Notes

1.....Which of the following best describes how, over multiple generations, natural selection can lead to adaptation in a population?
==== Due to natural selection, individuals with adaptive traits have higher rates of survival and reproduction, and as a result, these traits become more common in the population.
`````````(This option correctly captures the essence of natural selection, where individuals with traits that confer a survival or reproductive advantage are more likely to pass those traits on to the next generation, thereby increasing the frequency of those adaptive traits in the population over time.)`````````

2. ...In a population of birds, some individuals have gray feathers, and some have brown feathers. Feather color in the bird population is genetically determined.
Scientists have observed that the proportion of individuals in the population with brown feathers has increased over the past 30 years.
Based on this change in phenotype frequency, what must be true about genes in the population?
==== Over the past 30 years, the genes underlying the brown feather trait have become more common in the population.
```````(The correct answer is (Choice A): Over the past 30 years, the genes underlying the brown feather trait have become more common in the population. This observation is consistent with the principles of evolution and natural selection. If the proportion of individuals with brown feathers has increased, it suggests that the genes for brown feathers have provided some sort of advantage in the environment, leading to better survival or reproduction rates among those individuals compared to those with gray feathers. As a result, the genes for brown feathers would become more prevalent in the gene pool of the population over time. This is a classic example of how allele frequencies can change in a population, which is the basis of evolutionary change.)````````

3 .A population of guppies live in a stream. The male guppies exhibit a wide range of colors and patterns: some males are brightly colored, while others are more plainly colored.
Which of the following best describes a biotic factor that could lead to adaptation by natural selection in the guppy population?
= female guppies preferring to mate with brightly colored males
(Choice B: female guppies preferring to mate with brightly colored males. This preference can lead to an increase in the frequency of genes for bright coloration in the population over time, as brightly colored males may have more mating opportunities and thus more offspring. This is a classic example of how sexual selection can drive evolutionary change. Bold of the relevant parts of the response is used to improve readability.)

4.Which of the following are definitions of the term adaptation?
= a heritable trait that makes an organism more likely to survive and reproduce in its environment
=a process by which a population becomes dominated by organisms that are well suited to their environment
(Choice C- a heritable trait that makes an organism more likely to survive and reproduce in its environment. This is a direct definition of adaptation, as it describes a characteristic that has evolved through natural selection to be beneficial in the specific conditions of the organism’s environment.)
(Choice D- a process by which a population becomes dominated by organisms that are well suited to their environment. This choice describes the outcome of adaptation at the population level, where over time, those individuals with advantageous traits are more likely to survive and reproduce, leading to a population that is adapted to its surroundings).