Chapter 20 Protists

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Chapter 20 Protists

• Pages 496-520

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20-1 The Kingdom of Protista

• Kingdom of Protista is a diverse group that may
  include more than 200,000 species
• Is an organism that is not a plant, animal or
  fungus
• Multicellular protists are grouped with
  unicellular protists because multicellular
  protists are very similar to unicellular protists
• Were the first eukaryotes on earth and are
  thought to have evolved from a symbiosis of
  several cells according to Lynn Margulis

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20-1 The Kingdom of Protista

• Classification of Protists
• Are very diverse organisms
• Some biologists argue that they should be broken
  up into several kingdoms
• Currently we classify them based on the way they
  obtain nutrition
• Heterotrophs called animal like protists
• Autotrophs using Photosynthesis called plant
  like protists
• External digestion fungus like protists

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20-2 Animal Like Protosits Protozoans

• Animal like protists are sometimes called
• Protozoans
• Are heterotrophs
• Are distinguished from one another by the way
  they move
• There are 4 Phylums
• Zooflagellates Protists that swim using flagella
• Live in lakes and streams
• Absorb food through their cell membrane
• Most reproduce asexually through mitosis and
  cytokenesis

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20-2 Animal Like Protosits Protozoans

• 2. Sarcodines Protists that use pseudopods for
  feeding and movement
• Contain ameobas, foraminiferans, and heliozoans
• Ameobas use amoeboid movement and food vacuoles
  to digest food
• Foraminiferans are found in warmer ocean regions
  and secrete shells of calcium carbonate
• Heliozoans look like the suns rays because of
  spikes of cytoplasm that project from silica
  shells

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20-2 Animal Like Protosits Protozoans

• 3. Ciliates Use cilia (short hair like
  structures similar to flagella) for feeding and
  movement
• Are Found in both fresh and salt water
• Some of the best know are in the genus Paramecium
• Paramecium use Trochocysts (small bottle shaped
  structures) for defense if confronted by danger
• Paramecium have 2 types of nucleui
• Macronucleus working library of genetic
  information
• Micronucleus reserve copy of genetic
  information

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20-2 Animal Like Protosits Protozoans

• Ciliates continued..
• Gullet an indentation used by cilia to collect
  food
• Contractile vacuoles cavities in cilia's
  cytoplasm used to collect water
• Contracts to remove water to help cells maintain
  homeostasis
• Cilia reproduce asexually by mitosis or
  cytokinesis or sometimes by conjugation

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20-2 Animal Like Protosits Protozoans

• 4. Sporozoans Phylum of protists that do not
  move on their own and are parasitic
• Act as parasites on a large variety of organisms
  including birds, worms, fish and humans
• Reproduce by means of sporozites
• Sporozites can attach to host cell, penetrate it,
  and then live within it as a parasite

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20-2 Animal Like Protosits Protozoans

• Animal Like Protists Disease
• Animal like protists are some of the most common
  organisms in the world
• Some also cause serious disease
• EX Sporozoan Plasmodium causes the disease known
  as malaria- spread by female mosquito
• EX Zooflagellates Trypanosoma cause the disease
  African Sleeping Sickness spread by the tsetse
  fly
• EX Entamoeba ameobas cause amoebic dysentery
  causing intestinal bleeding

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20-2 Animal Like Protosits Protozoans

• Animal like Protists and Ecology
• Some animal like protists are beneficial and live
  symbiotically with other organisms
• EX Trichnomypha is a Zooflagellate that lives
  within the digestive tract of termites and
  digests the cellulose in the wood that the
  termites eat, breaking it down for them.

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20-3 Plantlike Protists Unicellular Algae

• Plant like protists are able to carry out
  photosynthesis
• We commonly call plant like protists algae
• We consider all forms of algae to be protists

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20-3 Plantlike Protists Unicellular Algae

• Chlorophyll and accessory pigments allow algae to
  harvest and use the energy from the sunlight
• Different forms of algae have adapted with
  different forms of chlorophyll Chlorophyll a,
  Chlorophyll b, and Chlorophyll c
• Each form of chlorophyll allows for algae to
  capture different wavelengths of the suns light
• Allows for an increase in the range of depths in
  which algae can live
• Allows for algae to use more than just the suns
  red and violet wavelengths

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20-3 Plantlike Protists Unicellular Algae

• There are 4 main groups of unicellular algae
• Euglenophytes
• Chrysophytes
• Diatoms
• Dinoglagellates

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20-3 Plantlike Protists Unicellular Algae

• Euglenas are plantlike protists with
• Members of phylum Euglenophyta
• Two flagella making them excellent swimmers
• No cell wall
• Can act as heterotrophs if no sunlight is
  available
• Have an intricate folded cell membrane called a
  pellicle allowing them to crawl through mud if
  there is no water to swim

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20-3 Plantlike Protists Unicellular Algae

• Chrysophytes are plantlike protsists with
• Members of phylum Chrysophyta
• Include the yellow green and brown algae
• Have gold colored chloroplasts
• Name means golden plants
• Cell walls sometimes contain pectin
• Generally store food in the form of oil instead
  of starch
• Reproduce asexually and sexually

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20-3 Plantlike Protists Unicellular Algae

• Diatoms are plantlike protists with
• Belong to the phylum of Bacillariophyta
• Produce thin delicate cell walls rich in silicon
  the main component of glass
• Are among the most abundant and beautiful
  organisms on earth

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20-3 Plantlike Protists Unicellular Algae

• Dinoglagellates are plantlike protists with
• Members of phylum Pyrrophyta
• ½ are photosynthetic and other ½ are heterotrophs
• Generally have 2 flagella
• Can reproduce asexually or by binary fission
• Like Chrysophyta, members of Pyrrophyta have cell
  walls that contain cellulose

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20-3 Plantlike Protists Unicellular Algae

• Ecology of Unicellular Algae
• Found in both fresh and salt water
• Are important organisms that act as the base of
  the food chain for other aquatic organisms
• Make up the majority of photoplankton-
  photosynthetic organisms found near the surface
  of the ocean
• Can grow in algal blooms an enormous mass of
  algae- that deplete the water of nutrients like
  oxygen that can other organisms like fish

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20-4 Plantlike Protists Red, Brown and Green
Algae

• Red, Brown and Green Algae have the following
  characteristics
• Look similar to aquatic plants
• Are mostly multicellular
• Possess highly specialized tissues
• Many have cell walls
• The three phylums differ by the photosynthetic
  pigments they use

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20-4 Plantlike Protists Red, Brown and Green
Algae

• Red Algae is a plant like protist with
• Members of phylum Rhodophyta
• Able to live at great depths
• Contain chlorophyll a and accessory pigments
  called phycobilins
• Lack flagella and centrioles
• Can be red, green or purple
• Are eaten by coral in coral reefs

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20-4 Plantlike Protists Red, Brown and Green
Algae

• Brown Algae is a plantlike protists with
• Members of the phylum Phaeophyta
• Contain Chlorophyll a c and a brown accessory
  pigment
• Largest most complex form of algae
• Are yellow-brown in color
• All are multicellular
• Commonly found in cool, shallow coastal water
• EX Giant Kelp

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20-4 Plantlike Protists Red, Brown and Green
Algae

• Green Algae are plant-like protists with
• Members of the phylum Chlorophyta which means
  green plants
• Share many characteristics with plants like cell
  wall composition, multicellularity, and
  photosynthetic pigments
• Contain chlorophyll a b
• Found in fresh and salt water
• There are three types of green algae
  unicellular, colonial, or multicellular

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20-4 Plantlike Protists Red, Brown and Green
Algae

• Reproduction in Green Algae
• Life cycle of many algae include both a haploid
  and diploid generation
• Some switch back and forth between haploid and
  diploid their entire lives
• EX In life cycle of algae Ulva, one of the
  phases produces male female gametes known as
  gametophytes
• Some switch back and forth between sexual and
  asexual reproduction
• Ex Chlamydomanas (single-celled green algae)
  reproduces asexually by producing zoospores

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20-4 Plantlike Protists Red, Brown and Green
Algae

• Human Uses of Algae
• Are major food source for ocean life
• They produce much of Earths oxygen through
  photosynthesis
• Chemicals in algae are used to treat stomach
  ulcers, high blood pressure, and other health
  problems
• Used in food products such as ice cream,
• Used in chemicals such as plastics

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20-5 Funguslike Protists

• Funguslike Protists
• Look similar to fungi
• Are heterotrophs that absorb nutrients through
  dead or decaying organic matter
• Have centrioles
• Lack chitin cell walls that true fungus have
• Include the groups Cellular Slime Molds,
  Acellular Slime Molds, and Water Molds

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20-5 Funguslike Protists

• Slime Molds are funguslike protists with
• Play roles in recycling organic material
• Form mold-like clumps that form spores
• There are two major groups
• Cellular Slime Molds
• Acellular Slime Molds
• Found in damp and rich organic matter such as the
  forest floor or backyard compost

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20-5 Funguslike Protists

• Water Molds are funguslike Protists with
• Are also called Oomycetes
• Are members of the Phylum Oomycota
• Thrive on dead or decaying matter in the water
  some are plant parasites on land
• Produce thin filaments known as hyphae
• Display both sexual and asexual reproduction
  during their lifetime
• In oomycetes, sexual reproduction takes place in
  specialized structures formed by the hyphae
  called the antheridium and oogonium

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Kingdom Fungi

• Chapter 21

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Fungi

• Eukaryotic
• Heterotrophs
• Have cell walls made of chitin (only similarity
  to plants)
• Digest food outside their body absorb it
  through cell wall.
• Multicellular
• Grow on their own food source.

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Fungi Structure

• The body is multicellular composed of many
  hyphae tangled together into a thick mass called
  a mycelium.
• Hyphae filament that can develop cross walls
  with 2 nuclei.

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Fungi Reproduction

• Most reproduce both asexually sexually.
• Asexual-takes place when hyphae break off begin
  to grow on their own.
• Can produce spores that scatter grow.
• Spores are produced in a sporangia.
• Sexual-takes place when hyphae of opposite mating
  types meet and fuse together.
• Fungi are diploid during a small part of their
  life cycles.

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Common Molds

• Ex. Bread Mold
• Zygospores-resting spore that contains zygotes
  formed during sexual phase.
• Rhizoids-anchor fungus to the bread.
• Stolons-stem-like hyphae that run along the
  surface of the bread.
• Gametangia-produce haploid gamestes when hyphae
  fuse.

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Yeast

• Unicellular fungi
• Yeast form asci (ascus-plural) with ascospores
  which become active in a moist environment.
• Budding-process of asexual reproduction.
• When baking bread, yeast causes the bread to rise
  because the fermentation (no oxygen present) of
  the yeast produces carbon dioxide.

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Club Fungi

• Ex. Mushrooms
• Basidium-spor-bearing structure that looks like a
  club.
• Gills-hold the basidia on the underside of
  mushroom caps.
• Stalk-stem.

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Imperfect Fungi

• Deuteromycetes-fungi that do not appear to have
  sexual reproduction.
• Penicillum-Penicillium notatum is a mold that
  grows on fruit is the source of the antibiotic
  penicillin.

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Ecology of Fungi

• Since fungi are heterotrophs, the cannot make
  their own food.
• They cannot move or capture food, but their
  mycelia can grow very rapidly into tissues
  cells of plants other organisms.
• Saprobes-obtain food from decaying organic
  matter.
• Parasites-harm other organisms while living
  directly on or within them.
• Symbionts-live in close mutually beneficial
  association with other species.

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Ecology of Fungi

• Fungi that are Decomposers play an essential role
  in balancing ecosystems by breaking down dead
  organisms.
• The breakdown is sped up by fungal production of
  digestive enzymes.
• They return important trace elements nutrients
  to the soil.

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Ecology of Fungi

• Fungi that are Parasites feed on living organisms
  and cause serious disease to plants and animals.
• Some cause disease in humans.
• The growth of yeasts in moist regions of the body
  is kept in check by competition from bacteria.
• Infections can be treated by antibiotics.
• Ex. Wheat rust, athletes foot, yeast infections
  in female reproductive tracts.

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Ecology of Fungi

• Lichens are an example of fungi that are
  Symbiotic.
• They are composed of an alga or a cyanobacterium
  a fungus living together.

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Ecology of Fungi

• Some fungi are Mutualistic.
• Almost half of the tissue of trees is beneath the
  ground as roots.
• These roots are tangled in a partnership with a
  web of fungal mycelia. This mix is called
  mycorrhizae.