#blackrobin #evolution #natualselection #geneticdrift #conservation #learning
notes: In the video I say natural selection is not the only form of selection, before giving an example of what is technically natural selection, there are other forms of selection, those being artificial and sexual selection, though some evolutionary biologists will argue with that.
On a small group of islands east of New Zealand, lives a special little bird, the Chatham Island black robin. They became so rare in the 1980s every robin alive today is more closely related than siblings. Protecting genetic diversity is becoming a more and more important part of modern conservation efforts. Genetic diversity is critical for helping a species survive far into the future, as the more diverse a population is the higher chance when faced with change some will have a mutation advantageous to the new situation, making them more fit and allow the species to evolve into the future. That is what protecting genetic diversity is about, ensuring species can evolve. One way this happens is by natural selection. It is pretty simple, take for example the famed white sand dunes of New Mexico, these gypsum dunes make anything dark stand out, so over time predators have eaten all the darker colored members of the species here, and those that where the lightest rarely become predated on, driving the population, which is what is actually evolving, to be very light. The Cichlids of Lake Victoria had to evolve when invasive Nile perch changed their ecosystem. Migration shows another way of bringing genetic diversity into a population, Conservationists did this with the florida panther, a special subspecies of mountain lion, that had become inbred and many deleterious genes were being expressed. Of particular interest to conservation is genetic drift. It deals with how genes from parents are distributed into their offspring. Only some of the genetic material of any one parent makes it into their offspring, usually around 50%, this means that there is a probability a particular gene may or may not be in the offspring. This is not a huge issue in large populations, but in small populations of endangered species this can be devastating. What happens is by chance genes are passed on or not, and in such a small population certain traits can become fixed, that is every member of the population has the trait, and because it is random chance it doesn’t matter if it makes individuals in the population fitter or not, in fact drift can work against selection leading to extinction.

sources
Massaro, Melanie; Sainudiin, Raazesh; Merton, Don; Briskie, James V.; Poole, Anthony M.; Hale, Marie L. (2013). "Human-Assisted Spread of a Maladaptive Behavior in a Critically Endangered Bird". PLOS ONE. 8 (12): e79066. doi:10.1371/journal.pone.0079066. PMC 3857173. PMID 24348992 – via PLoS Journals.
Witte; Msuku; Wanink; Seehausen; Katunzi; Goudswaard; and Goldschmidt (2000). "Recovery of cichlid species in Lake Victoria: an examination of factors leading to differential extinction". Reviews in Fish Biology and Fisheries 10: 233–41.
Lowe-McConnell, R. (2009). "Fisheries and cichlid evolution in the African Great Lakes: progress and problems". Freshwater Reviews 2: 131–51.
The genetic rescue of the Florida panther, 2005 pdf, George Washington University

If you like animals and nature Please Subscribe and Like

This is Backyard Expeditions. Here you can find wildlife footage and short documentaries on the natural world. Nature is full of surprises, often amazing things are happening just feet from you door. I am a biology student who was inspired by the likes of the BBC natural history unit, PBS, and animal planet as a Child. I have also long been a hobbyist photographer, filming interesting things over time. My goal is to document interesting behavior and highlight interesting species I encounter both in exotic locations, and on backyard expeditions.



Underwater Worlds

   • Life Underwater  



Journey through the Undergrowth (Macro footage of insects and Arachnids)

   • Macro Filmography Documentaries  



Bird Playlist

   • How can Woodpeckers drill wood withou...  



Birding Playlist

   • Playlist  



Conservation Playlist

   • Fundamentals of Conservation Biology