Ecosystems PDF

Ecosystems  Introduction The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley. Ecosystem: A self-regulating group of biotic communities of species interacting with one another and with their non-living environ...

Ecosystems  Introduction The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley. Ecosystem: A self-regulating group of biotic communities of species interacting with one another and with their non-living environment exchanging energy and matter The term oekologie (ecology)was coined by the German biologist Ernst Haeckel in the year 1866. Greek word “Oikos” meaning “home” and “logos” meaning “study” Ecology: The study of organisms in their natural habitat interacting with their surroundings This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination quesions will be in depth and can be solved by following text book only. Classification of Ecosystems Natural Ecosystems Terrestrial Ecosystems Man-made Ecosystems (aquaria, garden, dams & cropland of Forest maize, wheat, rice). Ecosystems Grass land Aquatic Ecosystems Ecosystems Desert Ecosystems Fresh water Ecosystems Standing water Running water Marine Ecosystems (lentic) Ecosystems (lotic) Ecosystems Natural Ecosystems Man-made Ecosystems Structure of Ecosystem Ecosystem Structure  Biotic Components of Ecosystems Producers (or autotrophs) Green plants and some bacteria which manufacture their own food. Consumers (or heterotrophs) Animals which obtain their food from producers Primary consumers = herbivores (rabits, insects) Secondary consumers = carnivores (Frog) Tertiary consumers = top canivorous (Snake, big fish) Omnivores = Humans, rat, fox Decomposers Bacteria and fungi that decompose dead organic matter and convert it into simpler parts  Functions of an Ecosystem  Food chain and food web ( food chain is a series of organisms that eat one another so that energy and nutrients flow from one to the next. Many food chains interacts to form food web)  Energy flow (The energy flow takes place via the food chain and food web)  Ecological pyramids (An ecological pyramid is a graphical representation designed to show the biomass or bio productivity at each trophic level in a given ecosystem)  Food Chain The transfer of food energy from the source (plants) through a series of organisms by repeated eating and being eaten up is referred to as food chain. Types: Grazing food chain-a common chain starting with plant or plant product Detritus food chain-chain derived by the organic wastes and dead matter from grazing food chains Trophic Level  Food web The interlocking pattern formed by several food chains that are linked together is called a food web.  Energy Flow in Ecosystems First Law of Thermodynamics energy can neither be created nor destroyed but only is transformed from one form to another. Second Law of Thermodynamics-The second law of thermodynamics states that no energy transformations are 100% efficient. 10 Percent Rule of Energy As a rule of thumb, 90 percent of the energy involved is degraded at each tropic transfer and only 10 percent of the energy is conserved in the organism's tissue.  Ecological Pyramid The graphical representations of different tropic levels in an ecosystem where producers occupy the base and the top consumer occupy the apex of the pyramid, is known as ecological pyramid. They are used to illustrate the feeding relationships between organisms. Types of Ecological Pyramids Pyramid of number = no of individual at each tropic level is considered Pyramid of biomass = biomass at each tropic level is considered Pyramid of energy = energy at each tropic level is considered  Pyramid of Number Pyramid of number is used to show the number of individuals in each tropic level. It is upright in case of grassland and pond ecosystems. Pyramid of Number Pyramid of Biomass tertiary consumers 75 g/m2 Pyramid of biomass records the total dry organic matter of organisms at each trophic level in a given area of an ecosystem. secondary 150g/m2 consumers The pyramid of biomass is used to show the total biomass of individuals primary at each trophic level. consumers 675g/m2 It is better than the pyramid of number for showing the relationships between organisms. producers 2000g/m2 17 Pyramid of energy Pyramid of energy is used to show the amount of energy transferred between tropic levels. It provides the best representation of the overall nature of an ecosystem. The pyramid of energy flow is always upright because there is always loss of energy while moving from lower tropic level to higher tropic level. Therefore, the energy reaching the next tropic level is always less compared to that in the previous tropic level. Ecological pyramids https://youtu.be/NeK5-mJhWeg Energy flow Energy flow  Succession  Ecological succession is the gradual process by which ecosystems change and develop over time.  It is therefore a series of predictable temporary communities or stages leading up to a climax community.  Each stage/temporary community is called a successional stage.  Each step prepares the land for the next successional stage.  All habitats are in the state of constant ecological succession.  Types of Succession  Primary succession  Primary succession refers to a series of community changes which occur on an entirely new habitat which has never been colonized before. For example, a newly quarried rock face or sand dunes. (pioneer and climax community).  Secondary succession  Secondary succession refers to a series of community changes which take place on a previously colonized, but disturbed or damaged habitat. For example, land obtained Succession starting on different types of area  Hydrarch / Hydrosere  Pond, swamp, bog  Mesarch / Mesosere  Area with adequate moisture  Xerarch / Xerosere  Lithosere: On bare rock  Psammosere: On sand  Halosere: On saline soil  Process of ecological succession  Nudation  Invasion  Migration (dispersal)  Ecesis (establishment)  Aggregation  Competition  Reaction  Stabilization  Nutrient cycles  Nitrogen  Nitrogen Fixation: Nitrogen in the atmosphere (N₂) is converted into ammonia (NH₃) or related compounds. This can be done by: Biological Fixation: Certain bacteria, often in the roots of legumes (like peas and beans), convert atmospheric nitrogen into ammonia. Abiotic Fixation: Natural processes like lightning or industrial processes (e.g., Haber-Bosch process) can also fix nitrogen. Nitrification: Ammonia in the soil is converted into nitrites (NO₂⁻) and then into nitrates (NO₃⁻) by nitrifying bacteria. Nitrates are more easily absorbed by plants than ammonia.  Assimilation: Plants take up nitrates from the soil and use them to make amino acids, proteins, and nucleic acids. When animals consume plants, they acquire nitrogen and incorporate it into their own tissues. Ammonification (Mineralization): When plants and animals die, decomposers like bacteria and fungi break down organic nitrogen in their bodies into ammonia, which returns to the soil. Denitrification: Denitrifying bacteria in the soil convert nitrates back into nitrogen gas (N₂) or nitrous oxide (N₂O), which is released into the atmosphere, completing the cycle. Nutrient cycles  Carbon  Nutrient cycles  Phosphorus  Weathering and Erosion: Rock Weathering: Phosphorus is primarily found in rocks in the form of phosphate minerals (e.g., apatite). Through weathering and erosion, these minerals break down, releasing phosphate ions (PO₄³⁻) into the soil and water systems. Erosion: Phosphates can be transported from land to aquatic systems through erosion and runoff. Absorption by Plants: Soil Uptake: Plants absorb phosphate ions from the soil through their root systems. Phosphorus is a vital nutrient for plants, playing a crucial role in energy transfer, photosynthesis, and nucleic acid formation.  Consumption by Animals: Food Chain: Animals obtain phosphorus by consuming plants or other animals. Phosphorus is essential for various biological functions, including the formation of DNA, ATP (adenosine triphosphate), and cell membranes. Decomposition: Organic Matter Breakdown: When plants and animals die, decomposers (bacteria, fungi) break down their bodies, releasing phosphorus back into the soil and water systems in the form of phosphate.  Sedimentation: Aquatic Systems: In aquatic environments, phosphates can be taken up by algae and aquatic plants. When these organisms die, their phosphorus-rich remains can settle to the bottom and form sediments. Over long geological timescales, these sediments can eventually form phosphate rock. Geological Uplift: Rock Formation: Geological processes, including tectonic activity, can lift phosphate-rich sediments from the ocean floor to land, where they become part of the Earth's crust and can eventually be exposed through weathering and erosion, continuing the cycle.  Human Impact: Fertilizers: Human activities, such as the use of phosphate fertilizers in agriculture, can lead to an excess of phosphorus in soils and water bodies. This can cause eutrophication in aquatic systems, leading to harmful algal blooms and hypoxic (low-oxygen) conditions. Wastewater: Phosphorus from sewage and industrial waste can also contribute to nutrient pollution in water bodies. Forest ecosystem  Abiotic Components  Inorganic and organic substances found in soil  Temperature, humidity, rainfall, light  Biogenic gases (CO2, O2)  Biotic components  Producers: Large trees, herbs, lianas (climbers), Orchids  Primary consumer: Deer, Elephant, moles etc.  Secondary consumer: Snake, Lizards etc.  Tertiary consumers: Tiger, Lion etc.  Decomposers  Tropical rain forest Tropical rainforests are dense, lush forests found near the equator, characterized by high biodiversity and high annual rainfall.  Tropical rain forest Climate: Temperature: Tropical rainforests typically experience warm temperatures year-round, averaging between 20°C and 25°C (68°F to 77°F). Rainfall: They receive high amounts of rainfall, usually over 1750 mm (69 inches) annually. Rainfall is distributed throughout the year, contributing to the forest's lushness. Biodiversity: Flora: Tropical rainforests are home to a vast array of plant species, including large trees (such as mahogany and kapok), ferns, orchids, and lianas (vines). Fauna: They host a diverse range of animal species, including mammals (such as jaguars and monkeys), birds (like toucans and harpy eagles), reptiles, amphibians, and insects. Many species are endemic, meaning they are found nowhere else on Earth. Structure: Canopy Layers: Rainforests have distinct layers: Emergent Layer: The topmost layer, where some trees extend above the canopy and receive the most sunlight. Canopy Layer: The upper layer of the forest, where the majority of the tree crowns form a dense ceiling, capturing most of the sunlight and sheltering many animal species. Understory Layer: The layer below the canopy, with less light and high humidity. It is home to smaller trees, shrubs, and a variety of animal species. Forest Floor: The lowest layer, receiving very little light. It is covered with decomposing plant material and is the habitat for various decomposers and detritivores.  Tropical deciduous forest Tropical deciduous forests, also known as tropical dry forests or monsoon forests, are a type of forest ecosystem found in tropical regions where there is a pronounced dry season.  Tropical deciduous forest Climate: Temperature: Tropical deciduous forests typically experience warm temperatures year-round, similar to tropical rainforests, with average temperatures ranging from 20°C to 30°C (68°F to 86°F). Rainfall: These forests have a pronounced wet and dry season. Annual rainfall generally ranges from 750 to 2,000 mm (30 to 80 inches), with a significant portion of it occurring during the wet season. The dry season can last several months.  Vegetation: Deciduous Trees: Unlike tropical rainforests, many trees in tropical deciduous forests shed their leaves during the dry season to conserve water. Common tree species include teak, mahogany, and various species of acacia and tamarind. Understory and Ground Layer: The understory often includes shrubs and smaller trees adapted to the seasonal variations in water availability. The ground layer may be covered with grasses and herbs, particularly during the dry season. Seasonal Adaptations: Leaf Drop: Many trees lose their leaves during the dry season to minimize water loss. This adaptation helps them survive periods of reduced water availability. Regeneration: Many plant species in these forests have evolved to regenerate quickly during the wet season to take advantage of the abundant water and nutrients.  Sub-tropical forest Sub-tropical forests are a type of forest found in regions between the tropical and temperate zones. They typically experience a range of temperatures and precipitation patterns, making them distinct from both tropical rainforests and temperate forests.  Climate: Temperature: Sub-tropical forests generally experience warm to hot temperatures, with average temperatures ranging from about 10°C to 25°C (50°F to 77°F). These forests may experience moderate seasonal temperature fluctuations. Rainfall: Rainfall can vary widely, from about 750 to 1,500 mm (30 to 60 inches) annually. Some areas may have a wet and dry season, while others may experience more evenly distributed precipitation throughout the year. Vegetation: Trees: Sub-tropical forests may contain a mix of evergreen and deciduous trees. Common tree species include eucalyptus, oak, and various types of pine and hardwoods. Shrubs and Ground Cover: These forests often have a diverse understory with shrubs, ferns, and grasses. In drier regions, vegetation may include xerophytic plants adapted to conserve water.  Sub-tropical Forest Types: Dry Sub-tropical Forests: These forests are found in regions with more pronounced dry seasons and often have drought- resistant plants. Moist Sub-tropical Forests: These are located in areas with more consistent rainfall and may be more similar in appearance to tropical forests.  Temperate rain forest Temperate rainforests are unique forest ecosystems found in temperate regions with high levels of rainfall and mild temperatures. They differ from tropical rainforests in terms of climate and species composition but share some similarities, such as high biodiversity and dense vegetation.  Climate: Temperature: Temperate rainforests typically have mild temperatures throughout the year, usually ranging from about 4°C to 18°C (39°F to 64°F). Extreme temperatures are less common than in tropical or boreal regions. Rainfall: They receive high amounts of rainfall, often ranging from 1,200 to 3,000 mm (47 to 118 inches) annually. Rainfall is relatively evenly distributed throughout the year, contributing to the forest’s lushness. Vegetation: Trees: Temperate rainforests are characterized by large evergreen trees such as Douglas fir, Sitka spruce, western red cedar, and giant sequoia. These trees are adapted to the high moisture levels and mild temperatures. Understory and Ground Cover: The understory often includes shrubs, ferns, mosses, and lichens. The forest floor may be covered with a thick layer of fallen leaves, branches, and decomposing organic matter.  Structure: Canopy: The canopy in temperate rainforests is typically dense, with trees reaching heights of 30 to 60 meters (98 to 197 feet). The canopy provides shelter and habitat for a variety of species. Understory: Below the canopy, the understory is lush with vegetation adapted to lower light levels. Ferns, shrubs, and small trees thrive in this layer.  Temperate deciduous forest Temperate deciduous forests are forest ecosystems characterized by moderate climates, distinct seasonal changes, and a mix of deciduous and evergreen trees. These forests are found in temperate regions with four distinct seasons, including a warm summer and a cold winter.  Climate: Temperature: Temperate deciduous forests experience a wide range of temperatures, with warm summers and cold winters. Average temperatures can range from about -5°C to 25°C (23°F to 77°F) throughout the year. Rainfall: These forests receive moderate to high rainfall, typically between 750 and 1,500 mm (30 to 60 inches) annually. Precipitation is generally evenly distributed throughout the year, though some regions may have a drier or wetter season. Vegetation: Deciduous Trees: The dominant trees in temperate deciduous forests are deciduous, meaning they shed their leaves annually in the fall. Common species include oak, maple, beech, and hickory. Understory and Ground Cover: The understory may include shrubs, small trees, and herbaceous plants. The forest floor is often covered with a layer of leaf litter, which decomposes and contributes to soil fertility. Wildflowers, ferns, and mosses are common in the understory.  Seasonal Changes: Leaf Fall: Deciduous trees shed their leaves in autumn as a strategy to conserve water and energy during the cold, dry winter months. The fallen leaves decompose and enrich the soil. Regrowth: In spring, trees and plants quickly regrow their leaves and flowers, taking advantage of increased sunlight and warming temperatures.  Evergreen coniferous forest Evergreen coniferous forests, also known as boreal forests or taiga, are forest ecosystems dominated by coniferous trees that retain their leaves throughout the year. These forests are found in the northern regions of the world, characterized by cold climates and specific types of vegetation  Climate: Temperature: Evergreen coniferous forests are typically found in regions with cold temperatures, including long, harsh winters and short, cool summers. Average temperatures can range from -40°C to 20°C (-40°F to 68°F). Rainfall: These forests receive moderate to low precipitation, usually between 300 and 850 mm (12 to 33 inches) annually. Precipitation can come in the form of snow during the winter months and rain during the summer. Vegetation: Coniferous Trees: The dominant vegetation consists of evergreen conifers, such as spruce, fir, pine, and larch. These trees have needle-like leaves that are adapted to withstand cold temperatures and conserve water. Understory and Ground Cover: The understory is often sparse due to the dense canopy, with some shrubs, mosses, lichens, and ground-cover plants like blueberries and cranberries. The forest floor may be covered with a thick layer of decomposing needles and moss.  Structure: Canopy: The canopy is made up of tall, evergreen coniferous trees that provide year-round cover. The dense canopy helps to insulate the forest floor and reduce temperature fluctuations. Forest Floor: The forest floor in these regions is often covered with a layer of needle litter, which decomposes slowly due to the cold temperatures. This contributes to a nutrient-poor, acidic soil.  Grassland ecosystem  Abiotic components:  Inorganic elements (C, H, O, N, P, S)  Temperature, humidity, rainfall, light  Biotic components:  Producers: Some scattered trees, Grass  Primary consumers: Grazing animals,  Tropical grassland  Notable features:  Located near the equator, between the Tropic of Cancer and the Tropic of Capricorn.  Although these areas are overall very dry, they do have a season of heavy rain.  Dominated by grasses  May have some drought- resistant, fire-resistant trees  Animals: giraffes, zebras, buffaloes, kangaroos, mice, moles, gophers, ground squirrels, snakes, worms, termites, beetles, lions, leopards, hyenas, and elephants.  Examples:  Savannas  Temperate grassland  Notable features:  Trees and shrubs are completely absent or rare.  cold winters (- 40⁰C) and hot summers (38⁰C)  Gentle slope  Animals: Rodents, bisons, wolves, hawks, owls etc.  Examples:  Prairies (South America)  Pampas (Africa)  Velds (Central Europe)  Polar grassland  Notable features:  Severe cold and strong wind  Arctic wolf, arctic fox, reindeer, migratory birds and insects are found.  Examples:  Arctic Tundra  Permafrost: Permafrost is soil, rock or sediment that is frozen for more than two consecutive years.  Desert ecosystem  About 1/3rd of the worlds’ land area is covered with desert  Tropical desert  Notable features: It is the driest and hottest place on earth. Rainfall is sporadic and in some years no measurable precipitation falls at all.  Examples: Sahara, Kalahari, Thar, Mexican deserts, Great Australian desert.  Temperate desert  Notable features: Temperate deserts can be much colder than tropical deserts The floor of the temperate desert is often covered by rocks and small pebbles  Examples: Mojave, Sonoran Deserts  Cold desert  Notable features: cold deserts occur in temperate regions at higher latitudes hot summers but extremely cold winters.  Examples: Atacama,  Gobi, Great Basin, Namib, Iranian, Takla Makan, and  Pond ecosystem  A pond ecosystem refers to the freshwater ecosystem where there are communities of organisms that are dependent on each other and with the prevailing water environment for their nutrients and survival.  Notable features:  Small freshwater ecosystem  Water is stagnant  Can be seasonal  Exposed to anthropogenic activities  Lake ecosystem  Organisms of aquatic ecosystem  Planktons (Algae, rotifers)  Nektons (Fishes)  Neustons (Water flea)  Benthos (Snail)  Periphytons (Crustaceane)  Zonation (Stratification)  Epilimnion (Warm, lighter, circulating surface layer)  Hypolimnion (Cold, viscous, non-circulating bottom layer) Types of lakes  Oligotrophic lakes (Low nutrient content)  Eutrophic lake (High nutrient content)  Dystrophic lake (Low pH)  Endemic lakes (Ancient, deep, having endemic fauna)  Desert salt lakes (High salt content)  Volcanic lakes  Mermictic lakes (Permanently stratified)  Artificial lakes  Streams  Notable features:  flowing water that is mostly unidirectional  a state of continuous physical change  many different (and changing) microhabitats  variability in the flow rates of water  plants and animals that have adapted to live within water flow conditions.  Stages Mountain highland (Young River) Second phase (Middle Aged River) Third phase (Old River)  Oceans  Notable features:  Marine ecosystems support a great diversity of life and variety of habitats.  The ocean is a major influence on weather and climate.  Plants: seaweeds, or marine algae (brown, green, red), sea grasses, phytoplankton  Animals: protozoans, marine invertebrates (echinoderms, mollusks, segmented and non- segmented worms, jellies, coral, sea anemones, hyroids) marine vertebrates (fishes, birds, mammals), and zooplankton.  Zones  Coastal zone  Open sea Euphotic zone (Abundant sunlight, high photosynthetic activity) Bathyal zone (Dim light) Abyssal zone (Dark zone) https://youtu.be/xwFr2hWjo5s  Exercise 1. The natural place of an organism or community is known as a. Niche b. Biome c. Habitat d. Habit 2. Which of the following require maximum energy a. Secondary consumer b. Decomposer c. Primary consumer d. Primary producer  Exercise 1. The natural place of an organism or community is known as a. Niche b. Biome c. Habitat d. Habit 2. Which of the following require maximum energy a. Secondary consumer b. Decomposer c. Primary consumer d. Primary producer 3. 4 3. 4  Ocean acidification is caused by which of the 5. following gases? a. Sulfur Dioxide b. Carbon Dioxide c. Nitric Oxide d. Ozone 6 Which one following is the example of man-made ecosystem  Ocean acidification is caused by which of the 5. following gases? a. Sulfur Dioxide b. Carbon Dioxide c. Nitric Oxide d. Ozone 6 Which one following is the example of man-made ecosystem 7. 8 7. 8  “Ecosystem” term was coined by------- 9. A Lindeman B AG Tansley C Grinnel D Turesson 10 What are the edaphic factors for the abiotic components? a) Sunlight, temperature, Wind b) Soil type, soil moisture, soil mixture c) Longitude, latitude d) Rainfall, humidity  “Ecosystem” term was coined by------- 9. A Lindeman B AG Tansley C Grinnel D Turesson 10 What are the edaphic factors for the abiotic components? a) Sunlight, temperature, Wind b) Soil type, soil moisture, soil mixture c) Longitude, latitude d) Rainfall, humidity  The food chain which starts with green plants is 11. called a) Food web b) Detritus food chain c) Grazing food chain d) None of the above Which is/are below the abiotic components of an 12 ecosystem? A Light B Water C Carbon D All of the above  The food chain which starts with green plants is 11. called a) Food web b) Detritus food chain c) Grazing food chain d) None of the above Which is/are below the abiotic components of an 12 ecosystem? A Light B Water C Carbon D All of the above  Which are the following are two basic classes of 13. ecosystem are: a) Aquatic and forest b) Ponds and lakes c) Rivers and forests d) Aquatic and terrestrial  Which are the following are two basic classes of 13. ecosystem are: a) Aquatic and forest b) Ponds and lakes c) Rivers and forests d) Aquatic and terrestrial