Star Trek

Look..In the episode "That Which Survives" when Captain Kirk, Dr McCoy, LT Sulu and Biologist Lt D'Amato, get's stuck on a Planet and is attack, they needed to do a study of the planet, D'Amato dies, Kirk then gives his tricorder to Sulu and says "I know it was D'Amato's field but see what you can find"..Sulu Should had known what to do, his hobby is botany and he was a Physicist before he became a helmsman, so what so hard about taking a few readings and studying the Planets environment ? for Sulu who has science background ? opinions ?  

Maybe Kirk just didn't know about Sulu's botany hobby, and a hobby may not take you to the level of expertise of someone who does something for a living.  Also, botany and environment have some overlap, but are 2 different specialties.

One would assume there is a difference between a Botanist and a Biologist.

Botany is a branch of BIOLOGY that deals with plant life, they sort of go together..When determining a Planets environment Botany is important and they were in search of a water source, botany can determine that also and with the tricorder  Sulu had it should had been easy.  

Agreed, I believe that they should have let Sulu show more of his knowledge onscreen instead of always relying on Spock. There's also a scene in This Side of Paradise where he should have noticed the exotic plant growing too close to barn. After all, wasn't he in the botany lab in the Man Trap?

Well, it is possible that anyone could have just slipped up.

Not really, if you'll notice some people on Kirks Enterprise are cross-trained, Chekov is a navigator but he also works Spocks science station and sometimes the Engineering Station, Uhura is in communications but she can take the helm when needed.As for Sulu who has a science background, it shouldn't of been hard for him to do a science study using the tricorder.. I made an error, D'amato was a Geologist  not a Biologist but they go hand in hand