Concept of the Ecosystem 2023/2024 PDF

USMANU DANFODIYO UNIVERSITY, SOKOTO COLLEGE OF HEALTH SCIENCES FACULTY OF CLINICAL SCIENCES DEPARTMENT OF COMMUNITH HEALTH MBBS PROGRAMME UG II 2023/2024 SESSION Concept of the Ecosystem By Prof. A.U Ka’oje ...

USMANU DANFODIYO UNIVERSITY, SOKOTO COLLEGE OF HEALTH SCIENCES FACULTY OF CLINICAL SCIENCES DEPARTMENT OF COMMUNITH HEALTH MBBS PROGRAMME UG II 2023/2024 SESSION Concept of the Ecosystem By Prof. A.U Ka’oje  Outline Introduction/definition of terms Ecosystem and its fundamental characteristics Important ecological concepts Food chain, ecological pyramid, food web  Lecture Expectation At the end of the lecture students are expected to have: Basic understanding of the ecosystem and; Know different forms of ecosystem; Describe Food chain  Introduction System = regularly interacting and interdependent components forming a unified whole The term `eco' refers to a part of the world. Ecology is the study of how organisms interact with one another and with their physical environment of matter and energy Ecological niche is the combination of function and habitat of each of the approximately 1.5 million species of animals and 0.5 million species of plants on Earth.  Ecologists Study Connections in Nature Ecology Levels of organization Population Genetic diversity Community Ecosystem Biosphere  Biosphere Parts of the earth's air, water, and soil where life is found A community of different species Ecosystem interacting with one another and with their Ecology nonliving environment of matter and energy focuses Populations of different species living in a Community on the particular place, and potentially interacting with top 5 of each other these Population A group of individuals of the same species levelss living in a particular place Organism An individual living being The fundamental structural and functional Cell unit of life Molecule Chemical combination of two or more atoms of the same or different elements Fig: Shows the Levels of Organization of Matter in Smallest unit of a chemical element that Nature Atom exhibits its chemical properties  Life is sustained by the flow of energy from the sun through the biosphere, the cycling of Mesosphere, thermosphere and nutrients within the biosphere, and gravity. exosphere are non-life supporting system The Earth’s Life-Support System Has Four Major Components are: Hydrosphere Geosphere Atmosphere Biosphere Troposphere: lowest atmospheric layer; 4-11 miles high (depending on Latitude Stratosphere: ozone layer  Vegetation Atmosphere and animals Biosphere Soil General structure of the Rock Crust earth showing that it Lithosphere consists of a land sphere, Mantle air sphere, water sphere, and life sphere Biosphere (living organisms) Atmosphere (air) Core Mantle Crust (soil and rock) Geosphere Hydrosphere (crust, mantle, core) (water)  What is an Ecosystem? The concept was proposed by the British ecologist A.G. Tansley in 1935, to describe the interaction of living things and their non-living surroundings, with which they interact. He defined ecosystem as 'a particular category of physical systems, consisting of organisms and inorganic components in a relatively stable equilibrium, open and of various sizes and kinds. An Ecosystem is a community of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment interacting as a system/ functional unit.  Life on earth is sustained by ecosystem, which vary greatly, but certain attributes in common Sustained by interactions of many organisms functioning together, interacting through their physical and chemical environments Humans are integral part of ecosystems Human population depends on many ecosystems that are widely dispersed around the globe Simplest entity that can sustain life Consist of several species and a fluid medium (air, water or both) It sustains two processes: the cycling of chemical elements and the flow of energy. An ecosystem is formed by the interactions between all living (biotic) and non-living things (abiotic). Both are linked together through nutrient cycles and energy flows.  All of the living parts of the forest community depended upon the non-living parts of the ecosystem for their survival: water, soil, air and light that provides energy for photosynthesis. An ecosystem is an ecological community, along with its nonliving environment, functioning as a unit. Ecological community is the living part of an ecosystem, which is a set of species connected by food webs and tropic levels. A food chain or web is a diagram showing who feeds on whom. A trophic level consists of all organisms that are at the same number of feeding steps/levels away from the original/initial source of energy. In many ecosystem, the original source of energy is the sun.  FORMS OF ECOSYSTEM MAN-MADE ECOSYSTEM ecosystem with the influence of Varies in size; can be as small as an oasis in a desert, man, this is usually controlled or big as an ocean, spanning thousands of miles. ex. fishpond, zoo) Natural vs. Man-made/artificial Terrestrial vs. Aquatic Ecosystem NATURAL ECOSYSTEM – ecosystem made naturally & occurred naturally with no influence by man ex. forest, backyard  Terrestrial Ecosystem are exclusively land-based ecosystems. different types distributed around various geological zones E.g, Forest ecosystem, Grassland Ecosystem, Tundra Ecosystem, Desert Ecosystem Aquatic Ecosystem: Are ecosystems present in a body of water. further divided into two types, namely: Freshwater Ecosystem: includes lakes, ponds, rivers, streams and wetlands. Marine Ecosystem: seas and oceans; more substantial salt content and greater biodiversity in comparison to the freshwater ecosystem.  Fundamental Characteristics of Ecosystems Structure: Living (biotic) Nonliving (abiotic) Process: Energy flow Cycling of matter (chemicals) Changes over time: Dynamic (not static) undergo development through a process called Succession, etc. Main structural component of Ecosystem  Precipitation Oxygen (O2) Carbon dioxide (CO2) Animation showing Producer major living (biotic) and Secondary nonliving consumer (fox) (abiotic) Primary components consumer (rabbit) of an ecosystem in a field Producers Water Decomposers Soluble mineral nutrients  Range of Tolerance for a Population of Organisms Limiting factor principle: Too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimal range of tolerance  Structure of Ecosystem can be split into two main components: Biotic Components Abiotic Components The biotic and abiotic components are interrelated in an ecosystem. It is an open system where the energy and components can flow throughout the boundaries.  Biotic components Environment is very much influenced by biotic factors which include all forms of life like plants, animals, microorganisms etc. The biotic components of an ecosystem can be classified according to their nutrition/mode of energy acquisition. Autotrophs: Organisms that produce their own food from an energy source, such as the sun, and inorganic compounds; largely the green plants Heterotrophs: Organisms that consume other organisms as a food source. Primary consumers, Secondary consumers (can either be carnivores or omnivores), Tertiary consumers (carnivores or omnivores), and Quaternary consumers are present in some food chains. Tprey on tertiary consumers for energy; usually at the top of a food chain as they have no natural predators. Saprotrophs (or decomposers)  Abiotic components Abiotic: are non-living component of ecosystem; are of three categories Climatic and physical factors -air, water, soil and sunlight; rainfall, temperature, humidity, soil texture and geomorphic conditions. Inorganic substances- various nutrient elements and compounds, such as carbon, nitrogen, sulfur, phosphorous, carbon-di-oxide, water, etc. These are involved in the cycling of materials in the ecosystems. Organic compounds- These are proteins, carbohydrates, lipids, humic substances, etc. largely form the living body and link the abiotic compounds with the biotic factors.  Temperature: all living things have a range of Abiotic factors determine the type temperatures in which they can survive of organisms that can successfully live in a particular area. beyond those limits it will be difficult for them to live. Some major non-living factors are: Oxygen Sunlight: many living things require oxygen; necessary for photosynthesis; necessary for cellular respiration, a process it influences organisms and their used to obtain energy from food; environment; Though, certain bacteria are actually killed it has a profound effect on the by the presence of oxygen growth and development of life. Soil Water the type of soil, pH, amount of water it all living things require water for holds, available nutrients, etc determine their survival, what type of organism can successfully live in or on the soil  Functional component/unit Productivity – It refers to the rate of biomass production. Energy flow – It is the sequential process through which energy flows from one trophic level to another. Energy captured from the sun flows from producers to consumers and then to decomposers and finally back to the environment. Decomposition – It is the process of breakdown of dead organic material. The top-soil is the major site for decomposition. Nutrient cycling – In an ecosystem nutrients are consumed and recycled back in various forms for the utilisation by various organisms.  Functions of Ecosystem Regulates the essential ecological processes, supports life systems and renders stability. Responsible for the cycling of nutrients between biotic and abiotic components. Maintains a balance among the various trophic levels in the ecosystem. Cycles the minerals through the biosphere. The abiotic components help in the synthesis of organic components that involve the exchange of energy.  Ecosystem Dynamics Hydrologic cycle Ecosystem is always in a dynamic (changes frequently) instead of a is the movement of water from the static balance atmosphere to Earth and back into the atmosphere. changes in one part of the ecosystem cause changes in Carbon cycle another begins with the fixation of atmospheric CO2 by means of photosynthesis performed by plants Several of the cycles that are and certain algae. important and that may be affected by humans include the Nitrogen cycle Phosphorous cycle, and Energy flow.  Energy flow in an Ecosytem Energy flows through ecosystems in food chains and webs. As energy flows, the amount of chemical energy available to organisms at each succeeding feeding level decreases. Arrows show how chemical energy in nutrients flows through various trophic levels in energy transfers; most of the energy is degraded to heat, in accordance with the second law of thermodynamics  Important Ecologic concepts Food Chain Is one way individuals in a community interact is by feeding on one another. Food chain: linkage of who feeds on whom; Sun is the ultimate source of energy on earth; It provides the energy required for all plant life. energy, chemical elements and some compounds are transferred from creature to creature flow of energy from a producer consumer eventually, to an apex predator. Decaying matter, along with organic debris, is broken down into its constituents by scavengers.  Trophic Levels A trophic level is the position occupied by an organism in a food chain. Producers: first level; at the base Consumers: Primary consumers make up the second trophic level. Secondary consumers make up the third trophic level. Finally tertiary consumers make up the top trophic level. Decomposers: Cause decomposition and return various important minerals for the running of the biogeochemical cycles.  2. Ecological Pyramid Pyramid of numbers, Eltonian pyramid Charles Elton (1927), first ecologist to describe the ecological pyramid. is the graphical representation of the number, energy, and biomass of the successive trophic levels of an ecosystem. In most food chains, the number of individuals Is this pyramid stable? decreases at each stage, huge numbers of tiny individuals at the base and a few large individuals at the top, as displayed by millions of plakton, a moderate number of large fish, and a few eagles.  3. Food Web a network of interconnected food chains.. It comprises all the food chains within a single ecosystem. It helps in understanding that plants lay the foundation of all the food chains. In a marine environment, phytoplankton forms the primary producer.  Environment The term environment is derived from a French word “Environia” which means to surround It is the surrounding in which organism or man lives Environment implies all the external factors - living and non-living, material and non- material - which surround man. Environment is the sum total of conditions that surrounds us at a given point of time and space. abiotic (physical or non-living) and biotic (living) factor According to P. Gisbert Environment is anything immediately surrounding an object and exerting a direct influence on it All factors (living and nonliving) that actually affect an individual organism or population at any point in the life cycle  Components of Environment PHYSICAL Environment: also called abiotic constituents Is a term used to describe factors in an individual's immediate surrounding such as the air we breathe, and water we drink and has the potential to have a positive and negative impact on the health and development Others include heat, light, noise, radiation, soil, housing, climate, geography, debris, etc. Water and temperature are the most important abiotic components affecting living beings. mainly determines the type of the habitat or living conditions of the human population. Divided into 3 parts that represent the 3 important states of matter constituting the environment: Atmosphere (gas), Hydrosphere (liquid) and Lithosphere (solid)  Biological Environment also called biotic component Biological environment consists of plants and animals (Vertebrates: birds, fish, rodents, & Invertebrates: protozoa, helminths and arthropods). This component interacts with the abiotic component of the environment. Interaction of two components forms various ecosystems like pond ecosystem, marine ecosystem, desert ecosystem etc. its intimately related to infective disease, bacteria and fungi are responsible for several diseases food eaten may impair health if it is deficient, excessive or toxic. its components can act as a: reservoir, (e.g. cattle, rodents and man), vector (e.g. mosquito, ticks) and agents of infection (e.g. bacteria).  Social component It denotes the complex of psychosocial factors influencing the health of the individual and the community. It is as important as the physical and biological environments in relation to health and disease in man health is clearly reflected in the differences in morbidity patterns of rural vs. urban, developing vs. developed countries. Many important public health problems are closely related to the lifestyles of people in different societies, e.g. HIV, DMHTN Socioeconomic and political factors are important determinants of health