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Title your page: Natural Selection and Selective Breeding Notes How Traits Change Over Time Selective Breeding: • The slide background color changes when the concept changes. – Blue: Selective Breeding – Orange: Natural Selection • Highlight or put a box around those two words to separate the two concepts in your notes. Natural Selection: DO NOT write this box for Natural Selection until you have written down all notes for Selective Breeding. These notes will start on slide 9 as designated by the orange background. 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 – Selective Breeding is often benefiting only the human and does NOT provide a survival advantage for the animal. List the following as EXAMPLES of Selective Breeding You do NOT need to draw the pictures You’ll notice each example shows that a HUMAN was responsible for the breeding process. 3. GARDENERS can breed red and white flowers to produce pink flowers 1. BREEDERS breed dogs to be friendly or aggressive. They can be bred to produce various sizes of dogs 4. JOCKEYS can breed horses for increased speed. 2. FARMERS can breed cows to produce more milk and to have more muscle providing more meat. 5. SCIENTISTS can breed two species as an experiment to ‘create’ a new species . (Zebra + Donkey = Zonkey) READ ONLY Careful breeding of food crops like corn and wheat have resulted in plants that yield more food per acre. 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. 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. wild guppies Guppy which has been selectively bred. In essence, when humans selectively breed organisms for certain traits, they are selecting certain genes (a segment of DNA that contains the code for a trait). Natural Selection: Plants and animals that can adapt to changes in their environment are able to survive and reproduce while those that cannot adapt do not survive -Natural Selection is a synonym to “Survival of the fittest” and refers to a competition among species for the same resources. Main Idea of Natural Selection “Only the BEST survives. If it is not the best, it will DIE” Write this phrase in BOLD in your notebook. READ ONLY 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 man selects for certain traits. Can you find the animals in the pictures below? Natural Selection • Natural selection is possible because of genetic variation among individual organisms within a population. • Over generations, traits that enhance survival of a species are selected over those that do not. – When all members of a population have the favorable trait, it is called an adaptation. • 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. Draw this picture and then label 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. Birds have further adapted to have different beaks that enable them to eat different foods. This decreases competition between species and increases survival due to the increased food supply for each species. Natural selection comes down to two facts and one conclusion: Fact (1): Organisms vary and these variations (differences) are inherited by their offspring. Fact (2): Organisms produce more offspring than can possibly survive in nature. As resources become scarce, individuals must compete with each other to survive. Most organisms will not make it to adulthood, and therefore very few will breed and pass on their genes. Thousands of frog eggs are laid in clumps in a fresh water pond. Each clump is laid by one female. Few will survive to adulthood. Apple trees produce far more seeds than could possibly survive to become full grown trees. Conclusion: 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. READ ONLY For example, this species of insect is well adapted (carries the right genes) to blend into its environment. Do you see the walking stick insect? It received those genes from its parents, whose genes were successful enough to allow them to survive long enough to breed. READ ONLY Natural Selection (in summary) 1. Organisms vary and these variations (genes) are inherited by their offspring. 2. Organisms produce more offspring than can possibly survive in nature. 3. 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. READ ONLY Evolution is a slow process. It is important to understand individual organisms do not change (adapt) over time. In general, individuals are either well adapted (have the right genes) or die before passing on their genes. Only populations of organisms evolve. Due to the movement of continents and global climate change, environments are constantly changing which is putting constant pressure on populations to evolve. Assignment Create a double bubble to compare and contrast Natural Selection and Selective Breeding. Include as many details as you can. Use your notes for help.