Final answer:
Observational studies in biology involve observing and exploring natural phenomena, while manipulative methods are employed in controlled experiments to test hypotheses.
Step-by-step explanation:
Observational studies involve observing and exploring natural phenomena without manipulating any variables. These studies are hypothesis driven as they aim to examine relationships between variables or patterns in data. An example of an observational study in biology would be monitoring the behavior of a certain animal species in its natural habitat to understand its feeding habits.
On the other hand, manipulative methods are employed in controlled experiments to test a specific hypothesis by manipulating one or more variables. In these experiments, scientists design and perform systematic observations or measurements under controlled conditions. For instance, studying the effect of different fertilizers on plant growth by assigning different groups of plants to receive different types of fertilizers would be an example of a manipulative study in biology.