Eye of the Beholder, Part III

In the last two posts, I was discussing the human predisposition to ignore organisms that aren't mammals, or at least aren't vertebrates. I'd like to talk about why, in a very real and practical sense, this bias matters.

The first point is that mammals, as I mentioned before, are a very small evolutionary group. Thus, we cannot learn much about the diversity of life on Earth by studying only mammals.

The second point, and perhaps a more immediate one, relates to conservation practices. The surefire way to get support for an environmental cause is to put up a picture of a dolphin, polar bear, elephant, seal, giraffe, you name it. As long as it's a mammal, it is worth saving. The problem is that mammals--especially the larger mammals that are going extinct at an alarming rate--are suffering due largely to habitat loss. Habitat is the operative word. The habitat that a polar bear lives in is important to the polar bear, but it is also home to countless other animals that don't happen to be furry. How can we even begin to do justice to the idea of saving a polar bear without understanding the needs of the organisms it lives with?

Even people who claim to be pro-animal-rights are often blind to the idea of animal diversity. You will never see a PETA protest decrying the extinction of a dragonfly. But insects, snails, worms, and slugs are all animals. And why stop at animals? Fungi are incredibly important to nutrient cycling in many habitats. We would be in trouble if we didn't have them. So would many cute, fluffy animals. Is anyone worried about how the fungi are doing worldwide? Apart from the small group of people known as mycologists, probably not.

It is frustrating to me that it is so difficult to get people to care about saving something other than mammals. (In fact, I'd be very happy if we could all stop talking about saving species and get on with the business of saving habitats. But that can wait for another post.)

In the meantime, please don't stop being concerned about large mammals. Just remember that in many ways, a campaign to Save the Snails could be at least as important as the one to Save the Whales.

Eye of the Beholder, Part II

How is it possible that on a planet with such huge diversity of life, we tend to think that animals are only things with fur or feathers?

To be fair, one reason is that many of the other organisms are microscopic and/or they dwell underwater. But I find that many people are simply unaware of the existence and ubiquity of non-mammals. Because humans are mammals, we are predisposed to appreciate cute, furry things, so they grab our attention.

This is unfortunate, because all organisms--not just animals--are complex and interesting in some way. It only takes a little effort to learn more about them. Even one's sense of aesthetics can be expanded through the pursuit of knowledge.

Case in point: I have a passion for marine invertebrates, particularly snails. I feel about gastropods the way cat-lovers feel about cats. Most people have a sort of "nod and smile" reaction when I talk about how beautiful snails are--at least, those people who aren't grossed out. But how can an animal that makes something as gorgeous as a sea shell not be beautiful in and of itself? How can the biological process that results in a shell not be fascinating? Indeed, when I talk about those issues and show people specimens, they do begin to see snails as more beautiful than before.

The English philosopher Herbert Spencer said, “Those who have never entered upon scientific pursuits know not a tithe* of the poetry by which they are surrounded.” Of course, he didn't mean that everyone should be a scientist, but he did mean that it is a virtue to be curious and to explore that curiosity. We can all at least take a walk around the block and notice many different living things besides the obvious people, cats, dogs, birds, trees, and grass.

The Spencer quote resonates very strongly with me. I find that the more I learn about an organism, the more fascinating and beautiful it becomes. The more different organisms I learn about, the more amazing the universe seems. There is no mystery or wonder lost in the gain of knowledge. Rather, I come to appreciate my subject more deeply, and I am inspired to ask more questions. It is worth remembering that there is no limit to the number of questions we have yet to answer. That is why, after years of studying biology, I can still be fascinated by a walk around my block.

*Spencer used the word "tithe" in its somewhat archaic sense of a tenth, or a small part.

Eye of the Beholder, Part I

Here's a little experiment for you to try. As quickly as you can, without thinking about it, name the first five animals that come to your mind.

What did you come up with? If you're like most people, your list consists only or almost only of mammals (cat, dog, horse, etc.). If there is a non-mammal on your list, it's almost certainly still a vertebrate (e.g. bird, frog, turtle).

What is remarkable about the results, is that our mindset is so vertebrate-centric, considering that vertebrates are an incredibly small part of the evolutionary tree. Mammals, as a subgroup of vertebrates, are an even smaller part of the evolutionary tree.

Take a look at this wondrous Tree of Life on Dr. David Hillis's website:

http://www.zo.utexas.edu/faculty/antisense/DownloadfilesToL.html

It looks overwhelming, but it represents only 3,000 species out of an estimated 9 million on Earth. If you download the image and magnify it, you will be able to find a branch for Homo sapiens, and you can begin to get a sense of where our single species stands in the grand scheme of diversity on Earth. With all these other kinds of organisms on the planet, why do we regularly pay attention to so few? I will talk more about this in the next post.

Life in Our Local Pond

One of the things I like best about science is that it makes me aware of things about the world that are right in front of me, but easy to miss. My wife and I like to visit a little pond in the cemetery near our apartment. It's a lovely place covered in lily pads, full of frogs and goldfish, and frequented by red-winged black birds that like to sit on the cattails. It's also frequented by the occasional duck and lots of dragonflies.

A while back we decided to collect a little pond water and some algae to provide for some baby snails we'd hatched from an egg mass. In our small sample of water and pond scum, we found representatives of several animal phyla. (In the traditional system of naming, or taxonomy, an animal phylum is the largest grouping of animals below the kingdom. For example, vertebrates like us are placed within the phylum Chordata, which also includes a variety of interesting invertebrates.) Of course there were arthropods such as insects and ostracodes, and oligochaetes (worms in the same group as earthworms). But we also found lots of rotifers of different kinds, a few lovely freshwater limpets, a neat flatworm, and (moving outside the animal kingdom) lots of interesting ciliates. My favorite ciliates were some Vorticella-like ones that lived attached to each other in a colony. When disturbed, they all sprang back together into a clump. But our favorite animal finds were hydra and freshwater bryozoans. Those are so cool I'll save them for their own posts in the future.

But for now, I want to say how exciting it is to be able to see such an amazing diversity of life in this tiny pond, sitting in a very disturbed habitat in the middle of a city. In just our little sample we can see so many totally different kinds of organisms, each making a living in its own way. Thanks to several centuries of people studying nature, we have a search image that lets us see more than we otherwise would know to look for. Not only that, but we can easily learn a great deal about the creatures we are looking at from the work that those previous scientists have done. One of my favorite professors, Dr. Howard Whisler of the University of Washington, began his course on eukaryotic microorgansisms by telling us he was going to "teach us how to look at pond scum". (I don't remember his exact words, but that's as close as I can recall). That skill is one of the most valuable and beautiful things I've learned in science.