Jobs

Chainlink nodes require Jobs to do anything useful.
In the case of a Request and Receive job, the Direct Request job monitors the blockchain for a request from a smart contract.
Once it catches a request, it runs the tasks (both core and external adapters) that the job is configured to run
Jobs eventually returns the response to the requesting contract.

Tasks

These are custom adapters built by node operators and community members,
They perform specific tasks like calling a particular endpoint with a specific set of parameters