质量灭绝和背景灭绝之间的差异

质量灭绝与背景灭绝

知道质量灭绝和背景灭绝之间的差异变得很重要，因为它们都是雨伞项下灭绝的类别。灭绝被定义为从地球上整个动物或植物的不可逆消失。重要的是要考虑消除整个物种，而不仅仅是一个物种人口的个体成员。灭绝是一个天然发生的过程。在过去的35亿年中，地球上存在生命，许多物种已经生活和灭绝。目前，大约有4000万种不同的物种生活在地球上，包括动物和植物。但是，与地球历史相比，到目前为止已经存在约50亿至500亿种。在这些物种中，今天只有大约0.1％的生活，这意味着目前曾在地球上居住的所有物种中有99.9％已灭绝。灭绝是由许多因素驱动的，例如地理变化，某些环境因素，竞争者，缺乏食物，缺乏适应性在某些环境中生存等等。有时会在很长一段时间内发生灭绝。然而，有时会发生在闪烁破坏这么多物种中。 Depending on the time that it takes for an entire species to become extinct, the extinction process can be divided into two types: background extinction and mass extinction.

什么是质量灭绝？

大规模灭绝发生很快，它一次消除了数百种，也许是数千种。质量灭绝的原因因素包括气候变化，大规模和连续的火山喷发，空气和水的化学，小行星或彗星罢工的变化以及地球地壳的变化。相信恐龙完全被巨大灭绝消灭。众所周知，大规模灭绝是地球历史上两个时代之间的边界。例如，白垩纪三级灭绝表明，在白垩纪期结束时和第三级开始时发生了质量灭绝。有史以来最大和最差的巨大灭绝发生在二叠纪时期结束时25100万年前。持续数千年的大规模火山喷发导致了这种巨大灭绝。

什么是背景灭绝？

Background extinction is a process that happen over a very long period. It usually eliminates only one species at a time. It is usually happened by drought, flood, arrival of new competitor species, etc. Usually, fate of a species depends on the ability of surviving and reproducing under different environmental condition where they inhabit. Sometimes certain species go extinct because they gradually change into new species. For example, the currently living North American horse species have evolved from earliest horse species which went extinct millions of years back. Background extinction can also occur suddenly. Usually this happens because the biology of a species cannot adapt quickly to rapid changes in its living habitats (ex: The digestive system of Koalas in Australia is unique among mammals and adapted to feed only on eucalyptus leaves. If sudden climatic changes wiped out eucalyptus forests, Koalas could go extinct suddenly).

质量灭绝和背景灭绝有什么区别？

•背景灭绝需要很长时间才能发生，而质量灭绝发生在短时间内。

•背景灭绝通常一次仅影响一个物种，而质量灭绝一次会一次影响许多物种。

•与背景灭绝不同，质量灭绝可以改变地球上的整个生命。

• Unlike the background extinction, mass extinction is used to denote the borderline between two periods of Earth’s history.

• Mass extinction can occur due to climate changes, massive and continuous volcanic eruptions, changes in the chemistry of air and water, asteroids or comet strikes, and shifts in Earth’s crust, whereas background extinction occurs due to drought, flood, arrival of new competitor species, etc.

摄影者：Marc Dalmulder（CC由2.0）