Theme 2: Living Beings and Their Classifications—Microorganisms
Conceptual Map
Taxonomy
KINGDOMS
Monera
Protoctista
Protozoa
Fungi
Plantae
Animalia
Algae
Lichens
THE CLASSIFICATION OF LIVING THINGS
In order for scientists to study the millions of species that exist, they need to order them in
groups, or classify them. Taxonomy is the science that studies and practices the classification
of living things.
Taxonomic Rank:
KINGDOM > PHYLUM > CLASS> ORDER > FAMILY > GENUS > SPECIES
THE FIVE KINGDOMS
KINGDOMS
CHARACTERISTICS
MONERA
Does not have a
defined cell
nucleus
(prokaryotes).
Unicellular.
Autotrophic or
heterotrophic
nutrition. No
tissue.
PROTOCTISTA
Has a defined
cell nucleus
(eukaryotes).
Unicellular or
pluricellular.
Autotrophic or
heterotrophic
nutrition. No
tissue.
FUNGI
Eukaryotes,
pluricellular,
heterotrophic
nutrition. No
tissue.
PLANTAE
Eukaryotes.
Pluricellular.
Cells form
tissue.
Heterotrophic
nutrition.
THE MONERA KINGDOM
The cell structure-- Prokaryotic cells have a very simple structure. From the exterior to the
interior we will find:
ANIMALIA
Eukaryotes.
Pluricellular.
Cells form
tissue.
Heterotrophic
nutrition.
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



A rigid and hard cell wall. Its function is to protect the cell. Antibiotics, medicine that
destroys bacteria, help destroy this wall.
A plasma membrane, which acts as a border between the exterior and interior of the
cell. It lets things pass into and out of the cell.
The cytoplasm is found in the interior of the cell. This is where all of the cell’s
functions take place.
The DNA, which contains the bacteria’s genetic information, is found freely in the
cytoplasm.
The ribosomes, which are little protein factories.
THE IMPORTANCE OF BACTERIA
Harmful bacteria produce illnesses, since many of them are parasites. Other bacteria
are beneficial. We use them to produce food products, like yogurt and wine. Another
type, called decomposers, act on organic material and turn it into inorganic material.
This kind of bacteria is called saprophytes.
THE PROTOCTISTA KINGDOM
Protozoa are unicellular organisms that are generally mobile and heterotrophic.

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
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Flagellates are protozoa that move by using flagella.
Ciliates are protozoa that move by using cilia.
Rhizopods are protozoa that move by using pseudopods.
Sporozoa are protozoa that are immobile. They reproduce
asexually, by spores.
Algae are unicellular or pluricellular organisms, are sometimes mobile, and are
autotrophic.
Algae are used in the food industry as a thickener for marmalades and sauces. In
medicine it is used to cultivate bacteria. They also extract substances from them to
make medications.
 Unicellular algae are formed by only one cell. They are individual
and can live on their own. They can also join together and form
colonies to live.
 Pluricellular algae are formed by many cells. The cells do not form
a tissue, as they do with more complex beings. The cells do not
share work; rather, all the cells perform all of the functions. If we
observe their color, we can observe three types.
Green algae
Brown algae
Red algae
THE FUNGI KINGDOOM
This kingdom includes yeast, mold and mushrooms. They are characterized as being formed
by eukaryotic cells, and all have heterotrophic nutrition. Depending on from where they obtain
organic material to feed themselves, they are either parasitic (they get the organic material
from another living being) or saprophytic (the material does not come from a living thing).
They can be:
 Unicellular, like yeast. Yeast is used to make alcoholic drinks, bread
cakes, etc.
 Pluricellular, formed by cells that group together but do not form
tissues.
The Structure of a Mushroom
LICHENS
Lichens are formed when algae and fungus join together. The algae and fungus have a
symbiotic relationship, which means that they both benefit from one another. Lichens are
used for:




Food
The pharmaceutical industry
Cosmetics, to extract essences for perfumes
Indicating contamination, because they don’t develop in
contaminated areas.
VIRUSES
Living beings must be able to provide nutrition for themselves, interact with their environment
and reproduce. But viruses do not provide nutrition for themselves, nor do they interact. In
order to reproduce and make copies of themselves, they depend on the intervention of
another cell. For this reason, viruses are not living beings. Therefore, they do not appear in
any of the five kingdoms of living beings.
The Structure of a Virus
BASIC VOCABULARY
Kingdoms-- Reinos
Monera-- Monera
Protoctista-- Protoctista
Fungus-- Hongos
Taxonomy-- Taxonomía
Phylum—Tipo
Class—Class
Order-- Orden
Family-- Familia
Genus—Género
Specie-- Especie
Ribosomes-- Ribosomas
Protozoa-- Protozoos
Algae-- Alga
Flagellates-- Flagelados
Ciliates-- Ciliados
Rhizopods-- Rizópodos
Sporozoa -- Esporozoos
Unicellular-- Unicelular
Pluricellular-- Pluricelular
Yeast-- Levaduras
Mold-- Mohos
Mushrooms-- Setas
Symbiosis-- Simbiosis
Symbiotic-- Simbiótico
Benefit—Beneficio; beneficiar
Lichens-- Líquenes
Virus—Virus
19—Criterios de Clasificación
REMEMBER: The classification of living things allows them to be ordered and organized by the
characteristics that define them.
Two kinds of criteria are used to classify living things: artificial criteria, which are based on the
observation of external characteristics, and natural criteria, which are based on genetic
similarities between living things. The current classification system uses natural criteria.
22—El Reino Móneras
REMEMBER: Bacteria belong to the Monera kingdom and are unicellular and prokaryotic
organisms. This means they are formed by one cell with a very simple structure and do not
have a nuclear membrane to protect their genetic material. They can live in any environment
and reproduce asexually by dividing themselves.