The Chatham Islands Robin (Petroica traversi), also known as the black robin, once had a dangerously small population — in 1980, only five birds remained, including just one fertile female, named Old Blue. With careful conservation, the population has now increased, but all modern black robins are descended from that small founding group.
This is an example of a genetic bottleneck, where a population experiences a dramatic reduction in numbers, leading to a loss of genetic variation.
Your Challenge:
What do you think a genetic bottleneck is? How could such a severe loss in population size affect the gene pool of the Chatham Islands Robin — and why does this matter for its future survival?
Genetic Population is a ruduction in population of a species due to enviorment events or human activities. When gene loss occurs in a population, it reduces the genetic variation amongst the livng creatures and makes it harder for them to survive because genetic variation is needed for a population to survive. This is a problem because the future generation may not have the genetic variation to survive in changes of enviormental events or human activities.
Genetic bottleneck*
Nice definition to start but include the word drastic when talking about the reduction. Perhaps elaborate on the cause. The elaborate on possible environmental and long term challenges
Population Bottleneck is when there is a great reduction in size within a population due to catastrophic disasters, for example, volcanoes. Survivors then reproduce and have what few alleles they share passed down onto future generations, resulting in genetic drift. A change in the allele frequency. A gene pool is the overall sum of different alleles present in a reproducing population.
The black robin went through population bottleneck by facing a great reduction in size and ended up having 5 individuals, with only one fertile female. After careful conservation their numbers went back up but the genetic diversity within the population’s gene pool was not the same as its original population. This is because many alleles were killed off meaning that those few survivors are the only descendants of the next generations. This affects their future because having low genetic diversity means the population is less able to survive against environmental changes.
Nice definition but what was the cause of the bottleneck in this case. Good statement about the reaction to environmental challenges but you should elaborate on the long term challenges for the black robin
A genetic bottleneck is a sharp reduction in population size, often caused by events like natural disasters or human activities, which significantly limits genetic diversity within a species. In the case of this the Chatham Islands Robin, an extreme bottleneck occurred when the population decreased to just a small amount of individuals, meaning the recovery population descended from a very limited gene pool. This reduction results in decreased genetic variation and an increased risk of inbreeding, potentially making the population less able to adapt to environmental changes or resist new diseases. For the Chatham Islands Robin, while there were concerns that the severe bottleneck would lead to an accumulation of harmful genetic flaws and threaten long-term survival, recent studies suggest that negative impacts like mutational load may not have increased as much as expected. Regardless, such genetic reduction remains a critical concern for the species’ future resilience and adaptability, meaning close genetic monitoring and conservation management are essential for its survival.
A population bottleneck is the reduction of alleles in a population due to an unselective natural disaster that drastically reduces its population size. the remaining surviving population are unlikely to be representative of the original population.
when severe loss in a population occurs (a population bottleneck), this can significantly affect the genetic diversity (alleles) within the gene pool. This reduction in genetic diversity can make the population more vulnerable to future environmental disasters, as they are less likely to adapt quickly to the changes. This can lead to further decline in population numbers, or in worse cases extinction. This can be seen from the population on the Chatham islands, the black robins had experienced a population bottleneck, leading to a severe loss in their numbers (having only 5 remaining). Due to that loss in numbers, you can see some of their alleles were lost too, as all the robins that came next, only inherited a select few alleles from the small population that remained.
Good answer touching on merit level. We need to elaborate on the causes and impacts for a higher grade.
Population bottleneck refers to when a population is reduced to low numbers due to human action, climate change or catastrophic environmental effects. The smaller surviving population is unlikely to be representative of the alleles within the original population.
Such a severe loss in population size will affect the gene pool of the Chatham Islands Robin as increased interbreeding may occur due to the surviving robins being forced to breed together. Genetic drift may act to further vary the genetic diversity. Alleles which once might have helped some individuals survive disease and illness may be lost, therefore putting the population at risk. The loss of genetic diversity may slow the process of adaptation therefore hindering the species chance at survival.
Mention inability to adapt to environmental changes and elaobarote on the lots of good generic statements you have made
Genetic bottleneck effect is the largely reduced of population numbers due to humans interference in some way whether it be habitat destruction, new predators being introduced or other human inflicted pressures. With only one fertile female and four other birds the populations gene pool will only have very little amounts of variation due to the fact that there aren’t many alleles to work with in the first place. The recovery will be slow and most species won’t have adaptations needed to fight natural illnesses and wild predators due to the mass amounts of conservation in order to just preserve the species. The modern version of the species would be less likely to be able to survive in the wild if set free and could once more reduce the population to low numbers.
More needed on the causes of the bottleneck in this case. Really good points about the long term impact!
Well done
A genetic bottleneck effect is a large reduction in the size of a population which is often caused by human activities or natural disasters and leads to a drastic decrease in genetic diversity. A gene pool is a combination of all genes present in reproducing species.
The Chatham Islands Robin experienced a genetic bottleneck when in 1980 only five birds remained due to being hunted by predators. After the species was then taken for safekeeping, the population increased but still wasn’t the same in numbers as the original population and neither was the genetic diversity, this decreases the chance of the species future survival.
Looks great so far girls!. Just elaborate on the specifics of this case. eg, The lack of genetic diversity impairs their ability to respond to environmental changes such as new predators, disease, etc
Genetic bottleneck occurs when a population’s size is drastically reduced, leading to a loss of genetic diversity. This reduction can be caused by natural disasters, disease outbreaks, or human activities, and it results in a smaller gene pool with fewer variations. A severe loss in population size within the black robin can significantly reduce genetic diversity within the species gene pool. This occurs because the small, left over number of black robins were left to reproduce. This could have potentially led to the loss of certain alleles and a less representative set of genetic traits compared to the original population. The reduced genetic diversity can make the species more vulnerable to environmental changes and diseases.