Zombies=Good?

Cannibalistic tadpoles are a big part of the ecosystem although you may have never heard of them. Research has proven that cannibalistic tadpoles and matricidal worms assist with evolution. These tadpoles normally ate algae and crustaceans, but they were observed spawning tadpoles that were not the same as these normal ones. The features were different from these tadpoles. They had bulging jaw muscles and serrated mouthparts. They were very aggressive and ate much bigger food than normal. It was noticed that the two very different tadpoles had the same parents, and the same genetic makeup. How could it be possible that they were so different in physical features and behavior? The explanation for this is the fact that these tadpoles display phenotypic plasticity. Phenotypic plasticity is the ability to change how they look and act and how their tissues function all in response to their environment. When prey is small and abundant, the jaw becomes small and mild. When there is fairy shrimp, which are much bigger, the tadpoles become much more aggressive. They grow much faster on the extra protein that they get from these fairy shrimp. A more recent study proves why phenotypic plasticity can set up permanent adjustments to species. In one species of toad, the carnivorous stage had no need for a diet. An experiment was done on tadpoles to try and confirm this. There were tadpoles that were raised on diets with varying sizes of fairy shrimp. The tadpoles that had 100% shrimp diet developed a short gut which was better for a carnivorous diet. It also had mouthparts that were altered but very badly adapted. This meant limited plasticity for these tadpoles with a 100% shrimp diet. If the tadpoles get a diet with little or no shrimp, they reverse the adaptations and none of this would occur. The phenotypic plasticity helps with evolution because of the adaptation of the jaw and other physical features based on the diet and environment around them. Another example of this would be lizards. Side-blotched lizards adjust their color to match the environment. Populations developed because of these lizards. After a volcanic eruption, the species moved onto the lava field and the environment favored more camouflaged lizards and mutations allowed them to become as dark as possible and evolve this way. Another experiment was done that switched tan and dark lizards between sandy and lava surfaces. It was observed that the skin colors were changed and adjusted to the new environment within a few weeks. Another observation was that the tan lizards did not get as dark as the actual dark lizards were originally, so it was inferred that they had a genetic indifference that did not allow them to change color as easily. The reason to this was a mystery until a later researcher found that there were genes in the offspring that were mutated in the darker lizard, which finally gave an explanation to why the tan lizards did not have the ability to change colors as easily. This was all a result of phenotypic plasticity and it proves the ability of it to be able to assist evolution. The cannibalistic tadpole and the lizard are only a few species that have phenotypic plasticity and others can also help assist with evolution in the future.

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Biology Teacher

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