Biology is the study of life. Plant biology (a. k. a. botany) is the study of plants, which includes among other things, how plants evolved on earth, their structure, how they grow and develop, and how they interact with the environment.iology is the study of life. Plant biology (a. k. a. botany) is the study of plants, which includes among other things, how plants evolved on earth, their structure, how they grow and develop, and how they interact with the environment.