Classification and the Six Kingdoms
SCIENTISTS CLASSIFY MILLIONS OF SPECIES:
400 years ago, scientists who studied insects classified them based upon their
appearance and behavior. If animals looked alike, researchers concluded
that they were related.
In the 1600’s much exploration took place. New inventions, like the
microscope, allowed us to see animals in a detail never before
CLASSIFICATION VS. TAXONOMY
Classification- the process of arranging organisms into groups based upon
similarities and differences.
A good system allows you to organize a large amount of information
so it is easy to find and understand.
Taxonomy- is the science of naming and classifying organisms.
A good system of taxonomy allows people to communicate about
organisms using the same language. Similar organisms have
also study biological relationships. A TAXON is a group
of organisms that share certain traits. These taxons can be
broad, like “animals”, or quite specific, like
“cats” or “roses”.
Taxonimists also study the relationships between species, trying
to discover how one species evolved as compared to other
species. They also try to find relationships among species to
see if they’re related or connected in some way.
Species that share ancestors are grouped
To classify organisms, scientists use similarities and differences among
Generally, these similarities and differences are things that
are visible, or measurable.
Features: Size, weight, fur, feathers, scales, color, shape,
body parts, way of feeding, habits, habitat, food.
Features: Organs, DNA, cells and cell structure, method of
getting energy, method of reproduction.
To determine how to classify organisms, scientists compare a variety
of characteristics, or traits. A “TRAIT” is a
behavior that can be used to tell two species apart, such as
size or bone structure. If two organisms share a trait,
taxonomists try to determine if they share the trait
because they share an ancestor.
Taxonomists take evidence and also try to reconstruct the evolution
of a species
BIOLOGISTS USE SEVEN LEVELS OF CLASSIFICATION:
SAMPLE FOR A CAT:
FAMILY: FELIDAE-THE CAT FAMILY
GENUS: FELIS-HOUSECATS, COUGARS AND MANY OTHERS
SPECIES: CATUS-ALL HOUSE CATS, NO MATTER WHAT THEIR BREED.
Like the cat, the turtle is also classified into seven levels.
However, only the largest categories, Animalia and Chordata, are the same as the classification for a house cat.
The more names an organism shares with another organism, the more closely related the two organisms are.
Order: Testudines (turtles)
Family: Emydidae (water turtles)
Genus: Clemmys (north american pond turtles)
Species: guttata (the spotted turtle)
Dichotomous keys and field guides help people identify organisms.
With millions of organisms on Earth, how could one specific one be identified?
Even if you know the larger categories, it can still be difficult to find the species, genus or even the family name.
Take a beetle for example. Even
if you knew it was in the Kingdom Animalia, Phylum arthropoda (animals
with jointed legs) and order Coleoptera (hard winged insects),
you’d still have to choose among 300,000 known species of beetles
that have been discovered in the world..
Taxonomists have come up with a tool to help, called a Dichotomous
Key. These keys ask a series of questions that can only be
answered in two ways. Your answer to each question leads to
another question. After a number of questions, you’ll
eventually identify the specific organism you’re looking at.
The questions in a Dichotomous Key gradually narrow down the list of possible organisms.
FIELD GUIDES are another tool
for identifying organisms. They include pictures or paintings of
species. Flower guides may start with the flower’s
color. Bird guides are often arranged by orders and families of
birds. Field guides also usually include a map showing where the
The Six Kingdoms:
Planate: Includes plants such as trees, grass and moss.
They are multi cellular and live on land.
Plants obtain energy from sunlight.
A plant cell has a nucleus, cell wall and chloroplasts.
Animalia: Includes animals, from lions, and tigers and bears to bugs
and multicellular microbes.
Animals are multicellular and able to move.
Animals obtain energy from eating food.
An animal cell has a nucleus but no cell wall or chloroplasts.
Protista: Includes organisms that doen’st easily fit into animals, plants or fungi
They are either unicellular organims or have a simple multi-cellular structure.
Most protists are single celled.
Multicellular protists lack complex structure.
A protest cell has a nucleus.
Fungi: Includes mushrooms, molds and yeasts.
All fungi except yeasts are multicellular.
Fungi obtain energy by absorbing materials.
A fungus cell has a nucleus anda cell wall, but no chloroplasts.
Archaea: (Ahr-kee-uh)- contains organisms that are similar to bacteria,
but have a cell structure that is so different that sicentists separate
them into their own kingdom.
archaea are unicellular organisms without nuclei.
Archaea cells ahve different chemicals than bacteria.
Archaea can live in extreme conditions.
Bacteria: are unicellular organisms with NO nucleus.
Bacteria are unicellular organisms.
A bacteria cell has no nucleus.
Bacteria reproduce by dividing in two.
The Six Kingdoms:
In a little more detail...
The two most familiar kingdoms are plants and animals:
250,000 species live on Earth.
They range from tiny mosses to the largest organisms on Earth, giant
The oldest living organism on our planet is the Bristlecone Pine. Some
Bristlecone pines were growing when the Egyptians built the
pyramids, 4000 years ago.
All plants are multicellular and eukaryotes, which means their DNA is stored in a
nucleus of their cells. All plants are able to make sugars using
sun’s energy. Plants cannot move from one place to another,
but they can grow around objects, turn towards light, and grow
Plant cells are different from animals cells because they have tough
walls outside their cell membranes.
Scientists have already named a million species in the animal kingdom. Many
different types of animals inhabit the planet, but more than 90% of the
named species are insects.
All animals get their energy by eating other organisms or by eating food
made by other oganisms. Animals have the abiltiy to move around
for at least
part of their lives. Most animals have mouths and some
type of nervous system. Plant and animal cells are both
eukaryotes, but animals have NO cell walls.
The other kingdoms are mostly microscopic organisms.
includes a wide variety of organisms. Most are unicellular. Protists that are multi
cellular are too simple to be classified as plants, animals or fungi. All
protists have large, complex cells with a true nucleus (Eukaryotes). Some
eat other organsims like animals do, some get energy from sunlight like
plants do. Some protists resemble fungi, but they don’t have as many
specialiized cells as plants, animals or fungi.
Many protists live in pond water or sea water. The largest of the unicellular species
are barely visible without a microscope. However, large organisms such
as weaweeks are also classified as Protista. Some seaweeds can grow
hundreds of feet in a single year.
Kelp for example.
Fungi are usually divided into three groups, mushrooms, molds and yeasts.
The trait that separates fungi from other organisms is that they take in nutrients from their surroundings instead of eating other organisms or using sunlight to make their food.
Most fungi have cell walls like plants.
Unlike plants, fungi act as decomposers, breaking down dead or decayed material into simpler parts that can be absorbed, or recycled by other
Bacteria live nearly everywhere on Earth.
This Kingdom includes organisms that cause disease and spoil food,
but most organisms in this Kingdom are helpful members of most biological communities.
All bacteria are unicellular organisms.
They have small, simple cells without a nucleus.
Most bacteria have a cell wall outside the cell membrane,
but this wall isn’t the same as the cell wall of a plant.
Bacteria reproduce by dividing in two, and can produce
many new generations in a short period of time.
In the mid 1990’s a researcher studying the genes of some bacteria
discovered a new group of organismsthat resemble bacteria in size and cell type,
but some species had very specific genetic differences.
They decided to call these organisms Archaea.
They differ so much that now scientists
classify archaea in a separate Kingdom called Archaea.
Archaea cells do not have nuclei. Their cell structure is also different than bacteria.
Like bacteria, archaea live in many environments, especially in the ocean.
They also live in some very extreme environments,
such as boiling mud
hot vents at the bottom of the ocean,
and deep under the sand.
What is Biodiversity?
A measure of all the different species living in an ecosystem.
The "variety" or living things in an area.
No-one knows exactly how many species live on Earth.
So far, more than 1.7 million species have been identified. Pretty much
everyone agrees that this number represents just a tiny fraction of the total
number of species living on Earth. The actual number is probably a hundred
It's difficult to estimate the total biodiversity on Earth
because many areas haven't been thoroughly studied.
Some experts think that the deep oceans alone could contain
10 million new species!
Factors affecting biodiversity:
Area- Within an ecosystem a large area will contain more species than a small
Climate- In general the number of species increases as you move from the poles
toward the equator. The tropical rainforests of Latin America, Southeast
Asia and central Africa are the most diverse ecosystems in the world.
These forests cover about 7% of the Earths' land surface and contain
about half of the world's species.
A niche is a particular area in an ecosystem where an organism can live.
The more niches available, the more biodiversity. Simple. More places
to live equals more creatures taking advantage of the opportunity. (Think
about it, it's no different than people moving into an area to take
advantage of houses that have been built, or house lots cleared, or
apartments built...it's the same idea. If there are more places to live, then
you can expect more living things to take advantage of the opportunity.
Why is it important? What's the value of biodiversity?
Economic Value- Many plants and animals and other organisms are essential for
human survival. In addition to providing food and oxygen, these
organisms supply raw materials for clothing, medicine and other products.
Ecotourism- Basically, people will pay money to experience nature
as it was intended to be.
Hunting, fishing, camping, hiking, wildlife tours, whale watches,
None of these things would happen without a healthy ecosystem.
Value to the Ecosystem:
All species in an ecosystem are connected to one another. Species
depend upon one another for food and shelter. A change that affects
one species will surely affect many others.
Keystone Species- a species in an ecosystem upon which many other
organisms depend. Keystone species influence the survival of
many other species in the ecosystem.
The problem is, we don't always know which species are keystone
species until it's too late.
Gene Pool Diversity:
Genes control the traits that all living things possess. Different organisms have different traits, and these "traits" or
characteristics make it possible
for living things to survive on Earth. Traits allow all living
things to adapt to the
changes that often occur on Earth. The
more traits you have, the better your chances are of being able to
these changes. (Like changes in
climate for example). All of the genes in a population of living
things is called
"gene pool diversity", meaning a
"variety" of genes in a population. Generally speaking, the more
variety in the
gene pool, the more chance that
"someone" will have the necessary traits to survive almost ANY change
happen. So a diverse gene
pool is a good thing, because it allows the species to survive.
Survival is a good thing,
and definitely one of the
advantages of having a large amount of biodiversity in an area.
Extinction of Species
Hey, it happens. Things change. Some organisms will have what it takes to survive and others won't. That's
way it goes. Sometimes, a species on Earth is driven closer to
extinction for a variety of reasons, some of
which are discussed in the next section.
to try to prevent species from being driven to extinction. It
involves learning as much about each
we can, and working to eliminate things that are causing problems for a
species. It's a big job, made
complicated that we don't even really even KNOW how many species
are out there! There are probably about
a HUNDRED species we've never even seen for each one that we HAVE seen, studied and named.
Endangered Species are in danger of being driven to extinction. Their numbers in the world are very low,
and if immediate action isn't taken, they might not survive.
Threatened Species are in trouble, and if things don't improve, their numbers in the world will continue to
fall, and the entire species could become Endangered.
Currently in Maine, 33 species are currently considered either Endangered or Threatened!
Causes of Extinction
hunted for skin, fur, claws, teeth, horns
for exotic pets
tropical fish, parrots, tortoises
endangered plants harvested for houseplants
other endangered plants sold for medicine
air and water
aka invasive species
Laws and Treaties