Kingdom Protista

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Type 1
Type 2
Picture Representations of The Three Types of
Protists
Type 3a
Type 3b
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Kingdom Protista

• http//videos.howstuffworks.com/hsw/14769-simply-s
  cience-protista-video.htm

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Characteristics of Protists

• 60,000 species
• Eukaryotes
• Generally unicellular
• 10 µm 60 m
• Some have cell walls
• Some are motile
• Some have pigments
• Various methods of feeding

• Most are aerobic
• Lack specialized features of fungi, plants and
  animals
• Do not develop complex sex organs
• Do not form embryos

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Classifying Protista

• They are divided into three major groups based on
  their type of nutrition
• Protozoa (animal-like)
• heterotrophs that ingest or absorb their food
• Algae (plant-like)
• autotrophs that carry out photosynthesis
• Slime Moulds and Water Moulds (fungi-like)
• heterotrophs

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• 1. Protozoa
• 2. Algae
• 3. Slime Moulds and Water Moulds

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1. Protozoa

• They feed on other organisms, they may be dead
  organisms. Some are scavengers, predators, or
  parasitic.
• They vary in shape and size. Most live as a
  single cell but some do form colonies.
• They are generally classified in 4 phyla based on
  their locomotion

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1a) Flagellates

• Phylum Zoomastigina
• They have one or more flagellum
• They have a hard, protective covering over their
  outer membrane

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1b) Sarcodines

• Phylum Sarcodina
• Also called amoeba
• They move and engulf their prey by producing
  limb-like extensions of their cytoplasm, called
  pseudopodia
• One example is foraminifera

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1c) Ciliates

• Phylum Ciliophora
• They are covered in hundreds of cilia, which
  allow them to move and sweep food particles to
  them for ingestion
• They are generally large and complex

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1d) Sporozoans

• Phylum Sporozoa
• They are parasites
• They form spores during their life cycle

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• 1. Protozoa
• 4 types of locomotion
• 2. Algae
• 3. Slime Moulds and Water Moulds

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2. Algae

• Simple, aquatic, chlorophyll-containing organisms
• Range from single cells to giant seaweeds
• Greater than 2 billion years old
• They are classified into 6 phylum based on their
  different types of chlorophyll and other
  pigments. (3 are mainly unicellular 3 mainly
  multicellular). There are also differences in
  their cell wall chemistry, and form of food
  reserve in their cells.

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2a) Green Algae

• Phylum Chlorophytes
• Same type of chlorophyll and colour as most land
  plants
• Cell walls contain cellulose
• Food reserves ?starch
• Commonly found in fresh water and damp places on
  land
• Many of the unicellular organisms have flagella

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2b) Brown Algae

• Phylum Phaeophtyes
• They are generally all the multicellular marine
  organisms that we call seaweeds

• Cell walls ? cellulose and alginic acid
• Typically found in cold water

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2c) Red Algae

• Phylum Rhodophtyes
• Typically found in warmer seawater

• Able to grow at greater depths than other algae
  because their pigments are able to move through a
  greater distance in water

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2d) Diatoms

• Phylum Chrysopyhtes
• The most abundant unicellular algae in the oceans
• They are a major food source at the base of
  marine and freshwater food webs
• Also a major source of atmospheric oxygen
• Cell walls ? rigid, silica

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Diatoms Sexual and Asexual Reproduction

• Asexual the organism splits into two, each then
  grows a new half to fit inside the old one. The
  rigid cell wall cannot grow once it has been
  formed. Therefore, each generation of diatoms is
  smaller than the one before
• Sexual reduction in size continues until now.
  The diatoms produce a zygote that grows to the
  original size before secreting a new cell wall.
• See Figure 12.32

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2e) Dinoflagellates

• Phylum Pyrrophytes
• Unicellular, photosynthetic and mostly marine
• They have protective coats of stiff cellular
  plates
• They are distinguishable because they have two
  flagella, one acts as a rudder and the other as a
  form of propulsion.
• They are also an important food source
• Reproduction is mainly cell division, they are
  capable of sexual reproduction

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2f) Euglenoids

• Phylum Eugenophytes
• They also have two flagella but one is longer
  than other
• Over ½ do not have chloroplasts and are
  heterotrophs
• They could be autotrophic
• or heterotrophic

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• 1. Protozoa
• 4 types of locomotion
• 2. Algae
• different types of chlorophyll and
• other pigments
• 3. Slime Moulds and Water Moulds

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3. Slime and Water Moulds

• Like fungi they have spores
• Like protozoa they glide from place to place and
  ingest food
• Like plants they have cellulose cell walls
• There are 3 groups 2 groups of slime moulds and
  1 group of water moulds

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3a) Water Moulds

• Phylum Oomycotes
• Most live as saprotrophs on dead organic matter
• Others live as parasites on fish, insects and
  plants
• They differ from other fungus-like protists by
  the nature of their spores and their sexual life
  cycle

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3b) Plasmodial Slime Moulds

• Kingdom Myxomycotes
• They are visible to the naked eye. They are blobs
  called plasmodium, which contain many nuclei
• They engulf their food
• They reproduce sexually where the plasmodium
  develops spore-bearing structures called
  sporangia. In dry periods spores develop and when
  damp conditions return the spores will germinate.
  The flagellae and the amoeboid cells fuse to make
  a zygote that will turn into a plasmodium

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3c) Cellular Slim Moulds

• Phylum Acrasiomycotes
• Exist as individual amoeboid cells with one
  nucleus each.
• Feed on tiny bacteria or yeast cells, when there
  is no food a chemical is released which causes
  the cells to gather together in a
  pseudoplasmodium.
• The pseudoplasmodium goes through the same
  reproduction as the plasmodial slime moulds.
• The two slime moulds are not suspected to be
  closely related

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Life Cycle of a Slime Mold