Principles of Inheritance Inheritance refers to the passing of genetic information from parents to offspring. DNA contains genes arranged in chromosomes, and di...
Inheritance refers to the passing of genetic information from parents to offspring. DNA contains genes arranged in chromosomes, and different versions of genes are called alleles, which can be dominant or recessive.
Punnett squares can be used to predict the inheritance patterns of specific traits by modeling the possible genetic combinations from parental genotypes.
Variation describes the differences between individuals of the same species. There are two main types:
Evolution is the gradual change in inherited characteristics of a population over generations. Natural selection is the driving mechanism, where individuals with advantageous variations are more likely to survive and reproduce, passing these traits to offspring.
Evidence for evolution includes fossil records, antibiotic resistance in bacteria, homologous structures in related species, and biogeography.
New species can arise through the accumulation of variations in isolated populations over many generations, leading to reproductive isolation. This process is known as speciation.
Understanding inheritance and variation allows for selective breeding programs to produce desired traits in crops and livestock.
Genetic engineering techniques can directly modify the genetic makeup of organisms, with applications in agriculture (pest resistance, improved yields) and medicine (gene therapies).
However, these technologies raise ethical concerns about unintended consequences, equitable access, and potential misuse.
Problem: In pea plants, tall (T) is dominant over dwarf (t). If a homozygous tall plant (TT) is crossed with a heterozygous tall plant (Tt), what are the possible offspring genotypes and phenotypes?
Solution:
For more information and examples, visit BBC Bitesize: Inheritance, Variation and Evolution (GCSE Biology).