What is the theory of particulate inheritance?
The theory of particulate inheritance states that discrete "particles" are passed from parents to offspring. While Mendel used the term particles, we now know that these particles are actually genes. Mendel also knew that particles may not be present in every generation, but they remain and keep their ability to be expressed in later generations.
For example, Perhaps one of your parents has blue eyes and the other brown eyes. You yourself have brown eyes but you keep the gene for blue eyes, which can be expressed in your offspring if you mate with someone who also carries the gene for blue eyes.
Below is a punnet square showing the parental generation and the particles the F1 generation (offspring of parents) inherits. Below we see the possible combinations the F2 generation (offspring of the offspring) could inherit from their parents.