Ecology And Animal Behavior MCQ - IIT JAM MCQ

According to evolutionary psychologists, patterns of behavior have evolved through natural selection, in the same way that physical characteristics have evolved. Because of natural selection, adaptive behaviors, or behaviors that increase reproductive success, are kept and passed on from one generation to the next generation.

Lantana camara and Prosopis juliflora are examples of prominent invasive species in India. Such invasive species cause harm and very soon become the cause for endangerment to other native species of that ecosystem.  

Brightly colored flowers can be easily recognized by bees and insects, who are also biotic agents of pollination. In this way, it is ensured that flowers can be easily pollinated when bees travel from flower to flower and so, it is a structural adaptation in plants for reproduction.

Cognition refers to the processing of information and responding to it in a manner that suggests thinking. So, problem solving abilities most appropriately demonstrate the cognitive behavior.

The scenario that represents a density-independent regulation on population is:

b) A population of crows was limited when a hurricane destroyed their nests in the region.

Density-independent factors affect populations regardless of their size or density. Natural disasters, like hurricanes, are typical examples of density-independent factors because they can limit populations by causing destruction or death without regard to how densely populated the area is. The other options are examples of density-dependent regulation, where the effect on the population changes with population density.

If the predator population increases, then population of prey will decrease as they will be fed on faster. Further, this would result in the population of the predator decreasing as they would be left with no food to feed on.

By giving alarm calls, animals save their kin from predation. By living in groups and by camouflaging themselves, they can avoid predation. But cannibalism would mean they are self predators, so this would be the wrong answer.

To eliminate the factor of shape, both the artificial flowers should have been round or both should have been square.

Humans care for their young ones and invest a lot of energy in them. That is the reason their relative number of survivors is more than others.

Mutualism is where individuals benefit from each other. Amensalism is where one individual gets harmed and the other remains unaffected. In commensalism, one gets benefitted and the other is unaffected. In parasitism, one gets benefitted while the other gets harmed.

Hotspots are areas with large number of endemic species. They are also known as biodiversity hotspots.

Competition exclusion affects species diversity. In the short run, competition should cause a reduction in the number of species living within an area, preventing very similar species from co-occurring in same ecological niche.

Same ecological niche will cause a greater competition between the species which are extant in it. Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region. So, resource partitioning most prominently happens between sympatric species with same ecological niche.

Habituation is learning not to respond to stimulus by becoming familiar with something. Getting stung by a bee is not an example of being familiar through habituation and not responding to that stimulus anymore.

Only celestial navigation such as the direction of sun and magnetic field of the earth have been known to be used as cues by birds during migration till now.

Logistic growth model is represented by S shaped growth curve where carrying capacity is a limiting factor in the per capita growth rate of population.

The carrying capacity can change as the environmental conditions change. The exponential growth model does not specifies the carrying capacity. When carrying capacity exceeds, the population starts declining.

Here, Birth rate: 400/1000 = 0.4 births per individual
Death rate: 150/1000 = 0.15 Deaths per individual
So, r = B-D = 0.4 - 0.15 = 0.25
Nt = No e^rt
We know that t = 6 months (given in the question)
Therefore, Nt = 1000 e^(0.25)(6)
In Nt - In 1000 = 1.5
ln Nt = 1.5 + 6.9
ln Nt = 8.4
by taking exponential of both sides
Nt = 4447.07 
 

In the question you’re given the following information:
K = 500, r = 0.1
Maximum population growth occurs at K/2
Therefore, the maximum population size = K/2 = 500/2 = 250
Logistic growth equation for a population                                  
dN/dt = rN[1 – N/K]
dN/dt = (0.1) (250) [1 – (250)/500)] dN/dt = 12.5 individuals/month

Formula for effective population size is = 4 × NM × NF / NM × NF
PE = 4 × 200 × 40/ 200+40
= 133.33

Formula for mark and recapture technique = N = (M × C) / R
N = estimated Number of individuals in the population
M = number of individuals captured and Marked
C = total number Captured the second time (with and without a mark)
R= number of individuals Recaptured (those with a mark)
So, N = 23 × 29/11 = 60.63