1.4
DESCRIPTION
TRANSCRIPT
AIM: How can organisms be improved using the idea of natural selection?
Warm – up:In evolutionary terms, why is one
organism more likely to survive than another?
Artificial selection
§ Artificial breeding can use variations in populations to create vastly different “breeds” & “varieties”
Artificial selection
§ Artificial breeding can use variations in populations to create vastly different “breeds” & “varieties”
“descendants” of the wolf
Artificial selection
§ Artificial breeding can use variations in populations to create vastly different “breeds” & “varieties”
“descendants” of the wolf
“descendants” of wild mustard
Artificial selection
§ Artificial breeding can use variations in populations to create vastly different “breeds” & “varieties”
“descendants” of the wolf
“descendants” of wild mustard
Selective Breeding
Selective Breeding
Selective Breeding: Process in which
Selective Breeding
Selective Breeding: Process in whichparticular individuals are chosen and allowed
Selective Breeding
Selective Breeding: Process in whichparticular individuals are chosen and allowed to breed, whereas others are prevented from
Selective Breeding
Selective Breeding: Process in whichparticular individuals are chosen and allowed to breed, whereas others are prevented from breeding.
Selective Breeding
Selective Breeding: Process in whichparticular individuals are chosen and allowed to breed, whereas others are prevented from breeding.
• Alleles that give characteristics favored by humans are retained, while undesirable characteristics are eliminated.
Selective Breeding
Selective Breeding: Process in whichparticular individuals are chosen and allowed to breed, whereas others are prevented from breeding.
• Alleles that give characteristics favored by humans are retained, while undesirable characteristics are eliminated.
• Raw genetic material is hidden and often allows for hidden variations to show through
Selective Breeding
Selective Breeding: Process in whichparticular individuals are chosen and allowed to breed, whereas others are prevented from breeding.
• Alleles that give characteristics favored by humans are retained, while undesirable characteristics are eliminated.
• Raw genetic material is hidden and often allows for hidden variations to show through
Selective Breeding
Selective Breeding: Process in whichparticular individuals are chosen and allowed to breed, whereas others are prevented from breeding.
• Alleles that give characteristics favored by humans are retained, while undesirable characteristics are eliminated.
• Raw genetic material is hidden and often allows for hidden variations to show through
Selective Breeding
Selective Breeding: Process in whichparticular individuals are chosen and allowed to breed, whereas others are prevented from breeding.
• Alleles that give characteristics favored by humans are retained, while undesirable characteristics are eliminated.
• Raw genetic material is hidden and often allows for hidden variations to show through
Selection
§ Artificial selection is similar to directional selection.
§ Similarities?
§ Differences?
Inbreeding
§ Involves breeding between closely related individuals with some desirable trait as the outcome
§ Loss of genetic diversity
§ If loss occurs to the extent at which every individual has identical alleles, that is referred to as complete homozygosity
§ Why is this a problem?
Yorkshire Terriers (Yorkies)
Yorkshire Terriers (Yorkies)
Yorkshire Terriers (Yorkies)
Bassett Hound
Bassett Hound
Bassett Hound
Example of Inbreeding in Plants
§ Wheat plants generally self pollinateØ High yieldØ Short stemsØ Pest resistanceØ High protein content of grain
Outbreeding
§ Involves crossing individuals from genetically distinct strains to form hybrids.
§ Hybrids have characteristics which are superior to the characteristics in either parent. (Hybrid vigour / Heterosis)
Liger
Mule
Mule
Mule
Mule
HOMEWORK
§ Complete Ques. 3 from Classwork H.O.
§ Read p. 450 – 453