Ecosystems and the Biosphere

 Ecosystems and the Biosphere

Photo from: https://www.ocean.org/blog/trophic-levels-part-1/

I. Introduction

An ecosystem is defined as a community of living organisms and their abiotic environment, with different types of ecosystems including freshwater, marine, and terrestrial. Ecology plays a crucial role in understanding how ecosystems function, including competition for resources, the influence of physical environment factors, and the dynamics of community interactions. Disturbances, both natural and human-induced, can impact ecosystems, and the concepts of resistance and resilience are important in evaluating ecosystem changes. Food chains and food webs illustrate the flow of energy and nutrients through ecosystems, with trophic levels and energy transfer being key components. Understanding these core concepts is crucial for comprehending the complexities of ecosystems and the need for conservation and sustainable management.

II. Ecology of Ecosystems

• Discussion of competition for limited resources among organisms within and between species
• Importance of resources such as food, water, sunlight, space, and mineral nutrients for energy and structure of organisms
• Role of physical environment factors such as climate, elevation, and geology in determining community dynamics
• Description of freshwater ecosystems as the least common but diverse systems comprising lakes, rivers, streams, and springs
• Overview of marine ecosystems as the most common, consisting of shallow ocean, deep ocean water, and deep ocean bottom ecosystems
• Introduction to terrestrial ecosystems grouped into biomes defined by dominant plant types in regions with similar climatic conditions

III. Ecosystems and Disturbance

• Explanation of disturbances as changes in the environment that affect ecosystem compositions, including natural processes and human activities
• Examples of natural disturbances such as forest fires and succession as a process of ecosystem restoration
• Mention of human impacts on ecosystems through agricultural practices, air pollution, deforestation, overfishing, and pollution
• Introduction to equilibrium as a dynamic state of ecosystems with resistance and resilience as parameters to measure ecosystem changes
• Importance of resistance and resilience in considering human impact on ecosystems and potential irreversible alterations

IV. Food Chains and Food Webs

• Definition of a food chain as a linear sequence of organisms through which nutrients and energy pass
• Description of trophic levels in a food chain, including producers, primary consumers, higher-level consumers, and decomposers
• Emphasis on photosynthetic organisms as the foundation of many food chains and primary consumers as herbivores
• Mention of carnivores as secondary and tertiary consumers, with apex consumers at the top of the food chain
• Explanation of energy loss at each trophic level and between trophic levels, limiting the number of steps in a food chain
• Implications of limited energy in a food chain for ecosystem dynamics and viability