Classification
Historical Development of
Classification  Classification: process of grouping
and naming organisms based on
evolutionary relatedness.
 Classification is important because
organized information is easier to
use and access. By organizing
living things into groups scientists
can identify relationships,
similarities, and differences easier.
 The first attempts at classification
where based entirely on physical
appearance.
 Aristotle was the first person to
develop a classification system.
His system included two major
groups, plants and animals.
Historical Development of
Classification
 More recently Carl Linnaeus
created a classification system with
several large groups that where
composed of smaller and smaller
groups. These groups included
kingdom, phylum, class, order,
family, genus, and species.
Linnaeus also classified organisms
based on appearance.
 He also created the current system
for naming organisms called
binomial nomenclature. This
system uses the two most specific
classifications (genus and species)
as the scientific name.
Current Classification
 Carl Linnaeus’ system is the bases of
the current system of classification.
 We currently use the same
classification categories plus one new
one, domain.
 However scientists have changed the
bases of classification from appearance
to evolutionary relationships.
 With the new knowledge about DNA
and how it is inherited and the ability to
identify how much DNA two individuals
have in common, scientists can now
establish the evolutionary relationship
between organisms.
 Those that are closely related share
many classification categories.
Assignment
 Assignment
comparing the
classification of many
living things like
compare a
chimpanzee to
humans to whales to
sharks to birds to
crocodile. How related
are they?
Dichotomous Key
 A series of paired statements that describe physical
traits used to identify and classify organism.
Phylogenetic Trees
 Phylogenetic trees are used to show the order in which living
things branched off from the common ancestor. The more
recently two groups branched off from each other the more
related they are.
 This also allows scientists to identify the order of appearance in
history for each group of living things.
Groups of Living
Things
Viruses
 Not actually a living thing because it is not capable of performing the
majority of life functions.
 Examples include flu, cold, chicken pox, warts, polio, and small pox.
 The structure of a virus is a protein coat (capsid) that surrounds
genetic information. The capsid is used to trick cells so the virus can
attach and inject the genetic material.
Eubacteria
 Bacteria that are found in
almost every condition except
extremely harsh environments.
 Examples include strep throat,
tetanus, tuberculosis, and E.
coli
 Bacteria cells are prokaryotic
(no nucleus or organelles). The
majority of bacteria are going to
be unicellular; however, some
bacteria form cooperative
groups called colonies. The cell
wall contains peptidoglycan.
Archeabacteria
 Bacteria that are found in
extremely harsh environments.
These bacteria are thought to be
the ancestors of eukaryotic
organisms.
 Examples include bacteria that
live in hot springs.
 Bacteria cells are prokaryotic (no
nucleus or organelles). The
majority of bacteria are going to
be unicellular; however, some
bacteria form cooperative groups
called colonies. The cell wall
does not contain peptidoglycan.
Protists
 This is a catch all category. If
the cell is eukaryotic (has a
nucleus) but the organism
cannot be classified as a plant,
fungus, or animal for any reason
it is classified as a protist.
 Examples include ameba,
euglena, paramecium, and
diatoms.
 The cells are eukaryotic and
most are unicellular. Some have
cell walls. Some have cilia and
flagella for movement.
Fungi
 Heterotrophic organisms that digest
and absorb food from the structures
they live on.
 Examples include mushrooms,
yeast, ringworm, athletes foot,
lichens, and mycorrhizza.
 The cells have a nucleus
(eukaryotic) and a cell wall made of
chitin. The bulk of the fungus is a
chain of single cells called mycelium
that cannot be seen by humans. The
visible structure is called the fruiting
body and is the reproductive
structure of the fungus.
Green Algae
 Plants that are made up of
individual cells that live in masses.
They do not have specialized cells
to perform different functions. A
large mass of algae is called a
bloom. Plants are autotrophic.
 Examples include volvox, and
fresh water algae.
 The cells of algae are plant cells
(eukaryotic) with a cell wall made
of cellulose and chloroplasts to
produce sugars. Some types of
algae have cilia and flagella to
allow them to move.
Bryophytes
 Plants that have specialized
cells, but do not have vascular
tissue to transport materials
around the body, seeds, or
flowers. Mosses are very cold
tolerant making them the only
plant that can live at the poles.
 Examples include mosses,
liverworts, and hornworts.
 Plant cells are eukaryotic with cell
walls made of cellulose and
chloroplasts to make sugar.
Seedless Vascular Plants
 Plants that have vascular tissue
(xylem and phloem) but they do
not produce seeds or flowers.
They reproduce by creating
spores. Most are tolerant of low
light conditions.
 Examples include ferns, club
mosses, and horsetails.
 Plant cells are eukaryotic with
cell walls made of cellulose and
chloroplasts to make sugar.
Gymnosperms
 Plants that have vascular tissue to
transport material and create seeds for
reproduction but the seeds are not
produced inside flowers, they are made on
cones.
 Examples include conifers, cycads,
ginkgoes, and gnetophytes.
 Plant cells are eukaryotic with cell walls
made of cellulose and chloroplasts to
make sugar.
Angiosperms
 Plants that have vascular tissue to
transport materials and produce seeds
inside of flowers.
 Examples include pecan trees, water
lilies, grasses, carrots, broccoli, and
roses.
 Plant cells are eukaryotic with cell walls
made of cellulose and chloroplasts to
make sugar.
Porifera
 Simplest animals. They do not
have symmetry (asymmetrical).
Some of the cells have cilia or
flagella in order to push water
through the animal because
that is how they will eat, obtain
oxygen, and remove waste.
 Examples include sponges.
 Animal cells are eukaryotic cells
that lack a cell wall and
chloroplasts.
Cnidarians
 Radially symmetrical animals that
posses nematocysts which are stinging
cells.
 Examples include jellyfish, sea
anemones, and corals.
 Animal cells are eukaryotic cells that
lack a cell wall and chloroplasts.
Platyhelminthes
 Animals that have three
different layers of tissue,
several organ systems,
cephalization (organization of
nervous tissue creating a
head) and sensory organs
including eye spots.
 Examples include flatworms
such as planaria and
tapeworms.
 Animal cells are eukaryotic
cells that lack a cell wall and
chloroplasts.
Nematodes
 Worms that are not segmented
but they do posses a one way
digestive tract. These worms also
have a tough outer skin that must
be molted in order to grow
suggesting they are more related
to arthropods than other worms.
 Examples include roundworms
and hookworms such as
heartworms in dogs.
 Animal cells are eukaryotic cells
that lack a cell wall and
chloroplasts.
Annelids
 Animals that have
segmented bodies, a closed
circulatory system (blood
stays in blood vessels), and
a one way digestive tract.
 Examples include leeches
and earthworms.
 Animal cells are eukaryotic
cells that lack a cell wall
and chloroplasts.
Arthropods
 Most varied group of animals that
have exoskeletons, segmented
bodies, open circulatory systems,
and jointed appendages. Many also
posses wings.
 Examples include:
 Crustaceans such as crabs,
lobster, and shrimp
 Chelicerae such as spiders, ticks,
mites, scorpions, and horseshoe
crabs.
 Uniramia such as centipedes
millipedes, and insects.
 Animal cells are eukaryotic cells that
lack a cell wall and chloroplasts.
Mollusks
 Animals that have soft bodies and
a muscular foot. Some have
external shells and some have
internal shells that have modified.
 Examples include snails, slugs,
clams, squid, octopi, and nautilus.
 Animal cells are eukaryotic cells
that lack a cell wall and
chloroplasts.
Echinoderms
 Animals that have spiny skin
and a unique water vascular
system to transport nutrients,
get rid of waste, and
exchange oxygen and carbon
dioxide.
 Examples include starfish, sea
cucumbers, brittle stars, sand
dollars, and sea urchins.
 Animal cells are eukaryotic
cells that lack a cell wall and
chloroplasts.
Fish
 Animals that have scales,
paired fins, a lateral line to
detect water movement and
gills.
 Examples include
 Jawless fish such as the
lamprey and hagfish
 Cartilaginous fish such as
sharks, skates, and rays.
 Boney fish such as perch
and sea horses
 Animal cells are eukaryotic cells
that lack a cell wall and
chloroplasts.
Amphibians
 Animals that have thin moist
skin so that they can move
oxygen across it, no scales or
claws, and live a double life.
As juveniles they live in water
with gills and no limbs. As
adults they live mostly on land
with lungs and strong
appendages.
 Examples include frogs,
salamanders, and toads.
 Animal cells are eukaryotic
cells that lack a cell wall and
chloroplasts.
Reptiles
 Animals that are exothermic, and
have thick dry scaly skin, and claws.
 Examples include snakes, turtles,
alligators, crocodiles, and lizards.
 Animal cells are eukaryotic cells
that lack a cell wall and
chloroplasts.
Birds
 Animals that are endothermic, have
efficient body systems, are covered
in feathers, and have modified front
limbs called wings.
 Examples include birds of prey, song
birds, and water fowl.
 Animal cells are eukaryotic cells that
lack a cell wall and chloroplasts.
Mammals
 Animals that are endothermic,
have efficient systems, have
mammary glands to produce milk
for young, and have hair.
 Examples include
 Monotremes such as a platypus
and echidna
 Marsupials such as kangaroos,
koalas, and opossums.
 Placental such as humans,
bears, and dogs.
 Animal cells are eukaryotic cells
that lack a cell wall and
chloroplasts.