U8-LESSON 2.pdf

Introduction to Biology Part III. Ecology Nguyen Thi Kim Dung Department of Ecology and Evolutionary Biology Email: [email protected]  CHAPTER 3 ECOSYSTEM AND FUNCTIONAL PROCESSES CONTENT OF CHAPTER 3 1. The concept of ecosystem 2. Components and structure of...

Introduction to Biology Part III. Ecology Nguyen Thi Kim Dung Department of Ecology and Evolutionary Biology Email: [email protected]  CHAPTER 3 ECOSYSTEM AND FUNCTIONAL PROCESSES CONTENT OF CHAPTER 3 1. The concept of ecosystem 2. Components and structure of ecosystems 3. Some examples of simple ecosystems 4. Functional processes of an ecosystem 1) Processes of production and decomposition 2) Food chains and food webs 5. The balance of ecosystems 1. Concept of ecosystems System perspectives Coexistence: Dependency - interaction Ecological system A unit of nature Definition A collection of organisms (of the same and different species) An area with relatively specific environmental factors Interactions between individuals, groups and environmental factors (energy and matter exchange) 1. Concept of ecosystems Some remarks related to an ecosystem A system that is almost self-contained Exchanging material within is essential The most obvious cases: Islands Lake Farm 2. Components and structure of ecosystems Abiotic components Physical factors: climate, land, terrain, water flow, etc. Inorganic factors: gases, liquids, minerals Organic factors: vitamins, lipids, glucose, protein, etc. Biotic components Producers: determine the existence and diversity of ecosystems Consumers: determine biodiversity, diversify physical processes and biological interactions, and maintain ecological balance. Primary consumers: herbivores Secondary consumers: carnivores Tertiary consumers: omnivores Decomposers: determine the existence of ecosystems Hệ sinh thái là gì? Vai trò của hệ sinh thái rừng trong môi trường thiên nhiên - KHBVPTR 3. Some examples of simple ecosystems  4. Functional processes of an ecosystem Ecosystem functions A subset of ecological processes and ecosystem structures The result of complex interactions between biotic (living organisms) and abiotic (chemical and physical) components of ecosystems through the universal driving forces of matter and energy Production processes Green leaves prepare food and roots absorb nutrients from the soil Herbivores feed on part of the plant production and in turn serve as food for carnivores The role of the production process: to produce biological productivity to impact on changing environmental conditions 4. Functional processes of an ecosystem Decomposition processes Non-bio mechanism forest fire Bio mechanism Thanks to saprophytes and organisms that eat waste Perform continuously and evenly across the biosphere Bacteria Fungi Small animals: protozoa, termites, nematodes, mollusks  Food chains and Food webs Food chains Flow of energy in an ecosystem is one way process The sequence of organisms through which the energy flows is regarded as a food chain Each organism obtains energy from the one at the level below Producers: plants Consumers: animals Primary consumers Secondary consumers Tertiary consumers Quaternary consumers Decomposers Food chains and Food webs Food webs A diagram showing how food chains are linked together into more complex feeding relationships A representative of actual feeding pathways within an ecosystem: Organisms can have more than one food source Organisms can have more than one predator Food chains and Food webs Significance of food chains and food webs To express the nutritional structure of the ecosystem To represent the diversity of the ecosystem To be the mechanism and conditions for controlling the balance of the ecosystem Relevant ecological issues: Sensitive/vulnerable ecosystems Bioaccumulation: the amplification of pollutants (heavy metals Pb, Hg, radioactive substances, agrochemicals DDT, 2,4 D, etc.) Bioaccumulation, bioconcentration et bioamplification des éléments trace métalliques par les organismes en mer (van der Hoop J., 2013) Review of micro- and nano-plastic contamination in the food chain https://doi.org/10.1080/19440049.2019.1583381 BIOGEOCHEMICAL CYCLE (within ecosystems) BIOGEOCHEMICAL CYCLE (within ecosystems) CIRCULAR ECONOMY  ENERGY FLOW (through ecosystems) Energy flow is the amount of energy that moves through a food chain. The energy input, or energy that enters the ecosystem, is measured in Joules or calories. Accordingly, the energy flow is also called calorific flow. Lindeman (1942) energy flow model (lake ecosystem) (Unit: gcal/cm2/yr) https://slidetodoc.com/trophic-levels-energy- https://botanycentral.blogspot.com/p/lindeman-single-channel-energy-flow.html transfer-and-pyramids-trophic-levels/  ECOLOGICAL PYRAMIDS What is ecological pyramid? It represents graphically the tropic structure of ecosystem Every tropic level is a feeding position in a food chain such as primary producer, herbivore, carnivore, etc. Types of ecological pyramids Number Biomass Energy Ecological Pyramids from: http://www.dr-evans.com/advancedbiology/ecological_pyramids.html 5. The balance of ecosystems System perspective: a unified whole Open and interconnected system Multi-dimensional interaction Synthetic perspective Multiple levels with different ratios Mechanisms that balancing ecosystems Individual level Self-sustaining responses Population level Biological interactions maintaining density Community level Ecological relationship between species through interactions Ecosystem level Adjustment of functional processes: production and decomposition processes SUMMARY An ecosystem consists of a community of organisms together with their physical environment. Ecosystems can be of different sizes and can be marine, aquatic, or terrestrial. Broad categories of terrestrial ecosystems are called biomes. In ecosystems, both matter and energy are conserved. Energy flows through the system—usually from light to heat—while matter is recycled. Ecosystems with higher biodiversity tend to be more stable with greater resistance and resilience in the face of disturbances, disruptive events