Thursday, February 28, 2008

So close and yet so far...

My department seminar for next week is hosting Milton Love. I've never gotten to see him talk or meet him, but I've soooo wanted to. I even wanted to go to UC Santa Barbra to work in his lab. This was before I saw the light, and started working with invertebrates.

One problem. I am teaching a lab at that time. Ahh! Can I end class an hour early?

Saturday, February 23, 2008

Animalpedia: Doridella and Membranipora

This a picture of a dorid nudibranch (Doridella steinbergae) and a bryozoan (Membranipora). Can you tell which is which?

The bryozoan is an encrusting animal that generally lives on kelps and also green algae. There is some debate as to if Membranipora is harmful to the kelp, but in general it is thought is can block the absorption of nutrients because it grows over the kelp.

Doridella is one of the few predators of Membranipora and is camouflaged to blend in with its prey. Normally, dorid nudibranchs have a circle of gills visible on their back, but Doridella’s gills are located behind the foot under a flap of skin. This helps them blend in better with the bryozoan. They feed on Membranipora by creating a suction seal, using their rasping tongue (called a radula) to cut through the outer membrane, then they suck out the insides.

Membranipora can create spines in response to predation by Doridella. Just put Membranipora in some seawater that has the nudibranch’s chemical cues in it, and it will make spines to protect itself from attack.

So did you find Doridella?

The two bumps on the top right are Doridella’s rhinophores, used for chemoreception. Only nudibranchs have rhinophores, so that’s the tip off.

Friday, February 8, 2008

Science and the public

I got this in my mail box this morning, and I thought I'd pass it along:

February 2008

February is a month when we celebrate the birth of various notable figures in history and take time to honor them and their accomplishments. One such person is Charles Darwin, born February 12 (1809-1882), and famous for his scientific work on evolution and natural selection. Darwin's work changed the way scientists view life on Earth and understand the history of the planet itself. The idea of evolution had been clearly framed in the year of Darwin's birth by Jean-Baptiste Lamarck in his "Philosophie Zoologique." But Darwin provided overwhelming evidence of evolution, and he persuasively proposed natural selection as a generalized mechanism by which evolution occurs. Much, but not all of the evidence for this profound contribution to science and society came from his travels around the world on the ship HMS Beagle from 1831 to 1836, opening his mind to a bewildering diversity of life. His curiosity and training in religion, geology, and biology allowed him to see patterns in that diversity which helped explain what he observed.

When Darwin published his major treatise "On the Origin of Species by Means of Natural Selection," in 1859, the world was in the middle of the industrial revolution and the US was on the brink of civil war. His work was controversial at the time, both among scientists and non-scientists. However, with advances in geology, paleontology, and genetics during the first half of the 20th century, nearly all scientists were convinced of evolution as a fact. And it was this evolutionary foundation which allowed science to make the enormous advances in biology and medicine that benefit people today. Unfortunately, a so-called "controversy" has re-emerged recently as various groups promote the teaching of religious agendas in science classes.

Too many people today are unfamiliar with or completely ignorant of the major points of Darwin's essay on natural selection. First, plants and animals produce many more offspring than the Earth can support. Second, this over-production allows only a relatively few to survive and reproduce. Third, individuals vary and those with traits most suitable to their environment are the ones most likely to survive. Fourth, traits are inherited and those that allow survival are passed on to future generations. Finally, populations that accumulate new traits change, that is, they evolve. These facts are now indisputable.

For some people the descriptive phrase "survival of the fittest" came to epitomize Darwin and natural selection. Non-scientists in the 19th and early 20th century interpreted this phrase to mean that only the strong survive, some people are "better" than others, and that the human gene pool would be better off without some elements---justifying eugenics and even ethnic cleansing. Although these value judgments have no place in science, they still persist among some groups and should be countered at every opportunity.

Darwin's work, however, was controversial for reasons that resonate in present discussions on politics, religion, and science. The theory of natural selection explained how evolution occurs and gave scientific evidence and support to the existence of a biological world not formed and directed of necessity by a higher power. In short, evolutionary processes do not require the direct intervention of a god any more than do the motions of planets in the solar system. This realization has thrown some religious groups into direct conflict with biological science,much the way planetary science and Christianity were in conflict in the 16th and 17th centuries. We now face this problem in some public schools in the United States.

The controversy today focuses on classrooms where students are taught the basics of evolution. Our students are taught evolution because they need to understand the world in which they live today and will live in as they grow up. Evolution is at the core of the field of biology, providing the framework for advances in molecular and cellular biology, physiology, development, genetics, and ecology. It is fundamental for understanding how animals and plants adapt to different conditions, resulting in the wonderful diversity seen today in, for example, rainforests and coral reefs, or even in our own backyards. It underlies our ability to domesticate and modify plants and animals for our use. And it provides an understanding of our own diseases.

Despite the tremendous advances we have experienced in biology through our understanding of evolutionary processes, making it possible to provide for our increasing population by enhancing food production and combatting diseases as never before, efforts are being made to insert into this scientific framework religious teaching in the form of creation science and its subsequent transformation, intelligent design. The religious nature of intelligent design was affirmed by the courts in the Dover decision; now evolution is under attack via proposals to teach religious "alternatives" to evolution and to promote the idea that there is controversy among scientists about evolution. In point of fact, evolution is accepted as fact by virtually all scientists, and controversy among biologists, as in any active science, is in the details of the evolutionary process.

Scientists around the world support science curricula without the imposition of religious perspectives. In January 2008, the Society for Integrative and Comparative Biology (SICB), one of the nation's oldest and most established professional societies, formally resolved to pro-actively support teaching evolution. The membership approved a resolution " support of the teaching of evolution as a scientific fact, and under the name of 'evolution.'" We encourage school systems and federal, state, and local administrators to ensure that biology curricula at all levels critically teach what is now known about evolution. Such a curriculum must include the basics of natural selection, as well as recent developments in understanding the mechanisms and consequences of evolution.

Students need to understand what modern biology has discovered about relationships among species and the evolutionary processes that determine how they survive. Such information is critical for students to make informed decisions in a world in which it is now possible to modify existing species and habitats, and even to create completely new species. Making moral decisions with such knowledge could rightly be directed through a framework of religious values. All such decisions, however, need first to be informed by reliable knowledge of the natural world and how it works.

John Pearse, President
Peter deFur, Chair, Public Affairs Committee
Society for Integrative and Comparative Biology

I think there are just too many people who don't understand the basics about how science works, or even about some of the fundimental things the field of science is based on. (you would not believe how many people don't think fish are animals) Part of the problem is that scientist don't communicate well to people in other disciplines, becuase we tend to forget that they are NOT trained to think critically. We put a lot of value on striving for knowledge and truth, and that is what we should be doing, but when it comes to communicating to others, we are too exacting and nice, unwilling to use anything we view as 'sloppy language' to help the general public understand an idea. So we talk and they don't understand it, end up dismissing it, or forgetting it in favor of something they remember.

Sunday, February 3, 2008

How does it do that? Jelly stings

This is a picture of a hydra tentacle. The cool thing is, if you look closely you can see a discharged nematocyst. This special cell is made by all members of the cnidarians (jellies, anemones, and hydras). It has a coiled up thread inside, that when triggered releases and stings the prey. When the trigger is ‘touched’ the bulb of the nematocyst is filled with calcium. This causes an osmotic reaction. In other words, the water from outside the bulb forces its way in to try and dilute the calcium. This causes the barb and ‘whip’ to evert. The firing of the nematocyst takes only a few microseconds.

After the nematocyst has fired, that cell is useless and falls off. New nematocysts are constantly being produced. This process is taken advantage of by some nudibranchs, who eat cnidarian tentacles. The mature nematocysts fire, but the immature ones are incorporated onto the back of the nudibranch where they finish maturing. These pilfered nematocysts can then be used to sting fishes trying to eat the nudibranch.

Tube Anemones

There are several types of nematocysts, depending on their function. There is a harpoon-like one used to inject venom, a sticky one for capture, a lasso-like one for capture and injection, and one that is only found in tube anemones which makes up the parchment structure of their tubes.