VARIATION

• What does variation refer to in living organisms?

  Variation refers to the differences that exist between individuals.
• What are the two main causes of variation in living organisms?

  Variation arises from a combination of genetic causes and environmental causes.
• What is the phenotype of an individual?

  The phenotype is the observable characteristics of an individual.
• What is the genotype of an individual?

  The genotype is the composition of genes within the cells of an individual.
• How is phenotype determined?

  Phenotype is determined by genotype and environmental influences.
• What is genetic variation?

  Genetic variation is controlled by genes and can be inherited from one generation to the next.
• What are the ways genetic variation arises?

  Genetic variation arises through meiosis, sexual reproduction, and mutations.
• How does meiosis contribute to genetic variation?

  Meiosis produces gametes with different combinations of genes due to crossing over and random arrangement of chromosomes.
• What happens during fertilization that contributes to genetic variation?

  During fertilization, male and female gametes fuse randomly, creating different combinations of genes in each zygote.
• What is a mutation?

  A mutation is a change in the structure of a gene, part of a chromosome, or the number of chromosomes in a cell.
• Can mutations be inherited?

  Mutations in gametes or zygotes can be inherited, while mutations in body cells cannot.
• What is albinism caused by?

  Albinism is caused by a mutation in a gene controlling the production of melanin.
• What is Down's syndrome and how does it occur?

  Down's syndrome occurs when an individual has an extra chromosome 21 due to improper separation during meiosis.
• How does antibiotic resistance arise in bacteria?

  Antibiotic resistance arises from mutations in some bacterial cells that make them resistant to certain antibiotics.
• What is environmental variation?

  Environmental variation is caused by different factors in an organism's environment and cannot be inherited.
• What are some environmental factors affecting humans?

  Environmental factors include diet, diseases, drugs, climate, upbringing, education, and exercise.
• What are the two basic types of variation within a species?

  • Continuous variation
  • Discontinuous variation
• What is continuous variation?

  Continuous variation shows a gradation from one extreme to another without breaks, often following a normal distribution.
• Give examples of characteristics that show continuous variation.

  Examples include height, weight, foot size, hair color, and intelligence.
• What is discontinuous variation?

  Discontinuous variation shows clear-cut differences with no intermediates, allowing individuals to be divided into distinct categories.
• Give examples of characteristics that show discontinuous variation.

  Examples include gender, ABO blood groups, and tongue-rolling ability.
• Why is variation important to living organisms?

  Variation allows individuals best suited to their environment to survive and reproduce, leading to natural selection.
• What is natural selection?

  Natural selection is the process where individuals with beneficial variations survive and reproduce, passing on their traits.
• What is inherited variation?

  Inherited variation is the phenotypic differences due to genes inherited from parents.
• What are some examples of inherited human features?

  Examples include ABO blood group, Rhesus blood group, and genetic sex.
• What is the difference between inherited and non-inherited variation?

  Inherited variation is genetic, while non-inherited variation is caused by environmental factors.
• What is continuous variation in terms of genetic control?

  Continuous variation is usually controlled by many genes and can be affected by environmental factors.
• What is discontinuous variation in terms of genetic control?

  Discontinuous variation is usually controlled by a single gene, with little influence from environmental factors.
• What are some important causes of environmental variation?

  Important causes include quantity and quality of food, exercise, social interactions, exposure to disease, and climate.
• How does random assortment during meiosis contribute to genetic variation?

  Random assortment during meiosis leads to different combinations of chromosomes in gametes.
• How does random fertilization contribute to genetic variation?

  Random fertilization determines which gamete fuses with another, creating genetic diversity.
• What is crossing over during meiosis?

  Crossing over is when homologous chromosomes exchange genetic material during meiosis, increasing genetic variation.
• What are the two types of mutations?

  The two types of mutations are gene mutations and chromosomal mutations.
• What is a gene mutation?

  A gene mutation is a change in the arrangement of DNA in a gene that alters a characteristic.
• What is a chromosomal mutation?

  A chromosomal mutation is a change in the number or structure of chromosomes in a cell.
• What are the important causes of environmental variation?

  • Quantity of food
  • Quality of food
  • Exercise and activity
  • Social interactions
  • Exposure to disease
  • Climate
  • Behavior
• What are the key concepts of genetic variation?

  • Controlled by genes
  • Can be inherited
  • Arises from meiosis, sexual reproduction, and mutations
• What are the key concepts of environmental variation?

  • Caused by environmental factors
  • Cannot be inherited
  • Influences growth and development
• What is the significance of variation in evolution?

  • Enables natural selection
  • Allows adaptation to environments
  • Facilitates species evolution
• What can affect children's growth and development?

  Exposure to disease