Darwin Day.

Way back in July 2011, when I started this blog, my first post was about a common misconception regarding the theory of evolution by natural selection.

Since today is Darwin Day, I thought I would revisit the topic. (Happy 205th Birthday Charles!)

Evolution is consistently in the media, and is often presented as something that still requires debating, as "just a theory", or as some skewed version of itself. One of the biggest problems is that evolution by natural selection is viewed as being mutually exclusive with religion. Last I checked, Pope John Paul II was a man of pretty strong faith, and he declared evolution to be a fact, so clearly the two can be reconciled. (Phil Platt, the Bad Astronomer, wrote an excellent column about it here)

From here.

Another problem is the issue of language. Words that have one definition in science can have very different meanings in other areas (such as work, law, hypothesis, or that dreaded one, theory). 

One of the words that causes problems is "fitness", as in survival of the fittest.  What does it mean to be fit? Does one have to go to the gym and bench a lot of weight to become fit?

Survival of the fittest at its most basic should really be regarded as survival of those best suited to their environment. Features and behaviors that benefit a organism in one environment might be a detriment in another. 

But fitness also is determined by how successful you are, not only at surviving, but at having your offspring survive to reproductive age, which ensures the passing on of your genes. (My grade 10's are often appalled when I tell them that, from a biology standpoint, if you don't reproduce you are a 'failure'). 

There is also an indirect type of fitness which provides explanation for colony and/or pack behavior. While individuals themselves may not reproduce, they benefit from helping close relatives rear offspring, as the offspring of close relatives contain similar genes, and the survival of those genes is still ensured. 

This difference between definitions of fitness can explain all sorts of physiological adaptations and behavioral adaptations, but often times the link to fitness is not obvious, lending the impression that the trait is not advantageous and therefore would not be selected for if evolution works the way it is stated. The difference between these definitions also highlights the  need for clear communication. Darwin himself knew he was making arguments that went against the popularly held beliefs of man's supremacy over animals, and that acceptance of his ideas was easily challenged in the eyes of the general public due ignorance about the nuances of language. 

I personally think that Chuck would be rolling in his grave if he knew that the debates that raged in the early years of his theory were still being held today, over 150 years after the publication of Origin. 

My Darwin v Lamarck tee has shrunk too much to wear...

...but I did wear these awesome earrings in honor of Darwin Day!

Lonesome George.

Sad news in the conservation world last week. Lonesome George, the last of the Pinta Island subspecies of Galapagos Tortoise died. Named because he was the last confirmed member of his subspecies, scientists had been trying for years to find a female Pinta Island tortoise for him to mate with, and when that proved fruitless, they attempted mating him with other Galapagos tortoise species. While George did eventually take to some of the ladies, the eggs were sterile.

Galapagos tortoises were among the animals observed by Charles Darwin to have adaptations that allowed them to be uncannily suited to their particular habitat. (Another being the more famous Darwin finches). The tortoises on each of the Galapagos islands all descended from a common ancestor, but evolved slightly different body structures and shell shapes to allow them to best survive on their particular island.

Tortoise populations were decimated when early explorers learned they could take the reptiles on their ships for long voyages because the tortoises can survive on little food and water, and aren't fast enough to escape pursuing sailors.

Lonesome George was an icon for conservationists everywhere, and a symbol of the devastating impact humans can have on the other creatures we share the planet with. At 100 years old, Lonesome George was different from other animals of species who go extinct- we didn't just learn of it, we struggled to stop it, but had to stand by, helpless, and watch it happen.

From here.

Christmas Cactus.

I have recently acquired a Christmas Cactus (really, I'm plant-sitting, but it's taking up enough of my kitchen.. this thing is huge!) and it seems to be happy. Over the past week, it's started churning out buds, and some of them have opened into gorgeous orange blossoms.

Like this one.

The flowers of a Christmas Cactus are specially adapted for specific pollinators. Nectar is produced and stored in a chamber at the base of the bloom, which is very long. A hummingbird must stick it's long beak down the flower to get at the nectar, and while doing so will brush it's head against the pollen covered stamens sticking out of the flower. Pollen from another plant will be deposited on the bright pink stigma from the top of the bird's head.

Side view.

Begin.

Recently, I had an interesting discussion with a friend of mine about the current state of education (a sadly common occurance due to the political environment we are currently living in... but that is another story.).
Now, this friend of mine is a very smart girl, but she's just not that into science. Her last formal science education was high school Biology; she never took Physics or Chemistry after Science 10. Not that there's anything wrong with this, but you know what they say, "the more you know, the more you know you don't know". I find this to be particularly true with science.

This friend expressed to me that she was recently embarassed by her naive misunderstanding of the concept of evolution. Controversial subject that it is, teaching evolution in schools often ends up spreading as many misconceptions as it does actual knowledge.

I blame pictures such as this one...

(Image from Observations of a Nerd)

Now, looking at it, it seems to imply that life is a logical progression from other primates towards man. To say this idea raised an uproar when Charles Darwin first proposed his theory of evolution by Natural Selection is an understatement. People were incensed by the idea that we could be descended from apes.

Here's where the misconception comes in. We are not descended from chimpanzees or neanderthals; we all share a common ancestor (much the same way that you and your cousin share a common ancestor -your shared grandparents- and yet are two different people at the same time). The difference between our relationship with neanderthals and chimpanzees is the degree of separation (just like your siblings have a closer common ancestor with you than your cousins). It is this idea of common ancestors that is often lost in the classroom; evolution is not a line of inferior creatures marching towards mankind. Darwin never proposed it to be - On The Origin of Species outlines how variation among offspring can over time lead to speciation by the mechanism of natural selection, not how one species "turns into" another. Life is rather more like the branches of a tree... we are one twig on the end of the primate branch, coming from the same main stem as the chimpanzees and other great apes, yet a distinct species of our own.