Lecture 2 Introduction to Ecology of Micro and.pptx

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1. Lecture 2 Introduction to Ecology of Micro and Macro-organisms

2. What is Ecology? Ecology is the branch of biology that studies how living things interact: With each other (plants, animals, microbes) With their environment (soil, water, air, climate)

3. What are Microorganisms? Microorganisms , also called microbes , are very small living things. You cannot see them with your naked eyes. You need a microscope to see them. 💡 Examples of Microorganisms: Type Example Where They Are Found Bacteria Rhizobium , E. coli Soil, water, gut Fungi (microscopic) Yeast Bread, beer, soil Algae (microscopic) Chlorella , Spirogyra Ponds, oceans Protozoa Amoeba , Paramecium Water bodies Viruses Influenza virus , HIV Inside host cells

4. What are Macroorganisms ? Macroorganisms are large living things that we can see without a microscope. 💡 Examples of Macroorganisms : Plants – trees, shrubs, grass Animals – dogs, cows, birds, insects Humans – we are also macroorganisms Fungi – mushrooms (visible fungi)

5. Basic Differences Between Micro and Macroorganisms Feature Microorganisms Macroorganisms Size Very small (microscopic) Large (visible) Seen with Microscope Naked eye Reproduction Very fast Slower Habitat Found everywhere Specific environments Importance Nutrient cycling, disease, food chains Consumers, producers, decomposers

6. Roles of Microorganisms in Nature Decomposers Break down dead plants and animals into simple substances. Return nutrients to the soil. Example: Bacteria and fungi in soil. 2. Nitrogen Fixers Convert nitrogen gas (from the air) into a form that plants can use. Example: Rhizobium in legume roots. 3. Photosynthesizers Some algae and bacteria make their own food using sunlight. They produce oxygen and act like tiny plants in water bodies. Example: Cyanobacteria , phytoplankton .

7. 4. Help in Digestion In animals and humans, gut bacteria help break down food. Produce vitamins and keep harmful bacteria away. 5. Cause Diseases Some microbes can cause illnesses in humans, animals, or plants. Examples: Typhoid (bacteria) , Influenza (virus) .

8. Roles of Macroorganisms in Nature 1.Producers Green plants use sunlight to make their food (photosynthesis). They are the starting point of most food chains. 2. Consumers Animals eat plants or other animals. Herbivores (plant-eaters), carnivores (meat-eaters), omnivores (both). 3. Decomposers Some animals like earthworms help break down dead matter. They improve soil fertility. 4. Ecosystem Engineers Some animals change their environment to help other species. Example: Beavers build dams → create ponds.

9. Interactions Between Micro and Macroorganisms 1.Mutualism (Both Benefit) Cow + gut bacteria → Bacteria help digestion; cows provide food and shelter. Plant roots + mycorrhizal fungi → Fungi help plants get nutrients; fungi get food. 2. Parasitism (One Benefits, Other Harmed) Tick on a dog → Tick gets blood; dog may get sick. Malaria parasite in human → Parasite multiplies; human gets disease. 3. Commensalism (One Benefits, Other Unaffected) Birds nesting in trees. Bacteria on our skin – They live there but don’t harm us.

10. Nutrient Cycles Involving Micro and Macroorganisms A. Nitrogen Cycle Bacteria fix nitrogen from air → Plants absorb it → Animals eat plants → Decomposers return it to soil. B. Carbon Cycle Plants take in CO₂ → Make food → Animals eat plants → Breathe out CO₂ → Decomposers release more CO₂. C. Water Cycle (indirect role) Microbes and macroorganisms affect evaporation, transpiration, and water quality.

11. Real-Life Examples 1. Coral Reefs Coral animals have algae living inside them. Algae give food to coral, and coral provides shelter to algae. 2. Cow’s Stomach (Rumen) Bacteria help cows digest cellulose (plant fiber ). Without microbes, cows cannot digest grass. 3. Human Gut Microbiome Trillions of bacteria in our intestines help us digest food and fight diseases. 4. Tree Roots and Soil Fungi Mycorrhizae fungi grow around roots and bring nutrients from deep soil.

12. Human Activities and Their Effects Activity Impact on Microorganisms Impact on Macroorganisms Pollution Kills useful microbes in soil and water Harms fish, birds, animals Deforestation Destroys soil bacteria and fungi Destroys animal habitats Pesticide Use Kills both good and bad microbes Affects food chains Antibiotic Overuse Causes resistant bacteria Makes diseases harder to treat Climate Change Affects microbial growth and cycles Alters animal migration, leads to extinction

13. How Scientists Study These Organisms Microorganisms: Microscope : To observe microbes. DNA sequencing : To identify microbes in an environment. Culture techniques : Grow bacteria/fungi in labs. Macroorganisms : Field observations : Watching animals/plants in nature. Camera traps : Used for studying wild animals. Satellite images : To observe forests, oceans, migration patterns.

14. Summary (Key Points) Microorganisms and macroorganisms are both essential for life on Earth. Microorganisms handle decomposition, nutrient cycling, and disease control. Macroorganisms control food chains, shape environments, and maintain biodiversity. Their interactions (like mutualism and parasitism) are very important. Human activities can upset the balance between these organisms. Protecting them ensures a healthy planet for all.

15. Thank You