Organism Physiology Paper
Samantha Oncher
BIO/101
April 11, 2016
Janet Moseley Sanders
Organism Physiology Paper
In this paper I will be giving a brief overview of the Western gray squirrel (Sciurus griseus) and I’ll describing the environment that the squirrel lives in, as well as explaining the major role the squirrel plays in its environment. I will also be discussing the main functions and structures of the western gray squirrel’s main organs and how the western gray squirrel has evolved physiologically to become suited to the environment around it. The last thing I will be examining is the changes if any that the western gray squirrel would have to face environmentally as well as biologically if transplanted to a significantly different environment.
One of three subspecies of native tree squirrels is the western gray squirrel. The western gray squirrel relies on the diverse old growth canopies of pine tree, oak tree, and fir tree forests, for natal dens, food, travel, and protection. The western gray squirrel will usually select larger patches of forested habitat usually away from human habitations. With an average body length of twelve inches and tail length of an additional twelve, the western gray is the largest of the native tree squirrels. This arboreal rodent has white-tipped gray hairs along much of its body and a white underbelly. It is noted for its large feet, pronounced reddish brown ears, and long bushy tail. Western gray squirrels do not hibernate, but will remain confined to their nests during periods of bad weather. Western grey squirrel's main source of food depends largely upon local habitat characteristics. Those that live in coniferous forests feed primarily on seeds of pinecones. Those that live in hardwood forests feed largely on nuts and acorns. There also known to eat berries, fungus, bark, sap, and insects. Western grey squirrels will feed on the ground as well as in trees. Like other squirrel species, they plan ahead and collect reserves of food when it is plentiful.
The western gray squirrels food caching habits play a vital role in the forest regeneration and forest ecosystem processes particularly by spreading fungi mychcorhizae, microbes vital for soil health and composition. Western gray squirrels eat a lot of seeds. Their seed caching activities may help disperse tree seeds, leading to fuller growth. They also prey on other animals in the ecosystem where they live. Western grey squirrels also provide a source of food for many predatory species within their habitat. Squirrels are hosts for parasites such as ticks, fleas, lice, and roundworms. The taxonomy classification for the western gray squirrel is as follows; Kingdome: Animalia, Phylum: Chordata, Class: Mammalia, Order: Rodentia, Family: Sciuridae, Scientific name: Sciurus Griseus ("Sciurus Griseus ", 2015).
There are allot of structures and functions found in the main organs of the western gray squirrel. The carotid arteries are major blood vessels in the neck that supply blood to the brain, neck, and face. The heart has four chambers: two atria and two ventricles. The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the oxygen-poor blood to the lungs. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle. The left ventricle pumps the oxygen-rich blood to the body. The lungs are main organs of the respiratory system that have the function of transporting oxygen from the air into the blood and removing carbon dioxide from the blood; located in the chest, one on the left and one on the right. The kidneys are a pair of organs that filter waste materials out of the blood and pass them out of the body as urine regulate blood pressure and the levels of water, salts, and minerals in the body produce hormones that control other body functions. The liver's main job is to filter the blood coming from the digestive tract, before passing it to the rest of the body. The liver also detoxifies chemicals and metabolizes drugs. As it does so, the liver secretes bile that ends up back in the intestines. The liver also makes proteins important for blood clotting and other functions. The brain is the portion of the central nervous system that is located within the skull. It functions as a primary receiver, organizer, and distributor of information for the body. It has a right half and a left half, each of which is called a hemisphere.
The western grey squirrel evolved from a smaller hairless rodents known as paraymids over thirty six million years ago. The major cause driving the evolution of squirrels is the geological and climatic change we see all over the world. The major evolutionary changes from the once known paraymids to the western grey squirrels is how they formed thick fur to keep warm. They adapted to living and nesting among trees to ensure their survival. They also evolved intellectually by storing their food supply when plentiful, instead of only gathering food at time of consumption.
If you were to take a population of western grey squirrels and relocate them to a significantly different environment, depending on how drastic the environmental change itself is could lead to the majority of the squirrels dying off. However, squirrels are known for their ability to adapt to ever changing climates and conditions. Squirrels can be located and traced all over the world from china to North America as well as in Australia. Western grey squirrels have been able to adapt to a number of habitats, as their native environments have become more urbanized and forests cleared. Though they require trees for nesting, squirrels will occasionally make use of outside leaf nests, eaves and attics, allowing them to thrive in suburban and urban areas, and areas without heavy forest cover. Because gray squirrels have a relatively flexible diet (and because acorns--a very common nut in many yards and parks--are a large part of their diet), they are able to further adapt to changing environmental conditions.
("The Other Side Of An Accurate Shot III", 2012). ("Western Grey Squirrel (sciurus Griseus)", n.d.).
Reference and Citations 1. Living with wildlife. (2016). Retrieved from http://www.dfw.state.or.us/wildlife/living_with/docs/TreeSquirrels.pdf 2. Sciurus griseus . (2015). Retrieved from http://www.iucnredlist.org/details/summary/20011/0 3. The OTHER side of an accurate shot III . (2012). Retrieved from http://www.ctcustomairguns.com/hectors-airgun-blog/archives/11-2013 4. Western Grey Squirrel (Sciurus griseus). (n.d.). Retrieved from http://www.planetscott.com/slideshow/albumViewLarge.asp?albumID=02597025e&iid=02862028090302102809 5. Anatomy of the Squirrel. (2000). Retrieved from https://repository.si.edu/bitstream/handle/10088/4757/VZ_rwt2.pdf?sequence=1 6. grey squirrel. (2014). Retrieved from http://www.arkive.org/grey-squirrel/sciurus-carolinensis/
