Exam 21: Microevolution: Genetic Changes Within Populations

Researchers study the inheritance of particular human traits by ____.

How can a researcher determine whether variation in a phenotypic trait is caused by environmental factors or by genetic differences? ​

Most new alleles probably arise from ____.

Natural selection results in ____. ​

In many species, sexual selection is the most probable cause of ____, differences in the size or appearance of males and females. ​

Disadvantageous recessive alleles are protected from natural selection due to ____. ​

The existence of discrete variants of a particular character is known as ____. ​

Individuals with one sickle cell allele and one normal hemoglobin allele are not affected by the malaria parasite because of ____.

The maintenance of the HbS (sickle)allele in humans is an example of homozygote advantage. ​

Seeds of many plants fall to the ground when they mature. This is an example of a characteristic that is influenced by ____.

Dispersal agents, such as pollen-carrying wind or seed-carrying animals, are responsible for ____ in most plant populations because they often introduce novel alleles into a population. ​

Directional selection favors ____.

When male moose engage in their annual battles, butting heads with their oversized antlers, they are exhibiting ____ selection. ​

Which circumstance violates the conditions of the Hardy-Weinberg model? ​

Knowing that each diploid organism has one copy of each gene, a scientist can calculate the relative abundances of the different alleles in a population. ​

The Hardy-Weinberg principle specifies the conditions under which a population of diploid organisms achieves ____. ​