Question

Which of the following is correct among the following statements related to species interaction?

• A. Calotropis releases a strong smell to prevent cattle and goats from eating its leaves.
• B. Predators help in maintaining species diversity in a community.
• C. Totally unrelated species never compete for the same resource.
• D. Closely related species competing for the same resources cannot co-exist indefinitely even if the resources are unlimited.
• A. Pisaster (starfish) and some invertebrates
• B. Abingdon tortoise and goats
• C. Sea anemone and clown fish
• D. Flamingo and resident fishes
• A. Mosquito
• B. Cuckoo
• C. Cuscuta
• D. Ticks
• A. Parasitism
• B. Competition
• C. Predation
• D. Commensalism
• A. Sigmoid shaped growth curve
• B. J-shaped growth curve
• C. Verhulst-Pearl logistic growth
• D. Logistic Growth

Answer 1

The Correct Option is B

To determine which statement is correct regarding species interaction, let's analyze each statement: 

• Calotropis releases a strong smell to prevent cattle and goats from eating its leaves.
• Predators help in maintaining species diversity in a community.
• Totally unrelated species never compete for the same resource.
• Closely related species competing for the same resources cannot co-exist indefinitely even if the resources are unlimited.

Explanation:

1. Calotropis releases a strong smell to prevent cattle and goats from eating its leaves: This statement reflects a plant defense mechanism called chemical defense, whereby Calotropis reduces herbivory through a strong odor. While true, it describes an individual plant's trait, not a broader species interaction concept.
2. Predators help in maintaining species diversity in a community: This is the correct statement. Predators regulate prey populations, thus contributing to maintaining diversity by preventing any one species from dominating an ecosystem. This aligns with the principle that predators play a crucial role in balancing species interactions within biological communities.
3. Totally unrelated species never compete for the same resource: This statement is incorrect as totally unrelated species can and often do compete for the same resources if their ecological niches overlap.
4. Closely related species competing for the same resources cannot co-exist indefinitely even if the resources are unlimited: This statement is misleading. If resources were truly unlimited, competitive exclusion would not occur. However, in nature, resources are usually limited, leading to competition.

Hence, the correct statement regarding species interaction is: Predators help in maintaining species diversity in a community.

Answer 2

Let's evaluate each statement regarding species interactions:

(1) Calotropis releases a strong smell to prevent cattle and goats from eating its leaves: This is incorrect. While Calotropis is known to be toxic to some herbivores, its strong smell is not the main mechanism it uses to prevent cattle and goats from eating its leaves. It produces toxic compounds that deter herbivores, but the statement about smell being the primary deterrent is not accurate.

(2) Predators help in maintaining species diversity in a community: This is correct. Predators play a crucial role in maintaining species diversity in ecosystems by regulating prey populations. By controlling the numbers of dominant species, predators allow less dominant species to thrive, thus increasing overall diversity in the community.

(3) Totally unrelated species never compete for the same resource: This is incorrect. Unrelated species can still compete for similar resources, such as food, space, or light. This competition, even between unrelated species, is a common ecological interaction.

(4) Closely related species competing for the same resources cannot co-exist indefinitely even if the resources are unlimited: This is incorrect. According to the competitive exclusion principle, closely related species that compete for the same resources may not be able to coexist in the same ecological niche indefinitely. However, in some cases, species can adapt or evolve different strategies to share resources or occupy slightly different niches, allowing them to coexist.

Thus, the correct answer is (2) Predators help in maintaining species diversity in a community.

Answer 3

The concept of commensalism refers to a type of symbiotic relationship between two living organisms where one organism benefits, and the other is neither helped nor harmed. In analyzing the given examples, we need to determine which pair of organisms exemplifies this relationship. 

Pisaster (starfish) and some invertebrates: This is not a commensalism example, as Pisaster often preys on certain invertebrates, benefiting at their expense.

Abingdon tortoise and goats: This pair is more indicative of competition or predation rather than commensalism, as goats can compete with or harm the tortoise's habitat.

Sea anemone and clown fish: This is a classic example of commensalism. The clown fish benefits by gaining protection from predators while living amongst the anemone's tentacles, which the anemone does not use to capture the clown fish, nor does it gain substantial benefit.

Flamingo and resident fishes: This relationship is not typically commensalism. Flamingos feed on small fish and crustaceans, suggesting a predator-prey or competitive interaction rather than one-sided benefit.

After evaluating all options, Sea anemone and clown fish is the most accurate example of commensalism from the given set.

Answer 4

Commensalism is a type of symbiotic relationship where one organism benefits from the interaction, while the other organism is neither helped nor harmed.

Let's evaluate each option:

(1) Pisaster (starfish) and some invertebrates: This is not an example of commensalism. It is more of a predation or competition relationship, as some invertebrates may be prey for the starfish, or they may compete for resources.

(2) Abingdon tortoise and goats: This is not a classic example of commensalism. It is an example of a relationship where goats may compete for resources with the tortoise, rather than one benefiting without harming the other.

(3) Sea anemone and clown fish: This is an example of commensalism. The clownfish benefits from the protection and shelter provided by the sea anemone, while the anemone is not affected by the clownfish's presence. The clownfish receives protection from predators and food scraps, but the sea anemone is neither helped nor harmed.

(4) Flamingo and resident fishes: This is more likely to be a mutualistic relationship, where flamingos may benefit from the resident fish in terms of food availability (the fish may stir up food for the flamingos), but it's not a classic example of commensalism.

Thus, the correct answer is (3) Sea anemone and clown fish, as this is a classic example of commensalism.

Answer 5

In the study of biological interactions, organisms exist in interconnected relationships within ecological communities. These interactions can range from mutualistic, where both parties benefit, to parasitic, where one organism, the parasite, benefits at the expense of the other, the host. Let us analyze the given options to determine which organism is not classified as a parasite:

• Mosquito: This organism feeds on blood from other animals, deriving nutrients at the expense of its host, thus classifying it as a parasitic organism. 
• Cuckoo: Known for its brood parasitism, the cuckoo lays its eggs in the nests of other bird species, leading the host birds to care for the cuckoo's young. However, this form of parasitism is debated in biological classification.
• Cuscuta: This is a parasitic plant, commonly known as dodder, that derives its nutrients from other plants through specialized structures called haustoria.
• Ticks: Like mosquitoes, ticks are ectoparasites that feed on the blood of their hosts, including mammals, birds, and sometimes reptiles and amphibians.

Upon reviewing these options, the cuckoo is the organism that is not conventionally regarded as a parasite. While it exhibits brood parasitism, it does not directly extract nutrients from a host body as typical parasites do, such as mosquitoes, Cuscuta, or ticks. Hence, the correct answer is Cuckoo.

Answer 6

Let's evaluate each organism to see whether it is classified as a parasite:

(1) Mosquito: A mosquito is a parasite in the sense that it feeds on the blood of other organisms, typically causing harm to the host. Mosquitoes are considered ectoparasites.

(2) Cuckoo: The cuckoo is not classified as a true parasite. Cuckoos are brood parasites, meaning they lay their eggs in the nests of other birds, leaving the host birds to raise their young. While this behavior is parasitic, it's different from the typical parasitic relationship because the cuckoo doesn't directly feed off the host, but exploits the host’s parental care.

(3) Cuscuta: Cuscuta is a parasitic plant. It attaches itself to other plants and absorbs nutrients from them, making it a true parasite.

(4) Ticks: Ticks are ectoparasites that feed on the blood of mammals, birds, and sometimes reptiles, causing harm to their hosts.

Thus, the correct answer is (2) Cuckoo, as it is a brood parasite but not classified as a typical parasite like the others.

Answer 7

The question pertains to interspecific interactions within ecological communities, specifically focusing on interactions that affect the intrinsic rate of increase ('r') of a species. Let's explore the options: 

1. Parasitism: A relationship where one organism (the parasite) benefits at the expense of another organism (the host). The fitness of the host decreases, but this doesn't necessarily involve the intrinsic rate of increase being significantly lower due to direct competition.
2. Competition: Occurs when two species vie for the same resources in an ecosystem, such as food or light. This interaction typically results in a decrease in fitness for one or both species because of limited resources. Specifically, the intrinsic rate of increase ('r') of one species can be significantly lower when another competing species is present.
3. Predation: Involves one species (predator) feeding on another (prey). This dynamic does not pertain to the intrinsic rate of increase being affected directly through resource competition.
4. Commensalism: A relationship where one species benefits while the other is neither helped nor harmed. This scenario does not involve direct interaction that lowers the intrinsic rate of increase of any species.

Based on the descriptions, the correct answer is competition as it directly involves the reduction in the intrinsic rate of increase ('r') due to resource scarcity caused by another species.

Answer 8

The process described in the question refers to a situation where the fitness (specifically the intrinsic rate of increase (r)) of one species is significantly reduced due to the presence of another species. This is a classic case of competition.

(1) Parasitism: In parasitism, one species benefits at the expense of the other, but it doesn't directly refer to a reduction in fitness due to the presence of another species in the same way that competition does.

(2) Competition: Competition occurs when two species vie for the same limited resources (such as food, space, or mates). This results in a reduction in the fitness of one or both species because the available resources are shared, which lowers the reproductive rate or survival rate of the competing species. This is the correct answer.

(3) Predation: In predation, one species kills and eats another species, but this doesn’t directly reduce the fitness of the predator in the presence of its prey (it actually increases the predator's fitness).

(4) Commensalism: In commensalism, one species benefits, and the other is unaffected. There is no reduction in fitness for either species in this relationship.

Thus, the correct answer is (2) Competition, as it involves a scenario where the fitness of one species is reduced in the presence of another species.

Answer 9

The realistic growth model, often referred to as the logistic growth model, accounts for environmental resistance that affects population growth. This model is characterized by a sigmoid (S-shaped) growth curve. The key stages of this growth model include: 

• Initial exponential growth: Population expands rapidly when resources are abundant.
• Deceleration: Growth rate slows as resources become limited and competition increases, leading to environmental resistance.
• Stabilization: Population reaches carrying capacity, leveling off as birth rates equal death rates.

Characteristics	Growth Model
Initial Rapid Growth	Both Models
Resource Limitation	Logistic
S-Shaped Curve	Logistic
J-Shaped Curve	Exponential

The Verhulst-Pearl logistic growth is synonymous with the logistic growth model. It incorporates the concept of carrying capacity, reflecting the maximum population size that the environment can sustain indefinitely. In contrast, the J-shaped growth curve represents an exponential model where population growth continues unchecked in the absence of limiting factors, often leading to a sudden collapse once resources are depleted.

Therefore, the option that is not associated with the realistic growth model is the J-shaped growth curve.

Answer 10

Let's evaluate each option in relation to the realistic growth model:

(1) Sigmoid-shaped growth curve: This is associated with the logistic growth model. The sigmoid curve (S-shaped curve) shows the growth of a population that increases rapidly at first but then slows down as it approaches the carrying capacity of the environment. This is a characteristic of the realistic growth model, which considers limiting factors like resource availability.

(2) J-shaped growth curve: This is not associated with the realistic growth model. The J-shaped growth curve represents exponential growth, where the population grows rapidly without any constraints, continuing to increase exponentially. This type of growth is unrealistic in nature as it ignores environmental limits.

(3) Verhulst-Pearl logistic growth: This is a form of logistic growth and is associated with the realistic growth model. The Verhulst-Pearl model describes population growth with limitations, incorporating factors like carrying capacity and resource limitations.

(4) Logistic Growth: This is directly associated with the realistic growth model, as it describes a population growth that initially grows exponentially but slows down as it approaches the environment's carrying capacity.

Thus, the correct answer is (2) J-shaped growth curve, as it is associated with exponential growth and not the realistic growth model, which incorporates environmental constraints.