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Five Kingdom System

9.4 Five kingdom system (ESGBY)

In this section learners are introduced to the most common way of grouping living organisms based on simple distinctive characteristics. Classification systems are always changing as new information is made available. Modern technologies such as electron microscopy make it possible to observe microscopic organisms in greater detail. The current system was developed by Robert H. Whittaker in 1969 and was built on the work of previous biologists such as Carolus Linnaeus.

The five kingdom system is the most common way of grouping living things based on simple distinctive characteristics. Classification systems are always changing as new information is made available. Modern technologies such as Genetics makes it possible to unravel evolutionary relationships to greater and greater detail. The five-kingdom system was developed by Robert H. Whittaker in 1969 and was built on the work of previous biologists such as Carolus Linnaeus.

Living things can be classified into five major kingdoms:

  • Kingdom Animalia
  • Kingdom Plantae
  • Kingdom Fungi
  • Kingdom Protista
  • Kingdom Monera (Bacteria)

A video showing a brief summary of the five kingdoms

Video: 2CXG

We will now identify the main distinctive features of each kingdom:

Kingdom Monera (ESGBZ)

The Kingdom Monera consists of prokaryotic, unicellular organisms. No nuclear membrane or membrane-bound organelles such as chloroplasts, Golgi complex, mitochondria or endoplasmic reticulum are present. Monera have a cell wall of protein plus polysaccharide compound, but not cellulose. They reproduce asexually by binary fission. Important examples of Monera include Archaea and Bacteria.

Bacteria are found everywhere and are the most numerous organisms on Earth. In a single gram of soil, there are about 40 million bacterial cells. The human body also contains \(\text{10}\) times as many bacterial cells as human cells!

Mycobacterium bacteria that causes Tuberculosis.

Staphylococcus aureus bacteria can cause skin infections, sinusitis and food poisoning.

Kingdom Protista (ESGC2)

Protista are eukaryotic and can be unicellular or simple multicellular. They reproduce sexually or asexually. Important examples of protists include the organism known as Plasmodium (which causes malaria), Amoeba and Euglena. There are two major groups of protists which include the Protozoans, whose cells are similar to animal cells in that they do not have cell walls and the plant-like cells which do have cell walls and are similar to algae.

Euglena an example of a protist.

Figure 9.9: Diatoms from Antarctic sea ice.

Kingdom Fungi (ESGC3)

Fungi are eukaryotic organisms that can be multicellular or unicellular. Mushrooms and moulds are examples of multicellular fungi and yeast is an example of a unicellular fungi. All fungi have a cell wall made of chitin. They are non-motile (not capable of movement) and consist of threads called hyphae. Fungi are heterotrophic organisms which means they require organic compounds of carbon and nitrogen for nourishment. They are important as decomposers (saprophytes) and can be parasitic. They store carbon as glycogen, not in the form of starch. Fungi reproduce sexually and asexually by spore formation. An important example of a useful fungus is Penicillium (a fungus which was used to make penicillin, one of the most powerful antibiotics ever created).

Figure 9.10: Examples of fungi.

Figure 9.11: Mushrooms are examples of fungi.

A TED video on the many uses of Fungi

Video: 2CXH

Sir Alexander Fleming discovered the first antibiotics in 1928, after observing that colonies of Staphylococcus aureus bacteria could be destroyed by the fungi Penicillium notatum. This observation that certain substances were deadly to microbial life lead to the discovery and development of medicines that could kill many types of disease-causing bacteria in the body.

Kingdom Plantae (ESGC4)

Organisms belonging to the plant kingdom are eukaryotic and multicellular organisms. They have a distinct cell wall made of cellulose. Cells are organised into true plant tissues. Plants contain plastids and photosynthetic pigments such as chlorophyll. They are non-motile. Plants make their own food by photosynthesis and are therefore said to be autotrophic. Plants undergo both sexual and asexual reproduction. They store food as starch. Important examples of plants are mosses, ferns, conifers and flowering plants.

Examples of plant variety

Kingdom Animalia (ESGC5)

Members of the animal kingdom are eukaryotic and multicellular but have no cell wall or photosynthetic pigments. They are mostly motile and they are heterotrophic, which means they must feed on other organisms and cannot make their own food. They reproduce sexually or asexually. Animals store carbon as glycogen and fat. Important examples of this kingdom include: Porifera (sponges), Cnidaria (jellyfish), Nematoda (nematode worms), Platyhelminthes (flatworms), Annelidas (segmented worms), Mollusca (Snails and Squid), Echinodermata (starfish), Arthropoda (Insects and Crustaceans), Chordata (includes all the vertebrates: fish, amphibians, reptiles, birds, mammals).

Examples of animal variety:

Animal Phyla

Porifera:A variety of sea sponges in the Caribbean Sea.

Cnidaria:A jellyfish.

Platyhelminthes:A marine flatworm, Pseudobiceros gloriosus.

Mollusca: An octopus.

Echinodermata: A variety of starfish.

Arthropoda:An example of an insect, the Festive Tiger beetle.

Classes of vertebrates

Figure 9.18: Fish

Figure 9.19: Amphibians

Figure 9.20: Reptiles

Figure 9.21: Birds

Figure 9.22: Mammals

TEACHER RESOURCES:

Investigate examples of life forms from each kingdom

Aim

To investigate examples from each kingdom.

Instructions:

  1. Research one beneficial and one harmful application of one member from each kingdom, with examples from their use in South Africa. Students can be grouped into smaller groups and each one is given one kingdom to research. (Use www.arkive.org as a research tool for your favourite animal or plant or http://bugscope.becnkman.uiuc.edu/ for nice pictures of insects). Results can be presented in the form of a poster.
  2. Go to your nearest supermarket or garden and find one representative organism for each kingdom. Present this information by drawing a diagram.

Activity: Investigate examples of life forms from each kingdom

In this activity a learners are to research one beneficial and one harmful application of one member from each of the kingdoms including examples of their use in South Africa. Learners can be grouped into smaller groups and each one is given one kingdom to research. Learners can present their results in the form of a poster.

Since this is an OPTIONAL activity, no detailed memorandum is provided. If teachers are keen to have learners do this, they will have to provide some form of guidance to learners about what level of detail is expected, e.g. a short paragraph on one beneficial and one harmful member of each kingdom. It is suggested that this be done in GROUPS of two or four, so each group gets only one kingdom to research (learner 1 and 2 find a beneficial plant and learner 3 and 4 find a harmful plant, for example. One can find the information and the other finds a picture.) Teachers should ensure that all 5 kingdoms are covered by the class, so it will be important to do some planning beforehand.

Dichotomous Key (ESGC6)

A dichotomous key is a tool that taxonomists often use to classify organisms correctly. It is a form of hierarchical grouping that involves making decisions in a series of steps, from general differences to very specific differences. It is called a dichotomous key because there are always two choices. There is a very specific way to set up a dichotomous key. For instance, one must always move from the general to the specific, and one must always ensure that the two choices in the decision tree are mutually exclusive and jointly exhaustive. Mutually exclusive means that there cannot be overlap between the two options, as this would result in wanting to place an organism in two groups. Jointly exhaustive means that your two options must cover all possibilities, otherwise you won't be able to place an organism in either of the groups.

Identifying arthropods using a dichotomous naming key

Aim

To use a dichotomous key to identify arthropods.

Table of specimens

ABC
DEF
GHI
JKL

Instructions

  1. Study the organisms in the table of specimens provided to you.
  2. Use the dichotomous key to find out to which taxonomic group each of these arthropods belong.
  3. Write the letter corresponding to the arthropod, and then your answer.
CharacteristicInstruction

1a

1b

Arthropod has eight legs

Arthropod does not have 8 legs

go 2 (Arachnids)

go 4

2a

2b

Arachnid has pedipalp with pincers

Arachnid does not have pedipalp with pincers

SCORPION

Go 3

3a

3b

Arachnid drinks blood

Arachnid does not drink blood

TICK

SPIDER

4a

4b

Arthropod has more than 16 legs

Arthropod does not have more than 16 legs

Go 9 (Myriapoda)

Go 5

5a

5b

Arthropod has 3 pairs of legs

Arthropod does not 3 pairs of legs

Go 6 (Insects)

CRUSTACEAN

6a

6b

Insect has hardened fore-wings

Insect does not have hardened fore-wings

COLEOPTERA

Go 7

7a

7b

Insects are social and/ or live in a hive

Insects are not social, do not live in a hive

HYMENOPTERA

Go 8

8a

8b

Insects does not have a sponge-like proboscis

Insects have a sponge-like proboscis

LEPIDOPTERA

DIPTERA

9a

9b

Myriapod with one pair of legs per segment

Myriapod with two pairs of legs per segment

CENTIPEDE

MILLIPEDE

Answers:

  • A: Hymenoptera

  • B: Millipede

  • C: Crustacean

  • D: Tick

  • E: Spider

  • F: Centipede

  • G: Lepidoptera

  • H: Coleoptera

  • I: Hymenoptera

  • J: Scorpion

  • K: Diptera

  • L: Hymenoptera

This website shows you an exercise with answers , using a dichotomous key: