Ecosystems: Basic Concepts CHAPTER 2 Environmental Studies, 2e

Chapter Objectives After studying this chapter, the reader should be able to: Explain what is meant by an ecosystem and define terms like species, population, and community Describe the major components of an ecosystem, the biotic community, and the abiotic conditions Appreciate the edge effect that comes into play in the transitional zone between ecosystems. Understand the meaning and role of producers, consumers, and decomposers in an ecosystem

Chapter Objectives (Contd) Trace the flow of matter and energy in ecosystems and explain concepts like food chains, trophic levels, and ecological pyramid Explain the concepts of ecological succession, habitat, and ecological niche Describe the water and carbon cycles Appreciate the importance of the Sun as the sustainer of all life. List the services provided by ecosystems and appreciate the economic value of such services.

The Story of the Himalayas The Himalayan range: Source of the great rivers Sustains 50 million people Immense biodiversity The destruction: Forests being cleared; quarries, roads Soil erosion, landslides, floods Glaciers melting

Ecosystem A community of living organisms interacting with one another and with its non-living physical and chemical environment. The interactions perpetuate the community and retain stability under varying conditions.

Biosphere: Terms Atmosphere Troposphere Hydrosphere Lithosphere

Ecosystem components Living component, called the biotic community (or biota) Non-living components called abiotic conditions.

Energy Energy can neither be created, nor destroyed. It can only be transformed from one form to another During transformation, a part of the energy is lost. Ecological pyramid

Ecosystem Emergence Ecological succession Climax ecosystem Habitat Ecological niche

Biogeochemical Cycles Matter cycles through the earth and the atmosphere. These natural cycles provide what is needed by ecosystems. water cycle carbon cycle oxygen cycle nitrogen cycle phosphorus cycle

Ecosystem Services Provisioning services: Genetic resources, wood, food, and fresh water, etc Regulating services: Regulation of climate, water purification, flood control, control of human diseases, etc. Cultural services: Education, recreation and experiencing the beauty of nature. Supporting services: Biomass production, production of atmospheric oxygen, and soil formation.

Food Chains And Food Webs

Photosynthesis

Trophic Levels

Keywords & Phrases of Chap.2 abiotic conditions aquatic life zone biogeochemical cycle biome biosphere biota carbon cycle community consumer decomposers ecological niche ecological pyramid ecological succession ecosystem ecosystem service ecotone

Keywords & Phrases of Chap.2 (Contd) edge effect energy flow food chain food web habitat photosynthesis population producer pyramid of biomass pyramid of energy species trophic level water cycle

Key Points of Chap. 2 Ecosystems represent complex interactions among organisms. Energy can neither be created, nor destroyed. When we transform energy from one form to another, some of it is lost. Organisms have roles like producers, consumers, and decomposers in the food chain; they maintain the flows of matter and energy.

Key points of Chap.2 (Contd) An ecosystem always moves towards a state of dynamic balance. Every species has its ecological niche in an ecosystem. Water and carbon are continuously cycled in the biosphere. Ecosystems provide invaluable services.

Ecosystem Natural Aquatic Marine Coastal Open ocean Deep sea Freshwater Lentic Lotic Terrestrial Forest Desert Grasslands Wetlands Manmade Rural Urban Agro Space