Genetics

Science and breeding programs

Throughout the course of time, evolution has changed many forms of life so that it better adapts to its environment. Organisms gain or lose characteristics so that they have a better chance of survival in the wild. This is known as natural selection.

Through selective breeding, however, humans have also played a major role in the changing of many species expressing favorable characteristics. Characteristics that are not always advantageous to the organism but desired by the breeders.

In trying to breed aesthetically pleasing features dog breeders are causing harm to many breed of dog. For example, the excessively wrinkled skin of the Chinese Shar-Pei, shown on the right, promotes skin infection, while Bulldogs and other flat-faced breeds such as the Pekingese have breathing problems because of their short, setback noses and shortened air ways. Bloodhounds suffer from persistent eye irritation and infection.

Regions of civilisation originated and became self sustaining through the selective breeding of crops and livestock. Characteristics such as high yield, fast growth and disease resistance were all highly sough after.

Wild grasses were selectively bred into crops such as corn and wheat. Pictured on the right is a wild teosinte plant. This wild plant has small fruit and large leafs. Through selective breeding teosinte evolved into corn with large seeds and a high yield per plant.

What is selective breeding?

How is it used by farmers?

How does selective breeding take place? Use the Belgian Blue as an example.

Describe the science behind the Belgian Blue?

Why is selective breeding sometimes referred to as "Evolution by human selection"?

How does selective breeding differ from natural selection? Solution