Transcript File

Classification and the 6
kingdoms
I. Taxonomy
Taxonomy (Classification) is the branch of biology
concerned with:
A. Reconstructing phylogeny (evolutionary
history)
B. Naming organisms and placing them into
hierarchical categories based upon their
evolutionary relationships
C. The eight major categories of classification, in
order of decreasing inclusiveness are: Domain,
Kingdom, Phylum, Class, Order, Family, Genus,
Species
Classification of the diversity of
species is studied by:
a) evolutionists
b) taxonomists
c) theorists
d) taxidermists
II. History of Taxonomy
– Aristotle’s System (more than 2,000 years ago)
1. He classified all living things known at that time into two
major groups—plants and animals.
2. He grouped plants and animals according to their
structural characteristics.
3. Plants were classified as trees, shrubs, and flowers.
4. Animals were grouped according to where they lived—
on land, water, or air.
5. Later observations convinced scientists that Aristotle’s
system did not work. They observed that some animals,
such as frogs, lived both on land and in water. Scientists
also realized that Aristotle’s classification system did not
show natural relationships among organisms.
Aristotle
B. Carolus Linnaeus
1. An 18th century Swedish botanist developed a method
of classification that is still used today, which is called
binomial nomenclature.
2. Binomial nomenclature is a system by which each
species is given a 2 word Latin name.
3. Linnaeus selected physical characteristics that led to
classification based on close relationships of organisms.
4. Example for plants: He based his classification of
flowering plants on the numbers and similarities of their
reproductive structures.
5. Example for animals: He selected characteristics of
organisms that also led eventually to classifications based
on evolutionary relationships.
6. Linaeus’ system uses 2 scientific names:
a. The first part of the name is the genus—
genus refers to the relatively small group of
organisms to which a particular type of
organism belongs.
b. The second part of the name is the
species- This is usually a description of
some important characteristic.
Example: Red Maple—common name
Acer rubrum—scientific name
(genus) (species)
C. Before 1969, all forms of life were classified
into two kingdoms
1. Animalia
2. Plantae (included plants, bacteria, fungi
and photosynthetic eukaryotes)
D. Proposed by Robert H. Whittaker (1969)
Kingdoms include:
1. Monera (all prokaryotes)
2. Plantae
3. Fungi
4. Animalia
5. Protista (eukaryotes that are not plants,
fungi, or animals)
III. Scientific Names
A. Common names are everyday names given to organisms.
Common names may not accurately describe an organism.
Example: Jellyfish is not a fish…but a Cnidarian.
B. A scientific name is composed of the genus and the species.
C. There are 3 rules to follow when writing scientific names:
1. Always capitalize the genus name.
2. Always leave the species in lowercase.
3. Always underline both names (unless typing...then
use italics).
Example: Home sapiens—Humans or if typing, Home sapiens
Felis domesticus—Cat
Canis familiaris—Dog
Rana pipiens—Frog
D. Trinomial nomenclature - when
organisms can be divided even further into
subspecies or varieties. Used when three
scientific names are given. Ex: Acer
rubrum var. drummondii is a Drummond’s
red maple. Acer is the genus, rubrum is the
species and drummondii is the variety of red
maple that grows in the coastal plains area.
IV. Classification system of organisms from
largest to smallest:
This is the system most scientists use that puts each
living thing into groups, organized from the most
general to the most specific. Therefore, each species
belongs to a genus, each genus belongs to a family,
and each family belongs to an order. These are
hierarchies.
A. Domain:: Eukaryotic/Prokarytoic
B. Kingdom:In the kingdoms, there are huge groups,
encompassing millions of kinds of organisms in each.
This group has the most, and as you go down, the
number of different kinds of organisms decrease. In
other words, the more specific it becomes.
C. Phylum or Division: A group of related classes.
1. Animal groups are called phyla.
2. Plant groups are called division.
3. All of the animals in the phylum vertebrata must belong to
the same kingdom.
4. Chordata is to Animalia as phylum is to Kingdom.
D. Class: A group of related orders.
E. Order: A group of related families.
F. Family: A group of closely related genera
G. Genus: A group of similar species that are alike
in general features and are closely related is a
genus.
Example: The leopard frog is know by the scientific name
Rana pipiens. The wood frog is known as Rana sylvatica.
What is the smallest classification division these frogs have in
common? genus
H. Species: Species are the _most specific. A
species consists of all the animals of the same
type, who are able to breed and produce young of
the same kind.
1. This biological classification group has the
fewest members.
2. Organisms that look alike and successfully
reproduce fertile offspring belong to the same
species. 2 organisms would be most closely
related if they are classified in the same
species.
3. Ex: 2 plants probably belong to the same
species if they can producefertile offspring.
4. The biological species concept defines species as
“groups of interbreeding natural populations, which are
reproductively isolated from other such groups”
-Cannot be applied to asexually reproducing
organisms
5. Alternative species definitions have been proposed,
one of which is the phylogenetic species concept
a. The phylogenic species concept defines a species
as “the smallest diagnosable group that contains all
the descendants of a single common ancestor”
b. Can be applied to sexually and asexually
reproducing organisms
c. May eventually replace the biological species
concept
I. The more categories two organisms
share, the closer their evolutionary
relationship
J. Today, scientists classify organisms
according to the
1. Evolutionary history of the species.
2. The external and internal characteristics
of organisms and
3. Chemical makeup—DNA (the genetic
material). This is the best way to determine
any taxonomic relationship between 2
organisms.
A group of related organisms that are
able to interbreed in nature & produce
fertile offspring is a:
a) species
b) phylum
c) genus
d) order
The taxonomic group that shows the
greatest similarity among its members
is the:
a) kingdom
b) class
c) species
d) family
Which statement describes organisms that
are classified in the same genus?
a) They must be in the same phylum, but
may be of a different species.
b) They must be of the same species, but
may be in different phyla.
c) They must be in the same kingdom, but
may be in different phyla.
d) They must be in the same class, but
may be in different phyla.
As we move through the taxonomic
groups from the kingdom to the
species level, organisms:
a) become more similar in
appearance
b) vary more & more
c) are less related to each other
Which of these taxonomic
classification groups has the
fewest members?
a) species
b) family
c) class
d) genus
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Classification of Humans:
Kingdom: Animalia
Phylum: Chordata
Class :Mammalia
Order:Primate
Family:Hominidae
Genus:Homo
Species: sapiens
Spurge
Cactus
V. Taxonomy Reveals Evolutionary
History
A. Linnaeus’s classification system was
based on the fact that organisms have
different degrees of similarities. Ex: Tigers
resemble gorillas more closely than they
resemble fish.
B. According to Darwin’s views, organisms
that are similar descended from a common
ancestor; therefore, classification provides
strong evidence of evolution.
C. Making evolutionary connections based on similar traits
can be misleading because not all traits are inherited from
a common ancestor. Ex: The wings of a bird and the
wings of an insect. Both enable flight, but the two kinds of
wings are built differently, and based on fossil evidence, we
know they evolved independently of each other.
D. Convergent evolution is when organisms evolve similar
features independently, often because they live in similar
habitats.
1. Convergent evolution is the process by which unrelated
species become similar as they adapt to similar
environments. Similar features that evolved through
convergent evolution are called analogous structures or
homoplasies.
2. Ex: Although they evolved in differently whales on land
and fish in water, whales and fish have similar structures.
The scientific name for the fruit fly is
Drosophila melanogaster. The word
Drosophila refers to the taxonomic group:
a) kingdom
b) genus
c) species
d) phylum
Scientists use a 2-name method of providing
scientific names to organisms that is
called:
a) binomial nomenclature
b) scientific nomenclature
c) theoretical nomenclature
The scientific name of an organism:
a) varies according to the native language
of scientists.
b) is the same for scientists all over the
world.
c) may refer to more than 1 species.
d) is different for scientist all over the
world.
The language of scientific
names is:
a) English
b) Latin
c) Spanish
d) French
Of the following, Felis leo, is
most closely related to:
a) Rana pipiens
b) Xenopus laevis
c) Felis domesticus
d) Elephas maximus
Scientific names come from the
taxonomic groups:
a) kingdom & phylum
b) class & family
c) genus & species
d) order & family
E. Unique characteristics help distinguish groups:
1. Modern taxonomists use the phylogeny (evolutionary
history) of an organism to classify it.
2. A phylogenetic tree is a family tree that shows the
evolutionary relationship thought to exist among groups of
organisms. Scientists construct a phylogenetic tree by
using several lines of evidence such as:
a. fossil records
b. An organism’s morphology compared to the morphology
of other living things
c. Embryological patterns of development
d. Comparisons of macromolecules such as DNA, RNA,
and proteins as well as an organism’s biochemistry.
F. Cladistic taxonomists use derived
characters to establish evolutionary
relationships
1. Derived characteristic -feature that
evolved only within the group under
consideration.
2. Example: a derived character for birds is
feathers.
The red maple tree is known by the scientific
name Acer rubrum. The sugar maple tree
is known as Acer saccharum. What is the
smallest classification division these trees
have in common?
a) phylum
b) order
c) genus
d) species
It is easy to group snakes based on color.
However, a scientist would prefer a
system that shows how snakes:
a) get their food
b) shed their skin
c) are genetically related
d) mate
G. Many taxonomists give varying degrees of importance
to characters and thus produce a subjective analysis of
evolutionary relationships called evolutionary systematics.
1. Evolutionary systematics is the approach of choice
when a great deal of information about a group of
organisms is available. When little information is available
about how a character affects the life of an organism,
cladistics is the better choice.
2. Ex: Evolutionary systematics places birds in an entirely
separate class from reptiles, which gives more importance
to characters like feathers that made powered-flight
possible.
H. Dichotomous keys: tool used by scientists to classify
organisms, using a system of questions. Ex:
VI. Biodiversity
A. The total number of species in an ecosystem
B. Number of named species is currently about 1.5 million
(biased toward large organisms in temperate regions)
a. 5% prokaryotes and protists
b. 22% plants & fungi
c. 73% animals
C. Estimated that 7 million to 10 million species may exist
D. Between 7,000 and 10,000 new species are identified
annually, mostly in the tropics
E. Tropical rain forests are believed to be home to 2/3 of
the world’s existing species, most of which have yet to be
named
F. Because tropical rain forests are being destroyed so
rapidly, species may become extinct before we ever knew
they existed
There is a six-kingdom classification
system:
1. Kingdom Archeabacteria
2. Kingdom Eubacteria
3. Kingdom Protista
4. Kingdom Fungi
5. Kingdom Plantae
6. Kingdom Animalia
Kingdoms 1 and 2 used to be combined
into Kingdom Monera
I. Both Archaebacteria and Eubacteria:
(_MONERANS)
A. Both are prokaryotes—_DO NOT HAVE A
NUCLEUS OR MEMBRANE BOUND
ORGANELLES
B. Small (microscopic), simple, and lack
membrane-bound organelles.
C. DNA is found _FLOATING IN THE
CYTOPLASM_.
D. Most _UNICELLULAR_ (1 cell)
E. Most numerous and widespread
organisms on the earth
F. Both reproduce by _BINARY FISSION_.
1. The cell pinches into 2 cells,
2. a form of asexual reproduction that produces identical
offspring.
3. In asexual reproduction, a single parent passes exact
copies of its entire DNA to its offspring.
4. Binary fission can occur every 20 minutes
5. Rapid reproductive rate allows for rapid evolution
6. Mutations in DNA replication are rapidly spread
G. Bacteria use _CILLIA_ and
_FLAGELLA_ to aid in movement
1. In bacteria, a "wheel-and-axle"
arrangement anchors the flagellum within
the cell wall and plasma membrane,
enabling the flagellum to rotate rapidly
H. Bacteria can have _PILI_, which enable
bacteria to attach to surfaces or to other
cells.
I. Both are _MICROSCOPIC _ and
_PROKARYOTIC_.
J. Metabolism in Bacteria
1. Anaerobic Metabolism
a. Some bacteria live without oxygen (and are poisoned by
it)
e.g. Tetanus bacteria
2. Some bacteria can switch between aerobic and
anaerobic respiration
e.g. Escherichia coli in our large intestines
3. Bacteria Food:
a. Familiar organic compounds such as sugars,
carbohydrates, fats, and proteins
b. Compounds poisonous to humans such as petroleum,
methane, benzene, toluene
c. Inorganic molecules such as hydrogen, sulfur, ammonia,
iron, nitrite
d. Sunlight such as:
1. Cyanobacteria perform photosynthesis
2. Sulfur bacteria use H2S instead of water
in photosynthesis
K. Some bacteria secrete sticky layers of
polysaccharide or protein slime
1. Aggregates (communities) of slimesecreting bacteria are called biofilms
2. Dental plaque is a biofilm
3. Bacteria embedded in biofilms are
protected from disinfectants and antibiotics
II. The Structure of Monerans
A. 3 Main Shapes of Bacteria (Monerans):
Examples:
1.Ball-shaped (_COCCI)--Staphlococci
mutans which Causes tooth decay.
2.Rod-shaped (BACILLI)--E.coli and
Clostridium botulinum which causes food
poisoning.
3.Corkscrew-shaped (_SPIRILIA)-Treponema pallidum which causes Syphillis
B. Bacterial Cells are also classified by their
arrangement:
1.DIPLO_refers to cells that are paired
2.STAPHYLO_ refers to cells arranged in
grapelike clusters.
3. STREPTO refers to cells arranged by
long chains.
III. Classification of Bacteria
A. Features used in prokaryotic classification:
1. Shape
2. Means of locomotion
3. Pigments
4. Nutrient requirements
5. Colony appearance
6. Gram staining characteristics
7. Nucleotide sequences
B. The kingdom used to be referred to as the kingdom
MONERA (bacteria), which now is divided into
Archaebacteria and Eubacteria. Archaebacteria and
Eubacteria probably diverged from each other several
billion years ago.
C. _ARCHAEBACTERIA_
1. They are the earliest monerans (prokaryotes or
bacteria).
2. The cell walls of Archaebacteria do NOT
contain PEPTIDOGLYCAN_.
3. Their relationship to each other is shown
through their RNA sequencing.
4. There are at least three major groups of socalled “extremophile” Archaebacteria, each living
in very different hostile environments.
a. _METHANOGENS_ obtain their energy by
making methane gas (CH4) from other organic
compounds. They are found in swamps.
b. _THERMOPHILES live in very hot water (140º
F – 176º F), such as the water near deep sea
hydrothermal vents. Some obtain their energy
from sulfur.
c. HALOPHILES_ live in very salty places, like the
Great Salt Lake, in Utah.
Halophiles
Methanogens
Thermophiles
Kingdoms Archaebacteria and
Eubacteria are sometimes referred to
asa) Kingdom Arachaialeu
b) Kingdom Euarchae
c) Kingdom Monera
d) Kingdom Protista
All bacteria:
a) cause disease
b) lack a nucleus
c) are autotrophic
d) contain a nucleus
D. EUBACTERIA_
1. Eubacteria have strong exterior cell walls made
of _PEPTIDOGLYCAN.
2. Eubacteria are found in practically every
environment on earth, and they have an impact on
humans every day. Some normally live in and on
your _BODY_. Some Eubacteria cause
_DISEASES_. Other Eubacteria are used by
humans to process foods, to control agricultural
pests, to produce various chemicals, and to use in
genetic engineering.
a. Some eubacteria obtain energy from
inorganic compounds such as hydrogen
sulfide, ammonia, and methane.
b. Some are photosynthetic and are found
in ocean and freshwater environments,
where they are producers.
c. Some are heterotrophs and are capable
of living in the absence of oxygen
(__ANAEROBIC) while others must have
oxygen (_AEROBIC_) to live.
IV. Bacteria and Human Life
A. Most bacteria are important and beneficial to life. Some
are harmful and produce endospores which can cause
botulism or tetanus. Others cause Lyme disease, strep
throat, and cavities in your teeth
B. Benefits to Human Life
1. Roots of certain plants.
a. Nitrogen-fixing bacteria are an important part of the
nitrogen cycle, live in the soil help to break down and
recycle organic and inorganic materials and put oxygen
back in the atmosphere.
b. Many foods such as pickles, yogurt, sauerkraut, and
swiss cheese depend on bacteria for their distinctive odors
and flavors.
2. Medicine and Human Health
a. Certain kinds of bacteria are used to make antibiotics,
such as neomycin and erythromycin, which are used to
destroy other bacteria.
b. Bacteria called probiotics are important for human
health. They live in the intestines and produce certain
vitamins, enhance the absorption of nutrients, and
strengthen the immune system.
c. Create environment hostile to pathogenic infection in
vaginal tract
d. Produce vitamin K in our intestines
3. Animal Metabolism
a. Leaf-eating animals (ruminants) depend on
bacteria to break down cellulose (e.g. rabbits,
cattle)
b. These animals couldn’t live without this bacteria
4. Pollution
a. Nearly all human-made substances are
biodegradable by some bacterial species
b. Oil-eating bacteria were used in clean up of
Exxon Valdez oil-spill disaster
c. Some sewage treatment plants use bacteria to
clean sewage
C. Harmful to Human Life
1. Endospores
a. Form inside some bacteria under
inhospitable
environmental conditions
b. Endospores are thickly-wrapped particles of
genetic material and a few enzymes
c. Endospores are resistant to extremes
1. Survival in boiling water, why is this bad??
2. Stable and long-lived (> 250 million years)
3. Ideal bioterror agent (e.g. anthrax spores)
Endospore
2. Poisons
a. Some anaerobic bacteria produce dangerous
poisons:
1. Clostridium tetani causes tetanus
2. Enters body through puncture wound
3. Produces paralyzing poison
b. Clostridium botulinum causes botulism
1. Reproduces in under-sterilized canned
food
2. Botulism toxin is very potent
3. Honey can produce botulism in infants
because their digestive system is too
immature to handle it
Tetnus
3. Disease
a. Bubonic Plague (Black Death)
1. Caused by Yersinia pestis and spread by rat fleas
2. Killed 100 million people in the 1300s
b. Lyme Disease (emerged in 1975)
1. Caused by spiral-shaped Borrelia burgdorferi
2. Carried by deer ticks which bite humans
3. Flu-like symptoms can lead to arthritis and heart and
nervous system problems
c. Other historical bacterial diseases disappear and then
reoccur
1. Tuberculosis (once thought to be vanquished from the
United States)
2. Gonorrhea and syphilis (sexually transmitted)
3. Cholera (water-transmitted in contaminated drinking
water)
Botulism
Bubonic Plague
Lyme Disease
syphilis
d. Common Diseases
1. Streptococcus bacteria may cause strep throat,
pneumonia, or necrotizing fasciitis (flesh-eating
bacteria)
2. Escherichia coli
a. Common inhabitants of digestive
system
b. O157:H7 E. coli strain is pathogenic
1. Transmitted through undercooked hamburger
2. Causes intestinal bleeding and can be fatal
D. _ANTIBIOTICS_
1. Chemicals that are capable of inhibiting (killing) the growth of
some bacteria.
2. _KILLS OR WEAKENS_ any organism that causes a
disease.
3. The first antibiotic was _PENICILLIN_, made by the fungus
Penicillium, and was discovered by _ALEXANDER FLEMING_.
4. Many pathogenic bacteria have become _RESISTANT_to
antibiotics. At first, a population of bacteria will die when
exposed to an antibiotic. But some may have mutations and be
able to survive. When those reproduce, they pass their
resistance on to their offspring.
5. Antibiotics would only be effective against bacterial
infections: antibiotics _DO NOT_ affect viral infections.
6. In other words, ANTIBIOTICS KILL BACTERIA.
ANTIBIOTICS DO NOT KILL VIRUSES.
II. Viruses
A. Do not belong to a kingdom because they are
not considered to be LIVING organisms
B. Examples of Viruses: flu, chicken pox, HIV,
cold sores, and some can cause cancer
C. The biggest viruses are 1/100 the size of
prokaryotic cells (bacteria/without a nucleus or
membrane bound organelles). Most bacteria
are even smaller than half the size of a
prokaryotic cell.
D. Considered to be non-living because
they CAN”T :
1. Grow
2. Develop
3. Obtain energy
4. Reproduce on their OWN; viruses must
use a HOST cell to reproduce
E. Virus classification or names come from:
1. The TYPE OF CELLS they affect; ex:
adenovirus affects the adenoids in the throat
2. The DISEASES they cause; Ex: poliovirus
causes polio
3. Some of the viruses are similar and are
therefore given a number as part of their name
4. BACTERIOPHAGES are viruses that affect
bacteria
F. Virus Structure
1. Contain an inner core of NUCLEIC ACIDS
a. Viruses either have DNA or RNA but
NEVER both
2. CAPSID : protein coat that surrounds the nucleic acid;
the way the proteins are arranged determines:
a. The SHAPE of the virus
b. The cells the virus can affect
c. The WAY the virus infects the cells
3. ENVELOPE: Some, but not all, viruses have an
envelope that acts like a plasma membrane
G. LYTIC Cycle (Virus Reproduction)
1. Viruses take over the genes of the host
cell
2. They use the genes to make more viral
genes and viral protein
3. This continues until the cell is so full of viruses
it actually BURSTS intern killing the host cell
and releasing more viruses into the body
4. Viruses can infect:
a. PLANTS
b. animals
c. bacteria
Cluster of Flu Viruses
Common Plant Virus
5. The only way a virus can infect a living cell is if a
receptor site on the host cell MATCHES that of
the virus.
a. Specific cells are only vulnerable to certain
VIRUSES
b. Ex: Tobacco mosaic virus can only invade the
leaves cells in a tobacco plant (The reasons
dogs don’t catch your colds)
6. Antibiotic DO NOT kill VIRUSES because Anti
means against and bio means life so against
life…viruses are non-living, you can’t kill
something that isn’t alive
H. Virus Types:
1. Virus can be either _DNA_ viruses or _RNA_ viruses
2. DNA virus-do one of the following:
a. Directly produce viral _GENES_ that makes more viral
proteins and parts.
b. Join to the host cell’s DNA to direct synthesis of new viruses.
3. RNA virus-does one of the following:
Protein Coat(Capsid)
a. Some RNA viruses enter the cell and use the host’s
ribosomes to produce new viral proteins EX: polio virus b. Some
RNA viruses are _RETROVIRUSES__. They use an enzyme,
called reverse transcriptase, which uses viral RNA as a template
to make viral DNA. The DNA is integrated into the hosts cell’s
DNA. Then, the viral DNA makes viral RNA, which translates into
viral proteins. EX: _HIV_
:
Chicken pox
Warts
Common cold
Mumps
Small pox
Influenza (flu)
Mononucleosis
AIDS
Antibiotics would be effective
againsta) bacterial pneumonia
b) the malarian protist
c) flu virus
d) viral meningitis
Which characteristic do viruses posses in
common with living cells?
a) They contain a nucleus & organelles
b) They make their own food.
c) They contain nucleic acids, such as
DNA or RNA.
d) They are given scientific names.