1. Artificial Selection
Breeding for a purpose

7. Dogs bred as sighthounds - clockwise from top left: Whippet, Borzoi, and Saluki
Can you see the similarities in their anatomy?
What physical characteristics do you think were selected?

8. 14th century print of a hunt.
Can you spot the sight-hounds?
How did you decide?

9. Dogs bred as herding dogs – clockwise from top left – Border collie, Lancashire heeler, Rottweiler, Old English Sheepdog
Do you think the characteristics that are bred for are physical or behavioural?
Why?

10. Dogs – bred for a purpose
Dogs have been selectively bred for a purpose for 15,000 years
Starting with some wolves, dogs were initially bred to help with:
hunting; producing hounds, terriers, and retrievers
farming; producing herding dogs and guard dogs
Modern breeding has given us companion dogs and toy dogs – whose purpose is to keep us company… funnily enough

11. The Auroch – where all domesticated cattle were bred from
Meat
Dairy
Draft

12. Artificial selection in plants

13. Wheat
Tall wheat plants have a high yield, but are easily damaged in wind and rain
Dwarf wheat plants have a low yield, but are robust against nasty weather
Q: What do you think happened when the two types were cross-bred?
A: A dwarf wheat with high yield that was robust!
Other types were produced, but they were discarded

14. How would you…? Discuss how you would breed for:
Better quality of milk from cows
- Increased number of offspring in sheep

15. In summary… Selective breeding = Artificial selection
Has been used for animals and plants
The method:
The desired characteristics are identified
They are bred together
Only the offspring exhibiting the desired characteristics are bred
This is repeated over several generations until the desired trait is fully developed

16. In summary…
Problems:
Traits are chosen to benefit humans, not the animal
Physical problems often occur in domestic animals eg. Inflammation of the udder (mastisis) in cows due to increased milk production
Usually involves inbreeding, which can lead to reduced genetic diversity

17. Would it be right to selectively breed humans??
Adolf Hitler believed in a master race (the Aryans) and implemented a plan to create this race.
This involved eugenics – the selective breeding of humans.

18. Nazi eugenics
Those considered “not worthy of life”, - let alone allowed to have children - included (but was not limited to) the criminal, degenerate, dissident, feeble-minded, homosexual, idle, insane, and the weak
400,000 people were sterilised against their will and 70,000 were killed

19. What do YOU think?