Nature is cyclical, each component of nature is closely related to another, no resource is wasted, and living things have evolved to make use of the waste of other organisms.
This is evident in the process of respiration. Animals evolved to use oxygen, which is a waste product, of plant photosynthesis; plants, in turn, use the carbon dioxide (CO2) that animals discard in cellular respiration.
View of the trees in the Karen Mogensen Reserve. Photograp by Tom Castendiek
The dry leaves that accumulate on the ground are known as leaf litter. Leaf litter is home to many small organisms such as insects, mice, lizards, frogs and snakes that use this web of leaves and twigs as shelter to avoid being eaten by other animals; dead leaves are also food for degrading organisms such as insects, fungi and bacteria.
Also, leaf litter retains rainwater and prevents it from evaporating, thus helping water filtration for tree roots and for the aquifers that provide water to rivers and sustain life.
Leaf litter on the ground. Photograph taken by Carlos-Venegas-Elizondo
Within this cycle of matter, fungi play a very important role as they decompose matter making it available to the environment, process it for use by other animals or serve as food for other species. For example, Leafcutter ants (Atta cephalotes) cut leaves that they carry to their nests, and on these leaves, they grow fungi that will serve as food for the Leafcutter colony.
Wood-decomposing fungus. Photograph taken by Carlos Venegas-Elizondo
In addition to their decomposing function, the fungi release nutrients into the soil, increasing its fertility. They also connect with the roots of trees, where the tree provides food for the fungus and the fungus provides nutrients (such as nitrogen), which are used by the tree to grow. This relationship between these two organisms (plant-fungi) is known as mycorrhizae.
Like organic matter and energy, other components of nature are constantly cycling, for example water and minerals, which circulate the environment and make life on earth possible.