Ecology Quiz: Ecosystems, Biomes, and Biodiversity

An ecosystem encompasses the dynamic interactions between living organisms, such as plants, animals, and microorganisms, and their physical surroundings, including air, water, and soil. This interconnectedness allows for energy flow and nutrient cycling, which are essential for sustaining life. Ecosystems can vary in size and complexity, but they all rely on these interactions to maintain balance and support biodiversity, making them vital for the health of the planet.

Plants are considered a biotic factor in an ecosystem because they are living organisms that interact with other living components, such as animals, fungi, and microorganisms. They play crucial roles in energy flow and nutrient cycling, providing food and habitat for various species. In contrast, soil composition, temperature, and water are abiotic factors, as they are non-living elements that influence the environment but do not possess life. Thus, among the options provided, plants exemplify the living aspects of an ecosystem.

Forests are ecosystems dominated by a high density of trees, which create a complex habitat supporting diverse flora and fauna. The dense canopy formed by the tree cover allows for a unique microclimate, fostering various understory plants and animal species. In contrast, grasslands, deserts, and tundras have lower tree densities and different environmental conditions that do not support such a high concentration of trees. Thus, forests are specifically defined by their abundant tree growth, making them distinct from other ecosystem types.

Tundra is characterized by its cold climate and unique ecosystem, where permafrost—a permanently frozen layer of soil—exists just below the surface. This biome experiences limited vegetation, primarily consisting of mosses, lichens, and low shrubs, due to the harsh conditions and short growing seasons. The presence of permafrost affects drainage and nutrient availability, influencing the types of organisms that can thrive there. In contrast, other biomes listed, such as taiga and temperate deciduous forests, do not have permafrost and have different climatic and ecological characteristics.

Habitat destruction is the leading cause of biodiversity loss as it directly eliminates the natural environments where species live, reproduce, and thrive. Activities such as deforestation, urbanization, and agriculture alter or completely remove ecosystems, making it difficult for many species to survive. This loss of habitat not only reduces the number of species but also disrupts ecological balance, leading to further declines in biodiversity. While climate change, pollution, and invasive species also contribute to biodiversity loss, habitat destruction is the foundational issue that exacerbates these other threats.

Bees pollinating flowers exemplifies mutualism because both species benefit from the interaction. Bees obtain nectar and pollen from flowers for food, while flowers receive assistance in reproduction as bees transfer pollen from one bloom to another, facilitating fertilization. This symbiotic relationship enhances the survival and reproductive success of both bees and flowering plants, illustrating the mutual benefits characteristic of mutualism.

Net primary productivity (NPP) refers to the amount of energy that remains after primary producers, such as plants, have used some of the energy they capture through photosynthesis for their own metabolic processes, including respiration. This remaining energy is available for consumption by herbivores and other consumers in the ecosystem. NPP is a crucial measure as it indicates the energy that supports the entire food web, highlighting the efficiency of energy transfer from producers to consumers.

Ecosystem services are benefits humans derive from nature, categorized into provisioning (resources like food and water), regulating (climate and disease control), and cultural (recreational and spiritual benefits). Industrial services, however, do not fit within these categories as they pertain more to human-made processes and economic activities rather than direct benefits from natural ecosystems. Thus, industrial services do not represent a type of ecosystem service.