What is the Difference Between Background Extinction and Mass Extinction

Main Difference – Background Extinction vs Mass Extinction

The end of a species on the earth is known as extinction. There are two types of extinctions as background extinction and mass extinction. The main difference between background extinction and mass extinction is that background extinction is caused by the poor adaptation to the ongoing changes in the environment whereas mass extinction is caused by the exposure to harsh conditions during a short period of time. Background extinction is a regular event in the process of evolution. The five mass extinctions can be identified at the end of the Ordovician, Devonian, Permian, Triassic, and Cretaceous periods.

Key Areas Covered

1. What is Background Extinction
      – Definition, Features, Background Extinction Rate
2. What is Mass Extinction
      – Definition, Features, Five Mass Extinctions
3. What are the Similarities Between Background Extinction and Mass Extinction
      – Outline of Common Features
4. What is the Difference Between Background Extinction and Mass Extinction
      – Comparison of Key Differences

Key Terms: Background Extinction, Cretaceous, Devonian, Evolution, Mass Extinction, Ordovician, Permian,   Triassic

What is Background Extinction

Background extinction is the ongoing extinction of an individual species. Ecological factors such as climate change, loss of habitat, and competitive disadvantages related to other species cause background extinction. Since background extinction is a result of the regular evolutionary process, the rate of the background extinction is steady over geological time. 

Figure 1: Tadorna Rusty

For example, the recent background extinction rate is one species per 400 years for birds. Tadorna Rusty is a duck, who is threatened by extinction is shown in figure 1.  

What is Mass Extinction

Mass extinction refers to the extinction of a large number of species within a short period of geological time. The too rapid, widespread environmental changes and catastrophic global events cause mass extinctions. In rapid environmental changes, species are unable to adapt to the change of the environment, and they cannot survive in the changed environment. Mass extinctions temporarily reduce the geological diversity. Five mass extinctions can be identified based on the fossil evidence at the end of the Ordovician, Devonian, Permian, Triassic, and Cretaceous periods.  

Ordovician

The Ordovician extinction occurred 440 million years ago. Trilobites, graptolites, and conodonts like deep-shelf benthic faunas became extinct in the Ordovician mass extinction.

Figure 2: Trilobites

Devonian

The Devonian extinction occurred 365 million years ago. The number of coral reefs, calcareous foraminifera, and brachiopods were reduced in Devonian mass extinction.

Permian

The Permian extinction occurred 250 million years ago. It is the largest known mass extinction in the earth’s history. 96% of the marine species were extinct in Permian mass extinction. The number of terrestrial tetrapods was drastically reduced in the Permian extinction.

Triassic

 The Triassic extinction occurred 210 million years ago. Around 23% marine and non-marine animal species were extinct including gastropods, sponges, cephalopods, brachiopods, bivalves, insects, and vertebrates.

Cretaceous

The Cretaceous extinction occurred 65 million years ago. Non-avian dinosaurs, ammonites, rudists, nannoplankton, and some marine reptiles were completely extinct in Cretaceous mass extinction. 

Similarities Between Background Extinction and Mass Extinction

• Both background extinction and mass extinction are involved in the end of species from the earth.
• Both background extinction and mass extinction occur due to either regular or rapid environmental changes.

Difference Between Background Extinction and Mass Extinction

Definition

Background Extinction: Background extinction is the ongoing extinction of the individual species.

Mass Extinction: Mass extinction is the extinction of a large number of species within a short period of geological time.

Causes

Background Extinction: Ecological factors such as the climate change, loss of habitat, and competitive disadvantages related to other species cause the background extinction.

Mass Extinction: The overly rapid, widespread environmental changes and catastrophic global events cause mass extinctions.

Time

Background Extinction: Background extinction requires a long time.

Mass Extinction: Mass extinction occurs within a short period of time.

Significance

Background Extinction: Background extinction is a regular process, which occurs as a result of the evolution.

Mass Extinction: Mass extinction occurs due to rapid environmental changes.

Conclusion

Background extinction and mass extinction are the two types of extinction of species. Background extinction is a regular process of evolution, which is caused due to the incapability to adapt to regular environmental changes. Mass extinction occurs due to rapid environmental changes where species do not have sufficient time to adapt to the changes. Therefore, the main difference between background extinction and mass extinction is the rate of environmental changes and their effect on species.

Reference:

1. “Background extinction.” Dictionary.com. N.p., n.d. Web. Available here.  02 Aug. 2017. 
2. “Mass extinction.” Dictionary.com. N.p., n.d. Web. Available here. 02 Aug. 2017. 
3. “Mass Extinction.” AMNH. N.p., n.d. Web. Available here. 02 Aug. 2017.

Image Courtesy:

1. “Duck Tadorna Rusty Threatened With Extinction Bird” (CC0) via MaxPixel 
2. “Kainops invius lateral and ventral” By Moussa Direct Ltd. – Moussa Direct Ltd. image archive (CC BY-SA 3.0) via Commons Wikimedia

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