t18 variation and selection

• natural selection is the process by which individuals with traits that are better suited to their environment survive and reproduce
• The first cause of variation is the alleles that individuals have inherited which are genetic causes
• selective breeding is the process of breeding animals or plants to produce offspring with desirable characteristics
• Another cause of variation is the environment (like for plants the ph of the soil and for humans languages)
• Some variation is caused by a combination of genes and the environment 
• Genetic variation is due to mutations 
• Mutations:

  Random changes to DNA
• Most mutations have no effect at all on the phenotype (appearance)
• Some mutations can influence the phenotype
• In order for any organisms to survive it has to adapt to its environment

  Structural adaptation :physical features that we see, like the organisms shape or colour

  Behavioural  adaptation:

  The way an organism behaves or acts, like when elephants spray themselves with water is an adaptation to the hot environment

  Functional adaptation:

  Processes inside an organisms like their metabolism or reproductive system , like camels conserving their water and only small amounts of concentrated urine