Processes and interactions within ecosystems

Ecosystems Overview

An ecosystem is a biological community of interacting organisms and their physical environment.
Ecosystems can vary in size from a small puddle to a large rainforest.
Ecosystems are made up of biotic (living) and abiotic (non-living) components.

Processes Within Ecosystems

Key processes within ecosystems include energy flow, nutrient cycling, and population dynamics.
Energy Flow: In an ecosystem, energy flows from the sun to producers (such as plants) via photosynthesis. This energy is then transferred through various trophic levels in the food chain from producers, to primary consumers, secondary consumers and finally decomposers.
Nutrient Cycling: Nutrients are cycled within ecosystems. This process begins when plants intake nutrients from soil, then animals eat these plants and gain nutrients. When these organisms die, decomposers break down their bodies, returning the nutrients to the soil.
Population Dynamics: Populations of organisms in an ecosystem can fluctuate due to a variety of factors, including availability of resources, predation and disease. The balance between birth rates and death rates determines the population size.

Interactions Within Ecosystems

Ecosystems are characterised by numerous interactions between different components, resulting in a balance or equilibrium.
Interactions can be predator-prey relationships, competition for resources, and symbiotic relationships, among others.
Predator-Prey Relationships: In most ecosystems, predators control the population size of their prey species and vice versa. This interaction causes population sizes to fluctuate in a cycle.
Competition: This occurs when two or more species vie for the same resource, which is in limited supply.
Symbiotic Relationships: These are close relationships between two different species, where at least one benefits. Examples include mutualism (both species benefit), commensalism (one species benefits and the other is not affected), and parasitism (one species benefits at the expense of the other).

Impact of Human Activities on Ecosystems

Human activities can dramatically influence ecosystems, leading to changes in components and processes.
Examples of such impacts include deforestation, urbanisation, pollution, and climate change.
These activities can lead to habitat loss, species extinction, alteration of nutrient cycles, and changes in energy flow among others.
Familiarity with these processes and interactions forms the basis for understanding of complex ecological concepts, conservation efforts, and the evaluation of human impacts on the environment.