CBSE Questions for Class 12 Medical Biology Organisms And Population Quiz 16 - MCQExams.com

"Verhulst-Pearl" logistic growth is described using the equation $$\dfrac{dN}{dt}=rN(\dfrac{K-N}{K})$$. In this K stands for
  • Temperature in degree Kelvin
  • Intrinsic rate of natural increase
  • Carrying capacity
  • Population density
A single bacterium is actively growing in a medium that supports its growth up to $$100$$ million. Assuming the division time of the bacterium as $$3$$ hours and the life span of non-dividing bacteria as $$5$$hours, which one of the following represents the maximum number of bacteria that would be present at the end of $$15$$ hours?
  • $$10$$
  • $$64$$
  • $$24$$
  • $$32$$
Which one of the following options is true with respect to Emigration?
  • It is the difference between the births and deaths in a population.
  • It is the difference between individuals who have come to a habitat and who have left the habitat.
  • It involves individuals of different species coming to a habitat from elsewhere during the period under consideration.
  • It involves individuals of a population leaving a habitat during the time period under consideration.
State whether the following statements are true or false.
Plants use spines and chemical poisons to prevent predation by animals, especially insects
  • True
  • False
An intimate relationship between two species in which co-evolution and adaptation occur is
  • competition
  • a community
  • predation
  • symbiosis
State whether the following statements are true or false.
Bacteria living in the human digestive tract and producing vitamins used by the human are best described as parasitic organisms
  • True
  • False
In a population of predator and prey it was seen that when the prey population was numerically high the predator population consumed more and more prey. This is because the predator population 
  • can digest any quantity of food
  • responds functionally
  • responds numerically
  • is a voracious feeder
Is an interspecific association in which all species involved benefit.
  • Commensalism
  • Mutualism
  • Competition
  • Parasitism
Competitive exclusion principle stating that inferior species is eliminated eventually after prolonged competition was given by 
  • Allen
  • Pearl-Verhulst
  • Gause
  • Darwin
Island bio geography theory states that the number of species on an island is determined by immigration rates of new species to the island and extinction rates of species on the island immigration rates to an island decline as its distance froooom the mainland increases and extinction rates decrease with increasing island size when the immigration and extinction rates on an island are equal, the number of species on the island reaches equilibrium. 
Which of the following gives the correct combination oof distance (near and far) and area (small and rage )of island where species (s-s) occur?
933022_33aa72abd24042009e8c353794e4cce4.jpg
  • $$S_1$$ - near island, small island
  • $$S_2$$ - near island, large island
  • $$S_3$$ - near island, far island
  • $$S_4$$ - near island, large island
Population of an insect species increases explosively during rainy season. It disappears at the end of the season due to
  • Death of food plants at the end of rainy season
  • J-shaped growth curve.
  • Increase in predator population
  • S-shaped growth curve.
Which is correctly labelled with respect to the given diagram? 
931821_3b0221fbc5cd42d5a35ee22675a6f95d.JPG
  • B : Logistic curve
  • C : Carrying capacity
  • C : Exponential curve
  • A : Carrying capacity
Which of the following equations correctly represents Verhulast Pearl logistic growth?
  • $$dN/dt = rN\dfrac({K-N}{K}) $$
  • $$dN/dt = \dfrac{rN}{K}$$
  • $$dN/dt ={N(K-N)}{K}$$
  • $$dN/dt =\dfrac{r(k-n)}{k}$$
In 2005, for each of the 14 million people present in a country, 0.028 were born and 0.008 died during the year. Using exponential equation, the number of people present in 2015 is predicted as 
  • 25 millions
  • 17 millions
  • 20 millions
  • 18 millions
In a life table, the number of individuals alive at the beginning of the 1 st year to 2 nd year interval isDuring this interval, 200 individuals die. The death rate for this interval is 
  • 0.25
  • 200
  • 800
  • 0.2.

The diagram shows the relationships among the midge larvae(Chaoborus nyblaci), larval salamander(Ambystoma tigrinum) and two species of the crustacean Daphnia(D. rosea and the larger D. pulex) that inhabit certain pond communities. Study the relationships and deduce which of the following is/are correct.
885510_bb3b31daedc8474bb12d407473768517.png
  • Presence of high numbers of larval salamander has an indirect effect on D. rosea and it is a positive effect
  • When larval salamanders are present, predation reduces the population growth rate of the larger Daphnia, facilitating the coexistence of the two species of Daphnia
  • The two species of Daphnia compete for the same resources and hence increase in resource availability will reduce the number of midge larvae and larval salamander
  • Increase in the number of D. pulex would lead to a decrease in the number of midge larvae
Deciduous trees are found mostly in which of these forests?
  • Tropical
  • Temperate
  • Boreal
  • Grasslands
If in a population showing sigmoid growth curve the value of K - N/K is 0.95, then what is true for this population.
  • The carrying capacity has been nearly realized.
  • The carrying capacity has not been substantially realized and it can accommodate many more organisms.
  • The carrying capacity is only 50% realized.
  • Data is insufficient to comment anything.
Study the following statements about Adamsia and select your option
A) It is a parasite on clown fish.
B) It is an example of commensalism along with clown fish. 
C) It is called sea anemone.
D) It is called hermit crab.
  • A and B are correct
  • B and C are correct
  • C and D are correct
  • A and D are correct
Match the column-I with Column-II:
Column-IColumn-II
(1) Cuscuta(A) Hemiparasite
(2) Lianas(B) Holoparasite
(3) Viscum(C) Commensal
  • 1-C ; 2-A ; 3-B
  • 1-A; 2-B; 3-C
  • 1-C ; 2-B 3-A
  • 1-B; 2-C; 3-A
Read the following given examples.
(i) Plant-pollinator mutualism
(ii) African catfish in our rivers for aquaculture.
(iii) Fish species with its parasites
(iv) Nile perch and cichlid fish
Which out of these options correctly gives the examples of "Co-extinctions" as a cause of biodiversity loss?
  • (i), (ii)
  • (ii), (iii)
  • (ii), (iv)
  • (i), (iii)
Population density in India has shifted from 81 per sq. km. in 1921 to _______ per sq. km. in 2011.
  • 153
  • 248
  • 382
  • 196
Few interactions are given following. How many of them are not examples of mutualism ? 
  • Fungus & roots of higher plants- mycorrhiza
  • Clown fish and sea anemones
  • Cuckoo and crow
  • Orchids and bumblebees
  • Cuscuta and Hedge plants
Which of these forests are found between the equator and the Tropic of Cancer?
  • Tropical
  • Temperate
  • Boreal
  • All of the above
State the following statement true or false:
Rainforest forms the largest habitat on the planet.
  • True
  • False
They may reduce survival, growth and reproduction of host and reduce its population density. They might render organisms more vulnerable to predation by making it physically weak. They are 
  • predator
  • parasite
  • Amensal
  • commensal
Association of an alga with a fungus in a lichen in an example for
  • Mutual-ism
  • Commensalism
  • Neutralism
  • Parasitism
Carrying capacity for a population is estimated at 500 the population size is currently 400 and max=0.What is dN/dt?
  • 0.01
  • 0.8
  • 8
  • 50
If A and B have n characteristics common while A and C have $$n/2$$ characteristics common, then which of the two organisms are more closely related?
  • A and C
  • A and B
  • Characteristics need to be known
  • None of these
How many statements are incorrect from following?
(A) Loranthus is a partial stem parasite
(B) Arceuthobium is a smallest angiospermic parasite
(C) Bauhinia and Tinospora are example of Lianas
(D) Sea anemone and hermit crab shows Amensalism.
  • Two
  • One
  • Three
  • Four
Which type of interaction shows in this graph between two organism X and Y
1284904_5b6bd91b09724595a3e54192e29ce686.JPG
  • Mutualism
  • Commensalism x
  • Parasitism
  • Predation
Increased IMR and decreased MMR in a population will?
  • Cause rapid increase in growth rate
  • Result in decline in growth rate
  • Not cause significant change in growth rate
  • Result in an explosive population
After poaching 3 lions in certain forest of Gujarat, only 15 are left in a year. Determine death rate per capita
  • 5.000
  • 0.200
  • 0.166
  • 0.800
Column-IColumn-II
(i) $$+ -$$(A) Amensalism
(ii) $$+ 0$$(B) Parasitism
(iii) $$+ +$$(C) Commensalism
(iv) $$- 0$$(D) Mutualism
  • i-B, ii-A, iii-D, iv-C
  • i-A, ii-B, iii-D, iv-C
  • i-B, ii-A, iii-C, iv-D
  • i-B, ii-C, iii-D, iv-A
Green Land biome
  • Tundra
  • Pampas
  • Taiga
  • Thaar

Number of deaths during a limited time period and place for a particular population is known as
  • Natality
  • Mortality
  • Migratory
  • Integrity
What is hibernation and aestivation?
  • Thermal adaptation shown by animals
  • wind adaptation shown by animals
  • adaptation of animals to escape from predators
  • none
Above given graph showing interactions between two species A and B identify the interaction between them:
1492657_5abd0953732a444f81a80fbc7b444351.PNG
  • Commensalism
  • Predation
  • Competition
  • Mutualism
Black Buck is a
  • Goat
  • Deer
  • Butterfly
  • Bird
Extinction of Abingdon tortoise in Galapagos islands After introduction of Goats, is an example of :-
  • Competitive exclusion
  • Competitive release
  • Resource partitioning
  • Interference competition.
'Polychlorinated biphenyls' cause harm to
  • Birds
  • Animals
  • Elephants
  • Tigers
Birth rate is called
  • mortality
  • vital index
  • natality
  • viability
Anuradha Sawhney is well known for her work in which of the following fields?
  • Micro Finance
  • Animal rights
  • Environment Protection
  • Rainwater Harvesting
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