taxonomy classification & organization. section one organization

TaxonomyTaxonomy

Classification & Organization

Section OneSection One

Organization

Quick Question…Quick Question… 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. PlantAnimal vs. Plant A fish and a frog are both animals. A rose and a tree are both plants.

A fish and a frog have animal characteristics.

These are a few of the characteristics of animals: Consist of cells containing organelles. Need to ingest food. Most are mobile. Lack chlorophyll. Lack cell walls.

Animal vs. PlantAnimal vs. Plant A rose and a tree have plant characteristics.

These are the characteristics of most plants: 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!Take A Guess!

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…An Example…

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:

Name House number Street Town State Country

John Doe10601 S. CentralOak Lawn, ILUSA

Example (Cont.)Example (Cont.)

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.



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.



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.

John Doe10601 S. CentralOak Lawn, IL 60453USA


Look at the address again. Here are all six of the categories in descending order. 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.)

John Doe10601 S. CentralOak Lawn, IL 60453USA

InformationInformation When organizing anything, start with the largest group, and

subdivide it into smaller categories. This is classifying by descending order.

For Example: USA

Illinois Another State

Oak Lawn Another Town

Another Street S. Central

10601 10501

John Doe Mary Doe

Note: A zip code identifies the state, the area in that state, and a specific post office or delivery area.

Classifying WordsClassifying Words Let’s try an exercise in the classification of words that

describe time. Put these words in descending order:

A. Hour F. Decade

B. Month G. Minute

C. Century H. Week

D. Eon I. Second

E. Day J. Year Eon – Century – Decade – Year – Month – Week – Day – Hour –

Minute – Second Let’s see how biologists use categorization when studying

organisms.

InformationInformation 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 OrganismsClassification of Organisms 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.

InformationInformation

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.

ReviewReview 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 Select The Letter Of The Correct Answer From The List Below:Answer From The List Below:

A. species D. category

B. class E. genus

C. kingdom 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 _________________.

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:Answers:

kingdom

taxonomy

species

category

Classification of OrganismsClassification of Organisms

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 How Are These Organisms Related?Related?

Think about it! How would you group these organisms by their

characteristics? First group: A & D Second group: B & C

KingdomsKingdoms

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)Animal Kingdom (Animalia)

These are some of the characteristics of animals: Consist of cells containing organelles. Need to inject food. Most are mobile. Lack chlorophyll. Lack cell walls.

Plant Kingdom (Plantae)Plant Kingdom (Plantae)

These are the characteristics of most plants: 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)Protist Kingdom (Protista)

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.

EuglenaEuglena

These are the characteristics of protists: 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 KingdomMonera Kingdom

The Monera include bacteria and blue-green algae. Monera have these characteristics:

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 KingdomFungi Kingdom

Organisms in the kingdom Fungi have this appearance. Lets look at bread mold to better understand the

characteristics of fungi.

Bread MoldBread Mold

These are the characteristics of members of the kingdom Fungi: 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).

ReviewReview

Kingdom Major Characteristics

Animal Heterotrophic, multicellular, lack cell walls and chlorophyll.

Plant 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…Quiz: Fill In The Blanks…

Organisms can be classified into five large categories called ____________. The ____________ are usually unicellular organisms that can move and form colonies. They are different from the ____________, which are 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 ____________.

kingdoms protists

animals

fungi

Section TwoSection Two

Classification of Animals

SymmetrySymmetry 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.

SpongeSponge

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 SymmetryBilateral Symmetry

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 SectionEarthworm Cross Section

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.

InformationInformation 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 ExplorationPhyla Exploration These are the major animal phyla:

Sponges Coelenterates Flatworms Roundworms Segmented worms Mollusks Arthropods Echinoderms Chordates.

Phylum – Sponges (Porifera)Phylum – Sponges (Porifera) 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 Phylum – Coelenterates (Coelenterata)(Coelenterata)

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 Phylum – Flatworms (Platyhelminthes)(Platyhelminthes)

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 Phylum – Roundworms (Nematoda)(Nematoda)

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 Phylum – Segmented Worms (Annelida)(Annelida)

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)Phylum – Mollusks (Mollusca) 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 Phylum – Arthropods (Arthropoda)(Arthropoda)

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 Phylum – Echinoderms (Echinodermata)(Echinodermata)

Echinoderms are spiny-skinned animals. The Echinoderms have these features:

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)Phylum – Chordates (Chordata)

Some chordates are simple; others are more complex.

Chordate characteristics consist of the following: 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).


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 ExplorationChordate Class Exploration

These are the chordate classes: Jawless fish. Cartilaginous fish. Bony fish. Amphibians. Reptiles. Birds. Mammals.

Class – Jawless Fish (Agnatha)Class – Jawless Fish (Agnatha)

The skeleton is made of cartilage. These fish have no jaws.

Class – Cartilaginous Fish Class – Cartilaginous Fish (Chondrichthyes)(Chondrichthyes)

These are the characteristics of the cartilaginous fish: Cartilaginous skeleton. Mouth containing a jaw. Visible gill slits.

Class – Bony Fish (Osteichthyes)Class – Bony Fish (Osteichthyes)

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)Class – Amphibians (Amphibia)

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)Class – Reptiles (Reptilia) These are the characteristics of

reptiles: 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)Class – Birds (Aves)

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)Class – Mammals (Mammalia)

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.

InformationInformation 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 SystemsClassification Systems

Protists Bacteria Blue-green algae Protozoa Slime molds True fungi

Plants Chrysophytes Green algae Brown algae Red algae Bryophytes Tracheophytes

Animals

Monera Bacteria Blue-green algae

Protists Protozoa Slime molds True fungi Chrysophytes Green algae Brown algae Red algae

Plants Bryophytes Tracheophytes

Animals

Classification SystemsClassification Systems


Protists Protozoa Slime molds True fungi Chrysophytes Green algae Brown algae Red algae

Plants Bryophytes Tracheophytes

Animals


Protists Protozoa Slime molds Chrysophytes

Plants Green algae Brown algae Red algae Bryophytes Tracheophytes

Fungi True fungi

Animals

InformationInformation All classification systems follow a pattern. These are the different groups in descending

order: Kingdom Phylum Class Order Family Genus Species

Let’s develop a chart of animal classification that includes humans.

Human ClassificationHuman Classification

Kingdom Animals

Phylum Chordates

Class Mammals

Order Primates

Family Hominids

Genus Homo

Species sapiens (Humans)

ReviewReview An important characteristic of an organism is its

organization or symmetry (balanced proportions). There are two major kinds of symmetry: 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.


Biologists generally classify each kingdom into the next smaller group, known as a _____________. An important characteristic of an organism in each phylum is its ___________ (balanced proportions). The fish are ____________ (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 ____________.

phylum

symmetryvertebrates

species

Section ThreeSection Three

Classification of Plants

Land vs. Water PlantsLand vs. Water Plants Plants can live in different parts of the

environment. Biologists separate plants into two general

categories: Land plants – embryophytes. Water plants – thallophytes.

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.

AlgaeAlgae 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 AlgaeTypes of Algae

Chlamydomonas Some water plants are unicellular.

Spirogyra Some water plants consist of cells that form long

threads.

Fucus Some water-dwelling algae consist of sheets of cells

that form large, tree-sized plants.

Classification of PlantsClassification of Plants

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 PlantsClassification of Plants

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.

ThallophytesThallophytes Most algae are thallophytes. Let’s compare a thallophyte with a land-dwelling plant

(embryophyte) to see the differences in their structure.

Embryophyte vs. ThallophyteEmbryophyte vs. Thallophyte

Blades

Air Bladder

Stipe

Holdfast

Flower

Leaf

Stem

Roots (Not Pictured)

ThallophytesThallophytes

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.

ReviewReview

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.


A. food D. roots

B. land E. fungi

C. algae 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 ______________.

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:Answers:

algae

water

food

roots


Most land plants are embryophytes. Embryophytes are multicellular and are more complex

than thallophytes. These are the two phyla in the embryophytes:

Bryophytes (lack vascular, or water conducting tissue called xylem and phloem).

Tracheophytes (have xylem and phloem).

Let’s examine the two embryophyte phyla.

Phylum – BryophytesPhylum – Bryophytes 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: The simplest land plants. Do not contain true toots, leaves or stems. Produce embryos. Do not contain vascular tissue (phloem or

xylem).

Phylum – TracheophytesPhylum – Tracheophytes

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 GenerationsAlternation of Generations 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 – TracheophytesPhylum – Tracheophytes

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.


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 – GymnospermsClass – Gymnosperms

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 – AngiospermsClass – Angiosperms

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.


A. seeds D. pines

B. ferns E. cones

C. flowering 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.

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:Answers:

cones

fruit

flowering

pines

Monocots vs. DicotsMonocots vs. Dicots

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 SeedDicotyledon Seed

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. DicotMonocot vs. Dicot 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 net-

veined leaves.

Monocots vs. DicotsMonocots vs. Dicots 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.

SummarySummary Let’s summarize the similarities and differences between

monocots and dicots.

Dicots Monocots

Two cotyledons. One cotyledon.

Veins of leaves form a network.

Veins of leaves are parallel.

Vascular stem bundles form a radial pattern.

Vascular stem bundles are scattered.

ReviewReview 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.


Many biologists used to classify ____________ as thallophytes (mostly aquatic, nonvascular plants). Ferns and other common land plants belong to the tracheophyte ___________ of plants. Most common plants consist of the cone-bearing gymnosperms and the seed-producing angiosperms (plants that have __________). Dicots include common trees, such as oak, maple and fruit trees. The __________, such as corn, wheat and rice are the major source of food for humans.

algae

phylum

flowersmonocots

Section FourSection Four

Dichotomous Key

ClassificationClassification 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 kingdom.


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.

ReviewReview 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.


When an organism is classified, biologists observe its physical characteristics to assign various ___________ (levels of classification). As the levels become ______________ in size, the characteristics of the organisms become more similar. A series of questions, called a(n) _____________ key, is used to do the classification. When using the key, two ____________ are given to answer each question.

taxons

smaller

dichotomouschoices

Section FiveSection Five

Testing Your Knowledge

This Is A Test of What You Have This Is A Test of What You Have Learned…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 Select The Best Matching Choice:Choice:

Answer Column:

A. Binomial nomenclature

B. Smallest taxon

C. Oak and maple trees

D. Algae

E. One cotyledon

F. Cone-bearing

G. Seeds in fruit

H. Largest taxon

Kingdom:Correct Answer: HA kingdom is the largest taxon into which an organism can be classified.

Linnaeus:Correct Answer: ALinnaeus was the Swedish biologist who developed a system of classification and binomial nomenclature.

Select The Best Matching Select The Best Matching Choice:Choice:

Answer Column:

A. Binomial nomenclature

B. Smallest taxon

C. Oak and maple trees

D. Algae

E. One cotyledon

F. Cone-bearing

G. Seeds in fruit

H. Largest taxon

Monocot:Correct Answer: EA monocot is a flowering plant that contains a seed with one cotyledon.

Gymnosperm:Correct Answer: FA gymnosperm is a cone-bearing conifer plant that contains exposed seeds.

Select The Best Choice To Select The Best Choice To Complete Each Analogy:Complete Each Analogy:

Flowering plants are to tracheophytes as humans are to _______________.

A. arthropodsB. mollusksC. echinodermsD. chordatesE. coelenterates

chordates

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 Select The Best Choice To Complete Each Analogy:Complete Each Analogy:

A genus is to a family as a _____________ is to a kingdom.

A. speciesB. phylumC. classD. orderE. subphylum

phylum

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…Fill In The Blanks…

The system of classifying organisms into different groups is called ____________. When classifying organisms, as the _____________ (categories) become smaller, the characteristics of organisms become more similar. Most biologists classify organisms into several kingdoms. Members of the ____________ kingdom often contain chlorophyll and cellulose and make their own food. An animal with a backbone belongs to the vertebrate ______________.

taxonomytaxons

plant

subphylum

TaxonomyTaxonomy~Classification & Organization~

taxonomy classification & organization. section one organization

Documents

centraloak lawn

category oak lawn

largest category

smallest category

ilusaexample cont

animal characteristics

different kinds of organisms

large area