Tails for Stress

 

Article:

• http://www.sciencedaily.com/releases/2013/03/130305200204.htm

Simliar Links:

• http://science.nbcnews.com/_news/2013/03/05/17199563-stressed-out-tadpoles-pump-up-their-tails?lite
• http://news.yahoo.com/stressed-tadpoles-pump-tails-000515982.html

When humans or animals are put into stressful environments, the body releases hormones know a the "fight or flight response". Scientists at the University of Michigan have discovered that when developing animals feel threatened, their bodies' can alter shapes. The scientist at the university have conducted many experiments to show tadpoles' tails increase when they are under stress. One of the professors, Robert Denver, said the animals change their shape as a survival mechanism. Tadpoles can also alter their shape and speed up the rate of metamorphosis with a drying water source, lack of food, or a high population of predators. This term of animals changing their body due to the environment is call phenotypic plasticity. The scientists used wood frog tadpoles and added a stress hormone to the environment. Some of the tadpoles were put in tanks. Dragonfly larvae, which eat tadpoles, were placed in small cages inside the tanks and were fed live tadpoles. When under attack, tadpoles release chemical signals called pheromones that travel through the water. The signals alerted other tadpoles of predators. The scientists found that tadpoles repeatedly exposed to the alarm pheromone over several days showed elevated whole-body levels of the hormone. In the laboratory, other tadpoles were exposed either to the alarm pheromone, to the hormone, or to a chemical that blocks the synthesis of the stress hormone. Over the course of the experiment, tadpoles treated with either the pheromone or the stress hormone developed longer, wider tails.



NOS:

• Science is collaborative
• Science is based on evidence
• Role of credibility
• Importance of repeatability
• Role of motive and curiosity