Classification of Organisms

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Questions and Answers

How are organisms classified into domains and kingdoms?

Organisms are classified into a three-domain system: Bacteria, Archaea, and Eukarya, based on their cell type, ability to make food, and number of cells in their bodies.

What is Domain Bacteria?

Domain Bacteria includes unicellular prokaryotes that can be found anywhere; some are autotrophs and some are heterotrophs.

What are prokaryotes?

Prokaryotes are unicellular organisms whose cells lack a nucleus.

What is a nucleus?

A nucleus is a dense area in a cell that contains nucleic acids, directing the cell's activity. Signup and view all the answers

What characterizes Domain Archaea?

Members of Domain Archaea are unicellular prokaryotes that can live in extreme environments and differ from bacteria in chemical makeup and cell structure. Signup and view all the answers

What is Domain Eukarya?

Domain Eukarya includes organisms classified into one of four kingdoms: protists, fungi, plants, or animals. Signup and view all the answers

What are eukaryotes?

Eukaryotes are organisms whose cells contain a nucleus. Signup and view all the answers

What is Protista?

Protista is a kingdom of any eukaryotic organism that cannot be classified as a fungus, plant, or animal. Signup and view all the answers

What are Fungi?

Fungi include mushrooms, molds, and mildew; they are heterotrophs that feed off dead and decaying organisms. Signup and view all the answers

What is Plantae?

Plantae includes all multicellular autotrophs that can make their own food through photosynthesis. Signup and view all the answers

What is the definition of a domain in taxonomy?

A domain is one of the three broad groups that all living things fall into. Signup and view all the answers

What characterizes Domain Animalia?

All animals are multicellular heterotrophs that have adaptations for locating and digesting food. Signup and view all the answers

What is a genus?

A genus is the level of classification that comes after family and contains similar species. Signup and view all the answers

What defines a species?

A species is a group of organisms that are closely related and can mate to produce fertile offspring. Signup and view all the answers

Study Notes

Classification of Organisms

Organisms are classified into a three-domain system: Bacteria, Archaea, and Eukarya.
Classification criteria include cell type, method of food production, and cellular organization (unicellular or multicellular).

Domain Bacteria

Bacteria thrive in diverse environments and can be autotrophs (produce their own food) or heterotrophs (consume other organisms).
All bacteria are unicellular prokaryotes, lacking a nucleus.

Prokaryotes

Prokaryotes are unicellular organisms without a nucleus, meaning their nucleic acids aren't enclosed in a membrane-bound structure.

Nucleus

The nucleus is a dense cell area that houses nucleic acids, which are crucial for directing cellular activity.

Domain Archaea

Archaea can inhabit extreme conditions, including deep ocean floors, hot springs, and volcanic environments.
Like bacteria, Archaea are unicellular prokaryotes and can be autotrophs or heterotrophs.
Archaea differ from bacteria chemically and structurally.

Domain Eukarya

Organisms in the domain Eukarya are classified into four kingdoms: Protista, Fungi, Plantae, and Animalia.

Eukaryotes

Eukaryotes are organisms with cells that contain a nucleus, distinguishing them from prokaryotes.

Kingdom Protista

Includes all eukaryotic organisms that are not classified as fungi, plants, or animals, often referred to as the "odds and ends" kingdom.
Members can be autotrophic or heterotrophic and vary from unicellular to multicellular.

Kingdom Fungi

Comprises organisms like mushrooms, molds, and mildew, including both unicellular and multicellular forms.
Fungi are heterotrophs that obtain nutrients by absorbing the remains of dead or decaying organisms.

Kingdom Plantae

All plants are multicellular autotrophs that produce their own food via photosynthesis.
They provide nourishment for many land-dwelling heterotrophs.
Plant structures vary widely and possess cell walls made of cellulose.

Domain

A domain is a high-level taxonomic category that includes all living organisms.

Kingdom Animalia

All animals are multicellular heterotrophs with varying adaptations for locating, capturing, and digesting food.
Animals inhabit numerous environments and distinctively lack cell walls.

Genus

Genus is a taxonomic rank that follows family and groups together closely related species.

Species

A species is a group of organisms that can interbreed and produce fertile offspring, indicating close genetic relationships.

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Description

Explore the fascinating world of organism classification in this quiz. You'll learn about the three-domain system: Bacteria, Archaea, and Eukarya, as well as the differences between prokaryotic and eukaryotic cells. Test your understanding of how organisms are categorized based on cell type and food production methods.