Cell Biology
Cells show some basic similarities in structures and functions.
Cells of higher animals possess organelles such as; Ribosomes, mitochondria, Endoplasmic reticulum, DNA, ATP etc.
These similarities and resemblance show that the cells have a common ancestral origin. Groups of organisms with similar transport pigments like haemoglobin are closely related unlike those with different pigments, and are thought to have evolved from a common ancestral origin.