Question

The idea that species evolve at a slow constant rate is called?

Answer 1

That is called gradualism.

Answer 2

The idea that species evolve at a slow constant rate is called gradualism.

Gradualism is a theory which maintains that evolution of species proceeds continuously at a steady pace, without the sudden development of new species or biological features from one generation to the next. The approach in which Charles Darwin deduced the emergence of one species from another species over geologic time has been attributed to gradualism.