Faculty of Science, School of Sciences,
Lautoka Campus
BIO509: Botany
Lecture 5: Kingdom Protista
The Three Domain System
Prokaryote
Eukaryote
Classification of organisms in Six Kingdoms
Protista
Kingdom Protista
• Very diverse and
heterogeneous.
dinoflagellate
• Combination of
characteristics
possessed by members
of Kingdoms Plantae,
Fungi or Animalia.
slime mold
A wide array of body
forms – unicellular to
large multicellular.
Most have complex
life cycles involving
sexual reproduction;
some reproduce only
asexually.
euglenoid
Paramecium
• Diverse ecological roles – plantlike forms
are producers, fungus like forms are
decomposers, animal-like forms are
predators, pathogens, parasites
Protists
Animal Like Protists
Protozoans
Plant Like Protists
Algae
Fungus Like Protists
Slime-Molds
Why are They Important?
• Autotrophic protists, like phytoplankton,
produce a significant portion of the Earth’s
oxygen.
• Play an important role in the carbon cycle.
• Important producers and
consumers in food chains.
• Act as a road map for
evolution!
Plant-like protists – the Algae
Ecologically extremely
important
haptophyte
Producers in marine and freshwater ecosystems
Many are part of
phytoplankton that
forms the basis of most
marine food chains
brown algae
Important for
carbon balance –
draw in carbon
dioxide for
photosynthesis and
calcareous shells
red algae
also contribute to
oxygen budget
diatoms
Porphyridium
Includes numerous
morphological forms –
unicells, filaments and
complex multicells
Zygonema
Some are macrophytes
Macrophytes are
superficially “plant-like” with
structures that look a little
like stems and leaves – but
these are very different
All algae have chloroplasts
Pediastrum
Penicillus
The algae have
traditionally been put
into groups based
most often on
the types of
reproductive
structures
photosynthetic
pigments
food reserves
Antithamnion
Caulerpa
Gongrosira
Haematococcus
Chlorophyta
it is common for
people to think about
three groups of algae
Rhodophyta
Chlorophyta – green
algae
Rhodophyta – red
algae
Phaeophyta – brown
algae
Phaeophyta
but there are many other
“algal” groups – either
people do not know
about them or confuse
them with the other
groups
dinoflagellates
cryptomonads
haptophytes
charophytes or
stoneworts
euglenoids
euglenoid
diatoms
cryptomonad
dinoflagellate
Phylum Chlorophyta
the green algae
Chlorophytes
about 7,500 species
widespread and highly diverse
Occur as unicellular, filamentous,
colonies, net, tubes, spheres or
macrophytes.
Have chlorophyll a and b similar
to higher plants.
Store their food as starch.
Occur in many
environments
marine and
freshwater
terrestrial – including
soil, exposed
surfaces (e.g., rocks
tree trunks), snow
“watermelon snow”
The snow turns
reddish or pink, with
slight scent of
watermelon
especially common
during the summer
in the Sierra Nevada,
California
caused by the presence
of Chlamydomonas
nivalis
cryophilic species
in addition to chlorophyll
contains a carotenoid
pigment that gives the
red colour
Chlorophytes also form symbiotic relationships with other organisms, including
Fungi, sponges, sloths
Ulothrix
Diversity of
forms
filaments
Chlamydomonas
many
unicells
Chlorococcum
Volvox
Diversity of
forms
colonies, tubes
or spheres
Pediastrum
Gonium
Volvox
Aggregates of flagellate cells
A hollow sphere, made up of
a single layer with 500 to
60000 photosynthetic, biflagellate cells and a small
number of larger, nonflagellate reproductive cells
the cells have eyespots which
enables the colony to swim
towards light
Ulva
Diversity of
forms
macrophytes
Ulva
Halimeda
Acetabularia
Questions???