Evolution by natural selection occurs when there is variation in traits among individuals in a population, those traits affect survival and reproduction, and they can be passed on to the next generation.
In the scenarios provided:
-
Penguins reproduce sexually, producing offspring that look different from one another - This scenario has variation among offspring, which is essential for natural selection to occur. If the differences provide some individuals with a better chance of survival or reproduction, then natural selection can act on this variation.
-
Microorganisms reproduce asexually, producing identical offspring - In this case, there is no variation among the offspring (they are identical). Without variation, natural selection cannot take place.
-
Corn is genetically modified and cloned to make identical crops - Similar to the microorganisms, the resulting crops are identical. Again, without variation, there is nothing for natural selection to act upon.
-
A banana tree branch is planted, producing a clone of the parent tree - This scenario also results in clones with no variation. Therefore, natural selection does not occur.
Based on this analysis, the only scenario in which evolution by natural selection could potentially take place is:
Penguins reproduce sexually, producing offspring that look different from one another.