Bottlenecks
Bottlenecks
We now know species can go from huge populations sizes numbering in the billions to extinct in a short period of time. The explanation is a drop in genetic diversity.
Learning Objective: Explain how a genetic bottleneck can occur, how it can lead to extinction, and provide a representative species that has experienced a bottleneck event.
The birth of a Giant Panda in captivity is a global event. With less than 250 in captivity and an estimated 1,000-2000 in 40 reserves in China, this species remains vulnerable to extinction. The panda’s brush with extinction appears to have begun approximately 43,000 years ago with a “bottleneck event” that greatly reduced its population size and genetic diversity. More recent habitat loss almost dealt a fatal blow to this iconic species.
This video introduces what a “bottleneck event” is and how it relates to genetic diversity and species survival.
Watch this video; you can select the closed captioning “cc” option if you would like to see the text.
Although the Northern Elephant Seal has dramatically rebounded in population size, it will take generations for new mutations to arise, increasing the diversity of alleles. In the mean time, the species will most likely be more vulnerable to environmental fluctuations, including pathogens, than it had been prior to the bottleneck event and drop in allele diversity.
The next section introduces the factors that lead a species to become endangered as well as possible solutions.
Check your knowledge – Bottlenecks
Review your notes. Can you explain how a decrease in genetic diversity can lead to extinction? If so, move forward to the next page.
Learning Objective:
Explain how a genetic bottleneck can occur, how it can lead to extinction, and provide a representative species that has experienced a bottleneck event.
Go back to the Extinctions Page
Go forward to the Endangered Species Page
Conservation Contents
Complete all five of these sections before taking the quiz and submitting your media piece.
This Module
10: What do I do next?
This Guide
10A: Conservation
Products Information
10A: Quiz & Media
