Meiosis and Genetic Variation Practice

During meiosis, crossing-over (gene exchange between chromosomes) may occur. Crossing-over usually results in

• overproduction of gametes

• the formation of identical offspring

• fertilization and development

• variation within the species

Which two processes result in variations that commonly influence the evolution of sexually reproducing species?

• mutation and genetic recombination

• extinction and gene replacement

• environmental selection and selective breeding

• mitosis and natural selection

The variations that exist in a population of wild giraffes are usually a result of events that occur during

• asexual reproduction

• genetic engineering

• mitotic division

• sexual reproduction

Which row in the chart below contains the correct sequence of events involved in the formation of a human embryo?

• 4

• 1

• 3

• 2

Base your answer to the following question on Which process is illustrated in the diagram below?

• nondisjunction

• segregation

• crossing-over

• replication

Two kittens in a litter are genetically different from each other and from their parents. These genetic differences are most directly due to

• evolution

• asexual reproduction

• sexual reproduction

• cloning

As a result of habitat destruction, the size of the Florida panther population has been drastically reduced. It is estimated that there are only 100 to 160 Florida panthers in the wild. Which statement best explains why the Florida panther population may not continue to evolve?

• There is a lack of genetic variation for selection to act upon.

• There is a lack of competition for limited environmental resources.

• There is no longer a chance of a trait providing a reproductive advantage to the population.

• There is no longer a chance of mutations occurring in the population.

The Florida panther, a member of the cat family, has a population of fewer than 100 individuals and has limited genetic variation. Which inference based on this information is valid?

• Over time, these animals will become less likely to survive in a changing environment.

• These animals are easily able to adapt to the environment.

• Over time, these animals will become more likely to be resistant to disease.

• These animals will begin to evolve rapidly.

Which statement best describes the process of crossing-over?

• It takes place between homologous chromosomes and results in an increased gene mutation rate.

• It takes place between homologous chromosomes and results in new gene combinations.

• It takes place between nonhomologous chromosomes and results in new gene combinations.

• It takes place between nonhomologous chromosomes and results in an increased gene mutation rate.

Sexual reproduction in a species usually results in

• an increase in the chromosome number in the offspring

• offspring genetically identical to the parent

• a decrease in biodiversity

• recombination of genes