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Natural selection As soon as humans become involved it can no longer be called ‘natural’. Obviously, humans don’t want to wait hundreds or thousands of.

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Presentation on theme: "Natural selection As soon as humans become involved it can no longer be called ‘natural’. Obviously, humans don’t want to wait hundreds or thousands of."— Presentation transcript:

1 Natural selection As soon as humans become involved it can no longer be called ‘natural’. Obviously, humans don’t want to wait hundreds or thousands of generations to see a change in a species. Neither do they want to wait for the precise change to ‘accidently’ occur. So humans speed up the process and direct it along very specific lines.

2 10,000 Years ago: 4,000 Years ago More recent Why these different times?

3 Domestication: Human domestication of plants began in the Domestication almost certainly began as

4  Humans naturally selected 1 – 2 – 3 –

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7  Selected mustard plant for the

8  Or selected for the

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10  The

11  Or selected just for the

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13 The same processes worked for animals like...

14 Domesticated and Bred Pigeons All Breeds came from a single original species

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16 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8 – The big mammals provide most of these traits.

17 SheepFrom Asiatic Mouflon sheep

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22 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8 –

23  Diet Herbivores are more efficient in terms of energy conservation

24  Some For example Cheetahs have a courtship in which the female is chased by the male for three days. This is not possible in captivity

25  Some animals are just plain nasty

26  Some animals are nervous and programmed for fast flight if they sense danger E.g.  Some animals are slower, less nervous and will seek protection in herds if attacked. E.g.

27  Some animals live in herds, have a dominance hierarchy established, and have overlapping home ranges Why is this useful?

28  Solitary, territorial animals that don’t like herds won’t imprint on humans. E.g.  Some animals are territorial during breeding seasons, when they fight and don’t tolerate each other E.g.

29  Some animals lack a well defined dominance hierarchy E.g. Bighorn sheep

30  For an animal to be of benefit to humans it needs to grow fast. E.g.  Animals like

31  Humans control the  Thus we decide which animal is allowed to mate with which other.  Consequently,

32  This results in ‘inbreeding’.  Inbreeding is  However, if we also control conditions, then this shouldn’t happen.  Many of our  So, whilst artificial selection is good for humans, its generally bad for the species involved.

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