If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Trait B is likely to have arisen earlier than trait A.
In an asexually reproducing species, variations arise through mutations and spread through the population over generations. When a new trait appears, it initially exists in only one individual and gradually spreads to more members over time. The selection of variants by environmental factors forms the basis for evolutionary processes.
Since trait B exists in 60% of the population while trait A exists in only 10%, trait B has had more time to spread through the population. A trait present in a larger percentage indicates it has been present for a longer duration, allowing it to be inherited by more individuals. Therefore, trait B arose earlier.
Explanation
This question tests the understanding of how traits spread in populations over time through evolutionary processes. In asexual reproduction, there is no genetic mixing between individuals, so traits spread only through the reproduction of individuals carrying those traits. A trait that arose earlier would have had more generations to spread through the population, resulting in a higher percentage of individuals carrying that trait. The textbook context mentions that 'Selection of variants by environmental factors forms the basis for evolutionary processes,' supporting the idea that beneficial traits spread over time.
Solution Steps
Step 1: Understand that in asexual reproduction, traits spread through inheritance over generations.
Step 2: Recognize that a trait present in a larger percentage of the population has had more time to spread.
Step 3: Compare the percentages - trait B (60%) > trait A (10%).
Step 4: Conclude that trait B arose earlier as it has spread to more individuals.