Biology 6.2.3 Flashcards
What is ‘Selective Breeding’?
Selective Breeding means to Select Individuals with Desirable Characteristics, & Breed them Together.
What Must happen for a new Breed to be Formed?
The Process of Selective Breeding Must be Repeated for Many Successive Generations, so that all Offspring possess the Desired Characteristic. At this point, a new Breed has been Formed.
What is another Term for Selective Breeding?
Artificial Selection.
What is ‘Artificial Selection’?
Artificial Selection (Selective Breeding) is the Process by which Humans Breed Plants & Animals for Particular Genetic Desired Characteristics.
What are Common Examples of Selective Breeding in Animals? (5)
-Cows that Produce Lots of Milk & Meat.
-Chickens that Lay Large Eggs.
-Domestic Dogs that have a Gentle Nature.
-Sheep with Good Quality Wool.
-Horses that are Fast.
All Breeds of Dogs Descend from…
Wolves.
Selective Breeding can be done with both ___ & ___.
Animals, Plants.
Common Examples of Selective Breeding in Plants: (5)
-Disease Resistance in Food Crops.
-Increased Crop Yield.
-Ability to Withstand Weather.
-Better Tasting Fruits.
-Large or Unusual Flowers.
What can Selective Breeding Lead to?
Selective Breeding can Lead to Inbreeding.
What Causes ‘Inbreeding’? Explain how it Occurs. (2)
-Inbreeding Occurs when only the Animals / Plants that Possess the Desired Characteristic are Bred Together. They are Closely Related, as they all Possess the Unique, Desired Characteristic.
-This Results in a Reduction in the Gene Pool. This is a Reduction in the Number of Alleles in a Population. So, there is Less Genetic Difference in Offspring, as there are Less Unique Alleles to Inherit.
As Inbreeding Limits the Size of the Gene Pool, there is an Increased Chance of: (2)
-Organisms Inheriting Harmful Genetic Defects.
-Organisms Being Vulnerable to New Diseases; there is Less Chance of New Resistant Alleles Being Present in the Reduced Gene Pool. So, if a new Disease appears, Since the Species cannot Create new Resistant Alleles in the Gene Pool, the Species may die out.
