A Little Bit More
Antler growth begins in spring, as increased day length stimulates the pituitary gland to produce testosterone (male hormone). The paired antlers each grow from a short base on the bones of the skull, called the pedicel and are entirely bony, excluding the velvet covering. Antlers are among the fastest-growing forms of animal tissue anywhere and an impressive rack (name for a set of antlers) can be completed by autumn.
During growth, the velvet nourishes the antlers from the outside (unlike horns that are nourished from the center and are not shed). While the antlers are growing, they are pliable and easily damaged. The bucks seem to be aware of their “delicate condition” and are careful not to bump or rub their racks. Antler development requires a considerable amount of energy and is not an indication of age but of nutrition. A buck may produce a multiple-point rack as early as its second year, skipping the “spike” stage, if food quantity and quality are adequate. However, a young buck requires twice the amount of protein and nutrients as an adult male since the young animal is still growing, as well as, developing its antlers so second-year racks are not normal.
By summer’s end, if the antlers have not been damaged, the two sides should be symmetrical. Growth ceases as cells at the base of each antler cut off the blood supply and the velvet dries out and peels. At this point the bucks seem eager to hasten the peeling process and rub their antlers on branches and saplings. “Buck rub” is a common sight every fall where deer are found. Soon after the antlers are clear of the velvet the buck’s neck muscles begin to enlarge in “anticipation” of the battles to come. Interest in food wanes at this time and the bucks begin to lose weight as they spend most of their energy sparring with other bucks and pursuing females.
Activities
Science – Symmetrical
Objectives: Better understanding of symmetry in nature
Materials: Digital camera, computer photo manipulation software
Symmetrical – capable of division by a longitudinal plane into two similar halves.
In nature, most organisms are symmetrical – one side is a mirror image of the other. Although we know this to be “basically true” it is not as accurate as we make it out to be. This is an activity that will emphasize the fact that although we’re “similar” on both halves of our bodies, we’re not the “exact same”. I think you and your students will find this intriguing.
The goal here is to use a full photo of a person’s head and make two photos, one with identical left halves and a second with identical right halves.
- Take a digital photo of someone in your class/home. This photo should be a directly front-on portrait shot filling the format reasonably well (like a passport photo).
- Download your photo onto a computer
- Using your computer software, create a “new” photo of the person with two identical halves of their face (two right sides as one and two left sides as the other).
- Print out the two remade photos, as well as the original photo, so students can easily see all three.
Do the two modified photos of this person look any different than the original photo?
Why does this person look different than their photos?
Do you find the “left” photo any more appealing than the “right” photo?
As I think you will see, although we ARE symmetrical, we’re not as much a mirror copy from one side to the other as we might assume. I guess this is why some people like to be photographed from a certain angle (they feel one side looks better than another).
Key Concepts
Structures and Functions, Life Cycles, Growth and Development
Questions
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