Classification of Living Organisms

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Questions and Answers

What is taxonomy and phylogeny?

Taxonomy is the branch of biology that classifies organisms and assigns each organism a universally accepted name. Phylogeny shows the evolutionary relationships that exist between organisms.

What is the difference between a kingdom and a species?

A kingdom is the broadest and least restrictive level of classification, while a species is the most specific level of classification.

What is the difference between a phylum and a division?

In the animal kingdom, each subdivision of a kingdom is called a phylum, while in the plant kingdom, each subdivision of a kingdom is called a division.

List the seven levels of classification in order from broadest to most specific.

Kingdom, phylum, class, order, family, genus, species Signup and view all the answers

Who was the first person to attempt to classify living organisms on Earth?

Aristotle Signup and view all the answers

What method did Aristotle use to classify living organisms?

Aristotle classified animals based on where they lived (air, sea, land) and plants according to the type of woody stems they had (herb, shrub, or tree). Signup and view all the answers

Who was the first to attempt a scientific classification of living organisms?

Linnaeus Signup and view all the answers

On what basis did Linnaeus classify living organisms?

Linnaeus based his classification on morphology (structures) Signup and view all the answers

What is binomial nomenclature?

Binomial nomenclature is the system of naming that involves giving an organism a two-part name. Signup and view all the answers

What are the two parts of a scientific name?

Genus and species Signup and view all the answers

In what language is the scientific name written?

Latin Signup and view all the answers

What is phylogeny and taxonomy?

Phylogeny is the evolutionary history of a species, while taxonomy is the science that groups and names species. Signup and view all the answers

How is the classification process used by modern taxonomists different from the methods used by Linnaeus?

Modern taxonomists consider morphology, cellular organization, evolutionary relationships, biochemical similarities, genetic similarities, and embryological similarities, while Linnaeus based his system on structural similarities (morphology). Signup and view all the answers

Why should the use of common names be avoided when classifying living organisms?

Common names are confusing and very misleading. Signup and view all the answers

What is a molecular clock?

A molecular clock is a system that uses DNA comparisons to estimate the length of time that two species have been evolving independently. Signup and view all the answers

What is the correctly written scientific name for the lion?

Panthero leo Signup and view all the answers

What is an example of a derived character?

Hair in mammals Signup and view all the answers

In cladistics, what determines the evolutionary relationship between two organisms?

Shared derived characters Signup and view all the answers

What is a shared derived character?

A characteristic that is unique to a particular group of organisms and has evolved in recent parts of a lineage. Signup and view all the answers

What is the system of classification that is based on shared derived characters?

Cladistics Signup and view all the answers

List the three domains and describe the basis for separating organisms into these domains.

Domain Bacteria: Cell walls composed of peptidoglycans. Domain Archaea: Live in extreme environments. No peptidoglycans in the cell wall. Domain Eukarya: Possess a nuclear membrane and other membrane-bound organelles. Signup and view all the answers

Why is the Protista kingdom referred to as the 'catch-all' kingdom and the 'odds and ends' kingdom?

The Protista kingdom contains organisms that do not fit into any other kingdom. Signup and view all the answers

Study Notes

Taxonomy and Phylogeny

Taxonomy classifies organisms and assigns universally accepted names.
Phylogeny illustrates evolutionary relationships among organisms.

Levels of Classification

Kingdom represents the broadest classification; species represents the most specific.
A phylum is used for animal kingdom subdivisions; division for plant kingdom subdivisions.
Seven classification levels from broadest to most specific: Kingdom, Phylum, Class, Order, Family, Genus, Species.

Historical Figures in Classification

Aristotle was the first to classify living organisms based on habitat (land, sea, air) and plant stem types (herb, shrub, tree).
Linnaeus advanced scientific classification, focusing on morphology (structures).

Naming Organisms

Binomial nomenclature is a two-part naming system consisting of genus and species.
Scientific names are written in Latin.

Modern Classification Techniques

Modern taxonomists consider various factors beyond morphology, including cellular organization, evolutionary relationships, biochemical composition, genetic data, and embryological similarities.
Avoid common names for classification due to their misleading nature; many common names do not accurately represent the organisms (e.g., catfish, jellyfish).

Molecular Clock

A molecular clock uses DNA comparisons to estimate the evolutionary timeline between species.

Derived Characters in Cladistics

Derived characters, such as hair in mammals, help determine evolutionary relationships in cladistics through shared characteristics.

Domains of Life

Three domains:
- Domain Bacteria: cell walls contain peptidoglycans.
- Domain Archaea: live in extreme environments; lack peptidoglycans and possess different membrane structures.
- Domain Eukarya: have a nuclear membrane and membrane-bound organelles.

Protista Kingdom

The Protista kingdom is termed "catch-all" due to its inclusion of diverse organisms that do not fit into other kingdoms, possessing traits of both plants and animals.

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Description

Test your knowledge on the classification of living organisms with these flashcards. Learn about taxonomy, phylogeny, and the different hierarchical levels such as kingdom and species. Perfect for biology students seeking to deepen their understanding of life's diversity.