The Sixth Extinction

Natural selection

A theory, developed by Charles Darwin in the mid-19th century, that posits that the Earth’s species are locked in a perpetual struggle to survive and reproduce. Darwin had two key insights. First, that some species… (read full term analysis)


Popularized by Georges Cuvier in the early 19th century, catastrophism is a theory positing that species go extinct because of sudden, catastrophic events. Examples could include earthquakes, floods, or the massive asteroid impact that killed… (read full term analysis)


A process in which the Earth’s oceans absorb carbon dioxide and quickly becomes more acidic, endangering the survival of many marine species, including coral. Because it is caused by the absorption of carbon dioxide from… (read full term analysis)


The theory, popularized by Charles Lyell in the early 19th century, that species gradually go extinct over extended periods as a result of gradual changes, such as environmental changes, decreasing resources, and so on. As… (read full term analysis)


A term for the modern era of the Earth, beginning with the emergence of Homo sapiens (human beings) about 60,000 years ago. The term “Anthropocene,” which literally means “age of man,” suggests that the defining… (read full term analysis)
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