When a population of bacteria is bombarded with antibiotics, the 'weak' ones will die. The ones with some resistance built in will survive, and divide to form a new population of copies of themselves, or a resistant population. This in itself is survival of the fittest in a very pure form.
An example of microevolution is the development of antibiotic resistance in bacteria due to natural selection. Over time, bacteria that are resistant to antibiotics survive and reproduce, leading to a population of bacteria that is predominantly resistant to that antibiotic.
All of the above examples are direct evidence for evolution. Genetic changes in plants, antibiotic resistance in bacteria, and pesticide resistance in insects all demonstrate how species can adapt and evolve to survive in changing environments. This supports the theory of evolution by natural selection.
Direct selection occurs when the bacteria are cultured in conditions where only the mutant will grow. For example, if a mutant bacterium has gained resistance to a specific antibiotic, only the mutant will be able to grow on media containing that specific antibiotic. Indirect selection occurs when the bacteria are cultured in conditions where the growth of the mutant is different from the growth of the wild type.
Evolution is the process by which living organisms change and adapt over time through natural selection. An example of evolution is the development of antibiotic resistance in bacteria. When exposed to antibiotics, only the bacteria with genetic mutations that make them resistant survive and reproduce, leading to a population of bacteria that is mostly resistant to the antibiotic.
A great example would be Antibiotics and Bacteria. When humans create an antibiotic, it wipes out a lot of the bacteria in your body. The ones that that don't get affected by it probably have a resistance to the antibiotic. As those bacteria multiply and grow, the others die out due to the antibioitic. Soon the anti-biotic resistant bacteria will take over the human body, and the humans would have to find another antibiotic to counter the new bacteria. The cycle goes on and on......
All bacteria, as are all organisms, are variants and some of these variants are resistant to antibiotics. So, a population of bacteria, in their immediate environment, are subjected to an antibiotic and most succumb. So, the resistant, survive the onslaught ( are naturally selected ) and reproduce progeny that are also resistant to the antibiotic. So, allele frequency shifts and evolution occurs die to the adaptive change conferred on the progeny population by natural selection.
You are an example of human micro-evolution as the population of humans has changed allele frequency over time. Micro-evolution is just evolution; change over time.
An example of microevolution in organisms is the development of antibiotic resistance in bacteria. Through repeated exposure to antibiotics, bacteria may develop genetic mutations that confer resistance to the drug, allowing those bacteria to survive and reproduce, leading to the evolution of a population that is no longer susceptible to the antibiotic.
An example of micro-evolution is the development of antibiotic resistance in bacteria due to natural selection. When exposed to antibiotics, bacteria with genetic mutations that provide resistance to the drug survive and reproduce, passing on the resistant trait to future generations. Over time, the proportion of resistant bacteria in the population increases, leading to the evolution of antibiotic-resistant strains.
Bacteria passing resistance to a medicine on to offspring is an example of vertical gene transfer, where genetic material is transferred from parent to offspring. This mechanism allows for the inheritance of beneficial traits, helping bacteria survive in the presence of antibiotics.
Bacterial resistances are developed due to mutations that are passed down from generations of bacteria. Antibiotics generally kill all but the strongest bacteria or bacteria that have resistances to these antibiotics, resulting in only these bacteria reproducing, passing on the antibiotic resistances to future generations. Over time, entire populations of bacteria can develop a resistance to an antibiotic if they are frequently exposed to it. Bacterial resistances are developed due to mutations that are passed down from generations of bacteria. Antibiotics generally kill all but the strongest bacteria or bacteria that have resistances to these antibiotics, resulting in only these bacteria reproducing, passing on the antibiotic resistances to future generations. Over time, entire populations of bacteria can develop a resistance to an antibiotic if they are frequently exposed to it. Bacterial resistances are developed due to mutations that are passed down from generations of bacteria. Antibiotics generally kill all but the strongest bacteria or bacteria that have resistances to these antibiotics, resulting in only these bacteria reproducing, passing on the antibiotic resistances to future generations. Over time, entire populations of bacteria can develop a resistance to an antibiotic if they are frequently exposed to it.
One example of inherent resistance is antibiotic resistance in bacteria. Some bacteria naturally possess genes that allow them to survive exposure to certain antibiotics, reducing the effectiveness of those drugs in treating infections. This inherent resistance can make it challenging to treat bacterial infections and necessitates the development of new antibiotics.