When Carolus Linnaeus developed his system

of classification, there were only two

kingdoms, Plants and Animals. But the use of

the microscope led to the discovery of new

organisms and the identification of

differences in cells. A two-kingdom system

was no longer useful, so he developed a new

one.

Today the current system of classification

includes six kingdoms that are placed within

three domains. The three domains are

Archaea, Bacteria and Eukarya.

#1: Archaea: Archaea is the Domain that all

Archaebacteria are classified under.

Approximately 4% of all organisms are Archaea.

This domain only includes one Kingdom: Archaea

(also called archaebacteria).

#2: Bacteria: Bacteria is the Domain that all

other bacteria are classified under. The

kingdom is called Bacteria or Eubacteria.

Approximately 7% of all organisms on earth

are bacteria. There are estimated to be about

1 million types of bacteria of which only 4,000

have been identified. These include bacteria

that are decomposers and non-harmful

bacteria that help our bodies, as well as

disease causing bacteria. This Domain only

includes one Kingdom: Bacteria or Eubacteria.

#3: Eukarya: Eukarya is the Domain that all

eukaryotes (organisms with an organized

nucleus) are classified under. Approximately

89% of all organisms are eukaryotes. In the

Eukaryota Domain, there are about 12.4 million

species. This Domain includes four Kingdoms:

Animals, Plants, Fungi, and Protista.

Click the Living Things picture to the left to

learn more about the three domains.

The six kingdoms are: Archaea, Bacteria,

Protista, Fungi, Plantae, and Animalia.

How are organism placed into their kingdoms? There are four ways: #1 Cell type (presence of a nucleus in the cell) All organisms are made of cells which carry on the functions necessary to sustain life. A cell is the basic unit of structure and function in an organism. Just as our bodies are made up of many structures (parts) that work together, cells have many structures (parts) that do the same. The structure is the parts it is made of and how it is put together. The function is the job each structure performs.

Exploring Classification

and The Six Kingdoms

of Life!

Prokaryotic Cells:

Organisms called Prokaryotes do not have an organized structure called a nucleus that contains genetic material and controls the cell. The genetic material just floats around inside of the cell. Pro = “before” and karyote = “nucleus”, no nucleus. You can remember that Pro rhymes with No for “NO” nucleus. Bacteria are examples of prokaryotes. Eukaryotic Cells:

Organisms called Eukaryotes do have an organized structure called a nucleus that contains genetic material and controls the cell. Eu = “true” and karyote = “nucleus”, true nucleus. You can remember that Eu rhymes with true and nu. Animals, plants, Fungi, and Protists are examples of eukaryotes. #2 Ability to make food Autotroph/Producers:

Organisms that make their own food;. Auto- means “self”, and –troph means “feeder.” Therefore, an autotroph is a self-feeder. They use the food they make as an energy source to carry out their life functions.

Examples are plants that make their own food by transforming the radiant energy from the Sun to chemical energy through the process of photosynthesis. Some bacteria are autotrophs. They use chemicals in their environment to make their own food. Some Protists, such as Euglena, can make their own food. They contain a structure called a chloroplast, and they use sunlight for photosynthesis. Heterotroph/Consumers:

Organisms that cannot make their own food are called heterotrophs. Hetero-means “other” and –troph means “feeder”. A heterotroph must feed off of others. They get their energy from eating autotrophs (plants) or eating other heterotrophs. Examples are animals, mushrooms, and molds. Euglena are able to consume food when light is not present. Heterotrophs transfer the chemical energy from food into other forms of energy they can use. #3 The number of cells in their body Unicellular:

All organisms are composed of cells. Unicellular organisms are single-celled (one). Uni = “one”. This one cell carries out all of the functions necessary to keep the organism alive. Bacteria

are examples of unicellular organisms. Many Protists are unicellular as well.

Multicellular:

All organisms are composed of cells.

Multicellular organisms are made of many cells.

Multi = “many”. All of the different cells are

specialized to do certain tasks. Humans have

skin cells, brain cells, and blood cells, just to

name a few. Animals and plants are examples

of multicellular organisms. Most Fungi are

multicellular, and a few Protists are as well.

#4 How an organism reproduces (makes more

offspring)

Asexual Reproduction:

Genetic material is passed from parents to

offspring (babies) during reproduction. Asexual

reproduction is a process that only involves

one parent, not two. A = “not”, not sexual.

The offspring will be identical to their

parent. The genes of the offspring are

exactly like the parent’s genes. Bacteria are

examples of organisms that reproduce

asexually. Bacteria will divide in half to form

two cells identical to the original cell. This is

called fission. Some plants, Fungi, and Protists

can reproduce asexually. In rare instances,

there are animals such as the sea anemone

that can reproduce asexually.

Sexual Reproduction:

Genetic material is passed from parents to offspring (babies) during reproduction. In sexual reproduction, offspring result from the combination of genetic material from two parents- a male and a female. They get half of the genetic material from each parent. The sperm from the male contains half of the genetic material, and the egg from the female contains half of the genetic material. Because offspring inherit a combination of genetic material from both parents, they are not exactly like either parent. Animals and most plants reproduce sexually. Some Fungi and Protists can reproduce sexually. A Paramecium is an example of an organism that can produce sexually or asexually.

Kingdom Archaea (archaebacteria)

In 1983, scientists took samples from a spot

deep in the Pacific Ocean where hot gases and

molten rock boiled into the ocean form the

Earth’s interior. To their surprise, they

discovered unicellular (one celled) organisms in

the samples. These organisms are today

classified in the kingdom Archaea.

.

Archaebacteria are prokaryotes that live

in extreme environments such as volcanic

vents, arctic temperatures, and hot

springs. Some examples are halophiles and

thermophiles. They can be autotrophic or

heterotrophic. They reproduce asexually.

They are called extremophiles. Can you

guess why?

Finding Archaea: The hot springs of

Yellowstone National Park, USA, were among

the first places Archaea were discovered. The

biologists pictured above are immersing

microscope slides in the boiling pool onto

which some archaea might be captured for

study. Click on the image above to learn more

about archaea and why they are called

extremophiles, are considered our oldest

relatives, and how they are responsible for

the colorful phenomenon below!

Kingdom Bacteria (Eubacteria)

Click on the image to

watch a fantastic

introduction video

about bacteria!

Like archaea, bacteria are single celled. They

are found everywhere and people are quite

familiar with them, including you!

Bacteria are classified in their own kingdom

because their chemical makeup is different.

Most Bacteria are helpful. Some produce

vitamins and foods like yogurt. However, the

bacteria, Streptococci pictured above, can give

you strep throat! Ouch!

Some of these bacteria are decomposers

which play an important and helpful role in

our ecosystem. Some are autotrophs while

others are heterotrophs. They reproduce

asexually. Most live in moderate environments.

Click on the Bacteria image and listen as the

Amoeba Sisters share more information on

Bacteria with you!

Kingdom Protists (Protista)

Click on the Protist image above for a

dynamic introduction to this odd kingdom!

Slime molds and algae are protists.

Sometimes they are called the odds and ends

kingdom because its members are so

different from one another. Protists include

all microscopic organisms that are not

bacteria, not animals, not plants and not

fungi. Protista are eukaryotes. Some are

unicellular, and some are multicellular. Many of

these organisms are microscopic such as

Amoeba, Paramecium, and Euglena. Some are

autotrophs and others are heterotrophs. They

can reproduce sexually or asexually.

You may be wondering why those protists

are not classified in the Archaea or Bacteria

kingdoms.

It is because, unlike archaea and bacteria,

protists are complex cells.

These

delicate

looking

diatoms

are

classified

in the

protist

kingdom.

Kingdom Plants (Plantae)

Click the image above for an awesome introduction to plants. You are probably quite familiar with the members of this kingdom as it contains all the plants that you have come to know - flowering plants, mosses, and ferns. Plants are all multicellular and consist of complex cells. Plants are also eukaryotes. All plants are autotrophs (producers), but in a few rare cases, some are also heterotrophs (Venus flytrap); however, they do not get their energy from the flies they trap. Some plants produce flowers, while others do not. Examples of plants are grass, trees, vegetable plants, and weeds. They can reproduce sexually or asexually. With over 250,000 species, the plant

kingdom is the second largest kingdom. Plant

species range from the tiny green mosses to

giant trees. Check out the world’s 7 largest

trees by clicking the image below.

Without plants, life on Earth would not exist!

Plants feed almost all the heterotrophs

(organisms that eat other organisms) on

Earth. Wow!

Learn more about plants by watching the

video below AND check out the top 10

strangest plants on earth!

Kingdom Fungi

Mushrooms, mold and mildew are all examples

of organisms in the kingdom fungi. They are

eukaryotes. Many are multicellular, but some

are unicellular. All are heterotrophs. Most feed

on dead or decaying organisms. They are found

almost everywhere on land, but some live in

water. They can reproduce sexually or

asexually.

Learn about fungal infections like ringworm

by clicking the harmless little fungi above.

Fun Facts about Fungi

Click above to learn more about

these FUN-GUYS!

Some fungi taste great and others can kill

you!

Fungi are organisms that biologists once

confused with plants, however, unlike plants,

fungi cannot make their own food. Most

obtain their food from parts of plants that

are decaying in the soil.

Kingdom Animals (Animalia)

The animal kingdom is the largest kingdom with over 1 million known species. See some by clicking below!

Sumatran Tiger - Kingdom: Animalia, Phylum, Chordata,

Class Mammalia, Order Carnivora, Family Felidae, Genus

Pathera, Species tigris

Members of the animal kingdom are found in

the most diverse environments in the world.

Animals Dogs, cats, fleas, and sea coral are

examples of animals. They are multicellular

eukaryotes that are heterotrophs

(consumers). Most, but not all, animals can

move from one place to another. Most

reproduce sexually, but some may be asexual

(sea anemones, whiptail lizards and some

fish, among others).

Check out live animal cams here!

And here!

And here!

And here!

And, here (Berry College in Rome, GA)

Check out reptiles here!

And Insects here!