Saturday, December 17, 2011

Crazy Plants: Duckweed

Duckweed in Spain
Duckweed is a quite unassuming-looking plant that is commonly seen floating on the surface of ponds and lakes. Believe it or not, one species is actually the smallest flowering plant known and is thus worthy of note. There are numerous species which can vary quite a bit in size The structure is simple, with one to three small leaves, each with a small root hair. It can reproduce both sexually and asexually,

The plant is generally considered a pest species. If not kept in check it can actually become a serious issue. If the pond is completely covered, photosynthesis cannot occur and this oxygen levels will drop in the water, leading the death of any fish or other aquatic creatures present. To help prevent this from occurring, there are a wide variety of products and methods used to control the plant. One of the basic methods is simply removing the plant by hand, but this will not eliminate it. Ducks and carp (including koi) are effective biological controls, as both will eat duckweed. Chemical methods can also be used, with some being more effective than others. Preventive measures can also be taken to prevent duckweed from becoming a problem in the first place.

Despite this, duckweed has the potential for doing a lot of good. It is being promoted by the UN for use as a food for poultry and other animals, particularly ducks. It is cheap to produce, and thus can be a quite quite useful component of animal feed.

Sources are Ohio State University, Texas A&M University, and the Food and Agricultural Organization of the United Nations. Image is from Wikimedia Commons and is copyright free.

Friday, December 16, 2011

Mismark Case Study: German Shepherd Dog

German shepherds are most commonly come in four colors: sable, black and tan (saddled tan), bicolor (tan point), and black. Sable and black and tan are seen in the above dogs in the order sable, black and tan, sable. Image is from Wikimedia Commons under a Creative Commons license.
According to the AKC, virtually any color of German shepherd is fine except for white. However, on further examination of the standard, it can easily be seen that this is really not the case. To begin with, liver and blue are serious faults, and as such are unlikely to show up in the show ring. On top of that, eyes are supposed to be quite dark, and the liver and blue dilutions will produce dogs with pale eyes. If these two points fail to keep these colors out of shows, this will: a nose that is not black is a disqualification. Though blue can appear near-black in color, the lack of pigment produced by the dilutions causes noses to be non-black. Thus, there are quite a number of colors deemed "unacceptable" than would be expected from an initial examination of the standard. Here's a list of some mismarks:

  • White
    • Varies from pure white to biscuit/cream
  • Blue
    • May be in combination with any color, replacing black with blue
  • Liver
    • May be in combination with any color, replacing black with liver
  • Fawn
    • Blue and liver dilutions combined
    • May be in combination with any color, replacing black with fawn
  • Panda (a new mutation that causes Irish white-type markings)
    • May be in combination with any previous color
    • Though not specified as a disqualification, it is generally considered "unacceptable"

This GSD is white
Since the German shepherd is such a popular breed, the mismarks have proven to be rather popular colors, particularly the white and panda dogs. Since the colors are undesirable, the movement has been to produce independent breeding populations of the specific color. As with and splitting of a breed, this is of great concern. By isolating the dogs of these specific colors from the general population, it narrows the gene pool and leads to the potential for a marked increase in the health problems seen in the newly formed breed. This is more true for the white dogs than the pandas due to the recessive nature of the gene. Inbreeding is required to keep the color going, and this only narrows the gene pool further. Though out crossing to more traditionally colored dogs was likely done to expand the gene pool, this only does so much. Since the breed is now accepted by several registries as being separate, this basically prevents any more crossing between the two populations from occuring.

One of these GSDs is liver
Another major issue I see with the German shepherd standard is the dislike of the dilute colors. This breed is touted as a working breed and highly capable. Putting aside the weak hind ends and other traits that would impede working ability so often seen in show lines, why should color be a point of concern in a working dog? It makes no difference if a dog is black or fawn: if it can do what it was meant to do, then that is all that should matter. Having an all white coat will not prevent a dog from being able to protect its master or sniff out criminals.

Thursday, December 15, 2011

Guess the Genotype #38

Can you guess this dog's genotype? What about its breed?
Image is from Flickr.com under a Creative Commons license.