Science & Technology in Action

3rd Edition

Fungi: Mushrooms

Teagasc

The kingdom of fungi includes organisms that are important both economically and ecologically. By breaking down dead organic material, such as plants and wood, they facilitate the recycling of nutrients in ecosystems.
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Contains the full lesson along with a supporting toolkit, including teachers’ notes.

Lesson excerpt

The kingdom of fungi includes organisms that are important both economically and ecologically. By breaking down dead organic material, such as plants and wood, they facilitate the recycling of nutrients in ecosystems. Fungi are neither plants nor animals but share some characteristics of both; forming a kingdom on their own. They generally cannot move around like animals but, like them, they do require an external source of food. They do not contain chlorophyll, like plants, so they cannot make their own food by photosynthesis. They reproduce by means of spores rather than seeds and in that respect they are similar to ferns and mosses.

Classification
Until the twentieth century living organisms were generally classified simply as plants or animals; there were just two kingdoms: Plantae and Animilia. Increased understanding of fundamental biology led to the addition of three more kingdoms:Prokaryota (e.g. bacteria), Protoctista (e.g. unicellar organisms like amoebae and algae) and Fungi (e.g. moulds and yeasts etc.). Today living things are divided into three domains: Bacteria,Archaea and Eukaryota; the Eukaryota are divided into four kingdoms: animals, plants, fungi, and protoctists (eukaryotes that do not fit elsewhere).

Within each kingdom organisms are further classified into phyla,classes, orders, families, genera and species. Sub-kingdoms, sub-divisions, sub-classes etc. are sometimes added to clarify relationships. 
Fungi are eukaryotes - they have complex cells where their genetic material is held in a nucleus with a membrane and they also contain other membrane-bound organelles such asmitochondria. Fungal cells have a cell wall that is made ofchitin rather than cellulose and they are less differentiated than typical cells of plants and animals

Fungi are heterotrophs, which means that they require an external source of organic compounds made by other organisms for their nutrition. Heterotrophs can be saprophytic, parasiticor symbiotic. Saprophytes live on dead organic matter whereasparasites and symbionts live on or in other living organisms. While symbionts may benefit their hosts, parasites can damage or even kill them.

Quiz questions

  1. Eukaryotic organisms are those with a nucleus and membrane-bound organelles. true
  2. The top ‘rank’ in the scientific classification of organisms is Domain. true
  3. A mutualistic relationship is one where one organism benefits to the disadvantage of the other. false
  4. Fungi can make their own food by photosynthesis. false