Ecology PDF

ECOLOGY Dr. Dipakshi Sharma This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examin...

ECOLOGY Dr. Dipakshi Sharma This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Introduction-Ecology 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 relationship of various organisms in their natural habitat interacting with their surroundings. Autecology---Study of single species/organisms. Synecology---Study of multiple species/ group of organism.  Ecosystem The term Ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley. It is defined as a basic structural and functional unit of Ecology. Each ecosystem has a definite structure and definite role to play in functioning of that place specific environment. eg. Grassland ecosystem, forest ecosystem, aquatic ecosystem etc. A self-regulating group of biotic communities of species interacting with one another and with their non-living environment exchanging energy and matter.  Classification of Ecosystem 1. Natural Ecosystem  Aquatic Fresh water Running water Standing water  Marine Terrestrial Grassland Forest Desert 2. Artificial/Engineered Ecosystem  Structural units/Components of an Ecosystem Biotic Components Abiotic Components 1. Producers 1. Physical Photo-autotrophs Climatic- Sunlight, Temperature, Humidity, Rainfall, Wind etc. Chemo-autotrophs- Nitrosomonas, Iron bacteria, Edaphic- Soil type, Soil moisture, Soil Methanogens reaction. 2. Consumers Geographic- Latitude, Longitude, Altitude Herbivores 2. Chemical Carnivores Macro/micro nutrients Omnivores Trace elements Detrivores Pollutants 3. Decomposers Organic substances  Functional units/Components of an Ecosystem Food Chain Biogeochemical Cycles Food Web 1. Gaseous Cycles Trophic Levels C, N, O and Hydrological Cycle Energy Flow 2. Sedimentary Cycles Phosphorus Cycle Sulphur Cycle  Food Chain The linkage between the living organisms (plants/animals) for the transfer of food energy is known as food chain. Food chains are not simple and straight. Types of Food Chains 1. Grazing food chain- Energy flow begins with plants fixing solar light. 2. Detritus food chain- Energy flow begins with dead organic matter broken down by decomposers.  Food Web The inter linkage between different food chains is known as food web. Two food chains involving same number of steps are said to be belonging to same trophic level. Significance of Food chain/Food web Energy flow Nutrient cycles Ecological balance Population size regulation  Trophic Level- The various steps in a food chain at which the transfer of food or energy takes place are called trophic levels. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Ecological Pyramids An ecological pyramid depicts how energy and biomass decrease from lower to higher trophic levels. The producer or first trophic level makes up the base of the pyramid. The successive three levels make the apex. Types of Ecological Pyramid 1. Pyramid of Numbers 2. Pyramid of Biomass 3. Pyramid of Energy  Pyramid of Numbers This pyramid depicts the relationship between herbivores, producers and carnivores at successive trophic levels in terms of their numbers.  Pyramid of Biomass Pyramid of Energy This Pyramid depicts the quantitative This Pyramid depicts the weight and relationships of the standing crops number of organisms at any level are instead of the geometric factor. based on the rate at which food is being produced. It is upright in shape.  Energy Flow in Environment Energy flow in the environment is uni-directional  Energy flow Universal energy flow model This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Energy flow Single channel energy flow model This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Energy flow Double channel or Y-shaped energy flow model This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Nutrient Cycles Nitrogen Carbon  Nutrient Cycles Phosphorus Sulphur  Production of biomass Primary production – Biomass production using photosynthesis Secondary production – Biomass production by consuming producers  Homeostasis It means resistance to changes in the external environment or The tendency to maintain a stable, relatively constant internal environment is called homeostasis. The term given by Claude Bernard, a French Physiologist in the year 1865 and was first used in 1926 by Walter Bradford Cannon. The regulation of homeostasis depends on three mechanisms:  Effector  Receptor  Control Center 1. Positive feedback: Stimulates change and it is responsible for the sudden appearance of rapid changes within ecosystems. 2. Negative feedback: Maintenance of homeostasis usually involves negative feedback loops.  Ecological 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 or seral 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: 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: refers to a series of community changes which take place on a previously colonized, but disturbed or damaged habitat. For example, land obtained after felling trees in a woodland, land clearance, or fire.  Classification of Succession at different type of area Hydrarch / Hydrosere: Pond, swamp, bog Mesarch: Area with adequate moisture Xerarch / Xerosere: Dry lands Lithosere: On bare rock Psammosere: On sand Halosere: On saline soil  Process of Ecological Succession 1. Nudation: The formation of a bare area or nudation by several reasons, such as volcanic eruption, flooding, landslide, erosion etc. 2. Invasion: Arrival of the reproductive bodies or propagules of various organisms and their settlement in the new or bare area.  Migration (Dispersal)  Ecesis (Establishment)  Aggregation 3. Competition and Co-action: Increase in number of species with the limited space. 4. Reaction: Modification of the environment through the influence of the living organism present on it. Reaction causes change in land, soil, water, temperature of the area. 5. Stabilization: Final or terminal communities become more or less stabilized for a longer period of time. It can maintain its equilibrium with the climate of the area. Final community is called the climate community which is determined by the climate of the region. Examples of climax communities are – grassland, forests, coral reef.  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 Notable features: – Found in tropical region (near the equator). – High rainfall, humidity and temperature – Large leaves – Rich in biodiversity – Fauna of these rainforests includes the jaguar, tapir, okapi, boa constrictor, African grey parrot, keel-billed toucan, crowned eagle, three-toed sloth, spider monkey, large flying fox and more. Layers – Emergent layer – Canopy – Understory – Forest floor Example: Amazon Rainforest, Congo Rainforest, Southeast Asian Rainforest etc.  Tropical Deciduous Forest Notable features:  Tropical deciduous forests form a natural cover almost all over India.  They are of two types-moist and dry. Moist forests are found on the eastern slopes of Western Ghats, North eastern parts of the Peninsular Chhota Nagpur plateau and along the Shiwaliks.  They shed there leaves for a particular period of time.  They are economically very important because of timber like sal and teak.  The animals found here are tiger, wolves, rabbit etc.  Sub-Tropical Forest Notable features: – Subtropical forests are within or bordering the tropical zone. – temperatures may vary only slightly over a year – Subtropical rainforests occur in Central America, the West Indies, India, Madagascar, mainland Southeast Asia, and the Philippines. – Small deciduous trees and shrubs are found. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Temperate Rain Forest Notable features: – The world's largest temperate rain forests are found on the Pacific coast of North America. – Temperate rain forests are also found in coastal Chile, Norway, the United Kingdom, Japan, Australia and New Zealand. – The mild weather conditions – Adequate rainfall – Coniferous trees dominate the forest – tall evergreen trees are also found – Animals: black bears, lynx, wolves etc.  Temperate Deciduous Forest Notable features:  Located in the mid-latitude areas (between the polar regions and the tropics).  The temperature varies widely from season to season with cold winters and hot, wet summers.  During the fall, trees change color and then lose their leaves.  Most of the trees are broadleaf trees such as oak, maple, beech, hickory and chestnut.  Animals: toad, chipmunk, gray squirrel, Yellow-breasted chat etc.  Evergreen Coniferous Forest Notable features: – They are found just in south of arctic tundra – Winters are long, cold and dry – Sunlight is available for few hours only – Soil has less nutrient and acidic – Major trees are Pine, Fir, Cedar etc. – Animals: moose, deer, reindeer, squirrels, wolves, bears, foxes, owls, woodpeckers hawks etc.  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, This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  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 This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  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:  Pampas- South America  Veldts- South Africa  Steppes- Asia and Europe  Downs- Australia This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  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. In areas not overlain by ice, it exists beneath a layer of soil, rock or sediment. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Desert Ecosystem About 1/3rd of the worlds’ land area is covered with desert 1. 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. 2. 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 3. 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 Turkestan  Pond Ecosystem Notable features: – Small freshwater ecosystem – Water is stagnant – Can be seasonal – Exposed to anthropogenic activities This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Lake Ecosystem Organisms of aquatic ecosystem: – Planktons (Algae, rotifers: limited locomotion) – Nektons (Fishes: active swimmer) – Neustons (Floating plants) – Benthos (Bottom dweller: Snail) – Periphytons (Crustaceane) Zonation (Stratification) – Epilimnion (Warm, lighter, circulating surface layer) – Hypolimnion (Cold, viscous, non-circulating bottom layer) This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Types of Lakes Oligotrophic lakes- Low nutrient content Eutrophic lake- High nutrient content Dystrophic lake- Low pH (Eg: Lake Suchar II in Poland, lakes Allgjuttern, Fiolen, and Brunnsjön in Sweden.) Endemic lakes- Ancient and deep having endemic fauna. Desert salt lakes- High salt content Eg: Great Salt Lake northern Utah, USA Volcanic lakes Mermictic lakes- Permanently stratified Artificial lakes This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Streams Notable features: Stages Mountain highland (Young River) Second phase (Middle Aged River) Third phase (Old River) This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Oceans Ecosystem 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) This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.