Biologists performed an experiment with flies to examine the effects of population size on the maintenance of genetic variation  and  on  egg-to-adult survival.  From  a  large  source  population, they  randomly  assigned  eggs  to  three experimental  populations  of  size  N,  equal  to  20,  60,  and0100.  For  later  generations,  they  collected  N  eggs  from each  population  and  moved  them  into  identical  vials  that  co0ntained  f2re0sh  me4d0ium.  Th6e0y  coun8te0d  the  number  of adult flies that emerged and used tissue samples from the adults for genetic analyses. Genetic variation was measured by  scoring  alleles  at  several  polymorphic  loci  and  expressed  as  the  average  number  of  alleles  at  those  loci.  The results are summarized in Figure 1 and Figure 2 below.

Which other process appears to have substantially influenced the outcome of this experiment? 

#Question id: 11160

#Unit 9. Diversity of Life Forms

A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of

#Question id: 11159

#Unit 9. Diversity of Life Forms

Which kind of DNA should provide the best molecular clock for gauging the evolutionary relatedness of several species whose common ancestor became extinct billions of years ago?

#Question id: 11158

#Unit 9. Diversity of Life Forms

Which of these items does not necessarily exist in a simple linear relationship with the number of gene-duplication events when placed as the label on the vertical axis of the graph below?

#Question id: 11157

#Unit 9. Diversity of Life Forms

Typically, mutations that modify the active site of an enzyme are more likely to be harmful than mutations that affect other parts of the enzyme. A hypothetical enzyme consists of four domains (A—D), and the amino acid sequences of these four domains have been determined in five related species. Given the proportion of amino acid homologies among the five species at each of the four domains, which domain probably contains the active site?

#Question id: 11156

#Unit 9. Diversity of Life Forms

Species that are not closely related and that do not share many anatomical similarities can still be placed together on the same phylogenetic tree by comparing their

#Question id: 11155

#Unit 9. Diversity of Life Forms

Nucleic acid sequences that undergo few changes over the course of evolutionary time are said to be conserved. Conserved sequences of nucleic acids