Old Biophilia

Happy St. Patrick’s Day!
March 17, 2010, 10:16 pm
Filed under: Diversity in the plant world

The Shamrock (Trifolium repens)

What is the first think we think of when we think of St. Patrick’s Day? Okay, I mean the second thing we think of….the shamrock! The shamrock is a clover of the variety Trifolium repens. Shamrock’s typically have 3 leaflets and is what St. Patrick used to represent the Holy Trinity. You are all probably familiar with the lucky four-leaf variant which is often confused with the Shamrock. While the four-leaf clover is a symbol of good luck, the three-leafed shamrock is mainly an Irish-Christian symbol.

It has been estimated that there are approximately 10,000 three-leaf clovers for every four-leaf clover, however this probability has not deterred collectors who have reached records as high as 160,000 four-leaf clovers. Clovers can have more than four leaflets: the most ever recorded is twenty-one, a record set in June 2008 by the same man who held the prior record and the current Guinness World Record of eighteen. Unofficial claims of discovery have ranged as high as twenty-seven.

I have come to know this plant very well. As an undergraduate, I studied how differences in leaf traits among clovers is related to their susceptibility to pathogens. Put another way, I once spent 24 hour in a greenhouse watching water evaporate off of clover leaves. Yes, I did. All in the name of Science!

**UPDATE: Don’t be surprised if you see a lot more ” lucky clovers” around:

Plant nurseries in clover after finding four-leaf gene

The science of weddings
March 11, 2010, 5:19 pm
Filed under: Human biology

I am getting married in 16 days. I like to think that i’ve taken a scientists approach to the wedding—I think many brides would covet my many excel spreadsheets. But my approach is nothing compared to that of bride Linda and her groom Nic. They added an unexpected dimension to their nuptials; they decided to conduct an experiment to determine what happens to our bodies when we say “I do”.

Researcher Paul Zak measured levels of oxytocin in the bride, groom, three close family members and eight friends before and after the ceremony (now those are some dedicated bridesmaids!!). Oxytocin is released from the pituitary gland in the brain and has been dubbed the “cuddle chemical” because of its association with bonding, trust, and generosity (it also triggers childbirth and the release of milk during breastfeeding).

As expected, the bride and groom both experienced a surge of the “cuddle” hormone during the ceremony (as did the mother of the bride and father of the groom!). The closer the genetic relatedness to the bride and groom, the higher the level of oxytocin.

Researcher Paul Zak proposes that this “group oxytocin” surge supports the theory that public weddings have evolved as a way of binding couples to their friends and families (perhaps to help out with future child-rearing in order to increase biological fitness!!). It is also not surprising that they observed a greater spike in the hormone in family members than in friends.

To learn about the action of the other hormones measured at their wedding (vasopressin–released during sex, involved in male aggression and pair bonding’ testosterone–released by the testes, levels tend to fall in the early stages of a relationship; ACTH and cortisol–“stress hormones”, moderate levels promote the release of oxytocin but high levels inhibit it), read the New Scientist article at http://www.newscientist.com/article/mg20527471.000-my-big-fat-geek-wedding-tears-joy-and-oxytocin.html?full=true

PS I wouldn’t want blood being drawn an hour before my vows but I am pretty jealous of the centrifuge in the bridal ready room

Can I borrow your spines please?
March 10, 2010, 4:42 pm
Filed under: Diversity in the animal world

This Urchin Crab (Dorippe frasconce) is carrying a fire urchin on its back (Astropyga radiata). Now why in the world would it want to do that?? The crab is taking advantage of the long sharp spines the urchin has to protect it from predators. Why grow your own spines when you can borrow someone elses?

Is it a plant or is it a slug??

Elysia chlorotica, a photosynthesizing slug!

You might be surprised to learn that the ability to make sugar from sunlight and carbon dioxide is not something that only plants can do! In fact, the ability to do photosynthesis evolved in Bacteria.

And now there is evidence that some animals have taken advantage of this lifestyle. Researchers have found that the sea slug, Elysia chlorotica, can photosynthesize! If you shine light on one of these guys, they convert carbon dioxide into sugar and make oxygen just like a plant!

If you are one of my students, hopefully you are thinking, “Wait one second!! Animals lack chloroplasts (as do bacteria by the way!), HOW in the world could an animal be photosynthesizing?!”

Well, the answer to that question is quite and interesting one. These slugs are about 3 cm long and look quite leaf-like. They are found off the east coast of North America, ranging from Florida to Nova Scotia. Basically, the sea slug eats the tiny algal cells and incorporates their chloroplasts into their own cells. The sea slugs have special cells that the line their digestive tubules that are capable of taking up the chloroplasts from the algae. Even crazier is that the chloroplasts can live inside the slugs’ cells for 9 – 10 months!! This is about the entire lifetime of the slug and can provide the slug with essentially all the energy it needs!

Still interested?? Another neat aspect of this story is the fact that chloroplasts themselves are not enough to do photosynthesis. The process also requires certain enzymes and proteins to keep the chloroplasts working. Researchers have shown that at some point in the evolution of these slugs genes from the algae were transferred over and now reside in the genome of the slug! Gene transfers are extremely common among single-celled organisms, but this is the first time it’s been described in multicellular organisms!! How did they get there?? The answer to that question could lead to major strides in gene therapy and genetic engineering.

This research was presented at annual meeting of the Society for Integrative and Comparative Biology in Jan 2010 and has yet to be published. Check out Dr. Sidney Pierce’s website for more information on this research: http://biology.usf.edu/ib/faculty/spierce

Welcome to “Biophilia”
March 5, 2010, 6:27 pm
Filed under: Human biology

The term “biophilia” was coined by Edward O. Wilson, a Harvard University entomologist, naturalist, and conservationist. I have had a fondness of E.O. Wilson ever since he declared that if he could start his life over he would work in microbial ecology! Back to biophilia—Wilson introduced the term to describe the instinctive bond between human beings and living systems. Literally, biophilia means “love of life or living systems“. It can be thought of as the “innate tendency to focus on life and lifelike processes” or the “connection that human beings subconsciously seek with the rest of life”.

So that is the inspiration for this blog….to share my love of life and living organisms and living systems with my friends, family, and students. I hope to highlight for you some of the wonders and marvels of the natural world.  In E.O. Wilson’s words, “If you study life deeply, its profundity will seize you suddenly with dizziness . . .”