Dinosaurs are not extinct! Well, not technically anyway. Some people would argue that birds are “new-school” dinosaurs. Based on birds’ phylogeny, avian dinosaurs evolved to become the many bird species we know today. That’s the beauty of evolution.
Did you know? Phylogeny is defined as the evolutionary history of organisms; how they are related and descended from each other through time. Think of it as a family tree that dates back over centuries.
What does evolution mean to a biologist? It means a change in an organism’s traits over time. Have you ever noticed that all people look and act differently from each other? These differences are partly a result of the variation of genes. These genes have been passed down from our ancestors to make us what we are today.
Evolution is a long process. Over time, the environment puts pressures on all living things so that they either succumb (die out) to or overcome (survive and thrive). If a trait helps an organism survive, then the organism has a better chance of reproducing and passing their genes (and their traits) on to their offspring. This is the theory of natural selection, published in 1859 by Charles Darwin. It is part of the theory of evolution.
Did you know? Darwin wasn’t the only person to come up with the idea of natural selection. A biologist and explorer named Alfred Russel Wallace proposed the same theory at the same time. This prompted Darwin to quickly publish his book, On the Origin of Species.
One example through which natural selection can be understood is camouflage. This is a combination of traits that some organisms have that help them blend in with their environment. For example, if an arctic hare were black, instead of white, it would not blend in with the snow and thus its predator, the wolf, wouldn’t have any trouble spotting it for his next meal. If a lioness were blue, she couldn’t prowl unseen in the long, beige grasses her habitat – she would be spotted easily from a distance by her prey. Species that blend into their surroundings have a better chance of survival and thus are able to reproduce and contribute to the continuation of their species.
Natural selection works as a result of pressure from the environment. Artificial selection on the other hand, results from pressure we as humans place on other species. We 'select' the traits we would like to see in future generations of living things and then breed organisms with those traits in mind. Dog breeding is a good example of artificial selection. Over time, dog breeders have selected traits like fur colour, temperament and body size to create new and interesting breeds.
Did you know? The term “survival of the fittest” is often wrongly attributed to Charles Darwin. In fact, a philosopher, Herbert Spencer, coined the term seven years before Darwin published On the Origin of Species.
The evolutionary process is slow, but it has produced a beautiful and intriguing variety of species.
How Darwin Won the Evolution Race
How Evolution Works
PBS: Evolution – a journey into where we’re from and where we’re going
Evolution 101: http://evolution.berkeley.edu/evosite/evo101/index.shtml
On the Origin of Species by means of Natural Selection, 6th Edition http://www.gutenberg.org/ebooks/2009
Tree of Life Project: http://tolweb.org/tree/
Article first published May 5, 2011
Photo Credit: Wikipedia commons