An example of metaphor in writing about science:
"the multiplying tissue cells of the oak will have to organise themselves into organs – in roots, trunk, and leaf canopy, which captures the sunshine…
Jakob von Uexküll
At the same time, the canopy serves as an umbrella that carries the precious moisture from the sky to the fine roots under the earth."
Uexküll, J. v. (1940/2010). A Theory of Meaning (J. D. O'Neil, Trans.). In A Foray into the Worlds of Animals; with, A Theory of Meaning (pp. 137-208). University of Minnesota Press.
The expression "captures the sunshine" seems to be figurative, as sunshine cannot be captured (though in a sense theleave capture the energy it carries). The reference to an umbrella does not seem to be analogy (as the function of an umbrella is to avoid getting wet), but simile.
Read about examples of science similes