A population of bacteria sees an increase in the number of bacteria resistant to a certain antibiotic over a number of generations. This is known as .

MICROEVOLUTION

Explanation: Microevolution simply means those changes in the alleles frequencies of an organism over time.

In other words,we will say that microevolution is the generation to generation change in a population's frequencies of alleles.

These changes can occur due to natural or artificial selection,

Gene flow, mutation and genetic drift.

From the question asked,when a population of bacteria sees an increase in the number of bacteria resistant to a certain antibiotic over a number of generations,it is simply known as microevolution.

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.