Transcript Organizing-Lifes-Diversity-for

• How did you group these items?
• Why did you group them this way?
Change Through Time
Organizing Life’s Diversity
Classification
How Classification Began
• Biologists want to better understand
organisms so they organize them.
• One tool that they use to do this is
classification
• Classification is the grouping of
objects or information based on
similarities.
How Classification Began
• Taxonomy is the
branch of biology
that groups and
names organisms
based on studies of
their different
characteristics.
• Biologists who study taxonomy are called
taxonomists.
Aristotle’s system
• The Greek philosopher Aristotle (384-322
B.C.) developed the first widely accepted
system of biological classification.
• He classified all the organisms he knew
into two groups:
Aristotle’s system
• plants
herbs, shrubs, and trees
• animals according to various characteristics,
habitat (land,water,air) and physical differences
(feet, wings, tails)
Aristotle’s system
• According to his system, birds, bats, and
flying insects are classified together….
– ??? Does that really work ???
– How common are they really?
• As time passed, more organisms were discovered
and some did not fit easily into Aristotle’s groups,
but many centuries passed before Aristotle’s
system was replaced.
Linnaeus’s system of binomial nomenclature
• Swedish botanist, Carolus Linnaeus (1707-1778),
developed a method of grouping organisms that
is still used by scientists today.
• Linnaeus’s system was based on physical and
structural similarities of organisms.
• As a result, the groupings revealed the
relationships of the organisms.
Linnaeus’s system of binomial nomenclature
• Eventually, some biologists proposed that
structural similarities reflect the evolutionary
relationships of species.
• This way of organizing organisms is the
basis of modern classification systems.
Linnaeus’s system of binomial nomenclature
• Binomial nomenclature is a modern
classification system using a two-word
naming system that Linnaeus developed to
identify species.
• In this system, organisms are name according
to their genus and species
• first word = genus
• Second word = species
Linnaeus’s system of binomial nomenclature
Homo sapiens
• italicized in print
• underlined when handwritten
• first letter of the genus name is uppercase
• first letter of the species is lowercase.
Scientific and common names
• Taxonomists are required to
use Latin because:
1. the language does not change
2. a common name can be
misleading.
3. it is confusing when a species
has more than one common
name.
common dog
Canus familiaris
Sycamore tree
buttonwood
Modern Classification
• Grouping organisms on the basis of their
evolutionary relationships makes it easier
to understand biological diversity.
• provides a framework in which to study the
relationships among living and extinct
species.
How are evolutionary relationships
determined?
• Classification systems today are based on
evolutionary relationships.
•extinct animals can be included in
classification schemes.
How are evolutionary relationships
determined?
• Evolutionary relationships are determined on
the basis of:
•similarities in structure
•breeding behavior
•geographical distribution
•chromosomes
•biochemistry
Taxonomy: useful tools
• Cladogram – branching diagram showing
evolutionary relationships
Taxonomy: useful tools
• Dichotomous Keys
• Aid in identifying unknown organisms
• Pairs of statements with two choices of
characteristics
• Only one choice will apply to the unknown
organism
• This will lead to another pair of characteristics..
And so on…
Taxonomic rankings
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
• Largest of
Smallest
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Kingdom
Phylum
Class
Order
Gamily
Genus
Species
1. Put these
animals into 3
groups.
2. What
characteristics
did you use for
your system of
classification?
Change Through Time
Organizing Life’s Diversity
The Six Kingdoms
The Six Kingdoms of Organisms
• The six kingdoms of organisms are :
1. archaebacteria
2. eubacteria
3. protists
4. fungi
5. plants
6. animals
Bacteria: Archaebacteria and Eubacteria
•Prokaryotes - organisms with cells that lack
distinct nuclei bounded by a membrane, are
microscopic and unicellular.
•There are two kingdoms of prokaryotic
organisms: Archaebacteria and Eubacteria.
Bacteria: Archaebacteria and Eubacteria
• Archaebacteria live in extreme environments
such as swamps, deep-ocean hydrothermal
vents, and seawater evaporating ponds.
• Most of these environments
are oxygen-free.
Prokaryotes
• All of the other prokaryotes, about 5000
species of bacteria, are classified in
Kingdom Eubacteria.
• Eubacteria have very strong cell walls and a
less complex genetic makeup than found in
archaebacteria or eukaryotes.
•some cause diseases, most are harmless and
many are actually helpful.
Kingdom Protists: A diverse group
A Paramecium
• A protist is a eukaryote
that lacks complex organ
systems and lives in moist
environments.
Cilia
Oral
groove
Gullet
•Unicellular and multicellular
Contractile
vacuole
Micronucleus and
macronucleus
Kingdom Fungi: Earth’s decomposers
• heterotrophs that do not
move from place to place.
• A fungus - is either a unicellular
or multicellular eukaryote that
absorbs nutrients from
organic materials in the
environment.
Kingdom Plantae:
Multicellular oxygen producers
• eukaryotic, multicellular,
photosynthetic autotrophs.
• None moves from
place to place.
Plants: Multicellular oxygen producers
• A plant’s cells usually
contain chloroplasts and
have cell walls
composed of cellulose.
• Plant cells are organized into tissue that,
in turn, are organized into organs and organ
systems.
Kingdom Animalia:
Multicellular consumers
• Animals are multicellular heterotrophs.
• Nearly all are able
to move from place
to place.
• Animal cells do not
have cell walls.
Animals: Multicellular consumers
• Their cells are organized into tissues
that, in turn, are organized into organs
and complex organ systems.
Cells
Tissue
Organs
Organ Systems
Organisms