Transcript 2 SIX KINGDOMS Nelson

SIX KINGDOMS &
DOMAINS
Section 9.1 cont….
The Kingdoms of Life
 The Greek
philosopher Aristotle,
divided all living
things into two large
groups, known as
kingdoms: Plantae
& Animalia.
Along Came The
Microscope
 Classifying organisms became more
difficult after the microscope was
invented.
 The new tool revealed a previously
unknown world of living things.
 Some microscopic organisms have
characteristics of both plants and
animals.
Protista
 In 1866, the German
biologist Haeckel
proposed classifying
microorganisms that
are neither animals
nor plants into a third
kingdom: Protista.
Fungi – The Fourth Kingdom
 As biologists learned
more about the structure
and way of life of
different organisms, they
added more kingdoms.
 Fungi, originally in the
plant kingdom, do not
carry out photosynthesis.
They obtain food by
absorbing materials into
their bodies.
Eubacteria
 Eubacteria consist of
very small cells that
differ in appearance
from the cells of the
other kingdoms.
 Bacteria lack a nucleus
and other organelles.
 They are classified in a
fifth kingdom:
Eubacteria.
Archaebacteria
 During the 1990s, there was
growing interest in certain
types of bacteria found in
extreme environments, such
as salt lakes or hot, acidic
springs.
 New studies found that
these bacteria were very
different from other bacteria.
 The new data led scientists
to rename and reclassify
these microorganisms into a
sixth kingdom:
Archaebacteria.
Prokaryotes & Eukaryotes
 The study of cells is an important first step in
understanding the diversity of life.
Prokaryotic Cells
Eukaryotic Cells
Eubacteria, archaebacteria
Protists, plants, fungi, animals
Small
Large
DNA circular, not bounded by DNA in nucleus bounded by
membrane
membrane
Genome: 1 chromosome
Genome: Many
chromosomes
Cell Division not by mitosis/meiosis Cell Division: mitosis/meiosis
Asexual reproduction
common
Multicellular forms are rare
Sexual reproduction common
Most are multicellular
Mitochondria and other membrane- Mitochondria and other organelles
bound organelles are absent
present
Many are anaerobic
Most are aerobic
Fossil Evidence
 The first forms of life were prokaryotic
organisms similar in appearance to bacteria.
 First prokaryotes appear: 3.5 billion years ago.
 First eukaryotes appear: 1.5 billion years ago.
 First multicellular organisms appear: 700
million years ago.
The Three Domains
 Recent research on the cell has shown that
living prokaryotes are far more diverse than
anyone had previously suspected.
 This research led to a new level of
classification above kingdoms, known as
domains.
 The domain system better reflects the
evolutionary history of life.
 The three domains are: Eubacteria,
Archaebacteria and Eukaryota.
Domain Eukaryota
 Kingdoms: Protista, Fungi, Plantae and
Animalia.
 The greatest biological diversity occurs
within the Kingdom Protista.
 For example, there is a much greater
genetic difference between some species
of protists than there is between, for
example, corn and humans.
Domain
Eubacteria
Archaebacteria
Kingdom
Eubacteria
Archaebacteria
Protista
Fungi
Plantae
Animalia
# of Cells Unicellular
Uni
Mostly
uni
Mostly
multi
Multi
Multi
Nucleus
No
No
Yes
Yes
Yes
Yes
Cell Wall
Yes
Some
Some
Yes
Yes
No
Nutrition
Autotroph
and
Heterotroph
Autotroph
and
Heterotroph
Autotroph
and
Heterotroph
Heterotroph
Autotroph
Heterotroph
Asexual
Asexual
Asexual
and
Sexual
Sexual
Sexual
Sexual
Reproduction
Eukaryota
Homework:
 P. 334 #5,6