Organisms and Populations

Topics in this chapter

• Population Attributes and Demography
• Population Growth Models
• Population Interactions
• Environmental Adaptations and Thermoregulation
• Life History Strategies

Cheat sheet

Practice questions

1. Question 1Q-4049FE

   Which of the following interactions is correctly matched with its specific ecological effect on the two interacting species, where '+' represents benefit, '-' represents harm, and '0' represents neutral?

   1. A.Mutualism: (+, +) where both species lose energy without gaining fitness
   2. B.Competition: (-, -) where fitness of one species is significantly reduced in the presence of the other
   3. C.Predation: (+, -) where the predator is adversely affected by the defense mechanisms of the prey
   4. D.Commensalism: (+, 0) where the host species derives considerable nutritional benefit from the commensal
   See the answer and solution
2. Question 2Q-A8BF07

   If a population has a per capita birth rate ($b$) of $0.015$ per individual per year and a per capita death rate ($d$) of $0.005$ per individual per year, calculate the intrinsic rate of natural increase ($r$) for this population.

   1. A.0.020 per year
   2. B.0.010 per year
   3. C.0.005 per year
   4. D.0.075 per year
   See the answer and solution
3. Question 3Q-16CB35

   During unfavorable conditions, many zooplankton species in lakes are known to enter a specific stage of suspended development. What is this phenomenon called?

   1. A.Diapause
   2. B.Hibernation
   3. C.Aestivation
   4. D.Migration
   See the answer and solution
4. Question 4Q-FADF5B

   Which of the following plant adaptations is typically observed in plants growing in water-scarce environments (xerophytes) to minimize transpirational water loss?

   1. A.Stomata distributed equally on both upper and lower epidermis in large numbers
   2. B.Presence of a thick, cuticular layer on leaf surfaces and sunken stomata
   3. C.Broad, thin lamina with massive intercellular air spaces
   4. D.Absence of root hairs to prevent excessive water absorption
   See the answer and solution
5. Question 5Q-DCC80B

   In the logistic growth equation, dN/dt = rN(K - N)/K, what does the variable 'K' represent?

   1. A.Intrinsic rate of natural increase
   2. B.Population density at time t
   3. C.Carrying capacity
   4. D.Biotic potential
   See the answer and solution