Must all ecosystems have quaternary consumers? why or why not?

What is a cordon and where is it found

The earth consists of a variety of different organisms. despite their diversity, however, some similarities on the structural and metabolic levels may be seen. these similarities can be attributed to a. similarities among organisms in their proteins and nucleic acids. b. the ability of organisms to readily adapt to sudden environmental changes. c. similarities in organisms' habitats and niches. d. the ability of all organisms to interbreed and produce new species.

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?