asalamon's blog

One longstanding debate in the field of biology is whether or not viruses should be considered alive.  Viruses are composed of a protien coat with some form of genetic material contained on the inside.  Unlike all other species not debated as "living," viruses lack the ability to reproduce on their own because of their simple design.  Instead, viruses are only able to reproduce or replicate within a host.  They use the machinery present in their host cells to replicate and spread the virus.  For those who believe viruses are not alive, this is the main point they cite.  Without a host cell, virsuses would not be able to survive therefore should not be considered alive.  The opposition believes viruses should be considered alive because of the success they have at infultrating thier hosts and reproducing.  Like all other species considered alive, success by a virus should be determined by their reproductive fitness.  Those who are not fit are removed from the population while those fit to survive pass on their ability to the next generation.  The niche that viruses find themselves in the ecosystem is one that they have remained in since their discovery.  Yes, they need a host but a host is their niche.  If they were not fit for this niche they would not survive or exist in the living world but they do.

While in class on September 6, Professor Brewer passed out an object that appeared to be some sort of organic plant trimmig.  The trimming contained three leaves and a stem.  The stem ended to become the base which all the leaves grew from. Of the three leaves, one extended straight from the branch.  This leaf was the longest of the three with a diamond-like shape with the edges having a slight scalloped appearance.  The other two leaves extended from the stem at approximatly 90* angles.  These leaves were shorter and stockier in appearance but still had the diamond-like shape with scalloped edges.  Due to the orientation of the leaves with the stem, there is bilateral symmetry expressed by this plant trimming.  The trimmed stem is a reddish color and extends about a third to halfway into the central plane of the leaf until it changes into the light green of the rest of the veins of the leaves.  From the central vein of each leaf, all other branches of veins emerge from in a pattern similar to the bronchi of the lungs.  The light color of the veins contrasts the bright medium to dark shade of the leaf's front and matches the lighter green of the underside of the leaf. From the underside of the leaf, the veins are still visable but only as raised lines of the leaf.  The underside of the leaf is softer with a slight texture while the front side is waxy, most likely the cuticle of the plant. 

The object passed out by Professor Brewer appears to be some sore of plant trimmig.  The trimming contians 3 leaves: one extends straight forward and two protrude from the end of the stem before the central leaf at 90* angles from the central stem.  The is a bilateral apperance to the symmetry.  The central leaf is longer than the other two and appears to be more elongated while the other two are more stocky in appearance.  The trimme stem is reddish and extends about a third to halfway into the leaves as the veins in the leaves.  When in the leaf, this color changes into a light yellow/green.  The veins in the leaves start with one central vein and branch off like the bronchi of the lungs.  The light color of the veins contrast the bright medium to dark shade of the leaf's front and matches the lighter yellow/green of the underside of the leaf. The underside of the leaf is softer with a slight texture while the front side is waxy, most likely the cuticle of the plant.