foothill high school science department 13-1 changing the living world section 13-1 changing the...
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FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
13-1 Changing The Living World
Section 13-1Section 13-1Changing the Living WorldChanging the Living World
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Selective Breeding
The Wide Variety of Animals & The Wide Variety of Animals & Plants Used By Humans, Have Plants Used By Humans, Have Been Developed By Selective Been Developed By Selective
Breeding – Allowing Only Breeding – Allowing Only Those Animals & Plants With Those Animals & Plants With Desired Characteristics Are Desired Characteristics Are
Allowed To Reproduce.Allowed To Reproduce.
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Key ConceptKey Concept::Humans Use Selective Breeding Humans Use Selective Breeding
To Pass Desired Traits On To To Pass Desired Traits On To The Next Generation of The Next Generation of OrganismsOrganisms
–Apples, Corn, PotatoesApples, Corn, Potatoes
–Dogs, Cattle, Mice, YeastDogs, Cattle, Mice, Yeast
Selective Breeding
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Selective Breeding
• Luther Burbank 1849-1926Luther Burbank 1849-1926–800 Varieties of Plants800 Varieties of Plants
• Disease Resistant PotatoesDisease Resistant Potatoes
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Selective Breeding - Hybridization
Crossing Dissimilar Individuals Crossing Dissimilar Individuals To Bring Together The Best Of To Bring Together The Best Of Both OrganismsBoth Organisms–Often Hardier Than ParentsOften Hardier Than Parents
–Disease Resistance + Increased Disease Resistance + Increased Food Producing CapacityFood Producing Capacity
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Selective Breeding - Hybridization
Postzygotic BarriersPostzygotic Barriers
–Reduced Hybrid ViabilityReduced Hybrid Viability• Embryos Don’t DevelopEmbryos Don’t Develop
–Reduced Hybrid FertilityReduced Hybrid Fertility• Offspring Vigorous but SterileOffspring Vigorous but Sterile
–Hybrid BreakdownHybrid Breakdown• 11stst Generation Viable & Fertile Generation Viable & Fertile• 22ndnd Generation Feeble & Sterile Generation Feeble & Sterile
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Selective Breeding - Inbreeding
• Used To Maintain A Desired Used To Maintain A Desired CharacteristicCharacteristic– Dog BreedsDog Breeds– Higher Risk of Homozygous Higher Risk of Homozygous
Recessive Alleles for Genetic Defect.Recessive Alleles for Genetic Defect.• Blindness & Joint Problems In German Blindness & Joint Problems In German
Shepherds & Golden Retrievers Shepherds & Golden Retrievers
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Increasing Variation
Key ConceptKey Concept::Breeders Can Increase The Breeders Can Increase The
Genetic Variation In A Population Genetic Variation In A Population By Inducing MutationsBy Inducing Mutations
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Increasing Variation
• Selective Breeding Impossible Selective Breeding Impossible Without A Diverse Gene PoolWithout A Diverse Gene Pool– Importance Of Diversity In Wild Importance Of Diversity In Wild
PopulationsPopulations
• Mutations Induced ThroughMutations Induced Through– RadiationRadiation
– ChemicalsChemicals
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Increasing Variation
• Most Mutations UndesirableMost Mutations Undesirable–Offspring DestroyedOffspring Destroyed
• Few Mutations DesirableFew Mutations Desirable–Breed To MaintainBreed To Maintain
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Increasing Variation – New Kinds of Bacteria
• Easy To Induce Mutations In Easy To Induce Mutations In Millions At OnceMillions At Once
• Mutations Particularly Useful Mutations Particularly Useful –Produce Oil Eating BacteriaProduce Oil Eating Bacteria
–Plastic Eating BacteriaPlastic Eating Bacteria
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Increasing Variation – New Kinds of Plants
• Drugs Disrupt Chromosomal Drugs Disrupt Chromosomal Separation During MeiosisSeparation During Meiosis–Offspring 2X or 3X Offspring 2X or 3X
Chromosomes (Chromosomes (PolyploidyPolyploidy))• Usually Fatal For AnimalsUsually Fatal For Animals• Tolerated & Useful In PlantsTolerated & Useful In Plants
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Increasing Variation – New Kinds of Plants
• PolyploidyPolyploidy May Instantly May Instantly Produce A New Species Larger Produce A New Species Larger & Stronger Than Their Diploid & Stronger Than Their Diploid RelativesRelatives–Bananas, Oats, Cotton, Tobacco, Bananas, Oats, Cotton, Tobacco,
WheatWheat
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Increasing Variation – New Kinds of Plants
AllopolyploidAllopolyploid–Two Different Species Form A Two Different Species Form A
Polyploid HybridPolyploid Hybrid– Bread Wheat – Triticum aestivumBread Wheat – Triticum aestivum
• 8000 years ago8000 years ago
• Cultivated Wheat & Wild GrassCultivated Wheat & Wild Grass
FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT
Allopolyploid
Polyploid formed between two species