The smallest biological unit that can evolve over time is:

     

a cell.

a species.

an individual organism.

a population.

an ecosystem.

 

Which of the following statements is TRUE?

     

Only mutations in somatic cells are   heritable & can play a role in evolution.

Mutations create new alleles in populations;   thus, they are necessary for evolution to occur.

The maximum number of alleles for a given   gene that can exist in a population is two.

All mutations are harmful to the mutant   organisms that carry them.

Mutations that arise in a population,   although initially rare, almost always increase in frequency through the   action of genetic drift &/or natural selection.

 

Which of the following is the BEST definition of biological EVOLUTION?

     

change in the genetic makeup of an   individual

change in the allele frequencies of a   population over time

the modification of traits by the environment   over the course of an individuals lifetime

the adaptation of organisms through natural   selection

the maintenance of Hardy-Weinberg   Equilibrium in a population

 

A plant population is found in an area that is becoming more arid (dry) over time. The average surface area of the leaves of plants in the population has been decreasing over the generations because plants with less leaf surface area lose less water through evaporation. This is an example of:

     

directional selection

disruptive selection

stabilizing selection

genetic drift

None of the above.