1. Humans are motivating evolution by introducing animal invaders to the surroundings such as the cane toad. Cane toads were introduced to control pest, specifically the cane beetle in sugar cane plantations. These toads were brought to Australia in 1935 to control the beetles and they got set up in the area. The problem with this arrangement was that the toads come out at night and the beetles strive in the day time (Kringer, 2013). Also the beetles live high up in the sugar canes and the toads are at the bottom of the sugar canes making it impossible to be able to eat the cane beetles (Kringer, 2013). These species responded to the climate and surroundings very well, predators could not eat them because the cane toads have poison gland that will kill any animal or organism that will intent to get to close. As part of the evolution adjustment cane toads develop longer legs that help in the habitat they live in. These animals are having a big effect in the areas where they live, predators like the green tree snakes are also evolving with smaller mouth, this way they will not eat the poisonous toads which are big in size. In the other hand the black snakes are developing resistance to the toad poison (Kringer, 2013). So, not only the cane toad evolved in the new environment, but force other animals to also evolve in order to survive. The cane toads can reproduce so fast and are so well adapted to the environment that now they compete with the regular native frogs for food plus there are expanding, similar to an invasion, into much bigger areas of Australia (Kringer, 2013). If this continues, it will cost a lot of money to control and manage something that started as an idea to get rid of a pest and become a pest itself.

Kringer, K. (2013). Invasive Species. Cane Toads. Retrieved from nonprofit organization

2. Humans have had a role in the changing of multiple species, from designer dogs and cats, to larger and sweeter ears of corn; but I chose the humble chicken to write my initial discussion post on. Modern chickens are very different than they were decades ago, thanks mostly to selective breeding. There are two basic types of chicken now, and they egg-layers and meat chickens. Between the two of them, the egg-layers resemble the original chicken the most, and even they have been tinkered with some, by breeding the chickens that had the highest amount of eggs laid at one time, resulting in a breed of chicken that lays pretty much daily. The other type of chicken is the more interesting, at least in my opinion. The meat chicken, or broiler, is the result of breeding chickens that have a mutation in the gene that regulates their metabolism, causing them to gain weight at an increased rate. Interestingly enough, this is also the gene that can lead to obesity in humans. One of the resources I found while looking up information for the topic was a link to a project that compares the growth rates between the two types of chickens, starting from when they hatched, and ending when they were six weeks old. They were fed the exact same diets, but by the end of the experiment, the meat chickens weighed in about four times greater than the egg-layer chickens, clearly showing that the mutation has made this breed of chicken perfect for the dinner table.

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