Variation

• Variation in species can be generated by genetics
• Mutations arise spontaneously and can sometimes lead to genetic disorders or death
• Genes can be inserted into a genome through genetic engineering
• Genetic causes of variation
• Children generally look a little like their mother and their father, but are not identical to either
• Every sperm and egg cell contains half of the genetic information needed for an individual
• When the chromosomes fuse during fertilisation, a new cell is formed, known as a zygote, which is diploid and has the full number of chromosomes
• Examples of genetic variation in humans include blood group, skin colour, natural eye colour, and whether you have lobed or lobeless ears
• Biological sex is also an inherited variation - whether you are male or female is a result of genes inherited from your parents
• Environmental causes of variation
• Characteristics of animal and plant species can be affected by factors such as climate, diet, accidents, culture, and lifestyle
• Features that show environmental variation include scars, language and accent, flower colour in hydrangeas, and growth in response to light availability
• Genetic and environmental causes together
• Some features vary because of a combination of genetic and environmental causes
• For example, tall parents passing genes for height to their children, but poor diet impacting their growth potential