Store Is Closed
Jul 30 2011 7:07:39 pm ESTTopics:
From the Genetics Science Learning Center at the University of Utah, I found this excellent Flash animation that displays a scaled representation of various organisms, bacteria, viruses, and molecules down to a carbon atom.
The animation helps put in perspective the size of the systems responsible for life. In particular, I am surprised by the size of viruses, and can appreciate the difficulty in detecting them.
Jul 25 2011 5:00:00 pm ESTTopics:
D’Arcy Wentworth Thompson notes that there is a tendency in all organisms for bodily surface to keep pace with volume.
Multicellular organisms, like unicellular organisms, require a constant supply of nutrients and various gasses. A unicellular organism may absorb the various nutrients and respiratory gases directly from their surrounding environment. However, as the sheer quantity of cells increases in an organism, the distance between the environment and the cells increases, and various organ systems are required to transport nutrients and gasses.
The circulatory system utilizes fractal branching structures to maximize surface area for distribution of these gases and nutrients. Air sacs and alveoli greatly increase the respiratory surface of the lung. The long tract of the intestine is itself lined with small villi to maximize nutrient absorption. These systems each utilize some method to increase surface area to keep pace with volume. Consider the following passage from “On G
Jul 22 2011 5:00:00 pm ESTTopics:
The remarkable diversity in color and iridescence of birds is achieved by pigments and structural colors.
Pigments are colored substances that reflect certain wavelengths of light, while absorbing others. It is the reflected light that is identified as the pigment’s color. Pigments are located on the skin or feathers of the bird and are independent of the structure of the feather. Bird pigments come in three different groups: melanins, carotenoids, and porphyrines.
Melanins are the primary determinate in human skin color. They also serve to color the skin and feathers of birds, as well as providing strength and durability to feathers. Melanins produce blacks, reddish browns, and pale yellows.
Interestingly, a feather without any pigmentation is the weakest of all. White birds will often have melanin fortified black feathers on their wings where they are subject to the greatest stress.
Carotenoids are naturally occurring organic pigments in the chloroplasts and chromoplas
Jul 21 2011 10:15:55 am ESTTopics:
From the entire range of the electromagnetic spectrum, most life that can perceive light evolved to perceive a narrow band—the visible light spectrum (400 nm-700 nm). This range of perception is based on hundreds of millions of years of adaptation.
An interesting phenomenon of the visible spectrum is that it penetrates water by about 6 orders of magnitude better than adjacent frequencies. In other words, the visible spectrum penetrates water much better than other frequencies. This phenomena is demonstrated in the graph below (Fernald, 1997).
Jul 18 2011 5:00:00 pm ESTTopics:
Many biological systems vary in proportion to the size of the animal. For example, as an animal increases in size, the skeletal system must increase in proportion to handle the added weight. However, the eye has ranges and limitations of magnitude of its own, resulting in less straightforward scaling.
From the simple eyespots of a unicellular organism, to the diverse range of simple and compound eyes of multicellular organisms, the eye has evolved to detect a narrow band of electromagnetic radiation: visible light. In the case of the unicellular organism, it might only be able to detect the presence of light and perhaps its direction. Whereas vertebrates have evolved to differentiate wavelengths of light as color, and determine shape and movement. In all cases, the shape and size of the eye is determined more by what the animal needs to see and less by the animal’s size. As D’Arcy Wentworth Thompson points out, “A big do
Jul 7 2011 5:00:00 pm ESTTopics:
I published a trail review of Wright Peak, Algonquin Peak, and Iroquois Peak from Heart Lake.
From Heart Lake, the trail to Algonquin Peak, the second highest summit in New York, is a manageable day hike. Along the way, the hiker has an opportunity to summit Wright Peak and Iroquois Peak, both high peak summits. From Heart Lake, the hike to Wright Peak is 3.8 mi, adding in a .4 mi spur from the main Algonquin trail. Not factoring in this spur, the distance to Algonquin peak is 4.3 mi, though some of this is relatively steep with some scrambling.
From the summit of Algonquin, an unmarked, but relatively well established trail leads to another high peak, Iroquois. The distance from the Van Hoevenberg trailhead to Iroquois Peak, not factoring in the Wright spur trail, is a sometimes difficult 5.4 mi.
Overall, this is an excellent warm up day hike for the high peaks. If Algonquin seems out of r
I recently published a photo gallery of the Indian Ladder Trail. The trail is carved within the Helderberg Escarpment, and traverses the Indian Ladder Gulf. The limestone escarpment is replete with fossils and underground streams.
The trail traverses many rock shelters and passes under two impressive waterfalls. The Empire State Plaza in Albany can be seen over ten miles away, as well as much of the surrounding region to a great distance.
I recently visited the Huyck Preserve in Rensselaerville, NY. A network of loop trails traverse Lake Myosotis, Lincoln Pond, Rensselaerville Falls, both natural and man-made dams, and the surrounding watershed within the 2000 acre preserve.
I posted a gallery of photographs from my explorations. Overall, I felt the trails were easy going with pleasant views.