Exercises: The kingdoms of living things

Name the six kingdoms of living things and give an example of an organism for each of them.

Classify these organisms into their kingdom: a holm oak, an amoeba, a mushroom, an eagle, and yoghurt bacteria. Justify each choice using a characteristic of the corresponding kingdom.

The diagram shows the classification tree of living things according to the five-kingdom model, but one kingdom is missing, marked with "?". Identify which kingdom it is and explain the characteristics (cell type, number of cells, and mode of nutrition) that define it.

Create a table showing the five kingdoms of the traditional classification (Whittaker-Margulis), specifying for each: cell type (prokaryotic or eukaryotic), whether its organisms are unicellular or multicellular, and its type of nutrition.

For centuries, mushrooms were considered plants. Explain at least two reasons why fungi are today classified in their own kingdom, separate from the plant kingdom.

A microscopic organism is unicellular, has eukaryotic cells, and moves actively in search of food. Which kingdom does it belong to? Explain why it cannot be either an animal or a bacterium.

A single-celled organism with a nucleus is discovered in a pond. It has chlorophyll when light is available, but in the dark, it engulfs food particles. Discuss which kingdom you would classify it into and what problem cases like this pose for kingdom classification.

A student observes a lichen on a bare limestone rock and states: “It is a simple plant, because it is green and performs photosynthesis.” Refute their statement by explaining the true biological composition of a lichen and which kingdoms its components belong to. Then, predict what would happen to each of these two organisms if you separated them and left them isolated on that same sunny rock with no soil, justifying your answer based on the type of nutrition of each one.

Compare two organisms belonging to the kingdom Protoctista: the Paramecium (unicellular, heterotrophic, and with cilia to move) and the giant Kelp (multicellular, over 20 meters long, and photosynthetic autotroph).

1. a) Justify why including both in the same kingdom creates contradictions when compared with the criteria that define Plants and Animals.
2. b) Explain why, despite their similarities to them, the paramecium is not classified as an animal nor kelp as a true plant.