I wanted to share a few thoughts about the importance and relevance of scientific illustrations in effectively investigating and communicating science. During the programs we run on Hurricane Island for students, we often dedicate time to nature journaling and drawing from observations of newly collected samples or specimens.
Why bother drawing when you can just snap a photograph? For one thing, drawing forces you to look more carefully at every detail of your subject as you depict it on the page. Illustrations can also simultaneously show several different stages of development, multiple angles, and highlight specific characteristics of the subject while still keeping it in the context of its environment. Most importantly, drawing allows you to omit distracting information to help focus the viewer on the details that are key to identifying an organism, or are important to that subject's life history. Zoe Keller has a beautiful example of this in her illustration of the lifecycle of Maine's Northern Black Racer snake Coluber constrictor (you can see more of her illustrations in her blog, Compass and Wheel). In one compelling image, Zoe is able to convey important information about how the pattern of Coluber constrictor is different from juvenile to adult snakes, what this snake's eggs look like, the structural anatomy of this snake's ribs and vertebra, and how snakes shed their skin.
If you think you can't draw, never fear! You don't need to be an expert artist to take down valuable visual information that can inform you back in the lab more reliably than photography. Even if you start with simple gestural drawings that note an organism's movement, or sketches that inform coloration, patterning, and shape, this can supplement your field notes and help you remember more about what you observed.
If you are interested in reading more about how to make good observations, the importance of illustration, or want to see some great examples from different naturalists field notebooks, I recommend Field Notes on Science & Nature, edited by Michael R. Canfield.