering plants in the perspective of geological | | | | fauna, some of the larger creatures in |
| time. Such a scale is provided by the science of | | | | ecosystems, such as mammals and reptiles the |
| geology. Geologists have subdivided the history of | | | | situation is equally as bleak. In the UN funded |
| our planet into time intervals of varying duration. | | | | report, an estimated 21% of all mammal species |
| The largest periods of time are divided into Eons, | | | | are threatened with extinction. |
| an example is the Phanerozoic Eon (visible life), | | | | By the middle of this Century, the human |
| representing the period of geological time from | | | | population is estimated to have grown from |
| approximately 550 million years ago to the | | | | today's level of approximately 6.8 billion to over 9 |
| present day. The Phanerozoic covers that period | | | | billion. That is an increase of 2.2 billion (32% |
| of time when fossils first become abundant, | | | | increase in just forty years). Two thirds of the |
| reflecting the obvious presence of life. Eons are | | | | population will live in cities it has been predicted, in |
| divided into Eras, such as the Cenozoic Era that | | | | China alone over 400 new cities with populations |
| covers the last 65 million years (sometimes called | | | | greater than 1 million will have to built to |
| the Age of Mammals). Eras are broken down into | | | | accommodate this increasing population. |
| Sub-eras and further divided into Periods, hence | | | | The increased demand for natural resources plus |
| well known sections of geological time such as the | | | | the adverse affect on global climate will have a |
| Jurassic and the Cretaceous. Periods are further | | | | dramatic impact on the diversity of life on Earth. |
| sub-divided into Epochs. The last 10,000 years of | | | | Scientists are aware of a natural extinction rate, a |
| geological time, roughly reflecting the adoption of | | | | sort of background rate of extinction. This |
| sedentary farming and domestication of livestock | | | | background rate represents low levels of |
| by people, is known as the Holocene (recent | | | | extinction as a result of evolution and adaptation |
| time). | | | | plus some local or restricted climate/environmental |
| For much of the Holocene, the Earth's climate has | | | | change. The fossil record, although far from |
| been relatively stable. In fact, using information | | | | complete shows evidence of larger extinction |
| sources such as ice cores and micro-fossil studies, | | | | events. There have been a number of extinction |
| it seems that the Earth's climate has been more | | | | events recorded in the fossil record. For instance, |
| stable than during any other 10,000 year interval | | | | many people may be aware of the Cretaceous |
| in at least the last 200,000 years or so. For much | | | | mass extinction event that ended the reign of the |
| of this time, the human population has grown | | | | dinosaurs, but a number of lesser extinction |
| steadily. It is only in the last 200 years or so that | | | | events are associated with the Cretaceous. |
| the human population has grown dramatically. The | | | | Palaeontologists have identified five major mass |
| growing demand for resources from the | | | | extinctions in the Phanerozoic. The history of life |
| increasing human population, in conjunction with | | | | on our planet has been punctuated by a series of |
| rapid climate change has been identified in a United | | | | mass extinctions, mass extinctions being defined |
| Nations (UN) report due to be published this week, | | | | in a number of ways, but normally they relate to |
| as causal factors in the dramatic decline of animal | | | | the number of marine and terrestrial genera that |
| and plant species. | | | | die out in a relatively short period of geological |
| 2010 - The Year of International Biodiversity | | | | time. Most scientists agree about the "big five" |
| This year, 2010 is the year of international | | | | mass extinction events, but some scientists are |
| biodiversity as declared by the United Nations. | | | | arguing that the Holocene epoch should also be |
| Biodiversity is the variety of life on Earth, | | | | defined as a mass extinction event - the sixth |
| biodiversity is essential to support dynamic and | | | | mass extinction. |
| robust ecosystems that ultimately provide our | | | | The Scale and Speed of Extinction |
| species with a sustainable environment, food, fuel, | | | | Although it is difficult to accurately assess the |
| health and prosperity. | | | | decline of fauna and flora, if mammals and birds |
| However, one of the conclusions in a United | | | | are examined in isolation, an alarming picture is |
| Nations (UN) report due to be released this week, | | | | revealed. There are approximately 14,000 species |
| is that animal and plant species are becoming | | | | of mammals and birds today. These types of |
| extinct faster than ever before. A rapidly growing | | | | animals are dying off at a rate approximately |
| human population in combination with an increasing | | | | 10,000 times faster than the standard background |
| demand for natural resources represents a grave | | | | extinction rate. The United Nations report uses |
| threat to nearly a third of all animal and plant | | | | data gathered from 120 countries, it concludes |
| species on the planet, the report states. The | | | | that the magnitude of damage to ecosystems is |
| increasing economic activity and industrialisation of | | | | much bigger than previously reported. This UN |
| countries such as India, China and Brazil is adding | | | | report will show that no country has succeeded in |
| to the environmental threats already generated | | | | halting the decline in biodiversity. Eighty-nine |
| by the developed western world, countries such | | | | percent of those countries that submitted data |
| as the United States and economic trading blocks | | | | had identified climate change as a major cause. |
| such as the Euro zone. | | | | For our species, the consequences could be dire. |
| Commentators are expecting this new report to | | | | We humans are at the top of the food chain and |
| be one of the frankest and most stark ever | | | | very reliant on robust and dynamic ecosystems. |
| published by the UN. It will include conclusions that | | | | The loss of a single species, the honey bee for |
| draw an explicit correlation between economic | | | | instance, would have a significant and detrimental |
| growth and extinction rates. For example, the | | | | impact on our ability to produce food. |
| faster and more dramatic the growth of | | | | Approximately, one third of all the vegetable and |
| economies, the quicker animal and plant species | | | | fruit crops grown on a commercial scale by |
| will be driven to extinction. The paper will point out | | | | humans, are pollinated by bees. |
| that the extinction threat extends across all the | | | | Given the current economic difficulties being |
| main ecosystems of the planet, affecting | | | | experienced by many countries, it is likely that this |
| organisms in environments as diverse as rain | | | | report and its conclusions will not be not be given |
| forests, grasslands, inshore environments and | | | | the prominence that it and the conclusions |
| coral reefs. | | | | deserve. The fossil record in two million years |
| With a relatively small portion of the known | | | | time could show one of the most dramatic and |
| invertebrates formerly studied, it is alarming to | | | | rapid extinction events in the history of life on |
| read the predictions regarding extinction from the | | | | Earth. |