Question

disruptive selection when individuals at each end of the curve have higher fitness than individuals in the middle, disruptive selection can occur. in disruptive selection, the distribution of phenotypes shifts toward both extremes, thus increasing the population diversity.
evolutionary theory evolves evolutionary theory is vital to all biological and biomedical sciences and is often called \the grand unifying theory\ of all sciences. like any scientific theory, evolutionary theory is constantly reviewed and refined as new data are gathered.

1. write in the missing information to complete the comparison of single - gene and polygenic traits.

	single - gene trait	polygenic trait
number of phenotypes
example	lizard skin color
effect of natural selection on		directional selection, stabilizing selection, or disruptive selection

Explanation:

Step1: Recall Single - Gene Trait Basics

Single - gene traits are controlled by a single gene. So for the "Controlled by" row under "Single - Gene Trait", we write "a single gene".

Step2: Determine Number of Phenotypes for Single - Gene Trait

Single - gene traits typically have a small number of phenotypes, often 2 - 3 distinct phenotypes (e.g., Mendelian inheritance with dominant and recessive alleles can give 2 - 3 phenotypes). So for "Number of phenotypes" under "Single - Gene Trait", we can write "Few (e.g., 2 - 3 distinct phenotypes)".

Step3: Recall Polygenic Trait Basics

Polygenic traits are controlled by multiple genes. So for "Controlled by" row under "Polygenic Trait", we write "multiple genes".

Step4: Determine Number of Phenotypes for Polygenic Trait

Polygenic traits show a continuous range of phenotypes (e.g., human height, skin color). So for "Number of phenotypes" under "Polygenic Trait", we write "Many (continuous range of phenotypes)".

Step5: Find Example of Polygenic Trait

Common examples of polygenic traits include human height, human skin color, or human eye color. Let's choose human height as an example. So for "Example" under "Polygenic Trait", we write "Human height (or human skin color, human eye color)".

Step6: Determine Effect of Natural Selection on Single - Gene Trait

Natural selection on single - gene traits can lead to changes in allele frequencies, and can result in directional selection (favoring one extreme) or disruptive selection (less common for single - gene traits in some cases, but generally, single - gene traits can be affected by selection that favors one allele over another, leading to changes like in peppered moths). A common description for the effect of natural selection on single - gene traits is that it can lead to changes in allele frequencies, often resulting in directional selection (favoring one phenotype over others). So for "Effect of natural selection on" under "Single - Gene Trait", we can write "Can lead to directional selection (favoring one phenotype) or changes in allele frequencies".

Answer:

	Single - Gene Trait	Polygenic Trait
Number of phenotypes	Few (e.g., 2 - 3 distinct phenotypes)	Many (continuous range of phenotypes)
Example	Lizard skin color	Human height (or human skin color, human eye color)
Effect of natural selection on	Can lead to directional selection (favoring one phenotype) or changes in allele frequencies	Directional selection, stabilizing selection, or disruptive selection