Rust (fungus) an autoecious fungus which can complete its life cycle on a single host species. Understanding the life cycles of rust fungi allows for proper disease management. There are definite patterns of relationship with host plant groups and the rust fungi that parasitize them. Some genera of rust fungi, especially "Puccinia" and "Uromyces", comprise species that are capable of parasitizing plants of many families. Other rust genera appear to be restricted to certain plant groups. Host restriction may, in heteroecious species, apply to both phases of life cycle or to only one phase. The fungi produce asexual spores which disperse by
Four causes after the ethologist Nikolaas Tinbergen and based on Aristotle's four causes, are complementary categories of explanations for animal behaviour. They are also commonly referred to as levels of analysis. The four questions are on function, what an adaptation does that is selected for in evolution; phylogeny, the evolutionary history of an organism, revealing its relationships to other species; mechanism, namely the proximate cause of a behaviour, such as the role of testosterone in aggression; and ontogeny, the development of an organism from egg to embryo to adult. Four causes The "four causes" are elements of an influential principle in Aristotelian