Citizen Science is a term used to describe people, non scientists or amateurs, involved in scientific study or research. This could be by participating in a bioblitz or bird counts and becoming more common using mobile apps to monitor everything from biodiversity to water quality. One example of a mobile app is Project Noah, using the app is straight forward and free, it allows you to take photographers and upload them to their site, you can tag the photo with information and where it was taken, so contributing to a worldwide project looking at biodiversity.
Also if you are unsure of the name of the animal or plant you have snapped you can add to a list for help identifying what species it is.
You can join missions or start your own, for example find as many plants with red flowers, you can collect badges and many other things.