Exercises: Components of an ecosystem

Classify the following elements of an ecosystem as biotic or abiotic: sunlight, an oak tree, air temperature, an earthworm, a rock, soil moisture, a mushroom, and wind.

Explain in your own words what an ecosystem is and name two biotic and two abiotic components of a pond.

A woodpecker lives in a pine forest, where it excavates its nest in tree trunks and feeds on insect larvae living under the bark. State its habitat and describe its ecological niche.

Look at the diagram: two species of birds, A and B, live in the same holm oak tree. Bird A feeds on acorns in the canopy, and bird B feeds on insects living on the trunk. Do they share a habitat? Do they share an ecological niche? Justify your answers based on the diagram.

In a desert, plants are spaced far apart from one another. Identify which abiotic factor you think limits their growth and explain how this factor influences other living things in the ecosystem.

An aquarium with fish, aquatic plants, a filter that oxygenates the water, and a lamp is a small artificial ecosystem. Identify its biotic and abiotic components and describe a relationship that occurs between them.

After clear-cutting a forest plot, it is recorded that the average soil temperature has increased by 7.5 °C and surface moisture has decreased by 40 % compared to the adjacent intact area. A technical report states that "these abiotic changes will only affect the felled trees, but not the rest of the living organisms in the soil". a) Refute the report's statement by explaining how the temperature change and desiccation directly affect decomposers (bacteria, fungi, and earthworms). b) Predict the cascading consequences that the loss of these decomposers will have on nutrient recycling and the forest's ability to regenerate naturally.

In a natural park, the Iberian lynx and the red fox coexist in the same Mediterranean scrubland environment. The lynx hunts almost exclusively live rabbits by stalking among dense vegetation, whereas the fox consumes small rodents, carrion, fallen fruit, and insects in both dense and open areas. a) Identify, with reasoning, the habitat of both species and compare their ecological niches, indicating which is a specialist and which is a generalist. b) If an epidemic reduces the rabbit population by 90 %, predict what will happen to the population of each species and justify which one is more likely to survive based on the breadth of its ecological niche.

In a school ground, there is a very shady area where plants grow poorly. Propose a simple experiment to find out whether the limiting factor is light or water, stating what you would keep constant and what you would measure.