Final answer:
An organism's genetic makeup is termed its genotype, encompassing all genetic information including different alleles on chromosomes. The phenotype is the expression of this genetic code as observable traits. Gregor Mendel's studies in heredity laid the groundwork for understanding the transition from genotype to phenotype.
Step-by-step explanation:
The genetic makeup of an organism is referred to as its genotype. The genotype consists of all the genetic information in an organism's cells, including genes located on chromosomes within the nucleus. Genes can have different forms, known as alleles, which are variations that contribute to an organism's uniqueness. While the genotype is the genetic code, the phenotype is the expression of this code, the observable traits of an individual, which results from both genetic and environmental influences.
Gregor Mendel's work on the laws of heredity further illustrated the link from genotype to phenotype. Each parent contributes to the genotype of their offspring through their alleles, ensuring that offspring share similar characteristics while also allowing for genetic variation. Through better understanding of genotypes and phenotypes, scientists can trace how traits are passed down from parents to children and how the unique combinations of alleles in each individual lead to the diversity of traits observed within a species.