Topic: Place of occurrence and structure of fungi, life functions of fungi, the importance of fungi

Target group

5th‑grade students of elementary school

Core curriculum

6. Fungi - heterotrophic organisms. Student:

1) presents the living environment of fungi (including lichen fungi);

2) lists features that allow the body to be classified into fungi;

3) demonstrates the diversity of fungal structure (single‑cell, multicellular);

4) presents selected life activities of fungi (nutrition, breathing);

5) presents the importance of fungi in nature and for man.

General aim of education

Students describe the structure and importance of saprobic fungi.

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• indicate where and under what conditions the mushrooms live;

• distinguish fungi: yeast, mold fungi and fruiting bodies, among them edible and poisonous;

• show the importance of fungi.

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• exposing

  • exposition.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers;

• signed mushrooms for the exhibition: yeast, mushroom, polypore, mold tightly closed in the jar and other available specimens;

• young and ripe fruiting bodies of mushrooms and items needed to carry out „Observation 1”: paper tray and magnifier;

• compressed yeast used to bake the dough and items and substances needed to carry out the „Observation 2”: water, glucose, beaker or jar, food foil, Lugol liquid, microscope instruments, microscope.

Lesson plan overview

Before classes

• The teacher prepares an exhibition of mushrooms. You should find on it: yeast, mushrooms, polypore, mold tightly closed in the jar and other available specimens. All mushrooms must be signed.

Introduction

• The teacher explains the aim of the lesson and together with students determines the success criteria to be achieved.

• The lecturer asks the pupils to look at the fungi exposed in the exhibition and then give associations related to the mushroom kingdom.

Realization

• The teacher instructs students to familiarize themselves with the content of the abstract and describe the conditions conducive to the development of fungi. The indicated pupil answers.

• Participants familiarize themselves with the content presented in the interactive illustration „Growing moulds on bread” . Then the teacher discusses the issues with the students.

• The instructor shows the companions pressed yeast and asks how to convince them that they are living organisms. Students give free answers. Then the teacher performs „Observation 2”. Students share their insights.

• The teacher asks why we count mushrooms for heterotrophic organisms. He asks students to define the term „saprobiontes” based on the abstract and explain why the fungal hypha grows into bread.

• The students perform Observation 1, write notes and conclusions in the notebooks.

Summary

• The instructor recommends students to discuss the structure and meaning of fungi.

• The teacher briefly presents the most important issues discussed in class. He answers the additional questions of the proteges and explains all their doubts. Students complete notes.

• The teacher asks students to carry out the recommended interactive exercise themselves.

Homework

Describe Agaricus adjustment of mushrooms for food intake and spore dissemination using the example of mushrooms.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Place of occurrence and structure of fungi, life functions of fungi, the importance of fungi

Lesson link

Fungi inhabit many environments on the Earth. They are most common on land, in moist and warm places, anywhere where organic matter can be found. In forests they are components of duff, they grow on fallen tree trunks and on the roots of living trees. Sometimes they cover the leaves of plants with white or brown stains. We can also come across them on rocks, walls and sometimes on the walls of buildings with excess moisture. Some infect other organisms and parasitize them, causing diseases. Others adapted to living in water.

The spores of fungi are suspended in the air, the make up dust and settle on all surfaces. Moisture, presence of nutrients (dead or living organic matter) and appropriate temperature (5‑40°C) are the conditions in which spores germinate.

The unicellular yeast are the fungi of the simplest structure. However mostly they are multicellular organisms with bodies built of thin, thread‑like hyphae making up the mycelium. Loosely arranged, branching hyphae grow through the substrate forming a thick web, which in the case of honey fungus can cover even up to a few square km and weigh up to a few tons. The cell walls of fungi contain chitin - the substance also present in the exoskeleton of insects.

Mushrooms, such as e.g. the common mushroom, king bolete, fly agaric toadstool form sporocarps made up of tightly weaved and densely packed hyphae. Sporocarps are most frequently composed of a stem and a cap topping it. They may take different shapes and colours. It is where the spores are formed, which enable the reproduction of fungi. Molds: mucor, penicillum and aspergillus are characterized by a loose mycelium which does not produce sporocarps.

Thanks to the gills the bottom part of the cap has a large surface and produces significant amount of spores.

Fungi are heterotrophic organisms. Most of them are saprobionts feeding on dead organic matter which comes from rotten tree trunks, fallen leaves, remains of animals or food products. Fungi break down their food by secreting digestive enzymes into the environment. They absorb the thus created simple organic substances into their cells. The method of obtaining nutritious substances present in fungi is called extracellular digestion.

Parasitic fungi develop at the cost of other organisms. The parasitic hyphae grow into the carrier's body and draw nutrients directly from their cells. Fungi use the nutrients absorbed to produce energy in the process of cellular respiration. Most fungi use aerobic respiration, only some, e.g. yeast, use the process of alcoholic fermentation.

Fungi use sexual and asexual reproduction. In single cell yeast during budding a protrusion appears on the cell wall of the mother cell, which gradually grows in size to create a new cell. It does not usually separate from the mother cell, thus creating colonies which can break down into single cells. Multicellular fungi (be it mold or the sticky bun) reproduce using the fragmentation of the mycelium. Hyphae torn away from the mother mycelium and transferred by people or animals become the beginning of a new mycelium. Most fungi produce thousands of spores which are caught up by the wind and reach distant places enabling the population of new regions.

Fungi play a very important role as a component of multiple environments. As saprobionts, like bacteria, they decompose dead organic matter, purify the environment of animal refuse and remains of other organisms. Thanks to that they enrich the soil with the elements obtained from the decomposing organisms, which are later absorbed by plants and built into their organs. That way fungi contribute to the formation of soil and ensure the circulation of matter in nature.

Yeasts conduct the process of fermentation, therefore they are found in numerous household applications and food industry. They are used for baking cakes and bread as well as in the production of wine and beer. Moldy cheese in turn is made using specially selected molds.

In pharmaceutical industry fungi are used for producing antibiotics - substances with bactericidal properties. The first antibiotic – penicillin – was obtained from the mycelium of penicillum. It was discovered by a Scottish doctor, Alexander Fleming.

Parasitic fungi cause nuisance diseases of plants. They contribute to lowered crops and the weakening of stand. Animal (also human) parasitic fungi cause diseases called mycosis. You can contract foot mycosis e.g. in a swimming pool or public bathrooms which are not properly sanitized. Therefore it is recommended to use protective footwear in such places. One should not use the same towels and nail care products as persons infected with mycosis, either.

Molds are the frequent cause of rotting of leather, wool or cotton, as well as books, if they are not stored in appropriate conditions, as well as food spoilage. Molds secrete poisonous substances, the so‑called alpha‑toxins.

Sporocarps of fungi have been used in cuisine for centuries. Chitin contained in the fungus cell walls makes them hard to digest, however their flavor and nutritious value (amino acids, vitamin A, B1, B2, PP) decide that they are a popular ingredient of dishes. Edible mushrooms are collected in forests (king bolete, sticky bun, birch bolete, chanterelle) or mass grown (common mushroom, oyster mushroom). Poland supplies 25% of common mushroom and forest mushrooms for the EU market. Some forest mushrooms cause food poisoning. Their toxins irreversibly damage liver cells, frequently leading to death. One of the most dangerous mushrooms is the death cap (Ammanita phalloides), mistaken for a common mushroom or parasol mushroom.

Particular species of mushrooms coexist with specific species of plants. Therefore king boletes can be found under oak trees, sticky buns under larch trees, birch boletes among birch trees and false saffron milkcap under spruce. These species live in symbiosis with the roots of specific trees and therefore are called mycorrhizaed fungi. Their hyphae entwine the roods and use the organic substances secreted by plants. The fungi are the sources of mineral salts, some vitamins and water for the trees.

• Fungi are organisms whose bodies, called mycelium are made of thread‑like hyphae.

• All fungi are heterotrophic.

• Fungi multiply by sexual and asexual reproduction through the fragmentation of the mycelium and spores.

• While picking mushrooms it is recommended not to pick mushrooms with gills, as those include lethally poisonous species.