Classification
Taxonomy
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Images courtesy: http://imaes.fws.gov ;http://www/glerl.noaa.gov; USDA-NRCS PLANTS Database / Herman, D.E., et al. 1996. North
Dakota tree handbook. USDA NRCS ND State Soil Conservation Committee; NDSU Extension and Western Area Power Administration,
Bismarck; www. Mbr-pwr.usgs.gov; afsc.noaa.gov; and National Agricultural Library, Agricultural Research Service, U. S. Department of
Agriculture."
Organisms
Classification
What is classification?
Why classify?
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Classification Systems
The concept of classifying organisms dates back to 300 B.C.
Over the course of many centuries, different classification systems
were used.
It was Carolus Linnaeus in the 18th century that is credited with
establishing the basic system of classification that we still use today.
He developed a system that classified organisms based on similarities
and differences in physical features and characteristics of organisms.
His system began by looking at individual organisms and grouping the
organisms that appeared similar into a category called species.
Different species had different characteristics.
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Classification Systems
Linneaus also noticed that there were species that shared some
characteristics.
Species that shared some common characteristics were grouped
together in a category called genus.
He continued this level of classification, creating larger and larger
groups that were defined by shared traits. Examples of these larger
groups were orders, classes and kingdoms.
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Classification Systems
Based on new research and new information, many scientists today use a
system similar to the one proposed by Linnaeus.
One of the most frequently used systems has eight categories or groups.
The term taxonomy is used when classifying organisms based on this
system. The eight categories are:
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
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How is the taxonomic system organized?
The taxonomic system is based on physical phenotypes and characteristics. Although
Linnaeus created it by looking at individual organisms, it is sometimes easier to
understand by starting with the larger categories or taxa.
Domain
Organisms are grouped into large
categories or taxa called domains.
Kingdom
Kingdom
Domains are divided into kingdoms.
Phylum
Phylum
Kingdoms are divided into phyla.
Phyla are divided into classes.
Classes are divided into orders.
Orders are divided into families.
class
order
class
order
family
family
genus
Families are divided into genera
(genus).
genus
species
Genera are divided into species.
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species
How is the taxonomic system organized?
1. Does the diagram show all of the
domains, kingdoms, phyla, etc. of
the taxonomic system?
Kingdom
2. Does each category (taxa) of the
taxonomic system have only two
options?
3. Are there always the same
number of taxa in each level of
the taxonomic system?
Domain
Kingdom
Phylum
class
order
Phylum
class
order
family
family
genus
genus
species
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species
How is the taxonomic system organized?
1. Are there more species of
organisms than kingdoms?
Domain
Kingdom
Kingdom
2. Does each taxa represent
smaller and smaller groupings of
similarities?
3. Would you find more differences
than similarities in organisms
from higher levels of taxa as
compared to lower levels?
Phylum
class
order
class
order
family
4. Is the taxonomic system a
HIERARCHAL system?
Phylum
family
genus
genus
species
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species
Most scientists recognize THREE domains of organisms.
Bacteria
Archaea
Eukaryota
Unicellular
prokaryotes
Unicellular prokaryotes that
tend to live in HARSH
conditions where other
organisms CANNOT survive
Unicellular and
multicellular
eukaryotes
Microscopic
Widespread, living in
almost every
environment, including
in the gut of animals
Microscopic
Includes protists,
algae, plants, fungi
and animals
Range from
microscopic to
macroscopic.
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Images courtesy: http://imaes.fws.gov ;http://phil.cdc.gov and www.nasa.gov
Domains
Domain: Bacteria
Classification of bacteria
Unicellular prokaryotes
Some are grouped by shape.
rods
cocci (circular)
aerobic- require oxygen to grow
anaerobic- require NO oxygen for growth
Some are classified by similarity in DNA.
Some are classified by differences in their chemical make-up.
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Images courtesy:;http://phil.cdc.gov
Some are grouped by conditions under which they grow.
Domain: Bacteria
Beneficial
Pathogenic
Some bacteria help ferment
wine and cheese.
Some staphylococcus
bacteria produce skin
infections.
Some bacteria help produce
yogurt.
Some bacteria help break up
waste at water and sewage
treatment plants.
Some bacteria produce
antibiotics such as
streptomycin.
Some streptococcus
bacteria can cause strep
throat.
E.Coli and salmonella
bacteria can cause food
poisoning.
Some bacteria live in our gut
and breakdown food.
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Domain: Archaea
Many live in harsh conditions in which
other organisms would not survive such
as hot springs, acidic water or high salinity
water.
Not as much is known about these organisms
as they were “discovered” as a separate
domain of organisms about 25-30 years ago.
They are classified by differences in DNA and
RNA structure and by the environment in
which they live.
It is thought that they may have been some of
the earliest organisms on the Earth.
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Image courtesy: www.nasa.gov
Unicellular prokaryotes
Check Understanding
1. One taxonomic system used by scientists begins by
classifying organisms into domains. How is the rest of
the taxonomic system organized?
2. Describe how organisms in the Bacteria Domain are
different from organisms in the Eukaryota Domain.
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Classification
Eukaryota Domain: Fungi and
Plant Kingdoms
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What Can You Recall?
1. Where would you find more differences than similarities in two
organisms? In two organisms that share the same phylum or
from two organisms that share the same genus?
2.
How are the organisms in the Bacteria domain similar to the
organisms in the Archaea domain? How are they different?
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Domain: Eukaryota
Characteristics found in
ALL Eukaryotes
Characteristics found in
SOME Eukaryotic Cells
Nucleus
Flagella- a “tail” or “thread”
that helps move the cell
DNA is found inside the
nucleus
DNA is divided into pieces
called chromosomes
Contain a cytoskeleton
Cell wall- a rigid structure
outside the cell membrane.
Chloroplasts- organelles
that contain pigments
needed for photosynthesis
Contain other organelles
Most eukaryotic cells divide
by mitosis
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nucleus
Domain: Eukaryota
One way of classifying the organisms within the Eukaryota domain is
by grouping them into 4 kingdoms
Fungi
Plants
Animals
Protists
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Examples
Yeast, mold, mildew and many more
Common characteristics
Heterotrophic: They obtain nutrients by consuming
other organisms. They do NOT have chloroplasts
and CANNOT make their own food.
They secrete digestive enzymes into the
environment to break down organic matter. They
then absorb the nutrients.
They have cell walls made of chitin. This is a
different material from plant or bacterial cell walls.
Fungi can be unicellular (yeast) or multicellular
(mushrooms).
Multicellular fungi have a filamentous structure.
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Images courtesy: http://phil.cdc.gov and "National Agricultural Library, Agricultural Research Service, U. S.
Department of Agriculture."
Fungi
Fungi Roles
Symbiosis with plants
Other Uses
Most plants have fungi which
grow on their roots.
Yeast are used in baking and
fermenting.
Fungi help to soak up water
and nutrients and provide the
nutrients to the plants.
Mushrooms and truffles are
used in/as foods.
The plant provides the fungi
with sugar that it made during
photosynthesis.
Penicillin is produced by a
mold.
Many plants would not be able
to sustain themselves without
their fungal partner.
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Examples
Mosses, worts, ferns, conifers, flowering plants
Common characteristics
Plants are photoautotrophic. They produce their
own food utilizing light and carbon dioxide
Plants have cell walls made of cellulose. This is a
different materials from fungi or bacterial cell walls.
Plants contain chloroplasts filled with chlorophyll and
other pigments needed for photosynthesis.
Plants are multicellular.
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Image courtesy: SDA-NRCS PLANTS Database / Herman, D.E., et al. 1996. North Dakota tree handbook. USDA NRCS
ND State Soil Conservation Committee; NDSU Extension and Western Area Power Administration, Bismarck.
Plants
Plants
Plants in the Plant Kingdom can be divided into different groups.
In contrast to other kingdoms the next level of classification is sometimes
called a DIVISION instead of a phylum.
Classification into divisions is based on differences in the structures,
methods of reproduction and seed production of plants.
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Classifying Plants
Plants
Non-vascular plants
(seedless)
Vascular plants
Seedless plants
Flowering plants
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Seed plants
“Naked seeds”
Plants
Vascular plants
Non-vascular plants
They have tubes (xylem and
phloem) for carrying water and
nutrients.
They do NOT have xylem and phloem.
Phloem is a system of tubes that
carries sugars and other nutrients
from the leaves and stems to all
other parts of the plant.
They have true roots and leaves.
They reproduce by either spores
or seeds
Examples: all plants except
mosses and worts
They have leaf-like structures.
They absorb water directly from the
ground.
They tend to be small in height because
of the difficulty in moving water over long
distances.
They reproduce by spores
Examples: mosses
and worts
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Image courtesy: Sheri Hagwood @ USDANRCS PLANTS Database
Xylem is a system of tubes that
carries water and minerals from
the roots to other parts of the
plant.
They have rhizoids which are similar to
roots.
Vascular Plants
Seedless plants
Seed plants
They are vascular plants
because they have a system of
tubes.
They are vascular plants
because they have a system
of tubes.
They reproduce using spores.
They reproduce using seeds.
Examples: ferns, clubmosses,
horsetails
Examples: gymnosperms and
angiosperms (pine trees,
flowers, maple trees,
evergreens, etc.)
Images courtesy: USDA-NRCS PLANTS Database / Herman, D.E., et al. 1996.
North Dakota tree handbook. USDA NRCS ND State Soil Conservation
Committee; NDSU Extension and Western Area Power Administration,
Bismarck,www. Mbr-pwr.usgs.gov; and : Jennifer Anderson @ USDA-
NRCS PLANTS Database
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Gymnosperms
(Naked seeds)
Angiosperms
(Flowering plants)
Seeds develop on the surface
of reproductive structures.
For example, seeds develop
on the surface of cones in pine
trees.
Examples: conifers
(evergreens and pine trees),
cycads, and ginkgos
Seeds develop in an
ovary and are enclosed
within a flower or fruit.
Examples: roses, maple
trees, tulips
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Images courtesy: USDA-NRCS PLANTS Database / Herman, D.E., et al. 1996. North Dakota tree handbook. USDA NRCS ND State Soil
Conservation Committee; NDSU Extension and Western Area Power Administration, Bismarck; Robert H. Mohlenbrock @ USDA-NRCS
PLANTS Database / USDA NRCS. 1995. Northeast wetland flora: Field office guide to plant species. Northeast National Technical Center,
Chester ;
Seed Plants
Check Understanding
1. Describe two ways in which fungi and plants are alike.
Describe two ways in which fungi and plants are
different.
2. Describe two different ways in which plants can be
classified.
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Classification:
Eukaryota Domain: Animal and
Protist Kingdoms
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What Can You Recall?
1. How are plants, fungi, animals and protists all ALIKE?
2. Describe one way in which a non-vascular plant is
different from and one way in which it is similar to a
vascular plant.
3. Explain how you would classify a pine tree based on
the following categories:
non-vascular
vascular
seedless
seed
flowering
non-flowering
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Animal Kingdom
Images courtesy:. Photo by Scott Somershoe, USGS. Patuxent Wildlife Research Center" ;
http://imaes.fws.gov;and www/asfc.noaa.gov
Characteristics
Heterotrophic: Animals
do NOT make their own
food. They must ingest
other organisms for
nutrients.
Multicellular
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Animal Kingdom
The animal kingdom can be divided into phyla according to
similarities and differences in DNA and RNA, body structures and
symmetry.
As scientists continue to research organisms, the number of
phyla and the organisms in them continue to be modified.
The diagram on the next slide shows ONE of the currently
accepted divisions of the animal kingdom into phyla.
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Porifera (sponges)
Phyla of the
Animal
Kingdom
Cnidaria (hydras, corals, sea anemones)
Ctenophora (comb jellies)
Platyhelminthes (flatworms)
Rotifera (rotifers)
Lophophorates
Animal Kingdom
Nemertea (worms with a proboscis)
Mollusca (clams, snails, squids)
Annedlia (segmented worms)
Nematoda (roundworms)
Arthropoda (crustaceans, insects, spiders)
Echinodermata (sea stars, sea urchins)
Chordata (lancelets, tunicates, vertebrates such as
mammals)
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In addition to classification into phyla, scientists also use other groupings to help
classify animals. These groupings are not part of the system of taxonomy, but they
are a method of classification.
One way to classify animals is to divide them into vertebrates and invertebrates.
Vertebrates have a backbone. Invertebrates do not.
Vertebrates
This group only includes
animals in the Chordata
phyla.
This group includes the
following CLASSES:
mammals, fish, reptiles,
amphibians, and birds
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Images courtesy: http://images.fws.gov; Evan H.C. Grant, USGS Patuxent Wildlife Research Center;www.nmfs.noaa.gov
Animal Kingdom
Animal Kingdom
Invertebrates
Animals in all other phyla.
This group includes jellyfish, spiders, insects, sponges, crustaceans, etc.
Octupuses
Starfish
Insects
Jellyfish
Snails
Sponges
Spiders
Images courtesy: afsc.noaa.gov; http://images.fws.gov; and www.oceanexplorer.noaa.gov
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Lobsters
Worms
Animal Kingdom
Another way to classify animals is by how they regulate their body temperature.
Two groups of animals are ectotherms (cold-blooded animals) and endotherms
(warm-blooded animals).
Endotherms
Have a body temperature
regulated by their metabolism
and other internal systems for
cooling the body.
Ectotherms
Have a body temperature
regulated by their surroundings
or environment.
“Warm up” by moving into sun on
onto warm surfaces.
“Cool down” by moving into
shady or cool places.
Can maintain a steady body
temperature even when
environmental temperature
changes.
Examples: Reptiles, fish,
amphibians and most
invertebrates
Examples: Mammals, birds,
some fish, a few reptiles, and
some insects.
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Protists
Originally this kingdom was defined as eukaryotic organisms that did NOT have
characteristics of plants, animals or fungi.
Research today that focuses on DNA and RNA structure is just beginning to
define some of the characteristics of this kingdom.
Characteristics
Eukaryotes
Most require a moist environment to live
Some can form colonies
Some can photosynthesize
Some use structures such as flagella to move
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Images courtesy: http://www/glerl.noaa.gov
Most are unicellular.
Protists
The Protist Kingdom can be divided into phyla based on differences in how
food is obtained, pigments, flagella, composition of a cell wall and
environments in which the organisms live.
As with plants and animals, scientists have also created informal categories
(not taxonomic categories) to help classify protists.
Algae
Protozoa
Slime molds
“Plant like protists”
“Animal like protists”
“Fungi-like protists”
Photosynthesize
Ingest food
Absorb nutrients like
fungi
May move
May move
Can move
Example: green,
red and brown
algae
Example: amoebas,
plasmodium (causes
malaria)
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Classification and Taxonomy
You have just explored a portion of the three domains and four kingdoms used in
one of the scientific classification and taxonomic systems.
Do you remember the following
diagram?
Domain
Kingdom
Kingdom
What levels of the taxonomic
system did you investigate?
Which levels did you NOT
investigate?
Phylum
class
order
Phylum
class
order
family
family
genus
genus
species
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species
Classification and Taxonomy
You did NOT investigate and
memorize all of the organisms in
the different phyla, classes,
orders, families, genera and
species.
Kingdom
How could you look at the
taxonomy of different organisms
and draw conclusions about their
similarities?
Domain
Kingdom
Phylum
class
order
Phylum
class
order
family
family
genus
genus
species
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species
Binomial Naming System
One way to compare two
organisms or to correctly identify
an organism is to use the
Kingdom
scientific name for an organism.
Domain
Kingdom
Phylum
Phylum
The scientific name comes from
the Binomial Naming System.
class
class
“Binomial” means “two.”
order
An organism is given TWO
names as its scientific name.
order
family
It is named with its genus and
species.
family
genus
This system was not discovered
but was put into common
practice by Carolus Linnaeus.
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genus
species
species
Binomial Naming System
When using the scientific name, the first
letter of the genus name is capitalized.
All other letters of the genus and
species names are lowercase.
Domain
Kingdom
Kingdom
The scientific name can either be
underlined or put in italics.
Example: scientific name (binomial
name) for “modern humans”
Homo sapiens
Phylum
class
order
class
order
family
Homo sapiens
family
genus
If the name is used several times in a
publication, it can be abbreviated after
writing in full the first time. Examples
H. sapiens , E.coli, T. rex
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Phylum
genus
species
species
Binomial Naming System
Compare these two organisms.
Homo erectus
Domain
Homo sapiens
Kingdom
Kingdom
Phylum
What conclusions can you make?
Are they the same species?
class
Are they from the same genus?
order
Are they from the same family?
class
order
family
Are they from the same order?
Phylum
family
genus
genus
Are they from the same class?
species
Are they from the same phylum?
Are they from the same kingdom?
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species
Using Taxonomy
Another way to compare organisms would be to look at the entire
taxonomic classification of two organisms.
Taxa
Human
Armadillo
KIngdom
Animalia
Animalia
Phylum
Chordata
Chordata
Class
Mammalia
Mammalia
Order
Primata
Cingulata
Family
Hominidae
Dasypodidae
Genus
Homo
Dasypus
Species
Sapiens
Novemcinctus
What conclusions can you make about the similarities that humans
and armadillos may share?
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Check Understanding
1. Describe two ways in which animals can be classified.
2. How are protists different from plants, fungi and
animals?
3.
Explain the type of information a scientific name can
tell someone about an organism.
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Classification
Making and Applying Connections
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Making and Applying Connections
A
B
C
D
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Images courtesy: http://images.fws.gov; Evan H.C. Grant, USGS Patuxent Wildlife Research
Center;www.nmfs.noaa.gov
1. In which of these animals is body temperature NOT regulated by changes
in its environment or surroundings?
Making and Applying Connections
2.
The table below shows eight different animals. Which of the following
conclusions can you make?
Animal
Phylum
Vertebrate
Alligator
Chordata
Yes
Bee
Arthropoda
No
Frog
Chordata
Yes
Bear
Chordata
Yes
Starfish
Echinodermata
No
Salmon
Chordata
Yes
Spider
Arthropoda
No
Octupus
Mollusca
No
A.
All of the animals belong to the same phylum.
B.
All of the animals that are NOT in the Chordata phylum are invertebrates.
C.
All of the animals in the Chordata phylum are reptiles.
D.
All of the animals are vertebrates.
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Making and Applying Connections
3. Madeline noticed that some types of organelles are not found in all
protists. She plans to research the type of organelles in protists and
whether the protists can photosynthesize or cannot
photosynthesize.
Which of these questions is Madeline most likely trying to answer?
A. Does the type of organelles differ between protists that
photosynthesize and those than do not photosynthesize?
B. Does the type of photosynthesis differ between protists?
C. Does the type of cell wall differ between protists that photosynthesize
and those that do not photosynthesize ?
D. Does the type of organelles differ between protists with different
flagella?
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Making and Applying Connections
4. Which of the following diagrams BEST shows the organization of taxonomic
levels from domain through species?
B
Species
A
Genus
Genus
Family
Order
Class
Family
Domain
Kingdom
Class
Order
Phylum Family
Family
Species
Order
Class
Phylum
Phylum
Kingdom
Kingdom
Domain
D
Domain
Kingdom
Domain
Kingdom
Phylum
Class
C
Order
Domain
Phylum
Class
Order Family
Genus
Species
Class
Family
Genus
Genus
Species
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Phylum
Order
Family
Kingdom
Genus
Species
Making and Applying Connections
5. Which of the following describe the level of classification of
Bacteria, Archaea and Eukaryota?
A.
B.
C.
D.
Species
Genus
Kingdom
Domain
6. Which of these would be the best evidence that an
organism should be classified at the taxonomic level of
Eukaryota?
A. It is unicellular.
B. It can survive in harsh conditions.
C. It is microscopic.
D. It has a nucleus.
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Making and Applying Connections
7.
Griffin has been copying the information about the taxonomic classification of
two different organisms into a chart. He leaves for lunch before completing
the chart. What would you expect the Class for Organism #2 to be?
A.
B.
C.
D.
Taxa
Organism 1
KIngdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Primata
Primata
Family
Hominidae
Hominidae
Genus
Pan
Gorilla
Species
Troglodytes
Beringei
Animalia
Mammalia
Plantae
Reptila
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Organism 2
Making and Applying Connections
8.
Catherine has been researching organisms from the Amazon jungle. She has
recorded information about each in the table below. What conclusions can she
make about the organisms?
Organism
Observations
Nucleus
Type of Organism
1
Has a cell wall made of chitin
Yes
Unicellular
2
Obtains nutrients by secreting
digestive enzymes and
absorbing nutrients from a
substance.
Yes
Unicellular
3
Has a filamentous structure
Yes
Multicellular
A. Organisms 1, 2 and 3 are most likely fungi.
B. Organisms 1 and 2 are most likely bacteria.
C. Organisms 1 and 2 are most likely animals.
D. Organism 1 is most likely a plant.
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Making and Applying Connections
9. Which of these explains how plants are different from animals and
fungi?
A.
B.
C.
D.
Plants are multicellular.
Plants have a cell wall.
Plants are photoautotrophic.
Plants have a nucleus.
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Making and Applying Connections
10. Juanita has collected the following information about a plant. What is the
scientific name of the plant?
Domain
Eukaryota
Kingdom
Plantae
Phylum
Magnoliophyta
Class
Magnoliopsida
Order
Fabales
Family
Fabaceae
Genus
Pisum
Species
Savitum
Non-vascular
No
Vascular
Yes
Seedless
No
Seed
Yes
Type of Seed
Flowering
A.
B.
C.
D.
Flowering-seed plant
Vascular-seed plant
Plantae magnoliophyta
Pisum savitum
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