Category: Evolution 2024

Posted on

The Rebirth of the Guadalupe Fur Seal

Title
Genetic Consequences of a Severe Population Bottleneck in the Guadalupe Fur Seal (Arctocephalus townsendi)


Background
The paper titled “the Genetic Consequences of a Severe Population Bottleneck in the Guadalupe Fur Seal (Arctocephalus townsendi)” describes how genetic diversity is influenced by the sharp decline of the Guadalupe Fur Seal population in the 1700 and 1800s and the slow recovery of its population numbers.
In the 1800s the Guadalupe Fur seal declined to an extent to be considered in a population bottleneck; which is an event where a population goes through a restriction point similar to squeezing water through a narrow pipe. This event can occur naturally to different animal populations due to numerous reasons such as disease outbreak or natural disasters. In the case of the Guadalupe Fur Seal however, it was human interest that drove them to the brink of extinction.

Continue reading “The Rebirth of the Guadalupe Fur Seal”
Posted on

Wrangel Island Mammoths

Background

Recent research sheds new light on this ancient puzzle, revealing intriguing insights into the timing and circumstances of mammoth extinction, especially focusing on the remarkable tale of the Wrangel Island mammoths, an island in the Arctic Ocean near Northern Siberia.

 In the Late Pleistocene there was rapid, worldwide decline of megafauna, partially due to changes in climate. This caused mammoths to spread off into isolated populations off the coasts of Siberia and Alaska using the Bering land bridge. Rising sea levels trapped mammoths on Wrangel island 6,000 years ago, before eventually the mammoths went extinct 4,000 years ago. The cause of mammoth extinction is still under debate though, some think it might be caused by population bottlenecks, local extinction/recolonization events.  Sampling bias could have also played a role in having inaccurate timing  of extinction, which makes interpretations of the causes of  extinction challenging (Dehasque et al., 2021; Guthrie, 2004; Nystrom et al., 2010).

Continue reading “Wrangel Island Mammoths”