Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

Monthly Update sign up
Mailing List signup
Search
Follow The Annenberg Learner on LinkedIn Follow The Annenberg Learner on Facebook Follow Annenberg Learner on Twitter
MENU

Life Science: Session 2

Classifying Living Things

How are living things classified?

The classification of life on Earth is an ongoing and dynamic endeavor. Early classification schemes identified the kingdom as the broadest grouping and employed a two-kingdom categorization strategy: Plants and Animals. However, a five-kingdom strategy has been dominant for many decades: Plants, Animals, Fungi, Protists, and Bacteria. With advances in the ability to discern fundamental differences in cell structure and function as well as evolutionary relationships, the domain is now considered the broadest grouping. The most fundamental difference is the presence of a nucleus. The organisms in the domains Archaea and Bacteria are prokaryotic (“before the nucleus”) while the organisms within the domain Eukarya are eukaryotic (“after the nucleus” or “true nucleus”).

In the video, a strategy for classification based on cell features was introduced to group life forms into domains and, within the domain Eukarya, into kingdoms. Classification into kingdoms in the Archaea and Bacteria domains continues to occupy microbiologists as techniques improve. And, within the Protist kingdom, it is very likely that several different kingdoms will eventually be defined, as this group does not accurately reflect evolutionary relationships.

Domain Eukarya
 

Domain Archaea

2+ Kingdoms

Domain Bacteria

22+ Kingdoms

Protist
Kingdom

protist

Fungus
Kingdom

mushroom

Plant
Kingdom

flower

Animal
Kingdom

earthworm

How many cells?

Unicellular

Unicellular

Unicellular, Multicellular

Unicellular, Multicellular

Multicellular

Multicellular

Is there a nucleus?

No

No

Yes

Yes

Yes

Yes

Is there a cell wall?*

Yes

Yes

Sometimes

Yes

Yes

No

How is food obtained?

Makes,
Absorbs

Makes,
Absorbs

Makes, Absorbs, Ingests

Absorbs

Makes

Ingests

*The cell walls in these different groups are not made of the same materials and, thus, the presence of a cell wall only reflects similarity within a group, not between groups.

prev: a closer look intro next: the plant kingdom



© Annenberg Foundation 2014. All rights reserved. Legal Policy