Question

Which of the following situations will lead to natural selection? a. The seeds of two plants land near each other and one grows larger than the other. b. Two types of fish eat the same kind of food, and one is better able to gather food than the other. C. Male lions compete for the right to mate with females, with only one possible winner. d. all of the above

Short answer

Situations B and C will lead to natural selection, as they involve organisms with advantageous heritable traits that promote survival and reproduction. Situation A does not necessarily involve natural selection as no specific advantageous trait is identified.

Step-by-step solution

Situation A

The seeds of two plants land near each other and one grows larger than the other. In this situation, there is no clear indication that the larger plant possesses heritable traits that provide an advantage over the smaller plant for survival and reproduction. The size difference could be due to other factors such as soil quality or watering conditions. Therefore, natural selection is not necessarily taking place in this situation, because no specific advantageous trait is identified.

Situation B

Two types of fish eat the same kind of food, and one is better able to gather food than the other. In this situation, one type of fish possesses a heritable trait that enables it to gather food more effectively than the other type of fish. This advantage directly affects the survival and reproduction of the fish with the advantageous trait, as they are more likely to have sufficient food resources. This leads to a higher likelihood that the advantageous trait will be passed on to future generations, resulting in natural selection.

Situation C

Male lions compete for the right to mate with females, with only one possible winner. In this situation, the male lions with heritable traits that provide an advantage in competing for the right to mate with females are more likely to reproduce, passing on their advantageous traits to future generations. This process of competition among male lions for reproductive opportunities can lead to natural selection, as it favors the survival and reproduction of individuals with advantageous traits.

Answer

Based on the analysis of each situation, we can conclude that situations B and C will lead to natural selection, whereas situation A will not necessarily lead to it. Therefore, the correct answer is not d. "all of the above", but rather a combination of situations B and C.

Key concepts

Heritable Traits

Heritable traits are characteristics passed down from parents to their offspring through genetic information. These traits are found in the DNA and determine various aspects of an organism, such as appearance, behavior, or ability to survive in certain environments.
For natural selection to occur, the traits must be heritable. This means they must be able to be inherited by the next generation.

• Genes carry the information for these traits.
• If a trait offers some benefits, it may become more common in a population over time.

For instance, in the example of the fish mentioned in the exercise, the fish that better gathers food possesses a trait that allows it to do so efficiently. If this trait is heritable, it can be passed on to the offspring, helping them also survive better in their environment. This transmission of beneficial traits is how natural selection acts upon populations, potentially leading to evolutionary changes over generations.

Reproductive Advantage

Reproductive advantage refers to the benefits an organism gains in its ability to reproduce and have offspring. When an organism has traits that improve its chances of reproducing successfully, it has a reproductive advantage over others.
This is a critical part of natural selection, as

• Individuals with such advantages are more likely to pass their genes to the next generation.
• This increases the frequency of advantageous traits in the population.

Consider the male lions from situation C of the exercise. Those with traits enabling them to dominate others in competition for mating will likely reproduce more. As a result, these lions will pass their advantageous genetic traits to their offspring, giving these next generations a similar advantage.

Survival and Reproduction

Survival and reproduction are key elements of natural selection. These are the processes by which organisms live in their environments long enough to reproduce and ensure the continuation of their species.
When organisms possess certain traits that give them an edge in survival and reproduction, they are more likely to thrive and multiply.

• This process results in the selection of traits that are beneficial for these purposes.
• Over time, it can lead to a population more suited to its environment.

In reference to situation B, the fish that are better at gathering food are more likely to survive and have enough resources to sustain themselves and their offspring. This greater chance of survival directly impacts their ability to reproduce and pass on successful traits, showcasing how natural selection favors organisms with a distinct survival edge. This process doesn't just aid survival but ensures these traits become prevalent in future generations.