TAXONOMY

Unit 10 - Taxonomy

Taxonomy and Classification - overview

Taxonomy is the science of classifying things, especially living things.

We are going to look at:

●form of scientific names of living things

●the 8 levels of classification of living things

●characteristics of Domains and Kingdoms, the two biggest categories

●the use of dichotomous keys to determine species

The Big Idea - Classification

Humans are curious and like to talk about the other living things in the world
around us, so we have always given names to these animals and plants (and other
things).

Sometimes, it is even necessary to communicate to other people in a very specific
way about these organisms.

“What kind of snake did you see in the garden?”

“I need you to get me some oregano to put in the soup I’m making.”

“They live over the mountain in the big grove of sweetgum trees.”

“That plant over there is poison ivy -- stay out of it!”

Open Ended

What are some potential problems with naming species? Why is it important to be s

Problems with naming

1. Sometimes different people in different
places call the same thing by different names.

Blazing Star

Gayfeather

Button Snakeroot

2. Sometimes people call a variety of different
things by the same name.

The solution

This system was invented and popularized by the Swedish
botanist and naturalist, Carl Linnaeus. He was one of the
most influential and successful scientists of the 18th
Century.

He even renamed himself to sound fancier and more
“sciency.”

Carl von Linné → Carl Linnaeus

Today, while we still use common names (e.g. red-tailed hawk, petunia, hen-of-the-forest)
in everyday life, we also have internationally accepted, unique names for every single
living thing. We call these scientific names.

How scientific names work --

The names always have two parts, so it is referred to as binomial
nomenclature (“two word naming”). The words are “latinized” with
suffixes that are like latin words.

1.The Genus -- this part is always Capitalized

2.

The specific epithet -- this part is never capitalized

●Together, they make up the scientific name of a species.

●The species scientific name is always in italics (or
underlined)

ex) Blue Jay -- Genus is Cyanocitta, species epithet is cristata; the
species name is Cyanocitta cristata (Cyanocitta cristata)

ex) Groundhog -- Genus is Marmota, species epithet is monax; the
species name is Marmota monax (Marmota monax)

Multiple Choice

Choose the correct form of the scientific name of the species black bear

• Ursus Americanus

• Ursus Americanus

• Ursus Americanus

• Ursus americianus

Grouping species

● Species nearly

always belong in
other identifiable
groups.

● Historically, this was

done using physical
characteristics.

● Now, genetic

similarity (DNA) is
predominantly used.

Levels of Classification of living things

There are eight major levels of classification: Domain,
Kingdom, Phylum, Class, Order, Family, Genus, and
Species.

The are many different mnemonics (memory aides) to
help remember these different levels, like this one:

Dumb King Phillip cut
open five green snakes

Dumb

King

Phillip

cut

open

five

green

snakes

Levels of Classification of living things

Each higher (larger, broader, more comprehensive)
level contains numerous groups of the next lower
level

examples:

● a Phylum contains many classes
● An Order contains many families
● A family contains many genera (plural of

genus).

Domains -- the most basic divisions

Based on basic cellular biochemistry

3 Domains (includes all of life)

Bacteria

Archaea

Eukarya

(humans are Eukarya -- we have complex
cells with a nucleus and organelles)

Kingdoms

The second biggest division

This has changed over time as scientists have learned more about the diversity,
genetics, and biochemistry of organisms.

Linnaeus originally put everything in two kingdoms -- animals and plants

We currently have 6 Kingdoms

protists

plants

bacteria

fungi

archaea

​Animals

Open Ended

Name the three domains

Characteristics of Domains and Kingdoms

3 Domains

6 Kingdoms

Characteristics

Examples

Archaea

Archaea

single-celled, lacks nucleus, live in harsh envir.

methanogens, extreme
thermophiles

Bacteria

Bacteria

single-celled, lacks nucleus, ubiquitous
(everywhere)

E. coli, Salmonella,
Streptococcus pyogenes

Eukarya

Animals

multicellular, nucleus, organelles, ingest food,
no cell wall, movement

corals, sponges, worms,
insects, reptiles, birds,
mammals

Plants

multicellular, nucleus, organelles, photosynthetic

ferns, mosses, trees,
grasses

Fungi

mostly multicellular, absorb their food, cell walls,

mushrooms, molds,
mildews, yeasts

Protists

mostly single-celled, most in water, diverse
ways of getting energy

amoeba, paramecia,
diatoms, Euglena

How much biomass is there of each Kingdom?

note: Animals make up the smallest fraction of life of all the Kingdoms.

There is 29 times more mass of bacteria than all the animals (including
people) put together.

Open Ended

Using the image name the different types of organisms. Ex: producer, primary consumer etc...

Using tools to determine species

The most common method of determining what species something is to use what is
called a dichotomous key.

This is a series of questions about an organism, each with two possible answers.

Gradually, if you answer each question carefully and correctly, the dichotomous key
leads you to your answer -- what the scientific name of the species is that you are
looking at.

Example of a dichotomous key -- you have a vertebrate animal
that you want to know what kind it is (what Class is it?)

START here
If a vertebrate had:

no fur
no feathers
external fertilization
no gills in adults

Then, it would be an
amphibian.