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: 11744

#Unit 6. System Physiology – Plant

Large pores in cell walls are the prominent feature of sieve elements, the sieve area pores range in diameter from

#Question id: 11745

#Unit 6. System Physiology – Plant

sieve cells of the sieve elements of phloem conduct sugars throughout the plant. The following statements given about characteistics of Sieve cells of sieve elements in seed plants;

a.)  There is no P-protein in gymnosperms

b.) Angiosperm contains sieve plate pores are open channels

c.) Pores in sieve areas appear blocked with membranes in gymnosperms

d.) Companion cells are sources of ATP and perhaps other compounds

Which of the following combination is correct?

#Question id: 11746

#Unit 6. System Physiology – Plant

Sieve element sap is rich in sugars and other organic molecules, These molecules represent an energy investment for the plant. How their loss be prevented when sieve elements are damaged?

#Question id: 11747

#Unit 6. System Physiology – Plant

A mechanism for preventing sap loss entails closing sieve plate pores with callose, which is

#Question id: 11748

#Unit 6. System Physiology – Plant

In mature cells, P-protein occurs in several different forms depending on the species. Such as;

#Question id: 11802

#Unit 6. System Physiology – Plant

Damaged sieve elements are sealed off, but because of the processs that plug sieve plates pores, excuded phloem sap from wounds that sever sieve elements. Exudation of sap enhanced by the inclusion of;