Transcript 5 Kingdom System vs. 3 Domain System

5 Kingdom System vs. 3 Domain System
Previously the
diversity of life was
classified based on 5
kingdoms
1. Monera (prokaryotes)
2. Protists (simple
eukaryotes)
3. Plants (autotrophic
eukaryotes)
4. Fungus (heterotrophs
who act as
decomposers)
5. Animals (heterotrophs
who consume their
food)
5 Kingdom System vs. 3 Domain System
Because of evolutionary analysis, most
scientists have adopted a 3 domain
classification system over the 5 kingdom
system.
Monera is now
divided between
the Domains
Bacteria and
Archaea.
Protists, plants,
fungi, and animals
are in the Domain
Eukarya.
Let’s Review Prokaryotes…
Structure: unicellular with no nucleus, no
membrane bound organelle
- cell wall with or without peptidoglycan
-can have flagella made of flagellin (not
microtubules like in eukaryotes)
- common shapes include round, rod or spiral
shaped
Heredity Material: circular DNA chromosome
supplemented with plasmids
Reproduction: asexual by binary fission
Let’s Review Prokaryotes…
Nutrition: (How They Obtain their Organic Compounds)
Photoautotrophs- manufacture organic compounds using light
Chemoautotrophs- manufacture organic compounds using
inorganic chemicals (NH3, H2S)
Heterotrophs- consume organic compounds
• Some may be parasites (feed on living organisms)
• Some may be saprobes or saprophytes (feed on decaying
matter)
Survival With or Without Oxygen:
Obligate Aerobes (require O2)
Facultative Aerobes (will use O2 if available)
Obligate Anaerobes (require no O2)
Domain Bacteria or Eubacteria
• The majority of
bacteria that people
come in contact with
such as pathogenic
bacteria or the
bacteria in yogurt
• Categorized by their
modes of nutrition,
shape, and motility
Some Examples of Bacteria
Anthrax is a bacteria that will produce
endospores when stressed. The endospores
are hard shells that surround a copy of the
DNA. The bacteria disintigrates and leaves
behind the spore. The spore has to be heated
to 121 degrees Celsius in order to be killed.
Cyanobacteria are the only
photoautotrophic prokaryotes.
They were formally called “bluegreen algae” but that
nomenclature has been
abandoned because algae are
eukaryotes.
Some Examples of Bacteria
Bacteria can
convert or “fix”
nitrogen gas
which can’t be
used by plants
into ammonia
that can be used
by plants. The
plants then
convert the
nitrogen into
amino acids and
other organic
compounds.
Domain Archaea or Archaebacteria
• Share traits with both bacteria and
eukarya
• “extremophiles”- live in extreme conditions
• 3 Most Common Types
Domain Archaea
1) Methanogens- anaerobic heterotrophic
bacteria that make methane
• Found in sewage treatment facilities, the
guts of ruminants such as cattle, hot springs
Domain Archaea
2) Extreme Halophiles- “salt lovers”
• Found in salt lakes and salted food
Commercial Salt Ponds
Great Salt Lake
Domain Archaea
3) Extreme Thermophiles- “heat lovers”
• Found in hot springs and volcanic vents
Grand Prismatic Springs at
Yellowstone
Deep Ocean Vents
Domain Eukarya
Kingdom “Protista”
• Diverse group of organisms that were lumped
together into a kingdom because they didn’t fit into
the other kingdoms
• Can be multicellular or unicellular
• Can be plant-like, fungus-like, or animal like
“Protists”
• Kingdom Protista is
not based on
evolutionary
relationships
• It is now not
accepted because
we now know that
some protists are
more closely
related to plants
and animals than
other protists
Domain Eukarya
Kingdom “Protista”
Plant-like
Animal-like
Fungus-like
Fungus-Like Protists
• They form filaments or make spores, like fungi.
Water Mold on a Dead Fruit Fly
Slime Mold: Closely related to Fungi
Protozoa: “Animal-Like Protists”
• Heterotrophs that feed on other organisms (dead
or alive)
Paramecium
Amoeba
Trypanosoma causes
sleeping sickness.
Protozoa Example: Malaria Parasite
Plant-like Protists
• Carry out photosynthesis
Dinoflagellates
Diatoms
Euglena
Plant-like Protists
Three Types of Algae
Giant Kelp
Nori
2) Phaeophyta or
Brown Algae
1) Rhodophyta or Red Algae
Sea Palm
Plant-like Protists:Three Types of Algae
3) Chlorophyta or Green Algae
It is believed that green algae and land plants
share a common ancestor.
• Use chlorophyll a and b, have cellulose in their
cell walls, and store sugars in the form of starch,
all like plants.
Ulva
Volvox