How did earth cool down enough to sustain life

According to the theory of punctuated equilibrium, at what rate does speciation occur? species change depending on the rate of natural selection. after periods of stasis, new species evolve relatively rapidly. species change slowly and eventually form new species. some species change quickly and others change slowly to balance the overall rate.

What type of competition exsist between two species. turtles and fish

According to this food web which of the following would be considered primary consumers