Allison Pearson
Source: Scientific American
Author: Allie Wilkinson
Date Published: December 3rd, 2014
Summary
The Cuban Crocodile, one of the world’s most endangered crocodiles, is slowly losing its genetic identity. It has been interbreeding with its cousin, the American crocodile, and thus has created many hybrid offspring that are now beginning to populate the island of Cuba. With each generation of hybrids, more of the Cuban Crocodile genes are replaced by American crocodile genes and lost, and the species could eventually go extinct because of this. When the island crocodiles were sampled, about 50% of them were hybrids, a much higher number than previously recorded. This brings up a new question: if the Cuban Crocodiles and the American Crocodiles can interbreed and produce fertile offspring, are they still considered separate species? According to the biological species concept, no… however, even though by biological definition the breeding is “natural”, biologists are still approaching the situation as if they were two separate species, and are doing whatever they can to stop the interbreeding between them so that the Cuban Crocodile can keep its identity.
Connection
This article relates to our current unit in Biology, evolution. This unit discusses the definition of a species and how new ones are created. In Chapter 15.1, the biological species concept is explained, and in the article it is brought up in order to determine whether or not the two crocodiles are still considered separate species. If we follow the biological species concept and treat the Cuban Crocodile and the American Crocodile as the same species but two separate populations, this interbreeding is an example of gene flow (14.4), which is the exchange of genes between two populations. If the gene flow continues, it could reunite these two populations back into a single one, which is probably what they were originally. Overall, the interbreeding of these two populations of crocodiles is an example of evolution because it is causing fewer genetic differences between the populations and causing their traits to change.
If the Cuban Crocodile becomes extinct, how will this affect the environment it lives in and the animals it feeds on? Will the food chain be altered drastically?
ReplyDeleteIf the Cuban Crocodile becomes extinct, the food chain will be altered drastically. It feeds on small mammals, birds, reptiles, amphibians, fish, and invertebrates, and without anything feeding on these animals, they could overpopulate. This could also lead to an overpopulation of the American Crocodile and other species the Cuban Crocodile competes with, because there would be more available resources.
DeleteAre the American crocodile genes replacing the Cuban crocodile because the genes are dominant, or because there are more of the American crocodiles than Cuban?
ReplyDelete