Title your page: Selective Breeding and Natural Selection Notes How Traits Change Over Time

Directions Write Cornell notes over the following slides. If you see a box like this: Write the question that follows in your “Questions” column on the left-hand page. You don’t have to take notes on it. It is to help you in your understanding.

Selective Breeding: The intentional mating of two organisms in an attempt to produce offspring with desirable characteristics. Humans influence genetics A person “selects” organisms to breed favored traits

Examples of Selective Breeding You’ll notice each example shows that a HUMAN was responsible for the breeding process. 1. BREEDERS breed dogs to be friendly or aggressive. They can be bred to produce various sizes of dogs. 3. GARDENERS can breed red and white flowers to produce pink flowers. 2. FARMERS can breed cows to produce more milk and to have more muscle providing more meat.

READ ONLY Careful breeding of food crops like corn and wheat have resulted in plants that yield more food per acre.

If you wished to breed the fastest racehorses, how would you do it? READ ONLY If you wished to breed the fastest racehorses, how would you do it? You would probably mate your fastest male and female horses knowing their offspring should also be fast. If you continued to breed only the fastest horses generation after generation, soon you will have horses ready to race in Churchill Downs.

If you wished to breed the prettiest guppies, how would you do it? READ ONLY If you wished to breed the prettiest guppies, how would you do it? By only selecting the most colorful guppies and those with the longest tails, then breeding them generation after generation. Guppy which has been selectively bred. wild guppies

While in the Galapagos Islands in the Pacific Ocean, Charles Darwin wondered about the origins of the many variations of plants and animals he collected there. He wondered if nature could select for certain traits in the same way that humans selects for certain traits (selective breeding.) Question: Can nature select certain traits in the same way humans can select traits in selective breeding?

Natural Selection: Natural selection - individuals better adapted to the environment are able to survive & reproduce. A.K.A. “Survival of the Fittest” - refers to a competition among species for the same resources Questions: Were the yellow or orange mussels fittest? What traits made them naturally selected for the rocky shoreline?

Camouflage is an ability that enables a species to survive Camouflage is an ability that enables a species to survive. Through Natural Selection, nature will “pick” the species that will survive. This means that predators will consume prey that is easier to see and the better adapted organism will live. Activity: Draw this picture and then circle which species is more likely to survive in each environment.

READ ONLY Light-colored moth Dark moth

While on the Galapagos islands observing finches, Darwin correctly concluded that the different beaks were adaptations to different diets(foods) available among the islands, thus forming the concept Natural Selection.

Question: What makes bird beaks different?

Questions: Name 2 long- or short-term environmental changes that might affect the finches and traits in subsequent populations. How do these environmental changes affect the finches and traits in subsequent populations?

Summary: Those offspring that do survive are best adapted to their environment and will pass their genes on to their offspring. The result is, over time, populations of organisms become better adapted to their environment by this process of natural selection.