Thursday, 25 October 2012

Evo-Devo Michael Vo s4287578


Harvard’s developmental biologist Cliff Tabin said the ‘fundamental aspect of evo devo is understanding how development is tweaked over time’ (J. Rubin, 2009).
How can a chicken and a human have such similar genetic makeup yet turn out, through development, to be completely different? The answer is in the genes. The embryo is generally the starting point for all species. In figure 3 it shows a number of species from their embryonic stage, to half way through its initial development to its final development before birth. As it develops, different combinations of genes are switched on giving the species different traits. Different factors can change the combination of genes that are switched on. These changes allow the species to adapt and survive depending on the circumstance. The University of Massachusetts published an article describing the environment’s effect on evolution of survival traits.
The Cichlid fish pronounced –sik-lid is ideal example of evolution – it has developed over 1000 new species in the past one million years. The study was conducted on jaw adaptation because the jaw is majorly linked to survival, making it an ideal marker. The study focused on the evolutionary development of the cichlid fish and how their jaws evolved when put in different feeding environments. The fish that were forced to feed from the bottom of the water eventually developed different jaws to the fish that had to feed from the surface of the water. Their individual adaptations were different because of the ways they had to eat. The fish whose only food source was on the bottom of the environment developed short, stout jaws for scraping their food from rocks as opposed to the the long jaws for catching food while swimming, found in the other fish. The article states that “biodiversity is due not only to differences in genes, but to changes in how and when genes are expressed.”(ScienceDaily, 2012).
Even though the fish in the study had the same genetic make-up, their physical development was different due to their environment and food source. What this means it that it’s possible for two creatures with the same or very similar genes to look entirely different when fully developed, even though as embryos they looked incredibly similar. Figure 1 gives an idea of all the variations of the same type of species that were found in different environments, while figure 2 shows 4 lower jaws from different breeds of Cichlid fish.  These two images show how the environment can affect a species shape, colour size and other physical attributes.
Looking at how the environment changes the physical qualities of a species is only one small part of the subject of evolution and development. Other interesting topics describe why bats developed wings, how dogs will eventually grow off its extra toe tail and also how toads/frogs will develop teeth. Other research papers of evo devo can predict distinct qualities of some species just by examining the environment. (Viegas, J., 2010)
Evo devo is a relatively new concept, changing the way scientists look at evolution.



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