Ecosystem Interactions Hey, my friend, I can explain to you the topic discussed in previous that you missed. First. Interspecies interactions refer to the ways in which populations from different species interact with each other. Here are some of the examples. mutualism refers to an interaction in which organisms of various species interact and benefit positively hence it is a +/+ relationship. For example, the oxpecker gets food by picking ticks off Zebras skin while the zebra benefits by getting rid of the tick (Townsend, Harper, amp. Begon, 2000). Competition refers to a situation in which organisms from different species compete for the same shared limited resources like food, water and space in which the less fit organism loses. This is a -/+ relationships. Predation, on the other hand, is whereby the predator kills then feeds on the prey while herbivory involves the herbivores feeding on the primary producer.(+/- relationship). Parasitism is a relationship in which one species benefits at the expense of the other but they do not kill the host.Only 10% of energy is transferred to the next trophic level. Most is used in metabolism, and the rest lost through excretion, hence making the successive level be smaller (Townsend et al., 2000). Ecosystems obtain all its energy from the sun that is transformed into chemical energy through photosynthesis in primary producers (plants) and moves up the trophic levels. It is converted to other forms like heat.Matter cycles through the ecosystem in various stages. For example, plants use carbon dioxide present in the atmosphere together with sunlight to make food. Primary consumers consume this food like human beings. Once these consumers die, carbon is stored in fossil fuel that may be mined in future and burned releasing carbon ReferencesTownsend,C.R., Harper,J.L., amp. Begon,M. (2000). Essentials of ecology. Oxford: Blackwell Science.