Transcript document

Taxonomy
Classification & Organization
Section One
Organization
Quick Question…
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Which of these objects does not belong in this group?
Of course, the answer is that the ROCK does not belong.
The rock is different because it can be classified as a
nonliving thing. A fish, a frog, a tree and a rose are all
living organisms.
Animal vs. Plant
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A fish and a frog are both animals.
A rose and a tree are both plants.
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A fish and a frog have animal characteristics.
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These are a few of the characteristics of animals:
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Consist of cells containing organelles.
Need to ingest food.
Most are mobile.
Lack chlorophyll.
Lack cell walls.
Animal vs. Plant
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A rose and a tree have plant characteristics.
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These are the characteristics of most plants:
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Many have chlorophyll.
Have rigid cell walls.
Are stationary.
Contain cellulose in their structure.
Most make their own food by photosynthesis.
Large vacuoles
Take A Guess!
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How many different kinds of organisms do you
think exist on our planet?
Biologists estimate that there are more than
5,000,000 different kinds of organisms.
Every year, scientists discover new organisms.
Why is classification, or grouping, necessary
when studying organisms? Think about it!
Let’s look at a familiar example to better
understand why grouping is helpful.
An Example…
John Doe
10601 S. Central
Oak Lawn, IL
USA
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A student in Canada wants to send a letter to a friend in the United
States of America.
Note that the zip code is not included in this letter.
There are several categories on this envelope:
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Name
House number
Street
Town
State
Country
Example (Cont.)
John Doe
10601 S. Central
Oak Lawn, IL
USA
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In Canada, which department (domestic or international)
sends the letter to the United States?
The international department sends the mail to other
countries such as the United States of America.
Which is the largest category in the address on the
envelope?
USA is the largest category, because it represents a whole
country.
Example (Cont.)
John Doe
10601 S. Central
Oak Lawn, IL
USA
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Once in the USA, which category in the address is first
used to sort the letter?
State is the first category used to sort the letter.
Which category in the address helps deliver the letter to a
single area in the state?
Oak Lawn (the town) is the third largest category. It
indicates where among many possible areas within the
state to deliver the letter.
Example (Cont.)
John Doe
10601 S. Central
Oak Lawn, IL 60453
USA
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The category Oak Lawn is an example of subgrouping, or
classification.
A zip code is another example of subgrouping, or
classification.
The first three digits, 604, classify either a large area within
a state or a large city.
The last two digits, 53, indicate either a post office or a
delivery area.
Example (Cont.)
John Doe
10601 S. Central
Oak Lawn, IL 60453
USA
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Look at the address again. Here are all six of the
categories in descending order.
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USA (Country)
IL (State)
Oak Lawn (Town)
S. Central (Street – it identifies only a small segment of a town.)
10601 (Identifies a house or building located on a particular street.)
John Doe (This is the smallest category in the address on the letter.
He is one resident of a particular house/building.)
Information
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When organizing anything, start with the largest group, and
subdivide it into smaller categories. This is classifying by
descending order.
For Example:
USA
Illinois
Oak Lawn
Another Street
Another State
Another Town
S. Central
10601
John Doe
Mary Doe
10501
Note: A zip code
identifies the state, the
area in that state, and
a specific post office
or delivery area.
Classifying Words
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Let’s try an exercise in the classification of words that
describe time.
Put these words in descending order:
A.
B.
C.
D.
E.
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Hour
Month
Century
Eon
Day
F. Decade
G. Minute
H. Week
I. Second
J. Year
Eon – Century – Decade – Year – Month – Week – Day – Hour –
Minute – Second
Let’s see how biologists use categorization when studying
organisms.
Information
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There is a wide diversity among organisms.
Grouping, or classifying, helps biologists
identify and study newly discovered organisms.
Any system of classification depends on
grouping organisms into categories based on
the organism’s characteristics.
What system of taxonomy, or classification, do
biologists use today to identify and study
organisms?
Let’s examine the major categories of
classification in descending order.
Classification of Organisms
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Biologists classify all organisms into large
categories called kingdoms.
A kingdom consists of a collection of
closely related phyla (singular phylum).
A phylum is a group of related classes.
A class is a group of related orders.
An order is a group of closely related
families having common characteristics.
A family is a group of closely related
genera (singular genus). Most genera are
similar; some have noticeable differences.
A genus is a group of closely related
species. For example, the oak genus
consists of pin oak, white oak, and many
other oak species.
Species is the basic (smallest) unit in the
classification of organisms. It is a kind of
organism, such as a dog or a sugar maple
tree.
Biologists do not agree on a single
classification system. For example, some
classify organisms into three, four, or five
kingdoms.
Information
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Each organism has a scientific Greek or Latin
name.
This name is based on a binomial system
invented by Linnaeus, a Swedish taxonomist.
The first word (genus name) is capitalized, the
second word (species name) is not capitalized.
For example, the scientific name for humans is
Homo sapiens.
Review
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Organization is the systematic grouping of
things to show interrelationships.
To develop an organizational outline, start with
the largest category and subdivide into smaller
categories.
Classification, or taxonomy, is a systematic
arrangement of organisms into categories based
on their characteristics and interrelationships.
Classification simplifies the identification and
study of organisms according to their
characteristics.
Select The Letter Of The Correct
Answer From The List Below:
A. species
B. class
C. kingdom
D. category
E. genus
F. taxonomy
1. The largest category of classification is called a _________________.
2. A system of classifying organisms is called _________________.
3. The most specific category for classifying an organism is a ________________.
4. In any organizational plan, start with the largest _________________.
Answers:
kingdom
1. The largest category of classification is called a _________________.
taxonomy
2. A system of classifying organisms is called _________________.
species
3. The most specific category for classifying an organism is a ________________.
category
4. In any organizational plan, start with the largest _________________.
Classification of Organisms
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Let’s use your knowledge of categorizing to
study the classification of organisms.
Taxonomy, or classification, is a method of
grouping organisms according to their
characteristics and interrelationships.
The purpose of classification is to help identify
organisms and to show relationships between
them.
How Are These Organisms
Related?
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Think about it!
How would you group these organisms by their
characteristics?
First group: A & D
Second group: B & C
Kingdoms
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Similar characteristics make it easy to identify
and group organisms.
Biologists group organisms into large categories
called kingdoms.
Throughout history, organisms have been
classified into two major groups – the animal
kingdom and the plant kingdom.
Let’s look at representatives of the animal
kingdom.
Animal Kingdom (Animalia)
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These are some of the characteristics of animals:
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Consist of cells containing organelles.
Need to inject food.
Most are mobile.
Lack chlorophyll.
Lack cell walls.
Plant Kingdom (Plantae)
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These are the characteristics of most plants:
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Many have chlorophyll.
Have rigid cell walls.
Are stationary.
Contain cellulose in the structure.
Most make their own food by photosynthesis.
Large vacuoles.
Protist Kingdom (Protista)
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Simple microscopic organisms cannot be classified as
either plant or animal.
These organisms belong to the protist kingdom.
Let’s look at the euglena to better understand the
characteristics of protists.
Euglena
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These are the characteristics of protists:
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All are unicellular (sometimes forming a colony).
Some have chlorophyll in chloroplasts.
Some are autotrophic (make food from simple materials).
Some are heterotrophic (take food from dead or living
organisms).
Some show mobility.
Some contain well defined nuclei.
Not all unicellular (single cell) organisms have similar
characteristics.
Members of the Monera kingdom are different from
protists.
Monera Kingdom
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The Monera include bacteria and blue-green algae.
Monera have these characteristics:
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Lack organelle membranes.
Can be unicellular or form filaments.
Cell walls that do not contain cellulose.
Can contain chlorophyll (sometimes in chloroplasts).
Can be parasitic.
Lack major cell organelles.
Many form spores to resist heat and drying.
Another kingdom, Fungi, has different characteristics.
Fungi Kingdom
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Organisms in the kingdom Fungi have this appearance.
Lets look at bread mold to better understand the
characteristics of fungi.
Bread Mold
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These are the characteristics of members of the kingdom
Fungi:
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Resemble plants in structure, but not function.
Have cell walls.
Lack chlorophyll.
Cannot make their own food.
Depend on the absorption of nutrient molecules.
Are either parasites or saprophytes.
Most are multicellular (few are unicellular).
Review
Kingdom
Animal
Plant
Major Characteristics
Heterotrophic, multicellular, lack cell walls and
chlorophyll.
Usually autotrophic, cell walls (cellulose), can be
multicellular/unicellular.
Protist
Autotrophic/heterotrophic, usually unicellular,
some form colonies, some have cell walls
(cellulose).
Monera
Autotrophic/heterotrophic, lack nuclear
membranes and most cell organelles, cell wall
(lacks cellulose).
Fungi
Heterotrophic, lack chlorophyll, have cell walls
(cellulose).
Quiz: Fill In The Blanks…
Organisms can be classified into five large categories
called ____________.
kingdoms The ____________
protists are usually
unicellular organisms that can move and form colonies.
animals which are
They are different from the ____________,
multicellular, heterotrophic organisms that lack cell
walls. The members of another large heterotrophic
group must absorb all their nutrients because they have
no chlorophyll with which to make food. These
organisms have cell walls with cellulose, and are called
____________.
fungi
Section Two
Classification of Animals
Symmetry
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An organism’s symmetry (balanced proportions) often
helps determine its classification.
There are two basic types of symmetry, radial and
bilateral.
Let’s look at two familiar examples to explain the
different types of symmetry.
Notice the individual pieces of this pie.
In addition to area, color and size,
all have the same shape.
The pie is radially symmetrical.
Sections from the center all have the same shape.
Let’s look at an organism that is radially symmetrical.
Sponge
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All parts of the sponge are regularly arranged around a
central axis.
Which of the following is most like the radial symmetry in a
sponge? A) A book B) A wheel C) A television D) A
human face
Answer: A wheel – A wheel is similar to the radial symmetry
of a sponge, because its parts are regularly arranged around
a central axis.
Bilateral Symmetry
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These parts of the chair are not the
same. They are mirror images of
each other.
This is called bilateral symmetry.
Objects that are bilaterally
symmetrical can be divided by only
one plane into equal halves (mirror
images).
Let’s examine bilateral symmetry
in an animal.
Earthworm Cross Section
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Study the cross section above with a plane drawn
through it.
Observe that the two sides are mirror images of each
other.
Symmetry is an important means of classifying
organisms.
Information
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Categories of classification, such as kingdom, phylum
and class, are called taxons.
Each kingdom is subdivided into lower taxons called
phyla (singular phylum).
Organisms with different characteristics are in different
phyla.
Some biologists divide the animal kingdom into nine
phyla.
Try to determine the differences and the similarities
among the phyla as you study them.
Phyla Exploration
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These are the major animal phyla:
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Sponges
Coelenterates
Flatworms
Roundworms
Segmented worms
Mollusks
Arthropods
Echinoderms
Chordates.
Phylum – Sponges (Porifera)
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Most sponges live attached to the
bottom in shallow waters.
Water enters a sponge through the
many pores.
The sponge separates food from the
water in its central cavity. Then, the
water leaves through the large
opening on top.
Sponges have no clearly defined
muscle or nerve cells.
Phylum – Coelenterates
(Coelenterata)
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Food and water enter a hydra (a coelenterate)
through its mouth.
Water and wastes also leave the hydra
through its mouth.
Coelenterates have radial symmetry.
A coelenterate is a hollow, cup-like animal.
Food and water enter and leave through its
mouth.
Digestion occurs in the cavity (before food
absorption) and in the cells (after absorption).
The body has two layers of cells enclosing a
jelly-like material.
Coelenterates usually have stinging cells and
tentacles.
Phylum – Flatworms
(Platyhelminthes)
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A flatworm is a long, ribbon-shaped, bilaterally
symmetrical organism that usually has an
easily identifiable head and tail.
Some flatworms, such as the planaria, are
free-living (nonparasitic).
Other flatworms, such as the tapeworm and
the liver fluke, are parasitic.
Parasitic flatworms can live part of their life
cycles in two or three different host
organisms.
Flatworms have bilateral symmetry.
Compare flatworm characteristics with those
of roundworms for differences and similarities.
Phylum – Roundworms
(Nematoda)
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Roundworms can be microscopic in size.
They are bilaterally symmetrical and have
smooth, unsegmented bodies.
Roundworms have a mouth and an anus, but
no distinct respiratory or circulatory organs.
Many are parasitic and are found in the soil.
Roundworms contain a digestive tract.
Phylum – Segmented Worms
(Annelida)
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These worms are different from other phyla of
worms because they have segments.
Segmented worms have well developed
digestive, circulatory and nervous systems.
All segments, except the first and last, contain
kidney-like organs.
Respiration takes place through the moist skin.
Segmented worms are more complex because
they have a segmented body, complete digestive
tract, and a circulatory system.
Segmented worms have no appendages. They
have short bristles on all segments (except the
first and the last) that are used for locomotion.
Phylum – Mollusks (Mollusca)
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Some of these soft-bodied animals secrete
a hard, protective shell. Some have
tentacles, others have a muscular foot.
Mollusks have a true circulatory system.
The squid is a mollusk that can swim
rapidly.
Phylum – Arthropods
(Arthropoda)
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Arthropods are joint-legged animals that have
an external skeleton (exoskeleton).
All have segmented bodies, usually with
three regions: a head, a thorax and an
abdomen.
They make up over 90% of the world’s
animals.
Spiders are the only arthropods without
antennae.
Phylum – Echinoderms
(Echinodermata)
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Echinoderms are spiny-skinned animals.
The Echinoderms have these features:
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Spines that cover their skins.
Epidermis that covers a firm endoskeleton.
Radial symmetry (usually five pairs).
Unique hydrovascular system
A complete digestive tract (usually).
Phylum – Chordates (Chordata)
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Some chordates are simple; others are more
complex.
Chordate characteristics consist of the following:
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Dorsal notochord.
Dorsal hollow nerve cord.
Gill slits.
Segmentation of muscles.
A tail.
Paired appendages (complex chordates only).
A segmented spinal column made of vertebrae (complex
chordates only).
Information
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Phyla often are divided into subgroups called
subphyla (singular subphylum). They are the
next classification group smaller than phyla.
A subphylum is grouped into even smaller
groups, called classes.
Let’s investigate some representative classes
from the chordate phylum (subphylum
vertebrates).
Chordate Class Exploration
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These are the chordate classes:
 Jawless
fish.
 Cartilaginous fish.
 Bony fish.
 Amphibians.
 Reptiles.
 Birds.
 Mammals.
Class – Jawless Fish (Agnatha)
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The skeleton is made of cartilage.
These fish have no jaws.
Class – Cartilaginous Fish
(Chondrichthyes)
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These are the characteristics of the
cartilaginous fish:
 Cartilaginous
skeleton.
 Mouth containing a jaw.
 Visible gill slits.
Class – Bony Fish (Osteichthyes)
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These fish have a bony skeleton and covered
gill slits.
The jawless fish is the only class of fish that
does not have paired appendages.
Class – Amphibians (Amphibia)
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These scaleless animals live on land and/or in
water. As larvae, they breathe through gills. As
adults, most breathe through lungs.
Most adult amphibians can live on land,
whereas fish cannot.
Class – Reptiles (Reptilia)
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These are the characteristics of
reptiles:
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Cold-blooded.
Lung-breathing.
Thick, dry, scaly skin.
Egg laying (some bear live young).
A reptiles skin contains scales,
whereas an amphibian’s skin does not.
Class – Birds (Aves)
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Birds are warm-blooded,
egg-laying animals.
They have feathers and
beaks, but no teeth.
Birds are the only class
of vertebrates that are
covered with feathers.
Class – Mammals (Mammalia)
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Mammals are warm-blooded with fur or hair.
Their young develop internally, then feed from
the mammary glands of the female parent.
Mammals usually have four limbs.
A feather is to a bird as fur is to a mammal.
Information
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Among biologists, there are differences of opinion as to
one system of classification.
Biologists use either a 3, 4 or 5 kingdom system of
classification.
Most biologists agree that multicellular animals belong
in a separate animal kingdom.
Let’s compare each system of classification. Observe
the similarities and the differences.
Note the color changes as an organism’s classification
changes.
Classification Systems
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Protists
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Chrysophytes
Green algae
Brown algae
Red algae
Bryophytes
Tracheophytes
Monera
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Bacteria
 Blue-green algae
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Protists
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Plants
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Bacteria
Blue-green algae
Protozoa
Slime molds
True fungi
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Protozoa
Slime molds
True fungi
Chrysophytes
Green algae
Brown algae
Red algae
Plants
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Bryophytes
 Tracheophytes
Animals
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Animals
Classification Systems
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Monera
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Bacteria
 Blue-green algae
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Protists
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Protozoa
Slime molds
True fungi
Chrysophytes
Green algae
Brown algae
Red algae
Bacteria
 Blue-green algae
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Protozoa
 Slime molds
 Chrysophytes
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Plants
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Protists
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Plants
Bryophytes
 Tracheophytes
Monera
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Animals
Fungi
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Green algae
Brown algae
Red algae
Bryophytes
Tracheophytes
True fungi
Animals
Information
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All classification systems follow a pattern.
These are the different groups in descending
order:
 Kingdom
 Phylum
 Class
 Order
 Family
 Genus
 Species
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Let’s develop a chart of animal classification that
includes humans.
Human Classification
Kingdom
Animals
Phylum
Chordates
Class
Mammals
Order
Primates
Family
Hominids
Genus
Homo
Species
sapiens (Humans)
Review
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An important characteristic of an organism is its
organization or symmetry (balanced proportions). There
are two major kinds of symmetry:
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Radial symmetry (spoke-like around a central axis).
Bilateral symmetry (two sides contain the same parts; each part a
mirror image of the other).
Taxons called phyla divide kingdoms.
Organisms in each phylum have different characteristics.
For example, fish (vertebrates) have backbones; worms
(invertebrates) have no backbones.
As animals are classified into lower taxons, such as genus
and species, their characteristics become more similar.
Quiz: Fill In The Blanks…
Biologists generally classify each kingdom into the
next smaller group, known as a _____________.
An
phylum
important characteristic of an organism in each phylum
symmetry (balanced proportions). The fish
is its ___________
are ____________
vertebrates (animals with backbones). Fish are
different from other phyla, such as the worms, which
are invertebrates. The subgroup having the most
similar characteristics among animals is known as a
species
____________.
Section Three
Classification of Plants
Land vs. Water Plants
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Plants can live in different parts of the
environment.
Biologists separate plants into two general
categories:
plants – embryophytes.
 Water plants – thallophytes.
 Land
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Biologists used to classify these plants as
embryophytes and thallophytes.
While embryophytes and tallophytes are not
currently used as taxons, it is convenient to use
these names when discussing plants.
Algae
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Let’s look at some certain types of algae (thallophytes).
Note: Some algae grow on land in a thin film of water
that covers environmental surfaces.
Remember: Some biologists classify algae in the plant
kingdom. Other biologists classify algae in the protist
kingdom.
Types of Algae
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Chlamydomonas
 Some
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water plants are unicellular.
Spirogyra
 Some
water plants consist of cells that form long
threads.
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Fucus
 Some
water-dwelling algae consist of sheets of cells
that form large, tree-sized plants.
Classification of Plants
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Let’s see how some biologists classify algae
with other plants in the 5 kingdom system.
Let’s look at a chart of the classification
system used by these taxonomists.
Classification of Plants
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Note: Some biologists use
additional subgroups in
their classification systems.
A kingdom consists of two
or more groups called
phyla. (One phylum, two
phyla).
Thallophytes and
embryophytes divide the
plant kingdom into two
separate groups that are not
considered taxons.
Thallophytes
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Most algae are thallophytes.
Let’s compare a thallophyte with a land-dwelling plant
(embryophyte) to see the differences in their structure.
Embryophyte vs. Thallophyte
Flower
Blades
Leaf
Air Bladder
Stem
Stipe
Roots (Not Pictured)
Holdfast
Thallophytes
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Thallophytes are simple plants that do not contain true
leaves, true stems, or true roots. They do not produce
flowers or seeds.
This is why some biologists classify thallophytes as
protists.
Thallophytes live in moist or water environments. Many
contain chloroplasts for photosynthesis.
Let’s review what you know about thallophytes.
Review
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These are the characteristics of thallophytes:
 Have
reproductive structures.
 Are mainly aquatic plants.
 Consist of either a single cell, colonies or filaments.
 Contain no true roots, stems or leaves.
 Do not produce flowers or seeds.
 Can contain chloroplasts for photosynthesis.
Select The Letter Of The Correct
Answer From The List Below:
A. food
B. land
C. algae
D. roots
E. fungi
F. water
1. Thallophytes include organisms called _______________.
2. The most common environment for thallophytes is ______________.
3. Algae make their ______________ by the process of photosynthesis.
4. Thallophytes do not contain true stems, leaves or ______________.
Answers:
algae
1. Thallophytes include organisms called _______________.
water
2. The most common environment for thallophytes is ______________.
food
3. Algae make their ______________
by the process of photosynthesis.
roots
4. Thallophytes do not contain true stems, leaves, or ____________.
Information
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Most land plants are embryophytes.
Embryophytes are multicellular and are more complex
than thallophytes.
These are the two phyla in the embryophytes:
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Bryophytes (lack vascular, or water conducting tissue called
xylem and phloem).
Tracheophytes (have xylem and phloem).
Let’s examine the two embryophyte phyla.
Phylum – Bryophytes
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Bryophytes include mosses and
liverworts. These are the simplest
land plants.
Mosses and liverworts do not contain
true leaves, true stems or true roots.
These are the characteristics of
bryophytes:
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The simplest land plants.
Do not contain true toots, leaves or stems.
Produce embryos.
Do not contain vascular tissue (phloem or
xylem).
Phylum – Tracheophytes
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Ferns are a class of
tracheophytes. They are more
complex plants than
bryophytes.
Let’s study the characteristics
of ferns and other complex
plants.
Alternation of Generations
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Ferns reproduce by alternation of generations.
Ferns (sporophytes) produce spores that germinate into
gametophytes.
Gametophytes produce embryos that grow into ferns.
One generation is very different from another.
Reproduction takes place to produce the alternate
generations.
Let’s look at the characteristics of ferns and other
complex plants.
Phylum – Tracheophytes
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These are the characteristics of
tracheophytes:
 Contain
vascular plants with true
phloem and xylem (water
conducting system).
 Contain roots, leaves and stems.
 Have a wide range of habitats.
Information
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One subphylum of tracheophytes is pteropsida,
land plants that contain conspicuous leaves, true
roots and conducting tissue.
Three classes, ferns (Filicineae),
gymnosperms and angiosperms (flowering
plants), divide the subphylum pteropsida.
Let’s examine the two classes of pteropsida
that you have not yet studied in this PowerPoint.
Class – Gymnosperms
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Gymnosperms include conifers and
other cone-bearing trees and shrubs.
They have exposed seeds.
Some plants in this class are pines,
cedars, spruces and yews.
Class – Angiosperms
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Angiosperms are plants with seeds
hidden in a fruit.
They also are called the flowering
plants.
Seeds and fruits are to angiosperms
as seeds and cones are to
gymnosperms.
Select The Letter Of The Correct
Answer From The List Below:
A. seeds
B. ferns
C. flowering
D. pines
E. cones
F. fruit
1. The seeds of gymnosperms are carried exposed in containers called
_________________.
2. The seeds of angiosperms usually are hidden in a __________________.
3. Another name for the angiosperms is ___________________ plants.
4. Conifers include the __________________ that have exposed seeds.
Answers:
1. The seeds of gymnosperms are carried exposed in containers called
cones
_________________.
fruit
2. The seeds of angiosperms usually are hidden in a __________________.
flowering
3. Another name for the angiosperms is ___________________
plants.
pines
4. Conifers include the __________________
that have exposed seeds.
Monocots vs. Dicots
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Angiosperms are divided into two subclasses,
dicotyledons (dicots) and monocotyledons
(monocots).
These are typical examples of monocots and dicots.
Dicots include most trees, such as oak or maple, as well
as most shrubs and vegetables.
Most pond and streamside plants, such as cattails, and
all grasses, such as wheat and corn, are monocots.
Dicotyledon Seed
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A lima bean is a dicot seed. It consists of
two cotyledons.
A cotyledon is a seed part that supplies
food to the developing embryo.
A corn kernel is a monocot seed. Most of
a corn seed consists of a single
cotyledon.
Let’s compare the characteristics of dicot
and monocot plants.
Monocot vs. Dicot
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Compare the veins (venation) in
monocot and dicot leaves.
Monocot veins run parallel to each
other, as in bellwort leaves.
Dicots, such as an elm tree, have netveined leaves.
Monocots vs. Dicots
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Let’s compare the stems of dicots and monocots.
The position of the phloem and xylem tissues is
different in the stems of monocots and dicots.
In all dicots, the xylem is inside the cambium layer, and
the phloem is outside.
There is no cambium in monocots; there are scattered
bundles of phloem and xylem.
Summary
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Let’s summarize the similarities and differences between
monocots and dicots.
Dicots
Two cotyledons.
Monocots
One cotyledon.
Veins of leaves form a Veins of leaves are
network.
parallel.
Vascular stem
bundles form a radial
pattern.
Vascular stem
bundles are
scattered.
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Review
Two traditional plant subgroups are thallophytes and
embryophytes.
Thallophytes, which include most algae, usually live in water.
Embryophytes are mainly multicellular land plants.
The two phyla of embryophytes are bryophytes (mosses and
liverworts) and tracheophytes (ferns and other common plants).
The three classes of tracheophytes (vascular plants) are the ferns,
gymnosperms and angiosperms.
Pines and other evergreen conifers are cone-bearing
gymnosperms.
Flowering plants are angiosperms.
The two subclasses of angiosperms are dicotyledons (dicots) and
monocotyledons (monocots).
Dicots include trees, such as oak, maple and fruit trees.
Monocots (one cotyledon), such as corn, wheat, rye and oats, are a
major source of food for humans.
Quiz: Fill In The Blanks…
algae
Many biologists used to classify ____________
as
thallophytes (mostly aquatic, nonvascular plants).
Ferns and other common land plants belong to the
phylum of plants. Most common
tracheophyte ___________
plants consist of the cone-bearing gymnosperms and
the seed-producing angiosperms (plants that have
__________).
flowers Dicots include common trees, such as
monocots such as
oak, maple and fruit trees. The __________,
corn, wheat and rice are the major source of food for
humans.
Section Four
Dichotomous Key
Classification
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Biologists use physical characteristics to sort
animals.
Each sorting or grouping of organisms produces
a new level of classification called a taxon.
As the taxons become smaller, the
characteristics of the organisms become more
similar.
Many biologists divide the animal kingdom into
nine phyla.
Let’s see how biologists classify animals into
one of the nine phyla that make up the animal
Information
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Biologists use a series of questions called the
dichotomous key to classify organisms.
Dichotomous means separating into two parts.
It describes the kind of choices you make when
using the key.
Review
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Biologists use physical characteristics to sort
organisms into taxons (levels of classification).
Kingdom, phylum, subphylum, class and subclass,
as well as other subgroupings, are taxons.
As the taxons become smaller, the characteristics of the
organisms become more similar.
Biologists use a series of questions called the
dichotomous key to classify organisms.
Dichotomous means separating into two parts. It
describes the kind of choices you make when using the
key.
Quiz: Fill In The Blanks…
When an organism is classified, biologists observe its
physical characteristics to assign various ___________
taxons
(levels of classification). As the levels become
smaller
______________
in size, the characteristics of the
organisms become more similar. A series of questions,
dichotomous key, is used to do the
called a(n) _____________
classification. When using the key, two ____________
choices
are given to answer each question.
Section Five
Testing Your Knowledge
This Is A Test of What You Have
Learned…
There are 10 questions on this test.
 Try to correctly answer all of the questions.
 If you miss a question, watch the screen
for an explanation of the correct answer.

Select The Best Matching
Choice:
 Kingdom:
Correct Answer: H
A kingdom is the largest taxon into which an
organism can be classified.
A.
B.
 Linnaeus:
Correct Answer: A
Linnaeus was the Swedish biologist who
developed a system of classification and
binomial nomenclature.
C.
D.
E.
F.
G.
H.
Answer Column:
Binomial
nomenclature
Smallest taxon
Oak and maple trees
Algae
One cotyledon
Cone-bearing
Seeds in fruit
Largest taxon
Select The Best Matching
Choice:
 Monocot:
Correct Answer: E
A monocot is a flowering plant that contains a
seed with one cotyledon.
A.
B.
 Gymnosperm:
Correct Answer: F
A gymnosperm is a cone-bearing conifer
plant that contains exposed seeds.
C.
D.
E.
F.
G.
H.
Answer Column:
Binomial
nomenclature
Smallest taxon
Oak and maple trees
Algae
One cotyledon
Cone-bearing
Seeds in fruit
Largest taxon
Select The Best Choice To
Complete Each Analogy:

Flowering plants are to tracheophytes as
humans are to _______________.
chordates
A.
B.
C.
D.
E.
arthropods
mollusks
echinoderms
chordates
coelenterates
Since flowering plants are part of the tracheophyte phylum, the
best analogy is chordates, the phylum to which humans belong.
Select The Best Choice To
Complete Each Analogy:

A genus is to a family as a _____________
is
phylum
to a kingdom.
A. species
B. phylum
C. class
D. order
E. subphylum
Since a family is made of more than one genus, the best analogy
is phylum, which is a component of a kingdom.
Fill In The Blanks…
The system of classifying organisms into different
groups is called ____________.
taxonomy When classifying
organisms, as the _____________
(categories) become
taxons
smaller, the characteristics of organisms become more
similar. Most biologists classify organisms into several
kingdoms. Members of the ____________
kingdom
plant
often contain chlorophyll and cellulose and make their
own food. An animal with a backbone belongs to the
subphylum
vertebrate ______________.
Taxonomy
~Classification & Organization~