All questions of Population Dynamics for Grade 9 Exam
Which of the following is/are poikilotherm:?- a)Tapeworm and rabbits
- b)Elephants
- c)Humans and fishes
- d)Tapeworm and naked mole rat
Correct answer is option 'D'. Can you explain this answer?
Which of the following is/are poikilotherm:?
a)
Tapeworm and rabbits
b)
Elephants
c)
Humans and fishes
d)
Tapeworm and naked mole rat
|
Divey Sethi answered |
In the given scenario, the laboratory population of fruit flies consists of 40 fruit flies, and during a specified time interval, 4 individuals died. To calculate the death rate, we divide the number of deaths by the total population.
Number of deaths = 4
Total population = 40
Total population = 40
Death rate = Number of deaths / Total population
= 4 / 40
= 0.1 individuals per fruitfly per week
= 4 / 40
= 0.1 individuals per fruitfly per week
Option a) "0.1 individuals per fruitfly per week" is the correct answer because it accurately represents the death rate calculated based on the given information.
The birth and death rates of four counteries are given below. which one will have the least population growth rate?
- a)P
- b)Q
- c)R
- d)S
Correct answer is option 'D'. Can you explain this answer?
The birth and death rates of four counteries are given below. which one will have the least population growth rate?
a)
P
b)
Q
c)
R
d)
S
|
Top Rankers answered |
Growth rate = Birth rate - death rate
For country P, it is 10/1000. For country Q, It is 15/1000
For country R, it is 17/1000. For country S, It is 7/1000
Hence, country S has the least population growth rate
For country P, it is 10/1000. For country Q, It is 15/1000
For country R, it is 17/1000. For country S, It is 7/1000
Hence, country S has the least population growth rate
A statement 933 females per 1000 males depict:- a)ecological ages
- b)generation time
- c)sex ratio
- d)biotic potential
Correct answer is option 'C'. Can you explain this answer?
A statement 933 females per 1000 males depict:
a)
ecological ages
b)
generation time
c)
sex ratio
d)
biotic potential
|
Aman Sharma answered |
Sex ratio is the no of female available per thousands of male in a population. Sex ratio is decline due to female feticides alarmingly in some part of India.
Orchid shows commensalism as interaction with:- a)bee
- b)mango tree
- c)both mango tree and bee
- d)none of these
Correct answer is option 'B'. Can you explain this answer?
Orchid shows commensalism as interaction with:
a)
bee
b)
mango tree
c)
both mango tree and bee
d)
none of these
|
Shivani Rane answered |
Commensalism is interaction in which one species is benefited by other is neither benefited nor harmed. Orchids growing on mango tree do not harm the mango plants but get shelter.
Small fish get stuck near the bottom of a shark and derive their nutrition from it? This kind of association is called- a)Parasitism
- b)Symbiosis
- c)Predation
- d)Commensalism
Correct answer is option 'D'. Can you explain this answer?
Small fish get stuck near the bottom of a shark and derive their nutrition from it? This kind of association is called
a)
Parasitism
b)
Symbiosis
c)
Predation
d)
Commensalism
|
Sonal Chakraborty answered |
Commensalism is a type of symbiotic relationship where one species benefits from the association, while the other is neither harmed nor helped. In this type of association, one species derives benefits from the other without causing any harm to the host.
Explanation:
In the given scenario, the small fish gets stuck near the bottom of a shark and derives its nutrition from it. The small fish is not harming the shark, nor is it providing any benefits to the shark. Therefore, this is an example of commensalism.
The small fish is using the shark as a shelter and also gets access to food particles that are present near the shark's mouth. The shark is not affected by the presence of the small fish, and it does not derive any benefit from it either.
In summary, commensalism is a type of symbiotic relationship where one species benefits from the association, while the other is neither harmed nor helped. The small fish getting stuck near the bottom of a shark and deriving its nutrition from it is an example of commensalism.
Explanation:
In the given scenario, the small fish gets stuck near the bottom of a shark and derives its nutrition from it. The small fish is not harming the shark, nor is it providing any benefits to the shark. Therefore, this is an example of commensalism.
The small fish is using the shark as a shelter and also gets access to food particles that are present near the shark's mouth. The shark is not affected by the presence of the small fish, and it does not derive any benefit from it either.
In summary, commensalism is a type of symbiotic relationship where one species benefits from the association, while the other is neither harmed nor helped. The small fish getting stuck near the bottom of a shark and deriving its nutrition from it is an example of commensalism.
The birth rate if 7 new plants are added to previous year plant population of 23 Salvinia plants will be:- a)0.3
- b)0.25
- c)0.4
- d)0.5
Correct answer is option 'A'. Can you explain this answer?
The birth rate if 7 new plants are added to previous year plant population of 23 Salvinia plants will be:
a)
0.3
b)
0.25
c)
0.4
d)
0.5
|
Rohan Unni answered |
The birth rate of a population = new individual added / previous population. Here birth rate= 7/23=0.3043. Hence, birth rate of Salvinia plants is equal to 0.3.
Interacting members of species live close to each other in following interaction/s:- a)parasitism
- b)competition
- c)commensalism, predation and parasitism
- d)commensalism
Correct answer is option 'C'. Can you explain this answer?
Interacting members of species live close to each other in following interaction/s:
a)
parasitism
b)
competition
c)
commensalism, predation and parasitism
d)
commensalism
|
Sushant Goyal answered |
Interacting members of species live close to each other in commensalism, predation and parasitism.
Mycorrhiza represents - a)symbiotic association between a fungus and liverworts
- b)parasitic association between a fungus and an alga
- c)parasitic association between a fungus and roots of plants
- d)symbiotic association between a fungus and roots of higher plants
Correct answer is option 'D'. Can you explain this answer?
Mycorrhiza represents
a)
symbiotic association between a fungus and liverworts
b)
parasitic association between a fungus and an alga
c)
parasitic association between a fungus and roots of plants
d)
symbiotic association between a fungus and roots of higher plants
|
Sonal Kulkarni answered |
A nutrient depletion zone can develop when there is rapid soil solution uptake, low nutrient concentration, low diffusion rate, or low soil moisture. These conditions are very common; therefore, most plants rely on fungi to facilitate the uptake of minerals from the soil. Mycorrhizae, known as root fungi, form symbiotic associations with plant roots. In these associations, the fungi are actually integrated into the physical structure of the root. The fungi colonize the living root tissue during active plant growth.
Human population follows the- a)J-shaped growth curve
- b)Z-shaped growth curve
- c)S-shaped growth curve
- d)All of the above
Correct answer is option 'C'. Can you explain this answer?
Human population follows the
a)
J-shaped growth curve
b)
Z-shaped growth curve
c)
S-shaped growth curve
d)
All of the above
|
Harshitha Chavan answered |
Logarithmic or Exponential phase : It is characterized by rapid growth in population which continues till enough food is available. But with the increase in reindeer population, there is corresponding decrease in the availability of food and space, which finally become exhausted, which leads to mass starvation and mortality. This sudden increase in mortality is called population crash. Lemming of Tundra, some insect, algal blooms and annual plants also show J-shaped curves. The population growth curve is S- shaped in most of the organisms, Human population also shows S-shaped curve.
In a pond, last year there were 30 lotus plants. Through reproduction, 25 new lotus plants were added in one year while 8 plants died. The birth and death rates for the lotus population respectively are ___ and ____ individuals per lotus per year.- a)0.83 , 0.26
- b)0.26, 0.83
- c)0.25 , 0.80
- d)0.80, 0.25
Correct answer is option 'A'. Can you explain this answer?
In a pond, last year there were 30 lotus plants. Through reproduction, 25 new lotus plants were added in one year while 8 plants died. The birth and death rates for the lotus population respectively are ___ and ____ individuals per lotus per year.
a)
0.83 , 0.26
b)
0.26, 0.83
c)
0.25 , 0.80
d)
0.80, 0.25
|
Abha Dhamija answered |
Total number of plants (in the beginning ) = 30
New plants added by reproduction = 25
Birth rate (of a population)
New plants added by reproduction = 25
Birth rate (of a population)
=0.83 individuals per lotus per year
Number of plants died =8
Exponential growth pattern in a population results into:- a)Sigmoid curve
- b)U-shaped curve
- c)J-shaped curve
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
Exponential growth pattern in a population results into:
a)
Sigmoid curve
b)
U-shaped curve
c)
J-shaped curve
d)
None of these
|
Shalini Saha answered |
Exponential growth pattern in population results into j-shaped curve. During exponential growth faster growth occurs and j-shaped curve is formed when time v/s growth is drawn.
The formula for exponential population growth is- a)dN/rN = dt
- b)r N/dN = dt
- c)dt/dN = r N
- d)dN/dt = r N
Correct answer is option 'D'. Can you explain this answer?
The formula for exponential population growth is
a)
dN/rN = dt
b)
r N/dN = dt
c)
dt/dN = r N
d)
dN/dt = r N
|
Abhiram Nair answered |
Ans.
Formula = the rate of change in population size) = (the contribution of each individual to population growth) x (the number of individuals in the population
In which of the following interaction/s one species is benefitted while other is harmed?- a)parasitism only
- b)competition only
- c)predation and parasitism
- d)competition and amensalism
Correct answer is option 'C'. Can you explain this answer?
In which of the following interaction/s one species is benefitted while other is harmed?
a)
parasitism only
b)
competition only
c)
predation and parasitism
d)
competition and amensalism
|
Nayanika Dasgupta answered |
In predation and parasitism one species is benefitted while other is harmed. Parasite obtain food from host by harming them.
In a population per capita birth rate is 0.15 and per capita death rate is 0.08 during a unit time period. What is the value of r (intrinsic rate of natural increase) for the given population ?- a)0.023
- b)0.07
- c)0.05
- d)0.25
Correct answer is option 'B'. Can you explain this answer?
In a population per capita birth rate is 0.15 and per capita death rate is 0.08 during a unit time period. What is the value of r (intrinsic rate of natural increase) for the given population ?
a)
0.023
b)
0.07
c)
0.05
d)
0.25
|
EduRev NEET answered |
Intrinsic rate of natural increase (r)
= Birth rate − death rate
=0.15−0.08=0.07
For which of the following would you expect distribution range to be badly affected if average Global temperature keeps increasing:- a)Stenothermal species
- b)Euryhaline species
- c)Both Stenothermal species and Euryhaline species
- d)Eurythermal species
Correct answer is option 'A'. Can you explain this answer?
For which of the following would you expect distribution range to be badly affected if average Global temperature keeps increasing:
a)
Stenothermal species
b)
Euryhaline species
c)
Both Stenothermal species and Euryhaline species
d)
Eurythermal species
|
Diya Datta answered |
A majority of organisms are restricted to narrow range of temperature. Such organisms are called stenothermal species. The distribution range of these species will be adversely affected if average global temperature keeps increasing.
Ecology is the study of the relationships between living organisms and:- a)Abiotic and biotic components
- b)Biotic components only
- c)Abiotic components only
- d)Non-living components only
Correct answer is option 'A'. Can you explain this answer?
Ecology is the study of the relationships between living organisms and:
a)
Abiotic and biotic components
b)
Biotic components only
c)
Abiotic components only
d)
Non-living components only
|
Milan Unni answered |
Ecology is the branch of biology that studies the relationships between living organisms and their environment. It is concerned with understanding how organisms interact with both the biotic (living) and abiotic (non-living) components of their surroundings.
An example of predation is :- a)Cuckoo laying eggs in crow’s nest
- b)Biological control of pest population
- c)Penicilliumwhose toxins kill bacteria
- d)None of the these
Correct answer is option 'B'. Can you explain this answer?
An example of predation is :
a)
Cuckoo laying eggs in crow’s nest
b)
Biological control of pest population
c)
Penicilliumwhose toxins kill bacteria
d)
None of the these
|
Abhishek Choudhary answered |
Biological control method adopted in agricultural pest control are based on the ability of predator to regulate prey population.
“In Competition, the superior competitor eliminates the inferior one”, this statement is called?- a)Gause’s principle
- b)Allen’s rule
- c)Darwinian fitness
- d)All of these
Correct answer is option 'A'. Can you explain this answer?
“In Competition, the superior competitor eliminates the inferior one”, this statement is called?
a)
Gause’s principle
b)
Allen’s rule
c)
Darwinian fitness
d)
All of these
|
Rajesh Datta answered |
E In competition, superior competitor eliminates the inferior one. This statement is called Gause’s competitive exclusion principle. Two closely related competing for same resources cannot co-exist indefinitely and inferior will be eliminated.
Species facing competition might evolve mechanism that promotes co-existence rather than exclusion and that mechanism can be- a)Interspecific competition
- b)Intraspecific competition
- c)Competitive release
- d)Resource partitioning
Correct answer is option 'D'. Can you explain this answer?
Species facing competition might evolve mechanism that promotes co-existence rather than exclusion and that mechanism can be
a)
Interspecific competition
b)
Intraspecific competition
c)
Competitive release
d)
Resource partitioning
|
Pooja Choudhary answered |
Species facing completion might evolve mechanism that promotes co-existence rather than exclusion that mechanism is called resource partitioning. In which they avoid completion by choosing different times of feeding or different foraging patterns.
Which of the following adaptations are examples of plant defenses against herbivores?- a)Thorns on Acacia trees.
- b)High reproductive rate of a parasitic plant.
- c)Chemical production in Calotropis that harms herbivores.
- d)Camouflage in insects like the Monarch butterfly.
Correct answer is option 'A'. Can you explain this answer?
a)
Thorns on Acacia trees.
b)
High reproductive rate of a parasitic plant.
c)
Chemical production in Calotropis that harms herbivores.
d)
Camouflage in insects like the Monarch butterfly.
|
|
Janhavi Bose answered |
Understanding Plant Defenses Against Herbivores
Plants have evolved various strategies to protect themselves from herbivores, which can cause significant damage. Among the adaptations listed, thorns on Acacia trees serve as a primary example of a plant defense mechanism.
Thorns on Acacia Trees
- Physical Barrier:
Thorns act as a physical deterrent, making it difficult for herbivores to consume the leaves and stems of the tree. This adaptation helps reduce the likelihood of being eaten.
- Predator Attraction:
In some cases, Acacia trees also have mutualistic relationships with ants. The thorns can provide shelter for these ants, which, in return, defend the tree by attacking herbivores.
Other Options Explained
- High Reproductive Rate of a Parasitic Plant:
This adaptation is not a defense mechanism but rather a strategy for survival and dispersal. Parasitic plants rely on host plants for nutrients, not defending themselves from herbivores.
- Chemical Production in Calotropis:
While this adaptation does harm herbivores, it is more of a chemical defense rather than a structural one. It represents a different category of defense mechanisms.
- Camouflage in Insects like the Monarch Butterfly:
This is an adaptation of the insect and does not pertain to plant defenses. It highlights predator evasion rather than plant strategies against herbivores.
Conclusion
In summary, thorns on Acacia trees exemplify physical defenses that discourage herbivores, while the other options either pertain to different organisms or do not directly relate to plant defense strategies.
Plants have evolved various strategies to protect themselves from herbivores, which can cause significant damage. Among the adaptations listed, thorns on Acacia trees serve as a primary example of a plant defense mechanism.
Thorns on Acacia Trees
- Physical Barrier:
Thorns act as a physical deterrent, making it difficult for herbivores to consume the leaves and stems of the tree. This adaptation helps reduce the likelihood of being eaten.
- Predator Attraction:
In some cases, Acacia trees also have mutualistic relationships with ants. The thorns can provide shelter for these ants, which, in return, defend the tree by attacking herbivores.
Other Options Explained
- High Reproductive Rate of a Parasitic Plant:
This adaptation is not a defense mechanism but rather a strategy for survival and dispersal. Parasitic plants rely on host plants for nutrients, not defending themselves from herbivores.
- Chemical Production in Calotropis:
While this adaptation does harm herbivores, it is more of a chemical defense rather than a structural one. It represents a different category of defense mechanisms.
- Camouflage in Insects like the Monarch Butterfly:
This is an adaptation of the insect and does not pertain to plant defenses. It highlights predator evasion rather than plant strategies against herbivores.
Conclusion
In summary, thorns on Acacia trees exemplify physical defenses that discourage herbivores, while the other options either pertain to different organisms or do not directly relate to plant defense strategies.
Statement I: Age pyramid of expanding population is broader at base and thin upwards.
Statement II: Number of individuals in pre-reproductive age is more than post reproductive age.
Statement III: population size is technically called as population density.- a)Only statement II and III are correct.
- b)Only statement I and II are correct.
- c)All statements are correct.
- d)All statements are incorrect.
Correct answer is option 'C'. Can you explain this answer?
Statement I: Age pyramid of expanding population is broader at base and thin upwards.
Statement II: Number of individuals in pre-reproductive age is more than post reproductive age.
Statement III: population size is technically called as population density.
Statement II: Number of individuals in pre-reproductive age is more than post reproductive age.
Statement III: population size is technically called as population density.
a)
Only statement II and III are correct.
b)
Only statement I and II are correct.
c)
All statements are correct.
d)
All statements are incorrect.
|
Prashanth Dasgupta answered |
Age pyramid of expanding population is broader at base and thin upwards. Number of individuals in pre-reproductive age is more than post reproductive age. Population size is technically called as population density.
Mediterranean orchid Ophrysensures pollination by :- a)Pseudocopulation only
- b)Sexual deceit and co-evolution
- c)Brood parasitism
- d)Co-evolution, sexual deceit and pseudo-copulation
Correct answer is option 'D'. Can you explain this answer?
Mediterranean orchid Ophrysensures pollination by :
a)
Pseudocopulation only
b)
Sexual deceit and co-evolution
c)
Brood parasitism
d)
Co-evolution, sexual deceit and pseudo-copulation
|
Yash Saha answered |
Mediterranean orchid Ophrys ensures pollination by co-evolution, sexual deceit and pseudo-copulation. One petal of flower bears an uncanny resemblance to female of bee in size, colour and markings.
What does the carrying capacity (K) of a habitat refer to?- a)The maximum growth rate a population can achieve
- b)The maximum number of individuals an environment can support
- c)The rate of immigration into a population
- d)The total biomass of a population
Correct answer is option 'B'. Can you explain this answer?
a)
The maximum growth rate a population can achieve
b)
The maximum number of individuals an environment can support
c)
The rate of immigration into a population
d)
The total biomass of a population
|
Abhijeet Sengupta answered |
Understanding Carrying Capacity (K)
The carrying capacity, often denoted as "K," is a crucial ecological concept that defines the limits of a habitat's ability to sustain a population. Here's a detailed explanation:
Definition of Carrying Capacity
- The carrying capacity refers to the maximum number of individuals of a particular species that an environment can support over time without degrading the habitat.
- It is influenced by various factors such as food availability, water supply, habitat space, and the presence of predators and diseases.
Importance of Carrying Capacity
- Understanding carrying capacity helps in the management of wildlife populations and natural resources, ensuring that ecosystems remain balanced and healthy.
- It aids in predicting how changes in the environment (like climate change or human encroachment) can impact species survival.
Factors Influencing Carrying Capacity
- Resource Availability: The amount of food, water, and shelter available directly affects how many individuals can be supported.
- Environmental Conditions: Changes in climate, habitat destruction, and pollution can lower the carrying capacity.
- Species Interactions: Predation, competition, and disease can either increase or decrease the effective carrying capacity.
Consequences of Exceeding Carrying Capacity
- When a population exceeds its carrying capacity, it can lead to overpopulation, resulting in resource depletion, habitat destruction, and a decline in population health.
- This often causes a population crash, where the numbers plummet due to starvation or increased mortality.
In summary, the carrying capacity (K) is essential for maintaining ecological balance, and understanding it allows for better conservation and management strategies.
The carrying capacity, often denoted as "K," is a crucial ecological concept that defines the limits of a habitat's ability to sustain a population. Here's a detailed explanation:
Definition of Carrying Capacity
- The carrying capacity refers to the maximum number of individuals of a particular species that an environment can support over time without degrading the habitat.
- It is influenced by various factors such as food availability, water supply, habitat space, and the presence of predators and diseases.
Importance of Carrying Capacity
- Understanding carrying capacity helps in the management of wildlife populations and natural resources, ensuring that ecosystems remain balanced and healthy.
- It aids in predicting how changes in the environment (like climate change or human encroachment) can impact species survival.
Factors Influencing Carrying Capacity
- Resource Availability: The amount of food, water, and shelter available directly affects how many individuals can be supported.
- Environmental Conditions: Changes in climate, habitat destruction, and pollution can lower the carrying capacity.
- Species Interactions: Predation, competition, and disease can either increase or decrease the effective carrying capacity.
Consequences of Exceeding Carrying Capacity
- When a population exceeds its carrying capacity, it can lead to overpopulation, resulting in resource depletion, habitat destruction, and a decline in population health.
- This often causes a population crash, where the numbers plummet due to starvation or increased mortality.
In summary, the carrying capacity (K) is essential for maintaining ecological balance, and understanding it allows for better conservation and management strategies.
An age pyramid with a wide base and narrow top indicates a population that is:- a)Changing
- b)Stable
- c)Declining
- d)Growing rapidly
Correct answer is option 'D'. Can you explain this answer?
An age pyramid with a wide base and narrow top indicates a population that is:
a)
Changing
b)
Stable
c)
Declining
d)
Growing rapidly
|
Rajesh Gupta answered |
An age pyramid with a wide base and narrow top indicates a population that is growing rapidly.
In an age pyramid, the width of each age group represents the proportion or percentage of individuals in that specific age group. A wide base indicates a larger population of young individuals, while a narrow top indicates a smaller population of older individuals.
When the base of an age pyramid is wide and the subsequent age groups gradually decrease in width towards the top, it suggests that there is a higher proportion of young individuals compared to older individuals. This is indicative of a population that is growing rapidly because there is a high birth rate.
Which growth pattern occurs when resources become progressively limiting in a population?- a)Logistic growth
- b)Exponential growth
- c)Constant growth
- d)Declining growth
Correct answer is option 'A'. Can you explain this answer?
Which growth pattern occurs when resources become progressively limiting in a population?
a)
Logistic growth
b)
Exponential growth
c)
Constant growth
d)
Declining growth
|
|
Rajesh Gupta answered |
Populations grow through births and immigration and decline through deaths and emigration.
When resources become progressively limiting for a population, the growth pattern turns logistic. This means that initially, the population may experience exponential growth when resources are abundant and unlimited.
However, as resources start to become scarce and limiting, the growth rate of the population slows down and eventually levels off. This pattern is known as logistic growth.
- Exponential growth (option b) refers to a rapid and unrestricted increase in population size without resource limitations.
- Constant growth (option c) implies a steady and consistent growth rate over time, regardless of resource availability.
- Declining growth (option d) suggests a decrease in population size over time, often due to factors like limited resources or environmental disturbances.
If N population density at time t, then population density at time t+1 can be written asNt +1=Nt +[(A+B)−(C+D)]
Select the correct option for A, B, C and D in the above equation. - a)A can be mortality and B can be natality
- b)B can be immigration and C can be natality
- c)C can be mortality and D can be immigration
- d)A can be natality and D can be emigration
Correct answer is option 'D'. Can you explain this answer?
If N population density at time t, then population density at time t+1 can be written as
Nt +1=Nt +[(A+B)−(C+D)]
Select the correct option for A, B, C and D in the above equation.
Select the correct option for A, B, C and D in the above equation.
a)
A can be mortality and B can be natality
b)
B can be immigration and C can be natality
c)
C can be mortality and D can be immigration
d)
A can be natality and D can be emigration
|
Jyoti Sengupta answered |
A and B are natality and immigration. They add to population density. C and D are mortality and emigration. They decrease population density.
Which of the following is not a factor that would limit the growth of a population ?- a)Food shortage
- b)Immigration
- c)Disease
- d)Famine
Correct answer is option 'B'. Can you explain this answer?
Which of the following is not a factor that would limit the growth of a population ?
a)
Food shortage
b)
Immigration
c)
Disease
d)
Famine
|
Dev Patel answered |
Immigration is the permanent inward movement of some individuals coming from outside into an existing population. This increase population density and would not limit its growth.
Consider the following statements about population growth and dynamics:
1. Exponential growth occurs only when resources are limited.
2. Logistic growth models show a sigmoid curve and account for carrying capacity.
3. Natality, mortality, immigration, and emigration are the four main factors that influence population size.
4. The intrinsic rate of natural increase (r) is constant and unaffected by environmental conditions.
Which of the following options is correct?- a)Statements 1 and 4 are correct.
- b)Statements 2 and 3 are correct.
- c)Statements 1 and 3 are correct.
- d)All statements are correct.
Correct answer is option 'B'. Can you explain this answer?
Consider the following statements about population growth and dynamics:
1. Exponential growth occurs only when resources are limited.
2. Logistic growth models show a sigmoid curve and account for carrying capacity.
3. Natality, mortality, immigration, and emigration are the four main factors that influence population size.
4. The intrinsic rate of natural increase (r) is constant and unaffected by environmental conditions.
Which of the following options is correct?
1. Exponential growth occurs only when resources are limited.
2. Logistic growth models show a sigmoid curve and account for carrying capacity.
3. Natality, mortality, immigration, and emigration are the four main factors that influence population size.
4. The intrinsic rate of natural increase (r) is constant and unaffected by environmental conditions.
Which of the following options is correct?
a)
Statements 1 and 4 are correct.
b)
Statements 2 and 3 are correct.
c)
Statements 1 and 3 are correct.
d)
All statements are correct.
|
Jay Chaudhary answered |
Understanding Population Growth Dynamics
Population dynamics is a crucial field of study in ecology, focusing on how populations change over time. Let's evaluate the given statements:
1. Exponential Growth and Resource Limitations
- Incorrect Statement: Exponential growth occurs when resources are abundant, allowing populations to grow rapidly without constraints. It does not occur only when resources are limited.
2. Logistic Growth and Carrying Capacity
- Correct Statement: Logistic growth is characterized by a sigmoid curve, which illustrates how a population grows rapidly at first, then slows as it approaches the carrying capacity of the environment. This model effectively integrates the concept of environmental limitations.
3. Factors Influencing Population Size
- Correct Statement: Natality (birth rate), mortality (death rate), immigration (movement into a population), and emigration (movement out of a population) are indeed the primary factors that influence population size, making this statement accurate.
4. Intrinsic Rate of Natural Increase (r)
- Incorrect Statement: The intrinsic rate of natural increase (r) is not constant; it can vary based on environmental conditions, resource availability, and other ecological factors.
Conclusion
Based on the evaluation:
- Statements 2 and 3 are correct, while statements 1 and 4 are incorrect. Thus, the correct answer is option B: "Statements 2 and 3 are correct."
Understanding these principles is essential for grasping how populations grow and interact with their environments, which is a key aspect of ecological studies in NEET.
Population dynamics is a crucial field of study in ecology, focusing on how populations change over time. Let's evaluate the given statements:
1. Exponential Growth and Resource Limitations
- Incorrect Statement: Exponential growth occurs when resources are abundant, allowing populations to grow rapidly without constraints. It does not occur only when resources are limited.
2. Logistic Growth and Carrying Capacity
- Correct Statement: Logistic growth is characterized by a sigmoid curve, which illustrates how a population grows rapidly at first, then slows as it approaches the carrying capacity of the environment. This model effectively integrates the concept of environmental limitations.
3. Factors Influencing Population Size
- Correct Statement: Natality (birth rate), mortality (death rate), immigration (movement into a population), and emigration (movement out of a population) are indeed the primary factors that influence population size, making this statement accurate.
4. Intrinsic Rate of Natural Increase (r)
- Incorrect Statement: The intrinsic rate of natural increase (r) is not constant; it can vary based on environmental conditions, resource availability, and other ecological factors.
Conclusion
Based on the evaluation:
- Statements 2 and 3 are correct, while statements 1 and 4 are incorrect. Thus, the correct answer is option B: "Statements 2 and 3 are correct."
Understanding these principles is essential for grasping how populations grow and interact with their environments, which is a key aspect of ecological studies in NEET.
Which of the following best explains why logistic growth occurs in populations?- a)Populations grow exponentially when resources are unlimited and then decrease rapidly due to the depletion of resources.
- b)Populations grow exponentially but reach a plateau when resources become limited, as determined by the environment's carrying capacity.
- c)Populations exhibit exponential growth indefinitely because they always have sufficient resources.
- d)Populations decline due to environmental factors without any increase in population size.
Correct answer is option 'B'. Can you explain this answer?
a)
Populations grow exponentially when resources are unlimited and then decrease rapidly due to the depletion of resources.
b)
Populations grow exponentially but reach a plateau when resources become limited, as determined by the environment's carrying capacity.
c)
Populations exhibit exponential growth indefinitely because they always have sufficient resources.
d)
Populations decline due to environmental factors without any increase in population size.
|
Lead Academy answered |
Logistic growth occurs when populations experience exponential growth under ideal conditions but eventually slow down and level off as resources become limited. The population size stabilizes around the environment's carrying capacity, where growth is regulated by factors like food availability, space, and other ecological constraints.
Which of the following are examples of parasitism?- a) interaction between sea anemone that has stinging tentacles and the clown fish
- b)The Monarch butterfly’s chemical defenses.
- c)A lichen growing on a tree branch.
- d)The human liver fluke’s life cycle involving two intermediate hosts.
Correct answer is option 'D'. Can you explain this answer?
Which of the following are examples of parasitism?
a)
interaction between sea anemone that has stinging tentacles and the clown fish
b)
The Monarch butterfly’s chemical defenses.
c)
A lichen growing on a tree branch.
d)
The human liver fluke’s life cycle involving two intermediate hosts.
|
Bs Academy answered |
the human liver fluke’s life cycle (D) is an example of parasitism, where one species benefits at the expense of another. The other options describe mutualistic or commensal relationships.
Topic in NCERT: Life Cycles of Parasites
Line in NCERT: "The human liver fluke (a trematode parasite) depends on two intermediate hosts (a snail and a fish) to complete its life cycle."
Which of the following is not an example of prey-predator relationship ?- a)Tiger eating a deer
- b)Plant Nepenthes trapping an insect
- c)Bacteria decomposing organic matter
- d)Crocodile killing a man
Correct answer is option 'C'. Can you explain this answer?
Which of the following is not an example of prey-predator relationship ?
a)
Tiger eating a deer
b)
Plant Nepenthes trapping an insect
c)
Bacteria decomposing organic matter
d)
Crocodile killing a man
|
|
Mira Joshi answered |
Bacteria decompose the organic matter which is not really living. Hence, it cannot be considered as a prey predator relationship.
Choose the wrong statements
- a)Two species may not live in same habitat
- b)The more dissimilar the niches of two species the stronger is their competition between them
- c)No two species can occupy exactly the same niche in the same geographical area
- d)All of these
Correct answer is option 'C'. Can you explain this answer?
Choose the wrong statements
a)
Two species may not live in same habitat
b)
The more dissimilar the niches of two species the stronger is their competition between them
c)
No two species can occupy exactly the same niche in the same geographical area
d)
All of these
|
|
Dev Patel answered |
According to the competitive exclusion principle, no two species can occupy exactly the same niche in exactly the same habitat at exactly the same time. Two species whose niches overlap may evolve by natural selection to have more distinct niches, resulting in resource partitioning.
So the correct answer is 'No two species can occupy exactly the same niche in the same geographical area.'
Exponential growth is observed in a population when- a)resources in the habitat are unlimited
- b)each species has the ability to realise its full innate potential
- c)both (a) and (b)
- d)none of these
Correct answer is option 'C'. Can you explain this answer?
Exponential growth is observed in a population when
a)
resources in the habitat are unlimited
b)
each species has the ability to realise its full innate potential
c)
both (a) and (b)
d)
none of these
|
|
Raghav Bansal answered |
When food and space for a population are unlimited, each species has the ability to realise fully its inherited potential to grow. Then the population grows in an exponential or geometric ratio.
A population with a larger proportion of older individuals than younger ones will likely to- a)grow larger and then decline
- b)continue to grow larger indefinitely
- c)grow smaller and may stabilize at a smaller population size
- d)not experience a change in population size.
Correct answer is option 'C'. Can you explain this answer?
A population with a larger proportion of older individuals than younger ones will likely to
a)
grow larger and then decline
b)
continue to grow larger indefinitely
c)
grow smaller and may stabilize at a smaller population size
d)
not experience a change in population size.
|
|
Anand Chaudhary answered |
Understanding Population Dynamics
A population with a larger proportion of older individuals is likely to face specific dynamics that influence its growth and stability.
Reasons for Option C: Grow Smaller and May Stabilize
- Higher Mortality Rates: Older individuals typically have shorter life expectancies, leading to increased mortality rates within this demographic. As these individuals age and pass away, the population will naturally decline.
- Lower Birth Rates: Populations with a higher proportion of older individuals often have lower birth rates, as older individuals are less likely to contribute to population growth. When fewer young individuals are born, the population's potential for growth diminishes.
- Age Structure Impact: The age structure of a population significantly influences its future growth. A population with more older individuals and fewer younger ones tends to transition towards stabilization or decline as the reproductive base shrinks.
- Potential for Stabilization: As the population decreases, it may reach a point of stabilization at a smaller size, given that the birth rates remain low and death rates may fluctuate based on health and environmental factors.
Conclusion
In summary, a population skewed towards older individuals is likely to experience a decline due to higher mortality and lower birth rates, potentially stabilizing at a smaller size. Hence, option C accurately reflects the expected demographic trends in such populations.
A population with a larger proportion of older individuals is likely to face specific dynamics that influence its growth and stability.
Reasons for Option C: Grow Smaller and May Stabilize
- Higher Mortality Rates: Older individuals typically have shorter life expectancies, leading to increased mortality rates within this demographic. As these individuals age and pass away, the population will naturally decline.
- Lower Birth Rates: Populations with a higher proportion of older individuals often have lower birth rates, as older individuals are less likely to contribute to population growth. When fewer young individuals are born, the population's potential for growth diminishes.
- Age Structure Impact: The age structure of a population significantly influences its future growth. A population with more older individuals and fewer younger ones tends to transition towards stabilization or decline as the reproductive base shrinks.
- Potential for Stabilization: As the population decreases, it may reach a point of stabilization at a smaller size, given that the birth rates remain low and death rates may fluctuate based on health and environmental factors.
Conclusion
In summary, a population skewed towards older individuals is likely to experience a decline due to higher mortality and lower birth rates, potentially stabilizing at a smaller size. Hence, option C accurately reflects the expected demographic trends in such populations.
The density of a population in a given habitat during a given period, fluctuates due to changes in certain basic processes. On this basis, fill up boxes A and B in the given flow chart with correct option.
- a)A — Natality, B — Mortality
- b)A — Immigration , B — Emigration
- c)A — Natality, B — Immigration
- d)Both (a) and (b)
Correct answer is option 'D'. Can you explain this answer?
The density of a population in a given habitat during a given period, fluctuates due to changes in certain basic processes. On this basis, fill up boxes A and B in the given flow chart with correct option.
a)
A — Natality, B — Mortality
b)
A — Immigration , B — Emigration
c)
A — Natality, B — Immigration
d)
Both (a) and (b)
|
Ananya Das answered |
The population density in a given habitat and at a particular time period, fluctuates due to the changes in four basic processes given below:-
1. Natality- It refers to the number of births take place in a population during a given period.
2. Mortality- It refers to the number of deaths take place in a population during a given period.
3. Immigration- It refers to the number of individuals of the same species have migrated into the habitat from somewhere else during a particular time period.
4. Emigration- It refers to the number of individuals of the same species have migrated out of the habitat during a given time period.
Natality and immigration add to the population density whereas mortality and emigration decrease the population density.
Which type of interaction benefits both species involved?- a)Competition
- b)Predation
- c)Mutualism
- d)Parasitism
Correct answer is option 'C'. Can you explain this answer?
Which type of interaction benefits both species involved?
a)
Competition
b)
Predation
c)
Mutualism
d)
Parasitism
|
|
Rajesh Gupta answered |
Interactions between species can have different outcomes. In mutualism, both species benefit from the interaction. This means that there is a mutually beneficial relationship where both species gain advantages, such as access to food, protection, or reproductive assistance.
Option d) Mutualism is the correct answer because it accurately identifies the type of interaction where both species involved benefit from each other.
When one population is harmed and the other remains unaffected, the relationship is called- a)Protocooperation
- b)Predation
- c)Amensalism
- d)Parasitism
Correct answer is option 'C'. Can you explain this answer?
When one population is harmed and the other remains unaffected, the relationship is called
a)
Protocooperation
b)
Predation
c)
Amensalism
d)
Parasitism
|
|
Dev Kumar answered |
No,It would be amensalism only when one population is being harmed by other population unconditionally means there is no intention of the population to harm the other population but it occurs due to release of some toxic substances by the population which harms the other population unintentionally and the population releasing toxic substances remains unharmed.
but Accord to your question ans can also be predation and parasitism.
How does a carnivore population increase?- a)Due to the decrease in the availability of grass
- b)Due to the increase in the population of omnivore
- c)Due to the increase in the population of scavenger
- d)Due to the increase in the population of herbivore
Correct answer is option 'D'. Can you explain this answer?
How does a carnivore population increase?
a)
Due to the decrease in the availability of grass
b)
Due to the increase in the population of omnivore
c)
Due to the increase in the population of scavenger
d)
Due to the increase in the population of herbivore
|
Aditi Singh answered |
Understanding Carnivore Population Dynamics
The growth of a carnivore population is closely linked to the availability of their prey, primarily herbivores. Here’s a detailed explanation of why the correct answer is option 'D'—the increase in the population of herbivores.
Relationship Between Carnivores and Herbivores
- Carnivores are animals that primarily consume other animals (herbivores or other carnivores).
- The population of carnivores is dependent on the availability of herbivores as a food source.
Impact of Herbivore Population on Carnivores
- An increase in herbivore population means more food availability for carnivores.
- With sufficient food sources, carnivores can reproduce more successfully and increase their population size.
Ecological Balance
- Herbivores play a crucial role in maintaining the balance of ecosystems.
- When herbivore populations thrive, it can lead to an increase in carnivore numbers, as they have ample resources to sustain themselves.
Other Options Explained
- a) Decrease in Grass Availability: This would negatively impact herbivores, leading to a decline in their population, which would, in turn, affect carnivores negatively.
- b) Increase in Omnivores: While omnivores may compete with carnivores for food, their population growth does not directly enhance carnivore numbers.
- c) Increase in Scavengers: Scavengers primarily feed on dead animals and do not significantly impact the population dynamics of living carnivores.
In conclusion, the growth of a carnivore population is intricately linked to the availability of herbivores, making option 'D' the correct answer.
The growth of a carnivore population is closely linked to the availability of their prey, primarily herbivores. Here’s a detailed explanation of why the correct answer is option 'D'—the increase in the population of herbivores.
Relationship Between Carnivores and Herbivores
- Carnivores are animals that primarily consume other animals (herbivores or other carnivores).
- The population of carnivores is dependent on the availability of herbivores as a food source.
Impact of Herbivore Population on Carnivores
- An increase in herbivore population means more food availability for carnivores.
- With sufficient food sources, carnivores can reproduce more successfully and increase their population size.
Ecological Balance
- Herbivores play a crucial role in maintaining the balance of ecosystems.
- When herbivore populations thrive, it can lead to an increase in carnivore numbers, as they have ample resources to sustain themselves.
Other Options Explained
- a) Decrease in Grass Availability: This would negatively impact herbivores, leading to a decline in their population, which would, in turn, affect carnivores negatively.
- b) Increase in Omnivores: While omnivores may compete with carnivores for food, their population growth does not directly enhance carnivore numbers.
- c) Increase in Scavengers: Scavengers primarily feed on dead animals and do not significantly impact the population dynamics of living carnivores.
In conclusion, the growth of a carnivore population is intricately linked to the availability of herbivores, making option 'D' the correct answer.
Which of the following statements are correct?
(i) Organisms with high reproductive rates (r value) evolve to maximize their reproductive fitness.
(ii) Organisms that breed only once in their lifetime are more likely to have large offspring.
(iii) The evolution of life history traits is unaffected by the constraints of the habitat.
(iv) Different species evolve life history traits based on both biotic and abiotic factors of their environment.- a) Only 1 and 4
- b)Only 2 and 3
- c)Only 1 and 2
- d)Only 3 and 4
Correct answer is option 'A'. Can you explain this answer?
Which of the following statements are correct?
(i) Organisms with high reproductive rates (r value) evolve to maximize their reproductive fitness.
(ii) Organisms that breed only once in their lifetime are more likely to have large offspring.
(iii) The evolution of life history traits is unaffected by the constraints of the habitat.
(iv) Different species evolve life history traits based on both biotic and abiotic factors of their environment.
(i) Organisms with high reproductive rates (r value) evolve to maximize their reproductive fitness.
(ii) Organisms that breed only once in their lifetime are more likely to have large offspring.
(iii) The evolution of life history traits is unaffected by the constraints of the habitat.
(iv) Different species evolve life history traits based on both biotic and abiotic factors of their environment.
a)
Only 1 and 4
b)
Only 2 and 3
c)
Only 1 and 2
d)
Only 3 and 4
|
|
EduRev NEET answered |
Statement A is correct. Organisms with high reproductive rates (high r value) evolve to maximize their reproductive fitness by increasing their population size rapidly.
Statement B is incorrect. Organisms that breed only once in their lifetime, such as Pacific salmon, typically produce many small offspring, not large ones.
Statement C is incorrect. Life history traits are shaped by both biotic (living) and abiotic (non-living) factors in the environment, which constrain and influence their evolution.
Statement D is correct. The evolution of life history traits is heavily influenced by the abiotic and biotic components of the organism's habitat, ensuring that the traits align with environmental conditions.
Therefore, the correct answer is Option A and Option D are correct.
Statement B is incorrect. Organisms that breed only once in their lifetime, such as Pacific salmon, typically produce many small offspring, not large ones.
Statement C is incorrect. Life history traits are shaped by both biotic (living) and abiotic (non-living) factors in the environment, which constrain and influence their evolution.
Statement D is correct. The evolution of life history traits is heavily influenced by the abiotic and biotic components of the organism's habitat, ensuring that the traits align with environmental conditions.
Therefore, the correct answer is Option A and Option D are correct.
Topic in NCERT: Life History Variation
Line in NCERT: "Populations evolve to maximise their reproductive fitness, also called Darwinian fitness (high r value), in the habitat in which they live."
Which of the following is not an example of using relative density to measure population density in a certain area ?- a)Counting pugmarks of tigers to find population density of tigers in a forest
- b)Counting the number of fishes caught in a trap to find population density of fishes in a lake
- c)Measuring biomass of bacterial culture to find out population density of bacteria in a petri dish
- d)Measuring biomass of phytoplanktons in 1cc water to find out population density of phytoplanktons in a lake
Correct answer is option 'C'. Can you explain this answer?
Which of the following is not an example of using relative density to measure population density in a certain area ?
a)
Counting pugmarks of tigers to find population density of tigers in a forest
b)
Counting the number of fishes caught in a trap to find population density of fishes in a lake
c)
Measuring biomass of bacterial culture to find out population density of bacteria in a petri dish
d)
Measuring biomass of phytoplanktons in 1cc water to find out population density of phytoplanktons in a lake
|
|
Geetika Shah answered |
Sometimes, for certain ecological investigations, there is no need to know the absolute population densities. Relative densities serve the purpose equally well. In this case, population size is indirectly estimated without actually counting them. For example, the number of fishes caught per trap is good enough measure of its total population density in the lake. The tiger census in our National parks and tiger reserves is often based on pug marks (animal's foot print) and faecal pellets.
Total number of individuals of a species per unit area and per unit time is called:- a)Population size
- b)Population density
- c)Demography
- d)Population dynamics
Correct answer is option 'B'. Can you explain this answer?
Total number of individuals of a species per unit area and per unit time is called:
a)
Population size
b)
Population density
c)
Demography
d)
Population dynamics
|
|
Chirag Unni answered |
Understanding Population Density
Population density is a crucial ecological concept that quantifies the number of individuals of a species within a specific area and timeframe.
Definition of Population Density
- Population density is defined as the total number of individuals of a species per unit area (e.g., per square kilometer) and per unit time (e.g., per year).
- It reflects how crowded a species is in a particular habitat, providing insight into resource availability, competition, and social structure.
Importance of Population Density
- Ecological Balance: Population density helps ecologists understand the balance within an ecosystem. High densities may indicate healthy breeding conditions, while low densities can signify environmental stress.
- Resource Management: Knowledge of population density is vital for wildlife management and conservation efforts, as it aids in assessing the sustainability of populations and the impact of human activities.
- Behavioral Insights: Studying population density allows researchers to examine social behaviors, territoriality, and interactions among species, which are influenced by how closely individuals are packed together.
Comparison with Other Terms
- Population Size: Refers only to the total number of individuals, without considering the area or time.
- Demography: Involves the statistical study of populations, including their structures and dynamics, but does not specifically focus on density.
- Population Dynamics: Encompasses the changes in population size and composition over time, influenced by birth rates, death rates, immigration, and emigration.
Understanding the concept of population density is essential for comprehending ecological relationships and managing biological resources effectively.
Population density is a crucial ecological concept that quantifies the number of individuals of a species within a specific area and timeframe.
Definition of Population Density
- Population density is defined as the total number of individuals of a species per unit area (e.g., per square kilometer) and per unit time (e.g., per year).
- It reflects how crowded a species is in a particular habitat, providing insight into resource availability, competition, and social structure.
Importance of Population Density
- Ecological Balance: Population density helps ecologists understand the balance within an ecosystem. High densities may indicate healthy breeding conditions, while low densities can signify environmental stress.
- Resource Management: Knowledge of population density is vital for wildlife management and conservation efforts, as it aids in assessing the sustainability of populations and the impact of human activities.
- Behavioral Insights: Studying population density allows researchers to examine social behaviors, territoriality, and interactions among species, which are influenced by how closely individuals are packed together.
Comparison with Other Terms
- Population Size: Refers only to the total number of individuals, without considering the area or time.
- Demography: Involves the statistical study of populations, including their structures and dynamics, but does not specifically focus on density.
- Population Dynamics: Encompasses the changes in population size and composition over time, influenced by birth rates, death rates, immigration, and emigration.
Understanding the concept of population density is essential for comprehending ecological relationships and managing biological resources effectively.
Read the following statements and select the correct option.
Statement 1: Brood parasitism in birds is an example of parasitism in which the parasitic bird lays its eggs in the nest of its host and the host incubates them.
Statement 2: During the course of evolution, the eggs of the parasite bird have evolved to resemble the host's eggs in size and colour to reduce the chances of the host bird detecting the foreign eggs and removing them from the nest.
- a)Statement 1 is correct but statement 2 is incorrect but statement 2 is not correct explanation of statement 1
- b)Both statements 1 and 2 are correct and statement 2 is the correct explanation of statement 1
- c)Statement 1 is correct but statement 2 is incorrect
- d)Both statements 1 and 2 are incorrect
Correct answer is option 'B'. Can you explain this answer?
Read the following statements and select the correct option.
Statement 1: Brood parasitism in birds is an example of parasitism in which the parasitic bird lays its eggs in the nest of its host and the host incubates them.
Statement 2: During the course of evolution, the eggs of the parasite bird have evolved to resemble the host's eggs in size and colour to reduce the chances of the host bird detecting the foreign eggs and removing them from the nest.
Statement 1: Brood parasitism in birds is an example of parasitism in which the parasitic bird lays its eggs in the nest of its host and the host incubates them.
Statement 2: During the course of evolution, the eggs of the parasite bird have evolved to resemble the host's eggs in size and colour to reduce the chances of the host bird detecting the foreign eggs and removing them from the nest.
a)
Statement 1 is correct but statement 2 is incorrect but statement 2 is not correct explanation of statement 1
b)
Both statements 1 and 2 are correct and statement 2 is the correct explanation of statement 1
c)
Statement 1 is correct but statement 2 is incorrect
d)
Both statements 1 and 2 are incorrect
|
Ameya Sharma answered |
Brood parasitism in birds
Statement 1: Brood parasitism in birds is an example of parasitism in which the parasitic bird lays its eggs in the nest of its host and the host incubates them.
Statement 2: During the course of evolution, the eggs of the parasite bird have evolved to resemble the hosts eggs in size and colour to reduce the chances of the host bird detecting the foreign eggs and removing them from the nest.
Explanation:
Brood parasitism is a type of parasitism where a bird lays its eggs in the nest of another bird species instead of building its own nest and incubates them. The host bird raises the offspring of the parasitic bird as its own. This behavior is commonly observed in cuckoos, honeyguides, and cowbirds.
The evolution of the eggs of the parasite bird is an adaptive strategy to ensure their survival. The eggs of the parasite bird have evolved to resemble the host's eggs in size and color, making it difficult for the host bird to detect and remove the foreign eggs from the nest. This adaptation increases the chances of the parasitic bird's eggs being incubated and hatched successfully.
Therefore, statement 1 is correct, and statement 2 is also correct as it explains the adaptive strategy of the parasite bird's eggs. However, statement 2 is not the correct explanation of statement 1, as it talks about the evolutionary adaptation of the parasite bird's eggs and does not explain the concept of brood parasitism. Hence, option B is the correct answer.
Statement 1: Brood parasitism in birds is an example of parasitism in which the parasitic bird lays its eggs in the nest of its host and the host incubates them.
Statement 2: During the course of evolution, the eggs of the parasite bird have evolved to resemble the hosts eggs in size and colour to reduce the chances of the host bird detecting the foreign eggs and removing them from the nest.
Explanation:
Brood parasitism is a type of parasitism where a bird lays its eggs in the nest of another bird species instead of building its own nest and incubates them. The host bird raises the offspring of the parasitic bird as its own. This behavior is commonly observed in cuckoos, honeyguides, and cowbirds.
The evolution of the eggs of the parasite bird is an adaptive strategy to ensure their survival. The eggs of the parasite bird have evolved to resemble the host's eggs in size and color, making it difficult for the host bird to detect and remove the foreign eggs from the nest. This adaptation increases the chances of the parasitic bird's eggs being incubated and hatched successfully.
Therefore, statement 1 is correct, and statement 2 is also correct as it explains the adaptive strategy of the parasite bird's eggs. However, statement 2 is not the correct explanation of statement 1, as it talks about the evolutionary adaptation of the parasite bird's eggs and does not explain the concept of brood parasitism. Hence, option B is the correct answer.
Which of the following equations correctly represents verhulst-Pearl logistic growth?- a)
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
Which of the following equations correctly represents verhulst-Pearl logistic growth?
a)
b)
c)
d)
|
|
EduRev NEET answered |
S-shaped growth curve is also called Verhulst-Pearl logistic curve and is represented by the following equation :
where dN/dt= rate of change in population size, r= intrinsic rate of natural increase, N= population density, K= carrying capacity and 
What does the shape of the given age pyramids reflects about the growth status of the related population ?
- a)(i) - Expanding (ii) - Stable
- b)(i) - Stable (ii) - Declining
- c)(i) - Expanding (ii) - Declining
- d)(i) - Declining (ii) - Stable
Correct answer is option 'C'. Can you explain this answer?
What does the shape of the given age pyramids reflects about the growth status of the related population ?
a)
(i) - Expanding (ii) - Stable
b)
(i) - Stable (ii) - Declining
c)
(i) - Expanding (ii) - Declining
d)
(i) - Declining (ii) - Stable
|
|
Suresh Iyer answered |
angular age pyramid has high proportion of preproductive individuals, moderate number of reproductive individuals and fewer post-reproductive individuals. It represents young or rapidly growing population.
In urn-shaped age pyramid, the numbe of reproductive individuals is higher than the number of pre-reproductive individuals. It represents declining or diminishing population with negative growth
In bell-shaped age pyramid, the number of pre-reproductive and reproductive individuals is almost equal. Post reproductive individuals are comparatively fewer. It represents stable or stationary population where growth rate is nearly zero.
Parameters related to age structure include- a)fecundity (birth rate)
- b)generation time
- c).Death rate
- d)all of these
Correct answer is option 'D'. Can you explain this answer?
Parameters related to age structure include
a)
fecundity (birth rate)
b)
generation time
c)
.Death rate
d)
all of these
|
|
Riya Banerjee answered |
The age structure of a population is the percentage of individuals of different ages such as young, adult and old.
Age structure is shown by organisms in which individuals of more than one generation time are important related to it.
Age structure is shown by organisms in which individuals of more than one generation time are important related to it.
The plant-animal interactions often involve co-evolution of the mutualists so that- a)the mutually beneficial system could be safeguarded against 'cheaters'
- b)a given plant species can be pollinated only by its partner animal species and no other species
- c)the animal utilises plant not only for ovipositions but also to pollinate the plant
- d)all of these
Correct answer is option 'D'. Can you explain this answer?
The plant-animal interactions often involve co-evolution of the mutualists so that
a)
the mutually beneficial system could be safeguarded against 'cheaters'
b)
a given plant species can be pollinated only by its partner animal species and no other species
c)
the animal utilises plant not only for ovipositions but also to pollinate the plant
d)
all of these
|
|
Anjali Sharma answered |
Plant-animal interactions involve co-evolution of mutualists. This means, the evolution of the plant (e.g., flower) and the animal (e.g. pollinator species) are closely linked with one another.
Obligate parasites are those organisms which- a)obtain nutrition from dead, decaying organic matter only
- b)obtain nutrition from living organism only
- c)are essentially saporphytes but can also become parasites
- d)are essentially parasites but can also become saprophytes
Correct answer is option 'B'. Can you explain this answer?
Obligate parasites are those organisms which
a)
obtain nutrition from dead, decaying organic matter only
b)
obtain nutrition from living organism only
c)
are essentially saporphytes but can also become parasites
d)
are essentially parasites but can also become saprophytes
|
|
Mira Joshi answered |
Parasitism is a relationship between two living organisms of different species in which one organism called parasite obtains its food directly from another living organism called host. The parasite is usually smaller as compared to its host. It spends a part or whole of its life on or in the body of the host. Obligate parasites obtain their nutrition from living organisms only.
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