Kingdom Protista
 Were the first eukaryote organisms in the world.
 This kingdom contains many species and a great variety of
organisms.
 The protests have a membrane enclosed nucleus and many
different cytoplasmic organelles.
 These show amazing diversity in cell organization; in methods
of reproduction; in metabolic needs and habitats.
 Most are unicellular, some are multi-cellular and quite large.
 Some are autotrophic and some are heterotrophic.
 Reproduction may be asexual or sexual.
 Habitats are both aquatic and terrestrial.
 The members of the Kingdom Protista are divided into three (3)
main groups:
 Animal – like protists.
 Plant – like protists.
 Fungus – like protists.
Animal – Like Protists:
 Are single – celled or colonial organisms called protozoa.
 Live in fresh and salt water, in the soil and in the bodies of other
organisms.
 They are heterotrophic.
 Most are motile and are divided based on their means of
locomotion:
 Rhizopoda (Sarcodines): Pseudopods
 Ciliophora: Cilia
 Zoomastigina: Flagella
 Apicomplexa (Sporozoa): Are non – motile
Rhizopoda (Sarcodines):
 Move and capture their prey by means of pseudopods or “false
feet”.
 Found in both fresh and salt water and in the bodies of animals.
 Reproduction is both sexual and asexual.
 The best known of the sarcodines is the amoebas.
Ciliophora:
 Live in both fresh and salt water.
 Are surrounded by hair-like projections called cilia.
 The beating of the cilia moves the organism through the water
and propels food and water into its oral groove.
 The paramecium is the most frequently studied member of this
phylum.
 Ciliates have a rigid outer covering called a pellicle that
maintains their shape.
 Asexual reproduction in ciliates is by binary fission
(chromosomal material is replicated and splits via cytokinesis).
 Some reproduce sexually by the process of conjugation (two
individuals fuse together exchange micro – nuclear material
and then separate).
 Ciliates differ from other protozoa in having two kinds of nuclei:
 Macronucleus: This large nucleus controls
cellular metabolism and divides during binary
fission.
 Micronucleus: s not necessary for life, but is
exchanged during conjugation.
Zoomastigina:
 Move by beating a long whip – like flagella.
 Most are unicellular.
 Some zooflagellates are free – living in fresh water, most live in
the bodies of animals or the tissues of plants.
 Reproduce sexually and asexually.
 Trichonympha is a pathogen that causes African Sleeping
Sickness.
 Another pathogen, Trypanosoma gambieuse, lives in the
digestive tract of termites. Termites do not have digestive
enzymes necessary to break down wood, but this particular
organisms does.
Apicomplexa (Sporozoa):
 Are non – motile and parasitic.
 They obtain nutrients from the bodies of their hosts.
 Cause disease in animals, including humans.
 Sporozoans get their name from the fact that they produce
spores during their asexual phase of reproduction; these spores
permit the spread of parasites.
 The best known sporozoan is the one that causes malaria in
humans, Plasmodium falciparum.
Plant – Like Protists:
 Are commonly called algae and resemble plants in that they are
all photosynthetic.
 Some are tiny, single-celled organisms with flagella and others
are large, multi-cellular organisms known as seaweeds.
 They have chloroplasts, which contain the photosynthetic
pigment chlorophyll.
 All types have chlorophyll A and some have chlorophyll B and
C.
 Some also have distinct pigments that give them distinct colors.
 Their methods of reproduction vary.
 They inhabit fresh water, salt water and most environments on
land.
 Based on their structure, photosynthetic pigments, cell wall and
food storage substances, algae are divided into six (6) groups:
 Eugelnophyta
 Chrystophyta
 Dinoflagellata / Pyrrhophyta
 Chlorophyta
 Phaeophyta
 Rhodophyta
Euglenophyta:
 Have both plant-like and animal-like characteristics.
 They contain chloroplasts and photosynthetic pigments like
plants do.
 Are also heterotrophs.
 He most common is the euglenoids.
 Have one flagella that is used in movement and one short
flagellum that is inactive.
Chrystophyta:
 Are referred to as the golden algae.
 They are mostly uni-cellular organisms that get their color from
large amounts of yellow-brown pigments.
 The most numerous are the diatoms.
 Diatoms are single-celled or colonial organisms that live in both
fresh and salt water.
 Their cell walls are glass-like shells made of silica, with tiny
holes for the exchange of gases and other substances.
 They usually reproduce asexually, but sexual reproduction does
occur.
 Diatomaceaous earth is mined and used in metal polish,
toothpaste, insulation and filters.
Dinoflagellata / Pyrrhophyta:
 Single-cellular algae found mainly in the ocean.
 Some are photosynthetic, storing food as oil or starch.
 Other lack chloroplasts and are heterotrophic.
 Serve as the major source of food for many aquatic animals.
 Reproduction is asexual.
 The cell walls of dinoflagellates consist of numerous armourlike plates made up of cellulose and silica.
 Each organism has two (2) flagella, one running in a belt-like
groove around the middle, and the other extending from one
end.
 The action of the flagella cause the dinoflagellata to twirl or roll
in the water.
 Some of the photosynthetic dinoflagellatas contain red and
yellow pigments.
 Some have the property of bioluminescence (the ability to
produce light).
Chlorophyta:
 These are called the green algae.
 Are found in fresh and salt water and in moist places on land.
 This group has unicellular, colonial and multicellular forms.
 Most contain chlorophyll A and B in chloroplasts and have a cell
wall composed of cellulose.
 Some green algae have flagella which are used in movement.
 Reproduction is usually asexual.
Phaephyta:
 Commonly known as brown algae.
 Include many of the common seaweeds.
 Members of this group are all multicellular and range in size
from microscopic to more than 50 meters long.
 They are usually found in cold ocean water.
Rhodophyta:
 Commonly known as red algae.
 Include many common seaweeds.
 Found in warmer water and in greater depths than brown algae.
 Not as big as brown algae.
Assignment:
Biological Sciences – An Ecological Approach: Read Pages 305-309
Concept Review: Page 309 #1-4
Fungus – Like Protisits:
 Are all heterotrophic.
 Most are decomposers that feed on dead and decaying matter
in cool, damp environments.
 A few are parasites.
 There are three (3) major phyla of fungus – like protists:
 Myxomycota
 Acrasiomycota
 Oomycota
Myxomycota:
 Commonly known as acellular slime molds.
 In the most commonly observed stage of their life cycle,
acellular slime molds resemble giant amoebas.
 This feeding stage is called the plasmodium and feeds by
engulfing bits of organic matter as it creeps along the forest
floor.
 When conditions become unfavorable, the plasmodium stops
moving and develops stalks, which are spore-producing
structures called fruiting bodies.
 Within the fruiting bodies, haploid spores are produced by
meiosis.
 The spores are eventually released and if they land in a moist,
suitable environment, they germinate to form flagellated
gametes (sex cells).
 Two gametes join to form a diploid zygote which undergoes
mitosis (cell division) and becomes a feeding plasmodium.
 Thus, sexual reproduction occurs in acellular slime molds.
Acrasiomycota:
 Slime molds in this phyla are called cellular slime molds.
 Live in fresh water, damp soil or in decaying vegetation such as
rotting logs.
 Life cycles of cellular slime molds is less complex than that of
acellular types.
 Reproduction is sexual and there is no diploid stage in their life
cycles.
Oomycota:
 Water molds and downy mildews are members of this phyla.
 Consist of finely branched, single-celled filaments, that look like
fungi and also have a fungus – like method of nutrition.
 Most water molds live on dead organisms in fresh water.
 Downy mildews are parasitic, that live on plants.
 One type of downy mildew caused the potato blight in Ireland.
Assignment:
Biological Sciences – An Ecological Approach: Read Pages 309-316
Concept Review: Page 316 #3,4,5,7