Bio Weekly Review 7

Evaluate the following statement: "A population is said to have evolved after one or more versions of a gene become more or less common."

Select the answer that best responds to whether the statement is True/False and why.

This statement is true. Evolution describes changing allele frequencies in populations over time and alleles are just different versions of genes.

Evaluate the following statement: "In order for evolution to be possible, a population must have some members of the population survive (the population can’t go extinct)"

Select the answer that best responds to whether the statement is True/False and why.

This statement is true. Evolution is measured from generation to generation. If there is no next generation evolution hasn't happened.

Evaluate the following statement: "A mutation becomes more common in a population when the organisms without the trait are less likely to survive, or to have fewer offspring"

Select the answer that best responds to whether the statement is True/False and why.

This statement is also true. It describes another way that evolution by natural selection can change populations over time.

Evaluate the following statement: "A mutation becomes more common in a population when the organisms with the trait are more likely to survive, or to have more offspring"

Select the answer that best responds to whether the statement is True/False and why.

This statement is true. This statement describes one of the ways that evolution by natural selection can act on populations over time.

Evaluate the following statement: "A beneficial mutation becomes more common in a population when more organisms in the same generation develop the same beneficial new mutation. For example, if being red is beneficial for organisms in their environment, many individuals will develop of mutation that makes them red."

Select the answer that best responds to whether the statement is True/False and why.

This statement is false. Mutations are random so it's very unlikely that multiple individuals will randomly get the same mutation at roughly the same time.

Evaluate the following statement: "Genetic mutations that lead to new traits occur randomly"

Select the answer that best responds to whether the statement is True/False and why.

This statement is true. When mutations occur you cannot predict if or how the mutations will chance a characteristic and the change is also random relative to the environment in which the organism lives.

Evaluate the following statement: "In order for evolution to be possible, a population must have traits that can be passed on to offspring."

Select the answer that correctly responds to whether the statement is True/False and explains why.

This statement is TRUE. Evolution is a change in ALLELE frequencies. Thus, for a characteristic to evolve it must be coded for by various alleles that can be passed from generation to generation.

In our evolution case study, the bird population initially had three beak size phenotypes--small, medium, and large. Following the drought, you correctly predicted that the next generation would have exclusively large and medium beaked birds as the smallest food source had died out.

Which of the following accurately describes why there were no small beaked birds in the next generation?

 

The small beaked birds died and thus didn't contribute alleles for small beaks to the next generation.

Evaluate the definition of evolution. Select the correct statement based on this definition.

 

Individuals cannot evolve. Populations evolve

Evaluate the following statement: "In order for evolution to be possible, a population must have variable traits (the individual organisms are not identical)"

Regarding natural selection, select the answer that best responds to whether the statement is True/False and why.

 

This statement is true. Evolution by natural selection can only occur if some individuals in a population have characteristics that makes them better able to survive and reproduce than other individuals without that characteristic.

Evaluate the following statement: "Evolution causes populations to change over time, not necessarily better or worse."

Select the answer that best responds to whether the statement is True/False and why.

This statement is true. Sometimes evolution results in better adapted populations and sometimes it doesn't.

Evaluate the following statement: "Evolution causes organisms to become more complex over time."

Select the answer that best responds to whether the statement is True/False and why.

This answer is false. Sometimes evolution increases complexity over time, but other times the change is random and doesn't increase complexity.

Dr. Ellie Armstrong and Dr. Anubhab Khan study populations of tigers.  Amur tigers live in extremely cold regions of Russia, China, and northern Korea. Dr. Armstrong and Dr. Khan found evidence that the frequency of alleles that allow better cold tolerance have increased significantly in these populations over time. 

Which of the following options best characterizes this scenario?

 

This indicates the Amur Tigers have evolved by natural selection.