Selective breeding—The selection of certain seeds or animals for reproduction so that the next generation has the same desirable traits.

To take advantage of hybrid vigor. Hybrid vigor – desirable characteristics that give the organisms a competitive edge over the parent organism. – Example: A disease-resistant plant or a chicken that grows larger than its parents.

What is Natural Selection? Organisms and species that survive and reproduce are the sole ancestors to the next generation. Those that fail to reproduce will not continue. This is selection happening natural rather than due to human intrusion. What is Selective Breeding? The selection of certain seeds or animals for reproduction so that the next generation has the same desirable traits. This selection happens because humans choose (or breed) only what they select. It is not natural.

The continued breeding of individuals with similar characteristics in order to maintain the desired characteristics of a line of organisms. Inbreeding Depression: The increased chance that a cross between two individuals will bring together two recessive alleles for a genetic defect. – Example: Deafness in Dalmatians

Loss of variety in the population Can amplify undesired traits unintentionally – Example: German Shepherd Dogs with hip problems. Diseases and pests can become resistant – Example: Due to selection and overuse of pesticides many pests and crop diseases have evolved and developed resistance rendering the pesticides useless.

It is VERY important to maintain natural populations of organisms as a source of genes or a Gene Pool. Natural populations are diverse enough to withstand changes in the environment. If there is a change in environmental conditions, some part of the population will have the genetic make up to survive and pass on their genes which will allow the population to survive.

Irish Potato Famine ( ) – New potato plants arise from pieces of the parent plant, not as a result of reproduction. – Ireland planted mostly the “Lumper” variety of potato, so the entire crop was ONE potato (No diversity). – The entire crop was victim to a rot causing fungus which destroyed potatoes, and left one million people to starve.

The results of selective breeding are all around us, from our pets to our food. Without selective breeding, we wouldn’t have an amazing variety of dogs. We also wouldn’t have broccoli, cauliflower, cabbages, kale, or Brussels sprouts—which all were derived from a single wild mustard plant. Now YOU the budding new scientists can take advantage of our understanding of genetic principles to produce healthy plants and animals by using selective breeding tactics.

Click the link to practice selective breeding and create your own “designer dog!”. – breeding.html breeding.html