Final answer:
Walter Sutton is known for investigating the number of chromosomes in grasshoppers, contributing to the chromosomal theory of inheritance, which underpins our understanding of genetics and genetic inheritance.
Step-by-step explanation:
Walter Sutton investigated the number of chromosomes in grasshoppers. He is known for his contributions to the chromosomal theory of inheritance, which states that genes are located on chromosomes and that these chromosomes are the vehicles for genetic inheritance. His work along with Theodor Boveri's provided a chromosome-based explanation for Mendel’s rules of inheritance. It was during his work on grasshopper cells that Sutton observed the pairing of maternal and paternal chromosomes during meiosis, which led to the concept that these pairs separate randomly and independently, providing a physical basis for Gregor Mendel's earlier theories. Sutton's research was foundational in the field of genetics and laid the groundwork for our understanding of genetic inheritance.