Selection

• Each time male and female individuals reproduce they create an offspring that is different from themselves
• This changes accrue over time to bring about much change in the descendants as there is inter-breeding between many individuals in each generation
• This changes might result in the offspring having certain advantageous characteristics that are not present in their contemporary offspring
• This means the offspring with the advantageous is more likely to survive and thrive compared with the one that does not have that advantage
• For example during a breeding cycle there are two calves born of different parents
• One is born with genes that are resistant to diseases and the other is not
• The one born resistant is more likely to survive and grow up
• The environment decides or select which offspring will survive
• This phenomenon is known as natural selection
• Natural selection-is when the environment decides which offspring will survive usually the strongest members of the given species will survive to breed the next generation
• Nature selects which offspring will survive to grow and produce the next generation
• Because the species with the advantageous characteristics survives and breeds the next generation that trait/characteristic is passed on to the next generation
• For example if there are many calves born and more of those which are resistant to diseases survive and breed the next generation
• The result is that in each succeeding generation more and more calves are born with those genes
• With time each generation will be different and should be better suited to the environment in which it lives
• The weaker members who lack the advantage die off and less of them breed
• Natural selection has been happening for millions of years
• It is a slow process
• Humans can influence the selection process to their advantage
• For example farmers can choose and plant the breeds they want to produce based on their needs
• Scientists breed crops that grow best in the local conditions for example drought resistant crops breeds and crop breeds that mature more quickly
• This is known as artificial selection
• Artificial selection-this is when humans influence the selection process to their advantage for example hybrid breeding of crops
• Typically the male and female individuals are carefully selected and mated
• Agriculture benefits greatly from artificial selection
• Breeds of cattle, sheep and goats that are suited to local conditions are bred
• Important features such as improved milk and meat yields, increased drought tolerance and increased resistance to diseases are fostered in the breeding process

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