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Living Things - Classification of Species

Grade 5IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Taxonomy is the branch of science concerned with the classification of living organisms. It helps scientists communicate globally using a standardized system.

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The hierarchical levels of classification, from broadest to most specific, are: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species. A common mnemonic is 'Dear King Philip Came Over For Good Soup'.

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Binomial Nomenclature is the formal system of naming species. Each name consists of two parts: the GenusGenus (capitalized) and the speciesspecies (lowercase), both usually written in italics (e.g., PantheraPanthera leoleo).

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Living things are generally divided into five kingdoms: Animalia (animals), Plantae (plants), Fungi (mushrooms/yeast), Protista (single-celled organisms like amoeba), and Monera (bacteria).

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Dichotomous Keys are tools consisting of a series of choices (usually two) that lead the user to the correct identification of an organism based on its physical traits.

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Animals are further classified into Vertebrates (with a backbone) and Invertebrates (without a backbone). Approximately 97%97\% of all animal species are invertebrates.

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Plants are classified into Vascular (containing xylemxylem and phloemphloem for transport) and Non-vascular (lacking specialized transport tissues, like mosses).

📐Formulae

Scientific Name=Genus (Capitalized)+species (lowercase)\text{Scientific Name} = \text{Genus (Capitalized)} + \text{species (lowercase)}

Species⊂Genus⊂Family⊂Order⊂Class⊂Phylum⊂Kingdom\text{Species} \subset \text{Genus} \subset \text{Family} \subset \text{Order} \subset \text{Class} \subset \text{Phylum} \subset \text{Kingdom}

Total Animals=Invertebrates (97%)+Vertebrates (3%)\text{Total Animals} = \text{Invertebrates (97\%)} + \text{Vertebrates (3\%)}

💡Examples

Problem 1:

A scientist finds a new organism. Its genus is MuscaMusca and its species is domesticadomestica. Write its scientific name correctly using binomial nomenclature rules.

Solution:

MuscaMusca domesticadomestica

Explanation:

In binomial nomenclature, the first word is the Genus (starts with a capital letter) and the second word is the species (starts with a lowercase letter). Both should be italicized or underlined.

Problem 2:

Identify the kingdom of an organism that is multicellular, cannot move from place to place, absorbs nutrients from decomposing organic matter, and does not perform photosynthesis.

Solution:

Kingdom Fungi

Explanation:

Fungi are multicellular (except yeast), heterotrophic (absorb food), and have cell walls made of chitin, distinguishing them from plants which perform photosynthesis.

Problem 3:

Using the hierarchy of classification, which group contains the largest variety of different organisms: a Phylum or a Family?

Solution:

Phylum

Explanation:

In the taxonomic hierarchy, levels become more specific as you move down. Since Phylum is higher than Family (Phylum>Class>Order>FamilyPhylum > Class > Order > Family), it contains a much broader and more diverse group of organisms.