History of the word usage.
Physical interaction.
Mutualism - Florence and Sandra (perhaps she's British), or perhaps she's from Mexico (from a wealthy academic family),
Commensalism - the British and the Suez canal, Egypt's waterways were traversed without harm (some would argue), hitching a ride
Parasitism - boll weevil, defoliation, English presence in Egypt in the early 1950's and WWII, braceros as cultural parasites (from a prejudice perspective),
Amensalism - Florence and her mother, the water usage and cotton production on the Texas High Plains
Role in evolution, of people, of songs.