Transcript Overview of six kingdoms II

Overview of
Organisms &
Diversity
Prokaryotes
• Prokaryotes are thought the
earth’s oldest organisms
• They are the most abundant
ones.
• Bacteria are prokaryotes.
• Prokaryotes are also the most
metabolically diverse of all
living organisms.
• There are two structurally and
metabolically different groups
of bacteria. They are so
different that they are in
separate kingdoms.
 Archaebacteria and
Eubacteria are different from
each other in many ways:
 Eubacteria have cell walls
made of peptidoglycan,
archaebacteria do not.
 The plasma membranes of
archaebacteria contain lipids
not found in any other living
thing.
 The gene translation machinery
of archaebacteria is similar to
eukaryotes, but not eubacteria.
 Examples of archaebacteria
are methanogens, halophiles
or thermophiles.
Eukaryotes
• Eukaryotes contain a membrane- •
bound nucleus, internal
membranes, and organelles such
as mitochondria and chloroplasts. •
• Another characteristic that
distinguishes eukaryotes from
prokaryotes is division of the
nucleus by mitosis.
Most eukaryotes have
mitochondria.
The theory of endosymbiosis
proposes that mitochondria are
the descendents of symbiotic,
aerobic eubacteria that entered
larger cells and then stayed
there as symbionts.
Evolution of Sexual Reproduction
• Asexual reproduction is
• Sexual reproduction has
primitive and prevalent.
advantages.
• The oldest eukaryotes
• Sexual reproduction provides a
reproduce asexually.
way to shuffle genetic material
and increase genetic variability in
• In a stable environment,
the offspring. Genetic diversity is
asexual reproduction produces
the raw material of evolution.
many identical offspring in a
short time.
• It appears that sexual
reproduction first evolved as a
• Asexual reproduction is also
way to repair damaged DNA
advantageous because no
strands.
energy is spent finding a mate.
• Eukaryotes have life cycles. Many
protists are haploid. Animals and
most plants are diploid, and
produce haploid gametes.
Multicellularity
• Unicellular organisms have limits
on their size.
• As a cell grows, it reaches a
point where there is too little
surface area to meet the needs
of the cell’s volume.
• Multicellular organisms are
made of many cells that are
permanently associated with
each other, each with a special
function.
• The advantage of
multicellularity is that it allows
cells to become specialized.
• True multicellularity only occurs
in eukaryotes.
 In multicellular organisms, cells are grouped into tissues, tissues into organs,
organs into organ systems, and finally systems into the organism.
Cells
Tissues
Organs
Organ Systems
Organism
Kingdom Archaebacteria
Characteristics of
archaebacteria:
 All are unicellular
prokaryotes.
 Cell walls lack
peptidoglycan.
 Genes have introns.
 Their plasma membranes
contain lipids that are not
found in any other living
things.
 They may be either
autotrophic or
heterotrophic.
 They may be the ancestors
of eukaryotic cells.
 Living archaebacteria are
divided into three groups
Genetic material
Cell wall without
peptidoglycan
Cytoplasm with
ribosomes
Plasma
membrane
Kingdom Eubacteria
Characteristics of eubacteria:
 All are unicellular
prokaryotes.
 Cell walls contain
peptidoglycan.
 Genes lack introns.
 All reproduce asexually by
binary fission.
 They may be either
autotrophic or heterotrophic.
Some are photosynthetic.
 Extremely diversified groups
 Certain types may be
ancestors of mitochondria
and chloroplasts.
Cytoplasm with
ribosomes
Plasma
membrane
Genetic material
Cell wall with peptidoglycan
Kingdom Protista
 Characteristics of protists:
 All are eukaryotic.
 Most are unicellular, but some
are multicellular.
 Protists can be autotrophic,
heterotrophic, or both at the
same time.
 All reproduce asexually, but
some can also reproduce
sexually.
Kingdom Fungi
 Characteristics of fungi:
 All are eukaryotic.
 Most are multicellular, but some
are unicellular.
 Cell walls are made of chitin,
not cellulose.
 Fungi have filamentous bodies
called hyphae.
 They are all heterotrophs with
external digestion of food. They
serve as primary decomposers.
 Fungi reproduce either sexually
or asexually.
Examples of fungi
• Common names of fungi with pictures
Kingdom Plantae
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Characteristics of plants:
All plants are eukaryotic.
All plants are multicellular.
All plant cells have cell walls made
of cellulose.
Most consist of two basic parts:
roots and shoots.
Most plants are terrestrial and
photosynthetic autotrophs.
Plants have evolved highly
specialized structures for
reproduction and survival on land.
Plants reproduce sexually,
although some can also reproduce
asexually.
Kingdom Animalia
 Characteristics of animals:

 All animals are eukaryotes.
 All are multicellular with cells that
lack cell walls.
 Most reproduce sexually.

All are heterotrophs with internal
digestion of food.
Animals have specialized tissues
for movement and reaction to
stimuli.
Animals inhabit nearly every kind
of environment in the biosphere.