Unit 7.4 Kingdom Fungi
Biology → Biology → CLASSIFICATION → CLASSIFICATION → Five Kingdom Classification | Author: admin | Feb 25, 2026
- Understand what Fungi are and why they form a separate kingdom
- Learn the unique characteristics that make Fungi different from Plants and Animals
- Identify the structure of a typical fungal body (mycelium, hyphae)
- Understand how Fungi reproduce — vegetative, asexual, and sexual methods
- Learn the four classes of Fungi with distinguishing features and examples
- Know the economic importance of Fungi — useful and harmful
- Connect all Fungi facts directly to competitive exam questions
Introduction
Have you ever seen white fuzzy growth on a piece of old bread? Or eaten mushrooms in your food? That fuzzy growth and that mushroom — both are Fungi! Fungi are one of the most fascinating groups of living organisms on Earth, and they are very different from both plants and animals.
For a long time, scientists classified Fungi along with Plants because both don't move. But slowly, scientists discovered that Fungi are so different from plants that they deserve their own Kingdom. In 1969, R.H. Whittaker placed Fungi in a separate kingdom in his Five Kingdom Classification — and that is exactly what we are going to study in this unit.
Fungi are found everywhere — in soil, on food, in water, on trees, and even inside our bodies. Some Fungi are very useful to us (like yeast that makes bread fluffy), while some are very harmful (like fungi that cause diseases). This unit will teach you everything about Kingdom Fungi — from its basic structure to its exam-level importance.
7.4.1What is Kingdom Fungi?
Fungi (singular: Fungus) are eukaryotic organisms that are neither plants nor animals. They cannot make their own food, they do not have chlorophyll, and they absorb nutrition from dead or living organic matter.
Think of Fungi as nature's recyclers. While plants make food using sunlight and animals eat other organisms, Fungi absorb digested food from whatever they are growing on. They release special chemicals called enzymes outside their body, break down the food material, and then absorb the nutrients. This method is called absorptive nutrition or saprophytic nutrition.
Fungi were earlier classified under Plants because both are non-motile (cannot move). But Fungi lack chlorophyll, have a cell wall made of chitin (not cellulose like plants), and feed by absorption — making them a completely separate kingdom.
Fungi cell wall is made of CHITIN — this is one of the most frequently asked facts in SSC, RRB, and UPSC exams. Plants have CELLULOSE in their cell walls.
Remember: Fungi = Chitin | Plants = Cellulose
7.4.2General Characteristics of Fungi
Study this table carefully — characteristics are frequently tested in MCQ format:
Fungi store food as GLYCOGEN — same as animals. This is different from plants which store food as STARCH. This comparison is frequently asked in SSC and RRB exams.
7.4.3Structure of Fungi — Hyphae & Mycelium
Hyphae (singular: Hypha) are long, thin, thread-like filaments that make up the body of a fungus. Think of them like tiny tubes or threads.
Mycelium is the entire network or mass of hyphae woven together. It forms the main body of the fungus — the white fluffy growth you see on bread or soil.
Hyphae can be of two types:
Think of Mycelium as a "city of threads". Each thread = Hypha. The whole city = Mycelium. Just like many roads make a city, many hyphae make a mycelium!
The mycelium that grows into the food/soil for absorbing nutrition = Vegetative Mycelium.
The mycelium that grows upward for reproduction = Reproductive Mycelium.
7.4.4Nutrition in Fungi
Fungi obtain nutrition in three main ways. Understanding each mode is important for exams.
Saprophytic
Most common mode. Fungi grow on dead and decaying organic matter — dead leaves, dead animals, rotting wood, stale food. They are the main decomposers in nature.
Parasitic
Some fungi live on living organisms (host) and cause diseases. They harm the host while taking nutrition from it.
Symbiotic
Some fungi live in close association with other organisms where both benefit from each other — called mutualism.
7.4.5Reproduction in Fungi
Fungi can reproduce by three different methods — from simple vegetative methods to complex sexual reproduction.
▶ Vegetative Reproduction
Simple, basic method. Happens by fragmentation — a piece of mycelium breaks off and grows into a new fungus. Also by Budding in yeast — a small bud grows out of the parent cell and separates.
▶ Asexual Reproduction
By producing special asexual spores. These spores are lightweight, travel through air/water, and germinate into new fungi. Types of asexual spores:
▶ Sexual Reproduction
Involves fusion of two compatible hyphae or gametes. Occurs in three stages:
The three stages of sexual reproduction in Fungi:
Plasmogamy → Karyogamy → Meiosis
Remember the correct sequence — it is directly asked in UPSC Prelims and TGPSC!
7.4.6Classification — The Four Classes
Kingdom Fungi is divided into four major classes based on type of hyphae, spores produced, and mode of reproduction:
"Please Always Be Decent"
Phycomycetes → Ascomycetes → Basidiomycetes → Deuteromycetes
7.4.7Economic Importance of Fungi
Penicillin → Penicillium notatum → Alexander Fleming → 1928 (UPSC, SSC, RRB)
Aflatoxin → Aspergillus flavus → stored grains → carcinogen (UPSC, TGPSC)
Wheat Rust → Puccinia | Smut → Ustilago (UPSC Agriculture)
7.4.8Special Associations
Lichens = Fungi + Algae → Pioneer organisms + Pollution indicators (UPSC, SSC, TGPSC)
Mycorrhiza = Fungi + Plant roots → Better nutrient/water absorption (UPSC, TGPSC)
Key Terms Glossary
Learn these terms — they appear directly in exam questions as fill-in-the-blank or MCQ options.
⭐ Exam Focus — Top Facts
These are the most exam-important facts. Study them carefully!
⚡ Quick Revision
One-liner bullets — ideal for last-minute revision before exam.
📝 Practice MCQs
Click on an option to check your answer. Instant feedback!