To Save a Mockingbird

2010/11/08
By Erik

This post was originally published on February 15, 2009.  

by Erik 

Check out the animation I created about my post. Enjoy! 


Darwin’s Mockingbirds! by spudinski01, made at DoInk.com 

On two small islands somewhere in the midst of the Galapagos Archipelago live some 100-200 mockingbirds. These specific mockingbirds however are some of the rarest bird species in the world, and the story that comes with them is so grand that while I type right now, I still don’t have a title. Let’s take a trip back in time. 

In September of 1835, the ship HMS Beagle arrived in the Galapagos Islands. Aboard this ship was a naturalist named Charles Darwin, and little did he know that while investigating this wondrous miniature world, he would start to form some of the most fundamental ideas in the history of science. It all starts with the Mockingbird. Darwin had encountered other mockingbirds on his travels through South America, but being the brilliant observer he was, something stood out to him while he visited the different islands. While on his travels through all of South America, the mockingbirds he found were mostly similar, but among the islands, the mockingbirds had very definite differences in size, beak, plumage, etc. He realized he was seeing more variation between Mockingbird species just miles apart than he had across the span of a whole continent. This got Darwin thinking. 

photo by ...Point&Click

photo by ...Point&Click

 

“I have specimens from 4 of the major islands, in each island each kind is exclusively found, the habits of all are indistinguishable, when I see these islands in sight of each other and possessed of but a scanty stock of animals, tenanted by these birds but slightly differing in structure and filling the same place in nature I must suspect they are only varieties … if there is the slightest foundation for these remarks, the zoology of these archipelagos will be well worth examining, for such facts would undermine the stability of species”- C. Darwin 

Basically, this is when his light-bulb flipped on, but it gets better. Today these very same birds are extremely endangered, and have vanished from from the island they used to inhabit, surviving on two small neighboring islets. The specific reason is somewhat hazy, but unfortunately, humans probably had something to do with it. At any rate, a conservation effort has been launched to re-introduce the mockingbirds to the island, and this is where it gets really cool. While among the islands Darwin collected four of these birds, each one different, and from a different island. Those very birds Darwin himself brought back over 150 years ago have had DNA samples taken from them to compare to the current surviving birds. By doing this scientists can see which birds today have DNA most similar to the mockingbirds back then, and use those birds for re-introducing as they would be best suited for the islands. The other awesome thing is that by looking at bird candidates, birds can be chosen who have the large gene variation as well. The idea behind this is to give them a jump start on adapting to their environment, since the individual with the best traits will survive, having more variation among individuals, helpful traits are more likely to turn up and help the species survive. 

Dr. Karen James of the Natural History Museum sums it up saying “We’re hoping to use the genetic profiles from the old specimens to help us select birds from the surviving populations to introduce to the old island.” Quite frankly, thank you Darwin, yet again. 

photo by Sparky the Neon Cat

photo by Sparky the Neon Cat

 

After finishing my initial post, I contacted Dr. Karen James herself to see if she could answer some questions. 

Q: Do you know if scientists used this method of “selecting the best” individuals in other conservation efforts? 

A: Most of the time they use these methods to monitor populations that have already been reintroduced; our project is one of the very few that proposes to use the method before the reintroduction, to select which birds should be reintroduced in the first place. 

Q: it seems like it would be a more effective way to “re-grow” a species, or more successful anyway. 

A: That’s the idea! 

-Happy Darwin Day to you and your class
Karen 

The natural History Museum at London is a highly regarded institution with a vast collection of specimens, and one of the biggest collections of historical scientific artwork in the world. It is definitely a good source to anyone who is interested. 

Are there any other species this method could be used for? How was the role Darwin’s Finches played in his thoughts on evolution different?

  • Dan

    Recently in the Taimyr Peninsula of Siberia, a almost perfectly preserved (but dead) mammoth had been found encased in ice. There is a huge possibility of being able to clone the mammoth via a modern day element. However, this mammoth is a female mammoth, and until another mammoth of the male gender then they may be able to restart the populace of mammoths. In addition there was an insufficient amount of DNA to create a clone. In the future, if there are better specimens of DNA, we may be able to recreate a mammoth regardless of keeping it as a species alive in the wild.

    http://www.actionbioscience.org/biotech/agenbroad.html

  • Andrea

    This is a very interesting post. I found some information on the first question. I found that scientists tried to regenerate an extinct animal called, the tasmanian tiger. This animal was a wolf-like animal that became extinct because of extensive hunting.
    The scientists regenerated this animal by taking some of the tasmanian tiger’s genes into an embryo of a mouse. After a while, the mice started to see that the bones in the mice were growing thicker and at a more rapid rate. A scientist stated that this was the first time that the transferring of DNA from an extinct animal has had a functional response. The article itself is below:
    http://www.guardian.co.uk/science/2008/may/20/genetics

  • Ms Baker

    Andrea and Dan,

    Those are both great examples of using DNA to restore extinct animals. However, the post really refers to currently endangered species and how we can use our understanding of natural selection and DNA to help save them.

    How was natural selection used to help the mockingbirds? Can it be used to help other endangered animals? If so, what kind of animals and how can it be done?

  • Dan

    Okay, thanks. In response, to the first question, artificial selection is used to help the mockingbirds by choosing the mockingbird with the finest traits (the one that will survive best in it’s environment)and giving it a head start, cultivating it and creating a large populous until they can be released into the wild as an adapted species that can survive further in the environment. I had a hard time finding an example of this being used, however I have found an article that mentions using artificial selection to make buffalo more resilient and numerous. Artificial selection and DNA modification are being practiced more and more (recently) in order to benefit either humans or the species being modified; we can only hope that some of it is going towards benefiting the species itself. Certain plants are being genetically modified to kill pests that are wiping out the species. E.G. a GM (genetically modified) corn named “Bt-corn” has been developed to grow a bacterium that creates insecticides, in order to expand the life expectancy of corn and get yields of corn without the cost of farming pesticides.

    http://lwicker.myweb.uga.edu/corn.htm
    http://www.buffalofieldcampaign.org/legal/esatalkpoints.html

  • Sabrina

    How was the role Darwin’s Finches played in his thoughts on evolution different?
    Darwins finches played differently then his thoughts on evolution because, the Finches played as an example for natural selection through evolution. It proved that natural selection can produce evolutionary change. The beaks of the Finches were a significant aspect to his natural selection process.
    This website tells more in depth about how to classify the different finches: http://txtwriter.com/Backgrounders/Evolution/EVpage05.html

  • Cartland

    Well, this post is really good! The topic stands out for me, I never get a chance to really notice that how Darwin come up the idea about the nature selection.
    It make me think about the example we discussed before during the class with was the non-poisonous king snakes mimic coral snake. I think it will also be an example for natural selection. The non-poisonous king snakes mimic coral snake in order to survive. If they don’t mimic coral snake, they might be eaten by predators. So they can not make their biological goal which is survive to reproduce. So they mimic coral snakes in the area that coral snakes live(we know that it won’t work that well if it is in the area which coral snakes do not live).
    The mockingbirds change their beaks because of the condition changes, the non-poisonous king snakes changes in order to live. They both want to survive during the condition to reproduce.

    source:
    http://evolution.berkeley.edu/evosite/evo101/IIIE1Atwork.shtml

    and biology text book

  • Naseem

    On the topic of natural selection, I just found this amazing article about a study performed by biologists Ryan Calsbeek and Robert M. Cox of Dartmouth College. These two researchers tested Caribbean Anolis lizards, a highly invasive species native to the Bahamas and Cuba, were experimented to see if natural selection can also occur by competition. Researchers covered the first island with bird proof netting, in order to keep bird predators away. Another island was left exposed to bird predators, and then another different island had bird predators and snake predators as well. The researchers observed mortality rates of the lizards on each island, and found that death by predators happened randomly with respect to certain traits like body size and stamina. Then they found that when a population is highly dense and crowded in an area, competition for resources is more likely to increase, and when that happens it favors more physically able lizards. What I really liked about this study was that, after just learning about Darwin and his evolutionary theory, and watching that Creation movie to understand his character more, I feel like this study was really an actual experiment that actually showed Darwin’s theory in action, fully and all in a big experiment spanning islands, rather than just in one instance where you just see it happen. I mean, here a lot of work went into this experiment, and it all played right before you in a big setting, like in the wild. Even Calsbeek and Cox mention that in the article on their study, this kind of experiment really opens the public to evolutionary biology’s “historical science” in the basic, experimental sense.

    Abstract:http://www.nature.com/nature/journal/v465/n7298/full/nature09020.html
    http://www.ncbi.nlm.nih.gov/pubmed/20453837

    Article:http://www.sciencedaily.com/releases/2010/05/100510105033.htm

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