Give two examples of organisms that may have coevolved

Coevolution is common among organisms participating in a mutual interaction. In mutualism, both the organisms benefit from each other. When coevolution occurs among mutually benefiting species, it is called mutualistic coevolution.

When coevolution is found among species that have negative effects on each other, it is called competitive coevolution. There are two kinds of interactions between species that can lead to competitive coevolution:

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.