There are 5 major mass extinctions but there have however been many more that have occurred throughout earths history that are potentially larger and more catastrophic than the big 5. It is difficult to compare these extinctions as the fossil record gets more incomplete the further back in time you go. The fossil record is also inconsistent with particular conditions favoring the preservation of fossil providing misleading information to the diversity at the time.
why watch this video?
Have you ever wondered if there where more than the big 5 mass extinctions?
Would you like to know why it is difficult to compare mass extinctions other than the big 5?
Have you ever been confused by the inconsistency of the fossil record?
Mass extinctions: the extinction of a large variety of species in a short window of time
The big 5: commonly believed to have been the biggest die-offs in Earths history.
Diversity curve: the taxonomic diversity at a particular time
- Although the “big five” mass extinctions are commonly believed to have been the biggest die offs in earths history this may not be the case. It is nearly impossible to compare mass extinctions such as the great oxygenation event with the big 5 as the species killed were microscopic and not preserved in the fossil record.
- One aspect of this video that may cause some confusion is the fossil record which is inconsistent and captures different fractions of diversity in different periods. The fossils preserved are also a factor of the conditions of the area as swampy areas preserve better.
- The way that evolution is affected after a mass extinction varies with some causing extinction at the species level and some wiping things out at a higher taxonomic level. Those that wipe out at a higher taxonomic levels alter the evolutionary scale in a grander way .
Self test questions
- What is a mass extinction
a) When more than 5 species die
b) The extinction of a large variety of species in a short window of time
c) The extinction of greater than 10 species
d) When the change in climate causes an extinction
2. Why is it difficult to compare mass extinctions?
a) The fossil record gets less complete the older it gets
b) There are only 5 and everything else must be compared to those
c) The death of certain species ranks above the death of others
d )The fossil record changes
3. Why do different mass extinctions after evolution differently?
a) Like snowflakes they are all different
b) some cause an even extinction across all branches of the evolutionary tree while some directly impact certain branches
c) evolution is unpredictable
d) the 5 mass extinctions create precedence
4. how many mass extinctions have there been?
c) Impossible to say as older extinctions have minimal evidence in the fossil record
5. Who classified the 5 major mass extinctions?
a) Carolus Linnaeus
b) Charles Darwin
c) James Hutton
d) Jack Sepkoski
answers: 1. B 2. A 3. B 4. C 5. D
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