Understanding cell division, inheritance, and evolution is fundamental to AQA Combined Science Biology Paper 2 studies.
Cell division occurs through two main processes: mitosis and meiosis. In mitosis, one parent cell divides to produce two identical daughter cells, maintaining the same chromosome number. This process is crucial for growth, repair, and asexual reproduction. Differences between mitosis and meiosis GCSE Biology show that while mitosis produces identical cells, meiosis creates four genetically diverse daughter cells with half the chromosome number. Meiosis is essential for sexual reproduction and genetic diversity through crossing over and independent assortment of chromosomes.
Inheritance, variation and evolution GCSE Biology explores how characteristics are passed from parents to offspring through genes. Genetic inheritance follows Mendel's laws, where alleles can be dominant or recessive, determining traits in organisms. Variation arises from both genetic and environmental factors. Genetic variation comes from mutation, meiosis, and sexual reproduction, while environmental variation results from factors like diet, climate, and exercise. Evolution through natural selection explains how species change over time, driven by genetic variation and survival of the fittest. Modern understanding of inheritance has led to developments in selective breeding, genetic engineering, and treating genetic disorders. AQA GCSE Biology Inheritance, variation and evolution exam questions often focus on these key concepts, requiring students to demonstrate understanding of genetic crosses, inheritance patterns, and evolutionary mechanisms. The study of these topics helps explain biodiversity, species adaptation, and the development of new characteristics in populations over time.
