Extinction- When Organisms Can't Adapt

Definition of extinction

We define extinction as the death of the last individual of a species (or another taxon). It means there are no more organisms rated to that group. In a way it is an end of a process that sooner or later touches every species. It is a natural evolutionary phenomena, extinct species are replaced by another and live keeps going. However, sometimes it happens faster than it should. In the history of the Earth there were five mass extinction, some scientist count today’s situation as sixth.

Species go extinct when they cannot adapt
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Why organisms go extinct?

There are many causes of extinction, usually it is the result of many factors. The environmental change plays a great role. Conditions on Earth change over the years, but when change is too fast and sudden, organisms cannot adapt to it. Sometimes there is complete habitat loss, in that situation species loses its “home”- the whole ecosystem collapses. Moreover, even if there is an usual habitat, there may be an introduced species- its better adjusted to the environment, or adapts faster. As a result, one species takes over the place of another in the ecosystem, and the first one goes extinct. However, there are situations when a species causes its own extinction. When populations grow too big and there is over-consumption, the ecosystem collapses leaving a species with very limited supplies and a lot of individuals. Therefore,  species goes extinct competing in a fading environment it destroyed.

One of the major causes of extinction is environmental change
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mass extinction

There were five major extinctions in the history of Earth. The first one, Ordovican-Silurian extinction, happened 439 million years ago, killing 86% of life. The reasons were glaciation and falling sea levels. However, life found its way back in a very similar way, and almost 100 million years later trilobites, giant plants, therefore animals, had gone again. Moreover, vertebrates did not appear for the next 10 million years. The third event is considered the worst because it killed almost 96% of all species. Permian-Trassic extinction was caused by a huge volcanic eruption that warmed the Earth and acidified the oceans. However, life found its way back and recreated till the event about 200 million years ago, that led to the reign of dinosaurs. But they did not last either and 65 million years ago a combination of volcanic activity, asteroid impact, and climate change killed 75% of species.

The Cretaceous–Paleogene extinction
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Outcomes of extinction

The previous paragraph may sound depressing, if we do not remember what it all led to. In fact, without those events humans would not have appeared on Earth. Moreover, homo sapiens were an introduced species back in the day, we also got rid of all natural enemies. Looking at extinction as a natural process helps us understand how change may be the only constant of life. Despite the mass extinction events, organisms went extinct and new appeared over millions of years. Even events that seems insignificant led to life as we know it today.

Extinction of modern organisms

Extinction is a natural process, however it may be dangerous. We struggle with overpopulation of our planet and over-consumption. Therefore, it leads to destruction of the environment and extinction of species. Moreover, scientist discuss if we are close to the next mass extinction event, or maybe if it has already begun. Every day 150 to 200 species go extinct, due to human activity. As a result, there are holes in ecosystem that lead to extinction of even more species. Some species may go extinct before being discovered by mankind. That problem is very complex, and stopping it may be the biggest challenge that humans ever faced.

Blue Macaw was officially declared extinct last year
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Author's message

I hope that article taught you about natural ways of extinction and the dangers of mass extinction. If you enjoyed reading, please share it with family and friends. In the next article we will look at the bigger picture and discuss outcomes of the entire evolution process. Meanwhile, checkout the external and internal links, and the previous articles from the series.

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