Introduction
An ecosystem is a community of living organisms that interact with nonliving elements in the same environment. Biotic and abiotic components of an ecosystem are interconnected through nutrient cycles and energy exchange. Studying and describing ecosystem processes helps to identify the most important species and expose underlying mechanisms. This essay will emphasize the significance of biodiversity and examine three different ecosystems. The characteristics of living and nonliving things will also be compared and contrasted.
Living and Nonliving Things
From a biological standpoint, all living things display seven characteristics: movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition (Starr, Taggart, & Evers, 2018). To clarify how these characteristics exactly apply to living organisms, a reference to an earthworm will be given. Earthworms contract circular and longitudinal muscles to move through the soil (movement) and escape the environment that poses a threat to their lives with the help of chemical-sensitive skin cells (sensitivity). This species feeds on manure, compost, fungi, and microorganisms (nutrition) and gets rid of the waste through the last body segment once everything is digested (excretion). The food supplies an earthworm’s body with energy-rich nutrients (respiration) and allows for a gradual growth up to one meter in length (growth). Earthworms are hermaphrodites but still have to mate to lay eggs (reproduction). Nonliving things might possess one or two of these characteristics but never display all of them.
Types of Ecosystems
Three notions are instrumental in understanding ecosystems: habitat, population, and community. Habitat is the living environment; the population is all the living organisms within a habitat, and community is the organisms that interact with each other (Starr et al., 2018). The descriptions of the three ecosystems below will focus on describing the habitat and the community. There are many more ecosystems in the world; however, those three were chosen for their striking differences.
Forest ecosystems. A forest is a terrestrial environment dominated by closely spaced trees that grow in a canopy. The members of each forest ecosystem community depend on each other for survival and can be assigned the following roles: producers, primary, secondary, and tertiary consumers, and decomposers. In a forest, producers are plants that can convert solar energy through photosynthesis. They usually grow in four levels (emergent, canopy, understory, and floor) with each level characterized by its access to sunlight. Primary consumers are herbivores and beasts of prey, for instance, for in the Amazon, it could be capybara and red howler monkey. Secondary and tertiary consumers feed on primary consumers and are typical carnivores. For instance, jaguars both prey on the primary (plant-eating birds) and secondary consumers (meat-eating caimans). Lastly, decomposers help dead plants and animals break down, returning the nutrients to the soil and letting plants, the producers, grow and prosper.
Desert ecosystems. Desert ecosystems are somewhat unique since the unusually dry climate made plants and animals evolve to survive in such harsh conditions. The defining factor that impacts relationships between all members and components is the limited amount of rainfall. The plant life is not as luscious as in a forest, but it exists. Such common desert plants as gourds, cacti, and dates store water, which helps primary consumers quench their thirst. Camel is a prime example of a primary consumer, feeding on grasses and low-growing shrubs. Secondary and tertiary consumers are foxes, hawks, snakes, owls, and roadrunners. Large decomposers typically prefer moist areas, so in a desert, this role is primarily played by bacteria.
Marine ecosystems. The marine ecosystem is an aquatic environment with high salt contents. Out of all the types of ecosystems on Earth, marine ecosystems are prevailing. As of now, scientists distinguish between six subtypes of marine ecosystems:
- Open marine ecosystems (open ocean and its upper layer);
- Ocean floor ecosystems;
- Coral reef ecosystems;
- Estuary (sheltered area of a river mouth);
- Saltwater wetland estuary (transition area between land and sea);
- Mangroves (saltwater swamps).
The unity and diversity of an ecosystem will further be explained using the example of coral reef ecosystems. These ecosystems are not homogenous: for instance, the Great Barrier Reef includes as many as fourteen subtypes, so the following statements are generalizations. Producers include zooxanthellae, seaweed, coralline algae, marine worms, algae, plankton, and sponges. Zooplankton, mollusks, starfish, and smaller fish are primary consumers while larger reef fishes such as parrotfish and surgeonfish are secondary consumers. Large organisms such as reef sharks feed on secondary consumers. Fan worms, snails, bristle worms, and bacteria decompose dead bodies to enrich the ocean soil with nutrients.
Conclusion
Ecosystems are interconnected communities within a particular habitat that include both living (growing, reproducing, digesting, excreting, and so on) and nonliving things. Each community is characterized by environmental factors such as climate and food chains consisting of producers, consumers, and decomposers. Regardless of the type, producers are typically plants, consumers are those feeding on plants and herbivore animals, and decomposers are organisms breaking down dead bodies.
Reference
Starr, C., Taggart, R., & Evers, C. (2018). Biology: The unity and diversity of life (15th ed.). Boston, MA: Cengage Learning.