Organisms and Populations (last 10 years) Flashcards
- If ‘8’ Drosophila in a laboratory population of ‘80’ died during a week, the death rate in the population is _________ individuals per Drosophila per week. (2022)
a. Zero
b. 0.1
c. 10
d. 1.0
Page number 191
b. 0.1
NCERT
If 4 individuals in a laboratory population of 40 fruitflies died during a specified time interval, say a week, the death rate in the population during that period
is 4/40 = 0.1 individuals per fruitfly per week.
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- In the exponential growth equation (2021)
insert an image
a. The base of exponential logarithms
b. The base of natural logarithms
c. The base of geometric logarithms
d. The base of number logarithms
Page number 194
b. The base of natural logarithms
NCERT
If you are familiar with basic calculus, you can derive the integral form of the exponential growth equation as
Nt = N0 ert
where
Nt = Population density after time t
N0 = Population density at time zero
r = intrinsic rate of natural increase
e = the base of natural logarithms (2.71828)
- Which of the following is not an attribute of a population? (2020)
a. Natality
b. Mortality
c. Species interaction
d. Sex ratio
Page number 191
c. Species interaction
NCERT
A population has certain attributes whereas, an individual organism does not.
An individual may have births and deaths, but a population has birth rates and death rates.
Another attribute characteristic of a population is
sex ratio.
An individual is either a male or a female but a population has a sex ratio
(e.g., 60 per cent of the population are females and 40 per cent males).
Natality - BR
Mortality - DR
Species interaction (not included) is not an attribute of a population
- The impact of immigration on population density is: (2020-Covid)
a. Both positive and negative
b. Neutralized by natality
c. Positive
d. Negative
Page number 193
c. Positive
NCERT
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- Natality refers to: (2018)
a. Death rate
b. Birth rate
c. Number of individuals leaving the habitat
d. Number of individuals entering a habitat
Page number 193
b. Birth rate
NCERT
Natality refers to the number of births during a given period in the population that are added to the initial density
- In a growing population of a country: (2018)
a. Pre-reproductive individuals are more than the reproductive individuals.
b. Reproductive individuals are less than the post
reproductive individuals.
c. Reproductive and pre-reproductive individuals are equal in number.
d. Pre-reproductive individuals are less than the reproductive individuals.
a. Pre-reproductive individuals are more than the reproductive individuals.
CHECK AGAIN NCERT
- Asymptote in a logistic growth curve is obtained when: (2017-Delhi)
a. The value of ‘r’ approaches zero
b. K = N
c. K > N
d. K < N
Page number 195
b. K = N
NCERT
A population growing in a habitat with limited resources show initially a lag phase, followed by phases of acceleration and deceleration and finally an asymptote, when the population density reaches the carrying capacity.
- When does the growth rate of a population following the logistic model equal zero? The logistic model is given as dN/ dt = rN (1-N/K): (2016 - I)
a. When N/K is exactly one
b. When N nears the carrying capacity of the habitat
c. When N/K equals zero
d. When death rate is greater than birth rate
a. When N/K is exactly one
CHECK AGAIN NCERT
- Which of the following is correct for r-selected species? (2016 - II)
a. Small number of progeny with small size
b. Small number of progeny with large size
c. Large number of progeny with small size
d. Large number of progeny with large size
c. Large number of progeny with small size
CHECK AGAIN NCERT
- A biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in population is: (2013)
a. Zero
b. 10
c. 15
d. 05
Page number 193
a. Zero
NCERT
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- While explaining interspecific interaction of population, (+) sign is assigned for beneficial interaction, (–) sign is assigned for detrimental interaction and
(0) for neutral interaction.
Which of the following interactions can be assigned (+) for one species and (–) for another species involved in the interaction?
a. Competition
b. Predation
c. Amensalism
d. Commensalism
Page number 197
b. Predation
NCERT
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- Which one of the following statements cannot be connected to Predation? (2022)
a. It is necessitated by nature to maintain the ecological balance
b. It helps in maintaining species diversity in a community
c. It might lead to extinction of a species
d. Both the interacting species are negatively impacted
Page number 197 - 198
d. Both the interacting species are negatively impacted
NCERT
In both parasitism and predation only one species benefits (parasite and predator, respectively) and the interaction is detrimental to the other species (host and prey, respectively).
- Inspite of interspecific competition in nature, which mechanism the competing species might have evolved for their survival? (2021)
a. Competitive release
b. Mutualism
c. Predation
d. Resource Partitioning
Page number 199
d. Resource Partitioning
NCERT
Gause’s ‘Competitive Exclusion Principle’ states that two closely related species competing for the same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually.
This may be true if resources are limiting, but not
otherwise.
More recent studies do not support such gross
generalisations about competition.
While they do not rule out the occurrence of interspecific competition in nature, they point out that species facing competition might evolve mechanisms that
promote co-existence rather than exclusion.
One such mechanism is ‘resource partitioning’.
If two species compete for the same resource, they could avoid competition by choosing, for instance,
different times for feeding or different foraging patterns.
MacArthur showed that five closely related species of warblers living on the same tree were able to avoid competition and co-exist due to behavioural differences in their foraging activities.
- Amensalism can be represented as: (2021)
a. Species A (+) ; Species B (+)
b. Species A (-) ; Species B (-)
c. Species A (+) ; Species B (0)
d. Species A (-) : Species B (0)
Page number 197
d. Species A (-) : Species B (0)
NCERT
ADD THE TABLE
- Match the items in Column-I with those in Column-II: (2020-Covid)
Column-I Column-II
- Herbivores-Plants (i) Commensalism
- Mycorrhiza-Plants (ii) Mutualism
- Sheep-Cattle (iii) Predation
- Orchid-Tree (iv) Competition(1) (2) (3) (4)
a. (iii) (ii) (iv) (i)
b. (ii) (i) (iii) (iv)
c. (i) (iii) (iv) (ii)
d. (iv) (ii) (i) (iii)
a. (iii) (ii) (iv) (i)
- Match Column-I with Column-II (2019)
Column-I Column-II
A. Saprophyte i. Symbiotic association of fungi with plant roots
B. Parasite ii. Decomposition of dead organic materials
C. Lichens iii. Living on plants or animals
D. Mycorrhiza iv. Symbiotic association of algae and fungi
Choose the correct answer from the option given below
(A) (B) (C) (D) a. (i) (ii) (iii) (iv) b. (iii) (ii) (i) (iv) c. (ii) (i) (iii) (iv) d. (ii) (iii) (iv) (i)
d. (ii) (iii) (iv) (i)
- Which one of the following plants shows a very close relationship with a species of moth, where none of the two can complete its life cycle without the other? (2018)
a. Hydrilla
b. Yucca
c. Banana
d. Viola
b. Yucca
- Which one of the following population interactions is widely used in medical science for the production of antibiotics? (2018)
a. Commensalism
b. Mutualism
c. Parasitism
d. Amensalism
d. Amensalism
- Mycorrhizae are the example of: (2017-Delhi)
a. Fungistasis
b. Amensalism
c. Antibiosis
d. Mutualism
d. Mutualism
- The principle of competitive exclusion was stated by: (2016 - II)
a. MacArthur
b. Verhulst and Pearl
c. C.Darwin
d. G.F. Gause
d. G.F. Gause
- If ‘+’ sign is assigned to beneficial interaction, ‘–’ sign to detrimental and ‘0’ sign to neutral interaction, then the population interaction represented by ‘+’ ‘–’ refers to:
(2016 - II)
a. Commensalism
b. Parasitism
c. Mutualism
d. Amensalism
b. Parasitism
- Gause’s principle of competitive exclusion states that: (2016 - I)
a. More abundant species will exclude the less abundant species
through competition
b. Competition for the same resources excludes species having
different food preferences
c. No two species can occupy the same niche indefinitely for the
same limiting resources
d. Larger organisms exclude smaller ones through competition
c. No two species can occupy the same niche indefinitely for the
same limiting resources
- In which of the following interactions both partners are adversely affected? (2015 Re)
a. Predation
b. Parasitism
c. Mutualism
d. Competition
d. Competition
- A sedentary sea anemone gets attached to the shell lining of hermit crab.
The association is: OS
a. Amensalism
b. Ectoparasitism
c. Symbiosis
d. Commensalism
b. Ectoparasitism
