Thursday, March 31, 2011

If Nothing Else...Remember This

Being tested on biology topics after my four years at this school taught me that I know little about plants and have forgotten a handful of details. At first I thought these details are useless, but then I considered this...those details are far from useless they are broad ideas centralized in one word. In fact these details are really important, because they enhance communication and give an opportunity to talk to people that may not know a lot about biology.

So as an example of this whole detail thing I'm talking about...let's talk about BIOTIC POTENTIAL. I thought this was about metabolically efficient organisms that produce little waste in comparison to how they obtain nutrients from their food. So large herbivores like cows should fit the definition right, since they eat vegetation and have a complex digestive system. Wrong. Rodents was the right answer.

So what is biotic potential. It turns out that biotic potential is defined as the maximum reproductive potential of a population. So in short I was about as wrong as I could because those large herbivores are lucky to have one calf or offspring a year.
On the other hand rodents have offspring like crazy...I mean when you say rabbit what do you think of? But with this lesson in what this detail means, you can now say instead, "those rabbits -do you know- what like crazy," you can say, "they just have a high biotic potential."

Wednesday, March 30, 2011

Six Legs vs. No Legs

Worms, more specifically earthworms. Those long slimy segmented squirmy organisms that live in the dirt. At first glance the may possibly seem like the most simple organism there could be. So, there is no possible way their could be a single similarity in earthworms with grasshoppers. Right?

Earthworms are a part of the Annelid phylum. Annelid came from the french word anneles which translates to "ringed ones", due to earthworms segmentation. You would believe the anatomy of an earthworm to be fairly simple; howe
ver, they were the first to show evidence of a complete digestive system. Of course its not extremely complex, still pretty impressive for such a simple looking organism. Basically the worm is made up of a through system starting with the mouth, crop, gizzard, intestinal tract and ending with the anus. The segmentations on the worms outer surface internally designate a closed area of organs, such as the nephridia. The nephridia works like waste management, excreting it from the body (nephdria). Typically the worm will have two of these bad boys, to keep things under control.
The worm has quite a bit of other unique anatomical characteristics about it, such that it has a vascular system, it breaths through its skin, and they are typically hermaphrodites so they reproduce asexually!

BUT, what I am getting at is what the heck do they have in common with a grasshopper? Grasshoppers are in the phylum Anthropoda. Anthropods have segments similar to the earthworms; however, each segment posses a set of appendages. Grasshoppers have an open circulatory system unlike the worm. They have three primary regions of their body, the head, thorax and the abdomen. Located in the thorax are malpighian tubules, which has a waste management type of function (MT). Sound familiar? THATS RIGHT, worms have something like this too, the nephridia.

There are so many differences in between these two organism, it is neat to see something that is conserved in both of their internal anatomy. It is even more interesting to think that we have a vary similar organ, our kidneys, that possesses a similar function as the nephridia and the malpighian tubules. It all goes back to evolution. Both the annelids and the anthropoda are both protosomes, a clade of invertebrate animals, making sense as why they would have some similarities in their anatomical make up.

First Hand Instructions to making Beer

I know it is long and quite a lot of information; however, listen until the end and you will not be disappointed :).

Monday, March 28, 2011

Getting Freaky in the Plant Kingdom...

I have heard on occasion (usually after my wife spends the day cleaning, washing clothes, doing laundry, and caring for our son!) that if women could figure out how to fertilize themselves, the male sex would be obsolete due to natural selection against worthlessness. Not only do plants reproduce sexually, but some also have a neat little trick up their stalks. Certain species of plants have the ability to reproduce asexually, without the genetic contribution of a neighbor. Great trick. Just don't tell my wife. Lets face it, plant reproduction isn't necessarily the most pressing issue on most of our minds right? I mean, how many of us realize on those gorgeous spring days when we can barely breathe due to our bodies reacting against the massive plant sperm overdose we have been subjected to. Uh, gross... 

Sexual reproduction in all land plants involves alternation of generations. This means that their life cycle is split into two distinct phases; one in which the genetic information is haploid, and the other in which the genetic information is diploid. There are differing details for different organisms, but the main idea is the same. Alternation of generations begins when two haploid gametes fuse to form a diploid zygote, which will divide by mitosis to form a viable diploid organism called a sporophyte. After maturation, the sporophyte develops one or more sporangia, which are the sexual organs that develop the haploid spore cells through meiosis. The spore cells then are able to divide by mitosis into a gametophyte that divides by mitosis, and thus gives rise to the haploid gametes capable of fusing together into another diploid cell, and thus repeating the cycle. A very complex cycle, and one that is necessary in order for plants to exchange genetic information.

Asexual reproduction skips the awkward movie and dinner approach to plant reproduction, and skips right to the good stuff... making progeny. Some plants such as the Kalanchoe, are able to form little plantlets from their leaves, while others such as silverweed, uses stolons, or horizontal connections between organisms to spread viable offspring. Plants such as Euphorbia and Ginger use rhizomes, which originate from the main stem of the organisms, and crawl laterally in order to shoot roots from the nodes, and effectively spread itself. Two other methods of asexual reproduction are through the use of bulbs and tubers, like tulips, and potatoes respectively. Another form is called apomixis, which essentially replaces normal sexual reproduction with asexual reproduction. In other words, sporophytes are able to be formed without fertilization This form is particularly important in ferns and flowering plants. The catch here is that plants who produce asexually these ways form clonal colonies, which contain essentially the same genetic information within the group.

It is truly remarkable how many adaptive ways of reproduction are displayed in the plant kingdom. So, think again if you were under the impression that you were a sexually talented being, and realize that you have been outdone for millions of years. Plants are truly the overachievers who are well beyond the constraints of gender specified reproduction. 

Saturday, March 26, 2011

CSI: Friend or Foe?

Is the television show CSI spreading a positive or negative message about science?? Interesting cases for both sides of the story are presented in this special audio presentation by Shane Bemiller and Phillip Wages.