Protists

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Protists

• Kingdom Protista
• (The hodge-podge Kingdom)

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• Section 20-1 Kingdom Protista
• Protist any organism that is not a plant,
  animal, fungus, or prokaryote
• - this kingdom is mostly unicellular, but
  includes many
  multicellular organisms as well
• - this kingdom will be broken into several
  kingdoms based on DNA analysis and other factors
• - similar to the first eukaryotes
• Classification of the Protists is based on
  Nutrition
• A) heterotrophic animallike protists
  protozoa
• B) autotrophic plantlike protists
• C) decomposers/parasites funguslike protists

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• Endosymbiont Hypothesis Lynn Margulis
• - hypothesis that explains the evolution of the
  first eukaryotic cells from symbiotic prokaryotes

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• Animallike Protists Protozoans
• - Unicellular heterotrophs
• - Four phyla based on locomotion
• a. Zoomastigina swim using flagella
• b. Sarcodina move with pseudopodia
• c. Ciliophora swim with cilia
• d. Sporozoa no locomotion

B.
C.
D.
A.
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• Zoomastigina Zooflagellates
• - most have one or two flagella
• - most absorb nutrients through cell
• membrane
• - often decomposers or parasites
• - reproduce primarily by mitosis
• - Trypanosomes African Sleeping Sickness
• - Trichomonas vaginalis most common protozoan
  infection in humans

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• Phylum Sarcodina Sarcodines
• - move and feed via pseudopods
• - temporary cytoplasmic extensions
• - ameboid movement
• - surround and engulf food into food vacuoles,
  digested nutrients are used, and undigested
  materials exit through the cell membrane
• - reproduce by mitosis and cytokinesis
• - Amoebas are best known examples
• - Foraminiferans
• - sarcodines of warm oceans with calcium
  carbonate shells
• - White Cliffs of Dover in England

Heliozoans
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• Ameba Feeding with Pseudopods

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• Phylum Ciliophora Ciliates
• - use cilia for locomotion and feeding
• - very fast swimmers
• - live in both fresh and salt water
• - most are free-living
• Internal Structures of Paramecium
• - trichocysts small defensive structures
• - macronucleus controls normal activities
• - micronucleus reserve copy of genes
• exchanged during conjugation
• - gullet oral groove into which food
  enters
• - food vacuoles form around food and
• lysosomes fuse with it to digest food
• - wastes exit through anal pore
• - contractile vacuoles keep water balance

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• Paramecium Anatomy

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• Paramecium Conjugation
• - normally paramecia reproduce by mitosis and
  cytokinesis
• - during stressful times they sometimes undergo
  conjugation
• - exchange micronuclei with each other
• - not reproduction because no new cells are
  formed, but it helps produce and maintain genetic
  diversity

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• Phylum Sporozoa Sporozoans
• - do not move on their own
• - parasitic
• - often have complex life cycles with more than
  one host
• - reproduce by means of sporozoites
• Animallike Protists and Disease
• 1. Malaria
• - Plasmodium parasite kills up to 2 million
  people per year
• - Female Anopheles mosquitoes are the vector
• - mosquitos saliva enters a person with
  sporozoites which get in persons blood

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• - sporozoites enter liver and red blood cells
• - when erythrocytes burst it causes severe
  chills and fever
• - many strains of malaria have evolved
  resistance to the drugs we use against the
  parasites
• - best control is to control mosquitoes

sporozoites
sporozoites
merozoites
male gametophyte in erythrocyte
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• 2. African Sleeping Sickness
• - Zooflagellate Trypanosoma
• - spread by Tsetse flies
• - damage the nervous system and can cause death
• 3. Amebic Dysentery
• - causes severe diarrhea and intestinal bleeding
• - Entamoeba
• - spreads by contaminated drinking water
• 4. Giardia
• - a flagellated protozoan that also causes
  diarrhea and digestive system problems
• Ecologically many protists are important
  decomposers and symbionts with other organisms
• - Trichonympha in termite guts digest cellulose

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• Sec. 20 -3 Plantlike Protists Unicellular Algae
• - often classified based on the type of
  photosynthetic pigments they have
• - have many different pigments to absorb the
  light that can penetrate into deep water (blue)
• - have chlorophyll a, b, and c
• - accessory pigments absorb wavelengths that
  chlorophylls cant
• Phylum Euglenophyta
• - have two flagella, but no cell walls
• - genus Euglena
• - found in lakes and ponds
• - eyespot allows them to swim toward light
• - can live autotrophically or heterotrophically

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• Phylum Chrysophyta Yellow-green golden-brown
• - means golden plants
• - cell walls of pectin rather than cellulose
• - golden algae often cause fish kills
• Lake Wichita
• Spring 2009

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• Phylum Bacillariophyta Diatoms
• - make shells of silicon (glass)
• - shells of two parts like a petri dish

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• Phylum Pyrrophyta Dinoflagellates
• - half are heterotrophic half autotrophic
• - most have two flagella and a shell of thick
  cellulose
• - many are luminescent
• - Pyrrophyta means fire plants

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• Ecology of Unicellular Algae
• 1. Phytoplankton
• - small photosynthetic organisms in the ocean
• - perform about half of all photosynthesis on
  Earth
• - are the base of the food chain all sea-life
  depends on these autotrophs
• 2. Algal Blooms
• - happen when excess nutrients are in water and
  algae grow very rapidly
• - when nutrients are used up and the algae die,
  their decomposition takes all of the oxygen out
  of the water which causes many other organisms
  to die
• - Red tides can make shellfish poisonous

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• Plantlike Protists Red, Brown, and Green Algae
• - these groups are mostly multicellular
• - most have cell walls and life cycles like
  plants
• Phylum Rhodophyta Red Algae
• - can live at great depth (260 meters) due to
  their efficiency at harvesting light energy
• - contain chlorophyll a and reddish accessory
  pigments called phycobilins which absorb blue
  light
• - important in coral reefs

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• Phylum Phaeophyta Brown Algae
• - contain chlorophyll a and c and the accessory
  pigment fucoxanthin
• - largest and most complex algae
• - mostly marine and often in cool, shallow
• coastal water
• - Kelp forests on west coast of U.S.
• - Sargassum forms huge floating mats
• on the ocean
• - many have air-filled bladders that
• help them float

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• Phylum Chlorophyta Green Algae
• - ancestors of green plants
• - cellulose cell walls, contain chlorophyll a
  and b and store food as starch
• - most are aquatic, but some live on moist land
• - both unicellular, colonial, and multicellular
• - Chlamydomonas
• - unicellular
• Ulva - multicellular

Volvox colonies
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Zygote (cross-section)
A thick-walled resistant zygote develops.
Diploid Stage
Meiosis and Germination
Nuclear Fusion
Haploid cell ( strain)
Haploid Stage
Haploid cell (- strain)
Mitosis
ASEXUAL REPRODUCTION
ASEXUAL REPRODUCTION
Cytoplasmic Fusion
More spores produced.
More spores produced.
SEXUAL REPRODUCTION



Gametes of different mating types meet.

Life cycle of a species of Chlamydomonas
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sporophyte (2n)
zygote
Diploid Stage
Meiosis
Fertilization
Haploid Stage
germinating spore (n)
male gametes
female gametes
10 cm
gametophyte (n)
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• Human Uses of Algae
• - algal chemicals are used to treat stomach
  ulcers, high blood pressure, arthritis, and other
  health problems
• - many foods contain algae or algal products
• - thickening agent in ice cream, salad dressing,
  puddings, and candy bars
• - industry uses algal chemicals to make plastics,
  waxes, deodorants, lubricants, even artificial
  wood
• - agar is used in biology labs to grow bacteria on

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