Download Domains and Kingdoms

Levels of
Classification
…But mostly Domains and
Kingdoms…
Levels of Classification
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Scientists use classification to help study
and organize life on Earth.
There are several levels of classification to
further break down how closely organisms
are related. The broadest level is at the
top of the list, the most specific at the
bottom.
Levels of Classification

Levels of classification from broadest to
most specific:
Domain
 Kingdom
 Phylum
 Class
 Order
 Family
 Genus
 Species

Domains and Kingdoms
Today, a three domain system of
classification is commonly used.
 The three domains are:
Bacteria
Archaea
Eukarya

How are Domains and
Kingdoms determined?
Organisms are placed into
domains and kingdoms based on
3 things:
 Their cell type
 How they obtain energy
 The number of cells in their
bodies

Cell Type
 Eukaryote:
Cells that have a
nucleus.
 Prokaryote: Cells that do not
have a nucleus.
How Organism’s Obtain
Energy
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Autotroph: Organisms capable of
producing their own food from the Sun’s
energy, or from inorganic chemical
material.
Heterotroph: Organisms that cannot
produce their own food and obtain their
energy from eating others.
Number of Cells

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Unicellular: An organism made of just one
cell.
Multicellular: A complex organism made
up of many cells.
The Domains: Bacteria
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Members of the domain bacteria are
prokaryotes. These cells do not have a
nucleus
In prokaryotes, nucleic acids are not
contained within a nucleus.
Some bacteria are autotrophs while others
are heterotrophs.
All bacteria are unicellular, meaning they
are made of just one cell.
Domains: Archaea


Comes from the Greek word meaning
“ancient”
Can be found in the most extreme
environments on Earth:
Hot Springs
 Very Salty Water
 Swamp land
 Cow intestines!

Domains: Archaea (cont.)
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Like bacteria, they are unicellular
prokaryotes. Some are autotrophs, some
heterotrophs
They are classified in a different domain
then bacteria because they have a
different structure and chemical makeup to
that of a bacterium.
Domains: Eukarya

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Eukaryotic cells are those which contain a
nucleus
The domain Eukarya is split into 4
kingdoms:
Protists
 Fungi
 Plants
 Animals

Kingdom: Protists
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Protists: A eukaryotic organism that cannot
be classified as an animal, plant or fungus.
Members are very different from one another,
so it is often referred to as the “odds and
ends” kingdom.
Can be either an autotroph or heterotroph or
both!
Most are unicellular but some, such as
seaweeds, are large multicellular organisms.
Kingdom: Fungi
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Mushrooms, mold, and mildew are all
members of the Fungi kingdom.
Most are multicellular, but some, such as
yeast, are unicellular eukaryotes.
All fungi are heterotrophs. They live
almost anywhere on land but very few also
live in fresh water.
Most fungi feed from absorbing nutrients
from dead or decaying organisms.
Kingdom: Plants
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Dandelions, mosses and peas are all examples
of the plant kingdom.
Plants are all multicellular eukaryotes, most live
on land.
They are ALWAYS autotrophs, and they provide
food for most heterotrophs on land
This kingdom is home to much diversity,
containing redwood trees that can be gigantic
and mosses that never grow more than a few
centimeters.
Kingdom: Animals
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A dog, a flea in a dog’s ear, or a cat that a dog
chases are all part of the animal kingdom.
They are ALL multicellular and ALL
heterotrophs
Animals have different adaptations that allow
them to locate, capture, eat, and digest food
Animals can be found basically anywhere on
the planet, living in a wide variety of
environments