Transcript Classification:

Classification:
Georgia Performance Standards:
SB3. Students will derive the relationship between single-celled
and multi-celled organisms and the increasing complexity of
systems.
b. Compare how structures and function vary between the six
kingdoms (archaebacteria,eubacteria, protists, fungi, plants, and
animals).
c. Examine the evolutionary basis of modern classification systems.
d. Compare and contrast viruses with living organisms.
SB5. Students will evaluate the role of natural selection in the
development of the theory of evolution.
e. Recognize the role of evolution to biological resistance (pesticide
and antibiotic resistance).
Essential Questions:
1.How does the evidence of evolution contribute to
modern classification systems?
2.Why classify?
3. On what criteria do Taxonomists base their
classification of organisms?
4.Are viruses alive?
5. What is the role of evolution in antibiotic and
pesticide resistance?
Why Classify?
• To study the diversity of life, biologists use a
classification system to name organisms and
group them in a logical manner.
• In taxonomy, scientists classify organisms and
assign each organism a universally accepted
name.
• By using a scientific name, biologists can be
certain that everyone is discussing the same
organism.
Early Efforts at Naming Organisms
• The first attempts at standard scientific names
often described the physical characteristics of a
species in great detail.
• Results in long names
• Difficult to standardize the names of organisms
• Different scientists described different
characteristics.
Binomial Nomenclature
• Carolus Linnaeus developed a two-word
naming system called binomial
nomenclature.
• In binomial nomenclature, each species
is assigned a two-part scientific name.
– First word is the genus
– Second word is the species
Chapter
17
Organizing Life’s Diversity
17.1 The History of Classification
 When writing a scientific name, scientists use these
rules:
 The first letter of the genus name always is capitalized,
but the rest of the genus name and all letters of the
specific epithet are lowercase.
 If a scientific name is written in a printed book or
magazine, it should be italicized.
 When a scientific name is written by hand, both parts of
the name should be underlined.
 After the scientific name has been written completely, the
genus name will be abbreviated to the first letter in later
appearances (e.g., C. cardinalis).
Linnaeus's System of Classification
• A group or level of
organization is called
a taxonomic category,
or taxon
• King Phillip Came Over
From Genoa Spain
• The are 7 taxonomic
categories. (from
smallest to largest)
• species
• genus
• family
• order
• class
• Phylum
• kingdom.
• Domain
The 7 taxonomic categories
• Species - a group of organisms that breed with one
another and produce fertile offspring.
• Genus - a group of closely related species.
• Family - genera that share many characteristics.
• Order - is a broad taxonomic category composed of
similar families.
• Class - is composed of similar orders.
• Phylum- several different classes that share important
characteristics.
• Kingdom - largest taxonomic group, consisting of closely
related phyla
Classification Pop Quiz:
1. How are living things organized for study?
2. Describe the system for naming species that Linnaeus
developed.
3. What are the seven taxonomic categories of Linnaeus’s
classification system from largest to smallest?
4. Why do scientists avoid using common names when
discussing organisms?
5. Based on their names, you know that the baboons Papio
annubis and Papio cynocephalus do NOT belong to the same
a. Class
b. family
c. Genus
d. species
Modern Evolutionary Classification
• Organisms are grouped into categories that
represent lines of evolutionary descent, not just
physical similarities
• This strategy of grouping organisms together
based on their evolutionary history is called
evolutionary classification.
 Modern classification systems are based upon
biochemical and genetic evidence that indicates
evolutionary relationships
How do we determine evolutionary
relationships?
1.
Look for structural similarities.
2. Look at breeding behavior.
3. Look at geographic distribution and find where organism are
located and their range.
4. Look at Chromosomes for similar structure and number.
5. Look at biochemistry: Look for similar DNA sequences and
therefore similar proteins
Phylogenetic Classification
• Phylogeny: the evolutionary history of a
species.
• Phylogenetic classification is a classification
system that shows the evolutionary history of a
species.
• Cladistics: It is assumed that a group of
organisms diverged and evolved from a common
ancestral group.
• Derived traits: Characteristics of the original
group that are retained.
Classification Using Cladograms
• Cladistic analysis identifies and considers only
the characteristics that arise as lineages evolve
over time.
– Characteristics that appear in recent parts of a
lineage but not in its older members are called
derived characters.
– Derived characters can be used to construct a
cladogram, a diagram that shows the evolutionary
relationships among a group of organisms.
Traditional Classification Versus Cladogram
Section 18-2
Appendages
Crab
Conical Shells
Barnacle
Limpet
Crustaceans
Crab
Gastropod
Barnacle
Limpet
Molted
exoskeleton
Segmentation
Tiny free-swimming larva
TRADITIONAL
CLASSIFICATION
Go to
Section:
CLADOGRAM
• Cladogram: a branching diagram using
cladistics.
•
Image taken from:http://evolution.berkeley.edu/evolibrary/article//evo_03
Chapter
17
Organizing Life’s Diversity
17.2 Modern Classification
Cladograms
 The greater the
number of derived
characters shared
by groups, the
more recently the
groups share a
common ancestor.
Modern Evolutionary Classification
• Molecular Clocks
– Comparisons of DNA can • Comparison reveal how
dissimilar the genes
also be used to mark the
are.
passage of evolutionary
time.
– A model known as a
molecular clock uses
DNA comparisons to
estimate the length of
time that two species
have been evolving
independently.
• Degree of dissimilarity
is an indication of how
long ago the two
species shared a
common ancestor.
Checkpoint Questions:
1. How is information about evolutionary relationships
useful in classification?
2. How are genes used to help scientists classify
organisms?
3. What is the principle behind cladistic analysis?
4. Describe the relationship between evolutionary time and
the similarity of genes in two species.
5. How have new discoveries in molecular biology affected
the way in which we classify organisms compared with
the system used by Linnaeus?
Constructing a Chart
Kingdoms and Domains
• The six-kingdom system of classification
includes the following kingdoms:
– Eubacteria
– Archaebacteria
– Protista
– Fungi
– Plantae
– Animalia.
The Three-Domain System
• The domain is the most inclusive taxonomic
category; larger than a kingdom
• The three domains are:
– Bacteria : kingdom Eubacteria
– Archaea,: kingdom Archaebacteria;
– Eukarya :Kingdom protists, fungi, plants, and
animals.
Key Characteristics of Kingdoms and Domains
Classification of Living Things
DOMAIN
Bacteria
Archaea
KINGDOM
Eubacteria
Archaebacteria
CELL TYPE
Prokaryote
Prokaryote
CELL
Cell walls with
STRUCTURES peptidoglycan
NUMBER OF
CELLS
MODE OF
NUTRITION
Cell walls
without
peptidoglycan
Unicellular
Unicellular
Autotroph or
heterotroph
Autotroph or
heterotroph
Streptococcus, Methanogens,
Escherichia
halophiles
EXAMPLES
coli
Go to
Section:
Eukarya
Protista
Fungi
Plantae
Animalia
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Cell walls of
cellulose in
some; some
have
chloroplasts
Cell walls of
chitin
Cell walls of
cellulose;
chloroplasts
No cell walls
or
chloroplasts
Most
unicellular;
some
colonial;
some
multicellular
Most
multicellular
; some
unicellular
Multicellular
Multicellular
Autotroph
Heterotroph
Autotroph or
heterotroph
Heterotroph
Amoeba,
Paramecium,
slime molds,
giant kelp
Mushrooms
, yeasts
Mosses,
ferns,
flowering
plants
Sponges,
worms,
insects,
fishes,
mammals
Section 18-3
Living
Things
are characterized by
Eukaryotic
cells
and differing
Important
characteristics
which place them in
Cell wall
structures
such as
Domain
Eukarya
Prokaryotic cells
which is subdivided into
which place them in
Domain
Bacteria
Domain
Archaea
which coincides with
which coincides with
Kingdom
Eubacteria
Kingdom
Archaebacteria
Go to
Section:
Kingdom
Plantae
Kingdom
Fungi
Kingdom
Protista
Kingdom
Animalia
The Six Kingdoms
• Kingdom Archaebacteria: Bacteria that live
in extreme environments void of oxygen. Cell
membrane lipids, RNA, and cell wall
structures are different than other bacteria.
• Kingdom Eubacteria: all other bacteria.
Strong cell walls and less complicated
genetic makeup. Live in many habitats
•
• Kingdom Protista: Eukaryote that lacks
complex organ systems and lives in moist
environments. Can be unicellular or
multicellular
The Six Kingdoms Continued
• Kingdom Fungi: Heterotrophs that do not move
from place to place. Uni or multicellular eukaryotes
that absorb nutrients from organic material.
• Kingdom Plantae: Multicellular photosynthetic
eukaryotes. Can not move from place to place.
Cells organized into tissues, tissues organized into
organs.
• Kingdom Animalia: Animals: multicellular
heterotrophs. Able to move from place to place. No
cell walls. Cells form tissues that form organs that
form organ systems.
Chapter
17
Organizing Life’s Diversity
17.3 Domains and Kingdoms
Domain Archaea
 Archaea are thought to be more ancient than
bacteria and yet more closely related to our
eukaryote ancestors.
 Archaea are diverse in shape and nutrition
requirements.
 They are called extremophiles because
they can live in extreme environments.
Chapter
17
Organizing Life’s Diversity
17.3 Domains and Kingdoms
Domain Bacteria
 Eubacteria are
prokaryotes whose cell
walls contain
peptidoglycan.
 Eubacteria are a diverse
group that can survive in
many different environments.
Chapter
18
Bacteria and Viruses
18.1 Bacteria
Mutations
 Bacteria reproduce quickly and their
population grows rapidly.
 Mutations lead to new forms of genes, new
gene combinations, new characteristics, and
genetic diversity.
 Rapid mutations cause bacteria to become
resistant to many antibiotics and pesticides.
Chapter
17
Organizing Life’s Diversity
17.3 Domains and Kingdoms
Domain Eukarya
 All eukaryotes are classified in Domain
Eukarya.
 Domain Eukarya contains Kingdom
Protista, Kingdom Fungi, Kingdom
Plantae, and Kingdom Animalia.
Chapter
17
Organizing Life’s Diversity
17.3 Domains and Kingdoms
Kingdom Protista
Protists are eukaryotic
organisms that can be
.
unicellular, colonial,
or multicellular
 Protists are
classified into three
different groups—
plantlike, animallike, and
funguslike.
Chapter
17
Organizing Life’s Diversity
17.3 Domains and Kingdoms
Kingdom Fungi
 A fungus is a unicellular or multicellular
eukaryote that
absorbs
nutrients from organic
materials in its
environment.
 Member of Kingdom
Fungi are
heterotrophic, lack motility, and have cell
walls.
Chapter
17
Organizing Life’s Diversity
17.3 Domains and Kingdoms
Kingdom Plantae
 Members of Kingdom Plantae form the base
of all terrestrial habitats.
 All plants are
multicellular and have
cell walls composed of
cellulose.
 Most plants are
autotrophs, but some are heterotrophic.
Chapter
17
Organizing Life’s Diversity
17.3 Domains and Kingdoms
Kingdom Animalia
 All animals are heterotrophic, multicellular
eukaryotes.
 Animal organs often are
organized into complex
organ systems.
 They live in the water,
on land, and in the air.
Chapter
17
Organizing Life’s Diversity
17.3 Domains and Kingdoms
Viruses—An Exception
 A virus is a nucleic acid surrounded by a
protein coat.
 Viruses do not possess cells, nor are they
cells, and are not considered to be living.
 Because they are nonliving, they usually
are not placed in the biological
classification system.
Characteristics of Viruses:
•
•
•
•
Viruses are not cells
Viruses are not alive
Viruses do not use energy
Viruses can reproduce only when inside
living cells
• Viruses do contain genetic info. & can
evolve over time.
Defenses Against Viruses:
• Why can’t we treat viral diseases with
antibiotics?
• Vaccinations also protect against some viral
diseases.
– Harmless viruses stimulate the immune system to
create defenses against the harmful form of the virus.
– Vaccines only work on viruses whose surface
proteins do not change (mutate). (Small pox,
measles, polio)
• HIV, cold viruses, and flu viruses (genes mutate too often for
vaccines to become effective)
Checkpoint Questions:
1.
What are the six kingdoms of life as they are now
identified?
2.
What are the three domains of life?
3. Why was the kingdom Monera divided into two separate
kingdoms?
4. Why might kingdom Protista be thought of as the “odds
and ends” kingdom?
5. Which kingdoms include only prokaryotes? Which
kingdoms include only heterotrophs?
Dichotomous Keys
• A tool used to identify organisms is a dichotomous key.
• A dichotomous key is a series of paired statements that
describe physical characteristics of different organisms.
• In this activity, you will use a dichotomous key to identify tree
leaves.