Biological rules

A heuristic or heuristic technique (problem solving, mental shortcut, rule of thumb) is any approach to problem solving that employs a pragmatic method that is not fully optimized, perfected, or rationalized, but is nevertheless "good enough" as an approximation or attribute substitution. Where finding an optimal solution is impossible or impractical, heuristic methods can be used to speed up the process of finding a satisfactory solution. Heuristics can be mental shortcuts that ease the cognitive load of making a decision.

four criteria showing a causal relationship between a causative microbe and a disease

proposition that two species competing for the same limiting resource cannot coexist at constant population values

hypothesis proposed by Louis Dollo which states evolution is not reversible

A postulation pertaining to evolution

observation in evolutionary biology

biological rule in allometrics, concerning the relationship between the extent of sexual size dimorphism and which sex is larger

generalized principle to describe patterns observed in living organisms

theory in embryology

the trend of social parasites to be parasites to species or genera they are closely related to

thumb|upright=1.3|Cospeciation and host-parasite associations. From top to bottom: Cospeciation: host and parasite speciate concurrently Host switching: speciation as parasite switches hosts and evolves in reproductive isolation Independent speciation: parasite speciates on same host, reasons unrelated to host Extinction: parasite goes extinct on host Missing the boat: host speciates but parasite does not end up reproductively isolated Cospeciation is a form of coevolution in which the speciation of one species dictates speciation of another species and is most commonly studied in host-parasit