Community Ecology Quiz: How Much You Know?

The given diagram represents a mutualistic relationship. In mutualism, both organisms involved benefit from the relationship. The "+" signs indicate that both organisms are benefiting from the interaction. Therefore, the correct answer is "+ +".

The relationship between a flower and the insect that feeds on its nectar is an example of mutualism because both the flower and the insect benefit from the relationship. The flower provides the insect with food (nectar), which is a source of energy for the insect. In return, the insect pollinates the flower by transferring pollen from one flower to another, aiding in the reproduction of the flower. This mutual exchange of resources and services between the flower and the insect demonstrates mutualism.

Omnivores are organisms that have the ability to consume both producers (plants) and consumers (animals). This means that they can obtain nutrients from both plant-based sources and other animals. Therefore, the statement "Omnivores consume producers and consumers" is true.

Producers are always autotrophic because they have the ability to produce their own food through photosynthesis or chemosynthesis. They do not rely on consuming other organisms for energy, but instead convert sunlight or inorganic compounds into organic molecules. This allows them to sustain themselves and provide energy for other organisms in the food chain. Therefore, the statement "Producers are always autotrophic" is true.

Primary consumers are called herbivores because they are the first level of the food chain and primarily feed on plants. They obtain their energy by consuming plant material, such as leaves, fruits, and seeds. This distinguishes them from secondary and tertiary consumers, which are carnivores and omnivores that feed on other animals. Herbivores play a crucial role in transferring energy from plants to higher trophic levels, making them an essential part of ecosystems. Therefore, it is true that primary consumers are called herbivores.

In a typical food chain, only about 10% of the energy is passed on to the next trophic level. This is due to the inefficiency of energy transfer between trophic levels. As organisms consume food, they use a significant amount of energy for their own metabolic processes, such as respiration and movement. Additionally, energy is lost as heat during these processes. Therefore, only a small fraction of the energy from one trophic level is available for consumption by the next level, resulting in an approximate 10% transfer of energy.

A keystone species is a species that plays a crucial role in maintaining the structure and functioning of an ecosystem. They have a disproportionately large impact on their environment compared to their abundance. Removing a keystone species can cause a significant disruption to the entire ecosystem, as their absence can lead to cascading effects and the decline of other species. Therefore, a keystone species is essential for the overall health and stability of an ecosystem.

This is an example of primary succession. Primary succession occurs in an area where there is no existing soil or organic matter, such as on exposed rock. The process starts with pioneer species like lichens and mosses, which gradually break down the rock and create a thin layer of soil. This allows for the establishment of small herbs and shrubs, which in turn create more soil and provide conditions for the growth of black spruce. Eventually, white spruce can also establish in the area. This sequence of vegetation colonization starting from bare rock is characteristic of primary succession.

The given statement is false because large organisms like eagles, lions, or salmon are actually secondary consumers, not primary consumers. Primary consumers are typically herbivores that feed on plants or other primary producers, while secondary consumers are carnivores that feed on other consumers. In this case, the small organisms like mice, rabbits, and sparrows would be considered primary consumers as they feed on plants or insects.

The FIRST trophic level refers to all producers. Producers, such as plants and algae, are the organisms that convert sunlight into energy through photosynthesis. They are the primary source of food and energy in an ecosystem, forming the base of the food chain. This trophic level includes all autotrophic organisms that produce their own food and do not rely on consuming other organisms.

The given pattern represents a predator-prey relationship. The "+ -" represents a predator (+) and its prey (-). The "- -" represents two prey species interacting. The "- o" represents a predator (-) and its parasite (o). The "+ o" represents a predator (+) and a parasite (o). This pattern suggests that both predation and parasitism are present in the ecosystem.

Occasional disturbances from natural forces such as fire are beneficial for many ecosystems. Fires can help to clear out dead vegetation, allowing new growth to occur. They can also help to control the population of certain plants and animals, preventing them from becoming too dominant. In addition, fires can help to recycle nutrients in the soil, promoting overall ecosystem health. Therefore, it is true that occasional disturbances from natural forces like fire are good for many ecosystems.

Consumers are organisms that obtain energy by consuming other organisms. They cannot produce their own food and rely on consuming other organisms for their energy needs. This makes them heterotrophic, as they depend on external sources for their nutrition. Therefore, the statement "Consumers are always heterotrophic" is true.

The given pattern represents a symbiotic relationship known as commensalism. In commensalism, one organism benefits (+) while the other is neither harmed nor benefited (o). The first and fifth rows indicate that one organism benefits (+) while the other is unaffected (o). The second and fourth rows show that both organisms are negatively affected (- -). Therefore, the correct answer is + o, representing commensalism.

The statement "energy decreases at higher trophic levels" describes the movement of energy in food chains. This is because as energy is transferred from one trophic level to another, some of it is lost as heat or used for metabolic processes, resulting in a decrease in the amount of energy available at higher trophic levels.

The trophic level that has the greatest biomass is the producer. Producers, such as plants and algae, are able to convert sunlight into energy through photosynthesis. This allows them to create organic matter and store energy, resulting in a large biomass. Secondary and third order consumers, as well as primary consumers, rely on consuming other organisms for energy and do not have the ability to create their own energy. Therefore, their biomass is typically lower than that of producers.

Chemosynthesis is the process that bacteria in hydrothermal vents perform, which is not performed by other organisms in most ecosystems. Chemosynthesis is a type of metabolism that allows bacteria to convert inorganic compounds, such as hydrogen sulfide or methane, into organic molecules. This process provides energy for the bacteria to survive and thrive in the extreme conditions of hydrothermal vents, where sunlight is not available for photosynthesis. Cellular respiration and photosynthesis, on the other hand, are processes performed by various organisms in different ecosystems.

An ecologist might be able to study primary succession in all of the given locations. Primary succession refers to the process of colonization and establishment of life in an area that was previously devoid of any life. In the case of a new island formed by a volcanic eruption, the ecologist can observe the gradual colonization of the barren land by pioneer species. In a gravel-filled valley that had been covered by a glacier until recently, the ecologist can study the colonization of plants and animals as the ice retreats. Similarly, on a huge boulder or rock layer on top of a mountain, the ecologist can observe the establishment of life forms.

Different species can share the same habitat, but competition among them is reduced if they occupy different niches. Niches refer to the specific roles and resources that each species utilizes within their environment. When species occupy different niches, they have access to different food sources or utilize different parts of the habitat, thereby reducing competition for limited resources. This allows multiple species to coexist in the same habitat without directly competing with each other.

Ecological succession refers to the process of change in the species composition of an ecosystem over time. In a temperate deciduous forest, the typical example of ecological succession starts with bare soil, which is colonized by pioneer species such as weeds and grasses. As the ecosystem develops, shrubs, conifers, and finally deciduous trees become dominant. This sequence represents the gradual progression of species in a temperate deciduous forest during ecological succession.

Trophic levels refer to the different positions in a food chain or food web, such as producers, primary consumers, secondary consumers, and so on. Despite the diversity of ecosystems, they all follow a similar pattern of energy flow and organization, with producers at the bottom and higher-level consumers at the top. This is because energy is transferred from one trophic level to another as organisms consume each other. Therefore, the statement that all ecosystems have similar trophic levels is true.

The given pattern represents a competition between two teams, with "+" representing a win and "-" representing a loss. The first team wins the first match, loses the second match, and wins the third match. The second team loses all three matches. Therefore, the correct answer is "- -", indicating that the second team lost both matches.

Lichens and mosses are considered pioneer organisms because they are the first to colonize and grow on exposed rock surfaces. They are able to survive in harsh conditions and can tolerate extreme temperatures and lack of soil. As they grow and decompose, they contribute to the formation of organic matter and soil, creating a more suitable environment for the growth of small herbs and shrubs. Eventually, this process leads to the establishment of larger plants like black spruce and white spruce.

Secondary succession is the correct answer because it refers to the process of ecological succession that occurs in an area that has previously been colonized by plants and other organisms but has undergone a disturbance that has removed most of the vegetation. In the case of abandoned farmland, when it is no longer actively managed or cultivated, the land is left to its natural processes, and over time, it will undergo secondary succession where new plant species gradually colonize the area and the ecosystem transitions back to a forested state.

Cellular respiration is the correct answer because it is the chemical process by which glucose and other organic molecules are broken down to release energy. This process occurs in the cells of living organisms and involves the conversion of glucose and oxygen into carbon dioxide, water, and ATP (adenosine triphosphate), which is the energy currency of the cell. Chemosynthesis is a different process in which organisms use chemical energy to produce carbohydrates, while digestion is the breakdown of food in the digestive system. Cell metabolism refers to all the chemical reactions that occur in a cell, including cellular respiration. Photosynthesis is the process by which plants use sunlight to convert carbon dioxide and water into glucose and oxygen.

The correct answer is exposed rock; white spruce. In ecological succession, a pioneer species is the first to colonize a barren area with no soil. Exposed rock is the initial stage of succession, where lichens and mosses can grow. These organisms break down the rock and create a thin layer of soil, allowing small herbs and shrubs to establish. Eventually, black spruce can grow in the area. Finally, white spruce is considered part of the climax community, which is the stable and mature community of organisms in the area.

A species may become invasive if limiting factors are absent from the environment. Limiting factors are factors that restrict the growth, abundance, or distribution of a population within an ecosystem. These factors can include availability of resources, competition, predation, and disease. When these factors are absent or reduced, a species can experience unrestricted growth and expansion, leading to invasive behavior.

During photosynthesis, carbon dioxide molecules are converted into glucose molecules. This process involves capturing the carbon atoms from carbon dioxide and incorporating them into the structure of glucose. Glucose is a sugar molecule that serves as a source of energy for plants and other organisms. Therefore, the correct answer is that the carbon atoms are incorporated into glucose molecules.

This statement is false because not all ecosystems use sunlight as their primary source of energy. While many ecosystems, such as forests and grasslands, rely on photosynthesis to convert sunlight into energy, there are also ecosystems in deep ocean areas where sunlight does not reach. In these ecosystems, organisms rely on chemosynthesis, using chemical energy from sources like hydrothermal vents, as their primary source of energy. Therefore, it is incorrect to say that all ecosystems use sunlight as their primary source of energy.

Succession refers to the gradual and predictable changes in a community over time. It occurs because immigrating species, which are species that move into a particular area, can outcompete or disrupt the existing species in that environment. This can happen through competition for resources, predation, or other interactions. As a result, the environment becomes less suitable for the species that were originally there, leading to a shift in the composition and structure of the community.