Following statements are regarding to cholera toxins which can affect the junction’s activity.

a. Toxins produced by Vibrio cholerae, the enteric bacterium that causes cholera, alter the permeability barrier of the intestinal epithelium by altering the composition or activity of gap junctions.

b. Vibrio cholerae also releases a protease that disrupts tight junctions by degrading the extracellular domain of occludin.

c. Toxin-induced changes in tight-junction permeability (increased paracellular transport) and in protein-mediated ion pumping (decreased transcellular transport) can result in massive losses of internal body ions and water into the gastrointestinal tract, which in turn leads to diarrhea and potentially lethal dehydration.

d. Toxin-induced changes in tight-junction permeability (decreased paracellular transport) and in protein-mediated ion pumping (increased transcellular transport) can result in massive losses of internal body ions and water into the gastrointestinal tract, which in turn leads to diarrhea and potentially lethal dehydration.

Which of the following statements are correct?

#Question id: 3413

#Unit 11. Evolution and Behavior

 Following certain conditions is present in a population?

A- Large Population

B- Each locus carries two allele 

C- Sexual selection 

D- Frequency dependent selection  

E- No linkage between genes

Which of the following above condition allowed to validity of Hardy- Weinberg Prediction?

#Question id: 3414

#Unit 11. Evolution and Behavior

The given below is the graphical representation of the changes in morphological features over a period of the geological time scale, where population A accumulates heritable morphological features and give rise to distinct species B. Population B splits in to a distinct species B1 and B2 Which of the following lineage represent the pattern of speciation by cladogenesis?

#Question id: 3415

#Unit 11. Evolution and Behavior

Imagine a plant of extremely variable height that is pollinated by three different pollinators, one that was attracted to short plants, another that preferred plants of medium height and a third that visited only the tallest plants. If the pollinator that preferred plants of medium height disappeared from an area. What is concluding of this condition?

#Question id: 3416

#Unit 11. Evolution and Behavior

The amount of change in q is directly proportional to the migration (m); The magnitude of change is also affected by the differences in allelic frequencies of the two populations (qI - qII); What is amount of change when 200 migratory individuals are merge in recipient population size of 1800. Allele frequency of q1 of source and recipient population is .80 and .20 respectively. 

#Question id: 3417

#Unit 11. Evolution and Behavior

In balancing selection, two or more alleles are kept in balance, and therefore are maintained in a population over the course of many generations. Which of the following example can support balancing natural selection?

A- Sickle cell allele kept in balance because heterozygotes have greater chance of survival if infected by the malarial parasite, compared with normal homozygotes

B. One morph has selective advantage over another morph

C. One homozygote has greater chance of survival than other genotype results in purity of population

D. many species of invertebrates exist as different colored forms, identical in all respects except color. Visually searching predators often develop a search image for one color form, usually the commoner

#Question id: 3418

#Unit 11. Evolution and Behavior

Which of the best explanation of directional natural selection occur by change in environmental condition?

A. Increase in the frequency of dark-colored mutants in polluted areas, became known as industrial melanism

B. Numerous insect pests become resistant to insecticides and numerous bacteria become resistant to antibiotics.

C. A plant that is too short may not be able to compete with other plants for sunlight. However, extremely tall plants may be more susceptible to wind damage

D- Beetles move into a new environment with patches of light-green moss and dark-green shrubs, both light and dark beetles might be better hidden (and survive better) than medium-green beetles