Natural Selection

DARWINIAN NATURAL SELECTION

 To understand artificial selection, one must first understand natural selection. For natural selection, what better place to start than Charles Darwin. He is the father of evolution, the creator of the idea of natural selection, and an integral part in the field of biology as a whole. So I decided to look at Darwin's Theory of Natural Selection, which is broken up into 4 postulates.

1. There is variation among individuals of the same species.

This is especially clear in the human population with our wide range of hair colors, eye colors, heights, skin tones, etc. But it holds true for all species; birds, fish, cows, beetles. Species are not made up of cookie-cutter animals. They are not all mirror images of each other. This is what makes individuals. 

2. At least some of these variations are hereditary.

When Darwin was writing On the Origin of Species, words like genes, traits, alleles, and chromosomes were not being used. The field of genetics was in its infancy if even conceived at all. But Darwin, being a bright man and ahead of his times, knew that some how a parent's characteristics got passed on to their offspring. This is essential to the idea of fitness. Being better adapted to surviving wouldn't do any good if you couldn't pass those "variations" on to your offspring. 

3. In every generation, there are more offspring produced than can survive. 

It is important to understand that there are environmental pressures on species. There are pressures to find food, escape predators, find prey, keep warm/cool, etc. When an individual is better adapted to deal with these pressures and passes those adaptations down to their offspring, they give their offspring a better chance to survive to reproductive age and then continue to pass on those traits. Not everyone is going to survive to pass on their genes though. If you have the adaptive genes, you are going to have a better chance of surviving to reproductive age to pass on those adaptive genes. 

4. Natural Selection operates on populations.

The idea that survival and reproduction are not random. Certain individuals with certain adaptive traits are going to survive to reproductive age. This makes those adaptive traits selected for and passed on to the next generation. Being able to survive and pass on your traits shows an individual's fitness. 

In the artificial selection of dogs, humans chose what traits are adaptive and are selected for. Great Danes have been selected for their large stature, terriers for the speed, bassett hounds for their long ears, and labradors for their retrieving skills. When you start to play with different breeds like a jigsaw puzzle or a Mr. Potato-Head you end up with some of our more intricate breeds, which I will be looking at this semester.  

My goal in life is to be as good of a person as my dog thinks I am.

My goal in life is to be as good of a person as my dog thinks I am. 

This is my childhood puppy, Bailey. We were best friends for 14 years. Ever since I was born, there has always been at least one dog in my household and for about 10 years we had two dogs. I loved growing up with a puppy. We got Bailey when I was 5 and I helped pick her out, and she was mine and my sister's puppy. She was sweet, kind, gentle, loving, energetic, outgoing, and attention-craving. She had a personality that was one of a kind. It is amazing the bond that can be made with a dog. They are an animal that gives you nothing but all their love. They make it very easy to love them back and get really attached to.

The history of dogs is really intriguing to me. To be so closely related to the wolf, and then to be domesticated and to be bred and cross-bred in to all the varieties of dogs we see today. Today, dogs come in all different sizes, shapes, colors, and functions. German shepherds are used on police forces, and dalmatians are used by firefighters. There are dogs that are good at hunting, and even in hunting there are dogs made for retrieving birds and foul and there are other dogs that are breed to catch quick ground animals and ones that burrow.

This semester I will be exploring how and why we have types of dogs we do today. I plan on starting with the domestication of dogs and working into focusing on a few different breeds and seeing what traits came from what other dogs. The overall topic will be artificial selection and how it is possible for humans to breed dogs in such a manner to get exactly the right traits from the right dog.

I thought I would start off this blog with a list of my favorite dogs just to look at cute pictures.

#3. The Husky: These cute little guys are Siberian-huskies. They can have piercing blue eyes. They have thick double-coat of fur to keep them warm.




http://www.tadoz.com/tag/siberian-husky-puppies



#2. Shar-pei. Who couldn't love these wrinkles? This is a dog I would love to know its history. How and why did anyone want to breed for wrinkles? It seems like a kind of silly (but awfully adorable) trait to want in a dog. Does it serve a purpose?







http://www.lasharpei.com/

#1. Labrador retrievers. My family has only owned labs. They are great with kids, very smart, and can be taught many tricks.












In my next entry, I will start to explain the theories of natural and artificial selection. And then in the rest of the semester I will explore how these theories apply to dogs and how humans have manipulated the theory of natural selection and almost created artificial selection.