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

MAKING THE SELECTION

•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

naturally rather than due to human intrusion.

•What is Selective Breeding?

• The selection by humans of certain seeds or animals for reproduction so that the next generation has the same desirable traits. • It is not decided by

nature.

• For food (corn was one grass, to make larger cows, chickens, and pigs)

• For entertainment (racing, animal shows, and TV performances “Wilbur the Pig”)

• For service (police dogs, seeing eye dogs, rescue dogs, ranching)

• For fashion and status (purse pups, thorough bred animals)

REASONS

• 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 causing the pesticides to be useless.

CONSEQUENCES?

• It is VERY important to maintain natural populations of organisms as a source of genes or a Gene Pool.

DIVERSITY

• WHY? 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.

• Irish Potato Famine (1845-1852)– New potato plants come from pieces of the parent plant. – Ireland planted mostly the “Lumper” variety of potato, so

the entire crop was ONE kind of potato (No diversity). – The entire crop was victim to a rot-causing fungus which

destroyed potatoes. There was no diversity to fight off the fungus and so that left one million people to starve. (They were dependent on potatoes for their main food source.)

A LOOK INTO THE PAST

• 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 scientists can take advantage of our understanding of genetic principles to produce new plants and animals by using selective breeding tactics.

CONCLUSIONS

GMO

• Big controversy in the news right now: whether to eat or NOT eat Genetically Modified Organisms (GMOs). Many people say NO, not a good idea. Many people say we have been eating GMOs for a long time.

• Maybe we just need to make sure we have diversity!!! Because really, isn’t EVERYTHING genetically changing? Either by man, or by nature?

• What do you think?