A bilaterally symettrical hog.
In American English, the term "hog" is used to refer to a grown swine. The terms "pig" and "hog" do not therefore refer to different species, but rather, to the same species at different stages of its life cycle. Being a mammal, hogs demonstrate bilateral symmetry. Bilateral symmetry is characterized by symmetry between the right side and left side, but not between the top and the bottom.
Types of Symmetry
There are two basic types of symmetry in biology: radial and bilateral. Radial symmetry is seen in an organism when an organism could be cut in half into equal sized pieces along many different lines. Bilateral symmetry is seen when an organism could be cut in half by a line going straight down the middle from top to bottom. Both types of symmetry are seen in biology, although bilateral symmetry is more common. Jellyfish have radial symmetry, while humans have bilateral symmetry.
Mammalian Features
Mammals are a class of vertebrate, air breathing animals who reproduce sexually. Some mammals are aquatic, but the fast majority are land based. All mammals demonstrate bilateral symmetry. There are many reasons for this; however, the main reason that mammals have bilateral symmetry is because having a streamlined body plan allows animals to do useful work. If one side of a mammal was much larger than another, it would have a hard time getting around. Asymmetrical animals, like sponges (not a mammal) are able to survive because they can simply soak up microscopic underwater food passively.
Hogs as Mammals
Hogs are members of the mammalian class, part of the order ariodactyla. Because hogs are a land dwelling mammal, they exhibit only bilateral symmetry. The reason for this becomes apparent when you consider the conditions the hog lives in. Being a land dweller with a large size, the hog cannot collect a sufficient quantity of food from simply passively absorbing microscopic nutrition. Thus, it must gather food using some kind of basic strategy, and bipedal locomotion (literally, two foot walking) helps tremendously in executing a food finding strategy.
Exceptions
The body plan of a hog is generally symmetrical. However, there can be exceptions in individual hogs, caused by genetic and environmental factors. Hogs have fur over their bodies, and it is possible for there to be asymmetrical patterns of coloration on their fur. This is the exception, of course, and not the rule. Also, if injured, hogs can experience asymmetrical growth from broken bones or injured muscles. This growth will be asymmetrical, based on the pattern of the hog's injury.
Tags: bilateral symmetry, symmetry seen, body plan, could half, demonstrate bilateral, demonstrate bilateral symmetry
