Morphology is the study of forms or the physical appearance of organisms.
Speciation is the splitting of lineage into distinct species capable of interbreeding and producing fertile offspring.
Species is a group of organisms that are genetically related and share features and characteristics. They are capable of interbreeding and produce live offsprings.
Vestigal organs are organs that have lost their function over time, they are usually small and underdeveloped. Example is the human tail bone.
