General Biology I: Discussion Board Post: Selective Pressure and Survival of the Fittest

Examples posted by other students

Hello Class and Professor.  The two organisms that I have chosen to look closer at are the polar bear and the cactus. I chose these because they live in drastically different climates that would be considered harsh environments.  The polar bear habitat consist of arctic sea ice. They can grow to be 9 ft long and weight up to 1300 lbs. This particular species has the perfect adaptations to be able to survive in this type of environment. Under their water-repellent fur, they have a thick layer of body fat that protects them by insulating them from the cold air and water. In spite of their tremendous weight, they are able to maintain a swimming speed of 6 milers per hour. They do this by paddling with their front paws and holding their back legs flat. While they do thrive in their environment, climate change is causing a decrease in the amount of arctic sea ice and therefore, as of May 2008, polar bears have been listed as an endangered species (World Wildlife Fund, 2015).  The cactus, or cacti for plural, have a great many adaptations that allow them to survive and thrive in their habitat. Most cacti species reside in desert environments while other in rain forests. The adaptations mentioned here will refer to those found in the desert. Most cacti species posses leaves that are reduced to spines. This is one of their many traits that minimize moisture loss and it also protects them from being eaten by herbivorous animals. The stems of the cacti have become thickened due to evolution which results in a perfect cylindrical shape and provides a high ration of volume to surface area, which also reduces moisture loss. This shape also protects the plant from getting too much sun exposure. Another benefit of the stem is that it creates a waxy coating that helps retain water while also absorbing it. Certain cacti have a taproot with a high saline content that allows for maximum uptake from fresh rain and for the plant to find water at lower depths than most plants (Hogan & Dawson, 2015). Thanks for reading.  Vickie References: World Wildlife Fund,. (2015). Polar Bear | Species | WWF. Retrieved from http://www.worldwildlife.org/species/polar-bear Hogan, M., & Dawson, A. (2015). Cactus. Eoearth.org. Retrieved from http://www.eoearth.org/view/article/162162/

Hello Class

The world has many different types of plants and animals and often times these things must adapt to their living environments in order to survive. I decided to choose an animal and a plant. I think my choices came from conversations that my son and I have had because is loves to find new and interesting things to tell me about on a regular basis. The animal I chose is a Blobfish, which yes it is a real fish if you have never heard of it, and the plant I chose if the Venus Flytrap. A habitat is defined as the place in which an animal or organism lives (Ireland, 2012) and a niche is defined as the job or role that an organism plays in the environment (Ireland, 2012).

The Blobfish is a fish that likes to live in the colder parts of the water which are normally way below sea level (ipfactly.com, 2014). Blobfish do not float to the surface like other fish do because they lack the air filled organ that other fish have called a swim bladder (ipfactly.com, 2014). In order for the Blobfish to survive in the lower depths of the sea, they cannot have a swim bladder or it would explode in the pressures of the water (ipfactly.com, 2014). In other words the Blobfish survives in its habitat because it lacks a certain organ which would otherwise help them to swim and float. The Blobfish thrives in its niche because it is a bottom dwelling fish that does not really swim. Blobfish hover over the ocean floor and do not swim really to get their food, it is proposed that they just suck in anything that swims past them (ipfactly.com, 2014).

The Venus flytrap is a plant that is actually a carnivorous plant. The Venus flytrap adapts to its environment by eating insects if they live in a low nutrient environment (Botanical Society of America, 2015). If the Venus flytrap lives in an area in which other plants may not be able to survive, this plant will eat living bugs that happen to land in their mouths. They use acids that they produce in order to break down the insect enough to digest it in a sense (Botanical Society of America, 2015). Venus flytraps survive in their niche because they in a way help to reduce the number of bothersome insects.

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