Archive for evolution

In Dog We Trust – The Case For Man’s Best Friend

Posted in biology, personal views with tags , , , on April 20, 2010 by cpolsonb

According to a recent survey about 36% of households in the USA have at least one dog. According to the Pet Food Institute this totals to around 57.6 million dogs, meaning there are nearly 3 times the amount of dogs in America as there are humans in Australia. Americans spend around $5.6 billion on food for their dogs and the American Veterinary Medical Association estimates around $7 billion dollars are spent annually on keeping dogs healthy. Why and how are humans so connected to an entirely separate and distantly related species like Canis familiaris? What makes dogs stand out from other domesticated animals and what can the study of human-canine co-habitation tell us about our own evolutionary history?

Let’s start with a very brief look at the ancestry of both dogs and humans. The canine group has its origins in North America and were originally small forest dwelling carnivores around the size of a fox. When open herd grazing ungulates like horse and antelope began to dominate the vast plains of North America the ancient canines radiated out from the forest onto the open ground. This created a canine ancestor that began evolving into a swift pack hunter in order to tackle the ungulate herds. It is thought that some of these ancestors migrated over the Bering straight into Asia, Europe and Africa around 10 million years ago. Over the next few million years these canids formed into the wolves, jackals, coyotes and painted dogs (not actually ‘dogs’) that we are familiar with today. The grey wolf (Canis lupus), the species from which domestic dogs arose evolved at the end of the Late Pleistocene around 300,000 years ago.

Meanwhile in Africa the ancestors of humans had been evolving steadily. The earliest member of the homo genus is currently identified as Homo habilis who lived from around 2.4-1.4 million years ago. Homo habilis was already using stone tools though it’s leg structure was more suited to tree dwelling than plains walking. After (and alongside) habilis arose Homo ergaster, who later gave rise to Homo erectus and Homo antecessor. Erectus and Antecessor were the first human ancestors to move far out of Africa and into Asia and Europe, both around 1.2 million years ago. Then from Antecessor came Rhodesiensis which finally evolved into Homo sapiens and Homo neanderthalensis. Homo sapiens have lived from around 250,000 years ago till present while poor old neanderthalensis disappeared around 30,000 years ago. So while canid ancestors beat us into Europe and Asia by a good margin the grey wolf from which dogs evolved arose at around the same time as modern humans.

The exact circumstances surrounding the first co-habitations of wolf and man are not known but evidence suggests the earliest interactions took place more than 100,000 years ago. Even before this time it is thought that humans may have been observing and learning from the wolves about how to hunt large ungulates on the tundra. What is known is that by 30,000 years ago dogs had split from wolves and were living alongside humans. The earliest clearly identified dog skeleton was found in Belgium and dates to 31,000 years ago. The March 2010 edition of the Journal Nature published a study that looked at tracing the geographic origins of the domestic dog using genetic markers. The genetic evidence shows that the domestic dog originated in the Middle-East, rather than East Asia as previously thought. It is logical to assume therefore that if the oldest dog remains we have are from Western Europe but dogs evolved in the Mid-East then the split must have taken placed many thousands of years before our oldest skeleton.

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Chronicle of Belief: Part 3 – Nature’s Value

Posted in biology, personal views, Philosophy with tags , , , , , on April 4, 2010 by cpolsonb

This third installment of Chronicle of Belief is about a subject very personal to me as a budding Biologist; nature. It is very easy to say that the natural world is a thing worth protecting and few fellow skeptics or rationalists would disagree, but why? What is so important about nature and is there an objective rational justification for why nature has value? To begin with let’s look at what my particular field, Conservation Biology is really all about.

For many people I imagine conservation conjures images of protesters and hippies, marching in the streets or standing in front of bull dozers. That sort of naïve environmentalism is however often irrational, counter-productive and/or used as a means to push some other ideological agenda. Conservation Biology is a scientific discipline that looks at how biological communities react to change, how different species and the environment interact with one another and how we as humans can ensure the continued existence of these systems. At it’s core Conservation Biology has a number of guiding principles:

Principles of Conservation Biology

1. Evolution is the basic axiom that unites all biology. Conservation biologists do not aim to conserve the status quo, nor stop the evolutionary process but to ensure that populations can adapt naturally to environmental change.

2. The ecological world is dynamic and non-equilibrial. Conservation based on a static view of nature is fundamentally flawed and a mis-representation of the natural world. A dynamic view allows for a deeper understanding.

3. The presence of humans must be included in conservation planning. Conservation biologists aims to integrate humans into the equation and study their impact.

These principles are text-book simplifications of a complex scientific field and highlight the dynamic, integrated approach that conservation biologists must take when approaching questions. It is also valuable to note that conservation biology is a ‘crisis discipline’, having been born from the outrage at anthropogenic mass extinctions and environmental destruction of the last few centuries. In this way it is also a science of eternal vigilance, there can never be a complete theory conservation biology as it is reactionary and time dependent. It is also not an exact science, biological systems are far too complex to ever predict with the certainty of say for example, a chemical reaction.

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Newsflash! Kevin Rudd Believes in Science!

Posted in News with tags , , , , on February 15, 2010 by cpolsonb

This little gem of a news article was found hiding in a corner on page 6 of the February 1 edition of ‘The West Australian’. Kevin Rudd, Prime Minister of Australia believes in evolution! To be perfectly honest I found myself quite conflicted over this morsel of an article and a flip-flopped across a couple of emotional responses. I thought I’d write a brief blog entry about it to try and clear my head and see where my chips land. I’ll start off with emotional response number 1:

Number 1: What the heck is with the headline?
I mean seriously? “PM talks about an evolution”… Is that the best they could do? Do headline writers really need to milk a pun out of every tidbit of news? Or perhaps I’m over thinking this and instead of a horribly lame pun it’s actually just an editing blunder.

Number 2: Awesome! Kevin Rudd is a champion!
How cool it is to have a Prime Minister leading us who speaks out so vocally in support of evolution. There are likely a few Prime Ministers in our history who would never have done such a thing (although politics is not my strong suit). There are certainly many American Presidents *cough* Bush Jr/Snr *cough* who would only say such a thing if it were ‘opposite day’. I admire also his choice of words, straightforwardly declaring it “empirical science”. I fear there were many newspaper readers to whom the word “empirical” drew a blank, caused more by lazy science standards than low iq. But yes, good on your Mr. Rudd, evolutionary theory has been fundamental to great innovations in science and technology, big tick in your science column (now let’s see some more money for R&D)

Number 3: What? This is news??
Why is it that the leader of my country believing in Science is newsworthy? Surely this should be a given, surely we expect those who lead our countries to understand basic principles of scientific fact? Kevin Rudd even doubting evolution should be front page news (barring world disasters), “shock! horror! How could we elect a man with such a loose grasp on the facts!?” they cry over our leaders suspected doubt of evolution… Oh how I long for the day when such a scenario would be the case. How would it seem if a newspaper ran an article reporting that the Prime Minister apparently believes in gravity? Or the germ theory of disease? Silly I should hope…

Where I settled
I think my reasoned response is somewhere in between both extremes. Yes it is fantastic and reassuring that Kevin Rudd believes in evolution (and defends it so strongly) but it is also a shame that this needs to be newsworthy. Like all politicians and indeed all people there is also plenty to not like about Kevin Rudd. Over this issue at least, an issue which is very close to my heart I nod my head respectfully in his direction. Compared to the kind of tripe that can pass for news these days, even these 8 lines are a blessing. In a world where The West Australian homepage has a lifestlye, entertainment, travel, opinion and sport section but no science, I’ll take what I can get and sing it’s praises to the heavens.

Belated Darwin Day Post

Posted in Trips and Visits with tags , , , on February 14, 2010 by cpolsonb

So Friday was Charles Darwin’s 201st birthday. I was hoping to get my blog set up in time to do a happy birthday post but things kept cropping up and distracting me. Nevertheless I thought I’d give my shout out to the father of evolutionary theory today.

For those few of you who may be unaware, British naturalist Charles Darwin was the man who at the right place and time managed to put together the pieces of the puzzle that formed evolution through natural selection. Why did I phrase it like that? It is important for science lovers and rationalists to understand that very rarely (if ever) have great scientific discoveries been whipped up by a single person from a vacuum. It is not widely known that simple and somewhat flawed versions  of common descent and transmutation of species have been around for thousands of years. Philosophers in Greece, Rome, Persia and China all toyed with ideas that to contemporary man sound strikingly similar to evolution.

Even Charles Darwin’s grandfather Erasmus Darwin developed much of the thinking that helped inspire Darwin to formulate his theory, especially with regards to the relatedness of all forms of life. To cut to the meat of my post, Darwin’s publication of ‘On the Origin of Species’ presented evidence to the world that evolution through means of natural selection is the driving force behind the diversity and history of all life on Earth. Darwin’s famous voyage on the HMS Beagle provided a good deal of evidence and inspiration that would help him solidify his ideas years later.

In Sydney Australia in 2009 an exhibition was held at the Maritime Museum focusing on Charles Darwin’s famous voyage with the Beagle, particularly in regard to his visit to Australia. Despite the fact that Darwin described Australia as dull and uninteresting I was able to forgive him long enough to make a trip to the museum while on a work trip in Sydney.

I present for you a small collection of photographs I took of objects at this awesome exhibit “Charles Darwin: Voyages and Ideas that Shook the World”:

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