Home » Biology » Classification



Animal kingdom

Colonial animals

Classifying groups of humans

Mollusk family tree

Classification butterflies

Plant kingdom

Fungi kingdom

Bacteria Kingdom

Archaea kingdom [move existing article to new location]

Protista – a super group of several different kingdoms



Content objective:

What are we learning and why are we learning this? Content, procedures, or skills.

Vocabulary objective

Tier II: High frequency words used across content areas. Key to understanding directions & relationships, and for making inferences.

Tier III: Low frequency, domain specific terms.

Building on what we already know

Make connections to prior knowledge. This is where we build from.

Why use scientific names?

Ever hear of the  cougar? Mountain lion? Puma? American panther? Florida panther? They’re all the same animal.

Guinea pigs? They’re not from Guinea, and are not pigs.

Jellyfish and starfish? Not fish.

Strawberries, bayberries, raspberries, and blackberries? Not true botanical berries!

(A berry is a fleshy fruit produced from a single flower, and containing one ovary. The plant’s entire ovary wall ripens into an edible outer layer.)

Actual berries include: Bananas (!), Blueberries, Cranberries, Coffee berries, Elderberry, Grapes.)

What about the pineapple?
What should we name a pineapple

Obviously, sometimes the common names for animals and plants are misleading.

Animals with Misleading names

Binomial nomenclature

That’s Latin for “2-word name system.”

We use a capitalized genus name, and an uncapitalized specific name.

They are italicized.

They can be abbreviated by making an initial of the first word and spelling out the second.

Example: E. coli is the abbreviation for the bacteria Escherichia coli.

There are many species of E. coli that live in the intestines of people and animals. Most of them are harmless. Many are an important part of a healthy human intestinal tract. However, some versions of E. coli can cause severe illness.

Escherichia coli bacteria

Photo from the National Institute of Allergy and Infectious Diseases (NIAID) Flickr account.  Scanning electron micrograph of Escherichia coli, grown in culture and adhered to a cover slip.

Examples for felidae (cat-like animals)

Examples for canines (dog like animals)

Animal versus Plant: The first way to categorize life

Carl von Linne, a Swedish botanist (plant scientist) created the first modern classification system for biology.

He was also called Carolus Linnaeus. Latin was the common language for European science, and so names were sometimes Latinized.

The Linnaean system – with modifications – is still used today. Here’s how it works.

Each particular type of organism is designated a species.

* Species are collected within a larger grouping, a genus.

* Similar genuses are grouped into a family.

* Families are grouped into an order

* Orders into a class

* Classes into a phylum.

* Phyla into a Kingdom.

KPCOFGS Kingdom Phylum Class order Family examples Linnaean

Levels of classification

Here we see a family tree of some carnivores.

Carnivore Feline Felis Mustelidae Canine Canis Classification

Animal, plant or other?

In Linnaeus’s time, people only recognized plants and animals.  Seaweed was thought to be a plant.

Today we know that seaweed is really in a protist, a kingdom that wouldn’t be understood and named until later.

Cardigan Bay Marine Wildlife Centre http://www.cbmwc.org/education/species-id-keys/

Cardigan Bay Marine Wildlife Centre

Mushrooms were thought to be plants – but they are really fungi.

They’re not plants at all. They don’t use photosynthesis.

What about bacteria? Or protozoans?

No one even knew of the existence of single-celled organisms at that time, so they weren’t part of the Linnaean system at that time.

6 Kingdoms of life

Today we sort life into six kingdoms:

Animals    Fungus    Plants

Protista    Bacteria   Archaea

There are also viruses, which by themselves aren’t fully alive, but are made of biological molecules, and reproduce inside living organisms.

3 Domain model

In 1977 Carl Woese blew the roof off the world of biology. His RNA study of little known single-celled organisms showed that there was an entire form of life our planet that had never been recognized. It was almost like discovering alien life on Earth.

The DNA of Archaea are more closely related to animals, than to bacteria!

By 1990 so much had been discovered about this strange new domain of life, that he proposed a new way of classifying life on Earth – and his argument was so compelling that biologists around the world accepted his new system.

MCAS sample questions

Feb 2016 MCAS.  The table below gives the common names, scientific names, and known geographic locations of several wild cats.

Panthera Feline classification

a. Using their common names, identify all the wild cats listed in the table that belong to the same genus.

b. Identify and explain one type of evidence scientists could have used to classify these wild cats.

The three kinds of tigers listed in the table are all classified as one species.

c. Based on the information in the table, identify which kind of tiger has the greatest chance of becoming a separate species. Explain your answer.

d. Describe how scientists could determine if one of the kinds of tigers becomes a separate species


Feb 2017 MCAS.  A botanist studied two groups of rice plants to determine how they are related. Both groups of plants have similar shapes, but one group has longer stalks. When the botanist cross-pollinated plants from one group with plants from the
other group, the seeds produced did not sprout or grow. Which of the following conclusions is best supported by this information?

A. The two groups are the same species because the plants have similar shapes.
B. The two groups are different species because they have differently sized stalks.
C. The two groups are different species because the seeds produced cannot
sprout or grow.
D. The two groups are the same species because the plants were cross-pollinated and produced seeds.

Learning Standards

Next Generation Science Standards

MS-LS4-2 Apply scientific ideas to construct an explanation for the anatomical similarities and differences among modern organisms and between modern and fossil organisms to infer evolutionary relationships.

Disciplinary Core Ideas – LS4.A: Evidence of Common Ancestry and Diversity
 Anatomical similarities and differences between various organisms living today and between them and organisms in the fossil record, enable the reconstruction of evolutionary history and the inference of lines of evolutionary descent.

NGSS Evidence Statement – Reasoning – Students use reasoning to connect the evidence to support an explanation. Students describe the following chain of reasoning for the explanation… Changes over time in the anatomical features observable in the fossil record can be used to infer lines of evolutionary descent by linking extinct organisms to living organisms through a series of fossilized organisms that share a basic set of anatomical features.

Benchmarks for Science Literacy

American Association for the Advancement of Science

Students should begin to extend their attention from external anatomy to internal structures and functions. Patterns of development may be brought in to further illustrate similarities and differences among organisms. Also, they should move from their invented classification systems to those used in modern biology… A classification system is a framework created by scientists for describing the vast diversity of organisms, indicating the degree of relatedness between organisms, and framing research questions.

SAT Biology Subject Area Test

Evolution and diversity: Origin of life, evidence of evolution, patterns of evolution, natural selection, speciation, classification and diversity of organisms.

Teaching About Evolution and the Nature of Science, National Academy Press (1998)

Biological classifications are based on how organisms are related. Organisms are classified into a hierarchy of groups and subgroups based on similarities which reflect their evolutionary relationships. Species is the most fundamental unit of classification.

National Science Education Standards, The National Academies Press, 1996
Biological classifications are based on how organisms are related. Organisms are classified into a hierarchy of groups and subgroups based on similarities which reflect their evolutionary relationships. Species is the most fundamental unit of classification.

Learning standards for dichotomous keys

National Science Education Standards, The National Academies Press, 1996

[Use of dichotomous key is a math skill] – Use Math in all aspects of scientific inquiry: Mathematics is essential to asking and answering questions about the natural world. Mathematics can be used to ask questions; to gather, organize, and present data; and to structure convincing explanations.

%d bloggers like this: