Excavata
Have an “excavated” feeding groove on one side of cell body
What is Excavata?
3 Major Clades of SAR.
What is Stramenopiles, Alveolates, Rhizarians?
Characterized by alveoli (membrane-bound sacs just under their plasma membranes)
What is Alveolates?
Often symmetrical
• Symmetrical internal skeletons are made of silica
• Mostly marine protists
• Pseudopodia
• Can engulf smaller microorganisms that get attached to the pseudopodia
• Cytoplasmic streaming: carrying the captured prey into the main part of the cell
What is Radiolarians (Rhizarians)?
There are two major clades of unikonts
Amoebozoans- Tubulinids and close protist relatives
Opisthokonts- Animals, fungi, and closely
related protist groups
• Lack plastids
• Highly reduced mitochondria(mitosomes)
• They lack functional electron transport chains = cannot use oxygen for energy
• Anaerobic biochemical pathways
• Most of them are parasites
• ex. Giardia intestinalis
• 2 equal-sized nuclei
• Multiple flagella
What is Diplomonads?
Straw hair” in Latin
• Numerous fine, hairlike flagella
• Paired with a shorter smooth, non-hairy flagellum
• Includes some of the most important photosynthetic organisms on the planet
What is Stramenophiles?
• Reinforced by cellulose plates
• Have 2 flagella
• One of them causes them to spin as they move through waters
Ex. Red tide because of carotenoids
Ex. Noctiluca- sea sparkle, bioluminescence
What is Dinoflagellates (Aveolates)?
Also called foraminiferans (foramen =little hole,ferre = to bear)
• Have porous shells called tests
• Consists of a single piece of organic material that’s hardened with calcium
carbonate
• Pseudopodia extend through the pores
• Swimming, test formation, and feeding
• Nutrition from the photosynthetic symbiotic algae within the tests
What is Forams (Rhizarians)?
Lobe- or tube-shaped pseudopodia (instead of threadlike as in rhizarians)
• Tubulinids
• Ubiquitous (found everywhere) in soil, freshwater, and marine habitats
•Amoeba proteus
Slime Molds (mycetozoans; “fungus animal”)
• Like fungi, they produce fruiting bodies that aid in spore dispersal
• They have diverged into two main branches
Brightly colored (yellow or orange)
• Form a mass called plasmodium
• Extend pseudopodia
What is Amoebozoans (Unikonta)?
• Characterized by a parabasal organ (similar to Golgi apparatus)
• Also have reduced mitochondria(hydrogenosomes)
• Generate some energy anaerobically (hydrogen gas as a by-product)
• Ex. Trichomonas vaginalis (STD aka Trich)
What is Parabasalids?
Unicellular algae
• Has a “glass-like” wall made with silicon dioxide
• The wall has two parts that overlap (think of a shoe box)
• Protection from the crushing jaws of predators (1.4 mil kg/m2
What is Diatoms (Stramenopiles)?
• Almost all are parasites in animals
• Virtually all animal species examined so far are attacked by them
• Spread through their host as tiny infectious cells called sporozoites
• They have life cycles involving both sexual and asexual stages
• Often requires two or more hosts for completion
• Ex. Plasmodium
• Lives in both mosquitoes and humans
What is Apicomplexans (Alveolates)?
Commonly found in marine,
freshwater, and soil ecosystems
• Most of them are heterotrophs
• Parasites of plants, animals, and other protists
• Many are also predators – consume other protists, fungi, and small
animals
• Chlorarachniophytes
• Mixotrophs
• Ingest smaller protists and bacteria & perform photosynthesis
Ex. Paulinella chromatophora
Exhibits endosymbiosis
Autotroph
What is Cercozoans (Rhizarians)?
• Most amoebozoans are free-living
•Entamoebas are symbiotic parasites
• Infect all classes of vertebrate animals and some invertebrates
• We are host to at least 6 species of them
• Only one of them,
E. histolytica, is known to be pathogenic
• They cause amoebic dysentery
• Spread via drinking/eating contaminated water and food
• 110,000 deaths worldwide each year
• The third-leading cause of death due to eukaryotic parasites (after malar
What is Entamoebas (Unikonta:Amoebozoans)?
• flagellated protists that include predatory heterotrophs, photosynthetic autotrophs, and pathogenic parasites
• A rod with either a spiral or a crystalline structure inside the flagella
What is Euglenozoans?
The largest and most complex algae
• Multicellular and most are marine
• Common along temperate coasts with cold-water currents
• Brown (or olive) color due to carotenoids in plastids
Have holdfasts (roots), Stipe (stem), Blades (Leaves)
What is Brown Algae (Stramenopiles)?
Possess cilia for movement and feeding behaviors
• Most are predators (of bacteria or other protists)
• Ciliary beating – gradual, slow, and controlled movement of cilia
• “The wave” in the stadium
What is Ciliates (Alveolates)?
Archaeplastida has the defining characteristics of____ and is made of what two things?
Plastids- acquired from cyanobacterial endosymbiont
Include Red and Green Algae
Archaeplastida: Red Algae
• Also known as rhodophytes
• Photosynthetic pigment phycoerythrin masks the green of chlorophyll
• Some shallow water species have less phycoerythrin
• Some completely lack them and live as parasites on other red algae
• You can see the color difference depending on the depth of water
Depends on water currents for reproduction and alteration of generations.
Archaeplastida: Green Algae
Green algae and plants are closely related
• Have a structure and pigment composition much like the chloroplast of plants
• Some scientists want to include them in a new ”plant” kingdom
• Viridiplantae (viridis = green)
It uses decomposer to break down food, can be mutualistic, parasitic, single-celled (yeasts) or Multicellular
What is Fungi?
The two group of Euglenozoans.
What is Kinetoplastids & euglenids?
Kinetoplastids
• Have a single, large mitochondrion that contains an organized mass of DNA called kinetoplast
• Include species that feed on prokaryotes in freshwater, marine, and moist terrestrial ecosystems
• Some parasitize animals, plants, and other protists
• Ex.Trypanosoma
• Photosynthesis
• Heterotrophic
• Phagocytosis
Euglenids
• Has a pocket at one end where flagella emerge
• Some are mixotrophs (Photosynthesis & Heterotrophic)
• Phagocytosis
Egg-fungus”
• Water molds, the white rusts, and the downy mildews
• Because of their morphology, they were previously classified as fungi
• Cell walls made of cellulose
• Have branching filaments (hyphae)
What is Oomycetes (Stramenopiles)?
Most of them are amoebas
• Pseudopodia
• Alter its shape
• Move by extending them out
What is Rhizarians?
Green Algae is divided into two groups.
Chlorophytes and Charophytes.
**Only showed examples of chlorophyte in class
7000 species
• Most live in fresh water (some marine and terrestrial)
Examples
Chlamydomonas
• Resemble gametes of more complex chlorophytes
• Live independently as phytoplankton or
• Symbiotically within other
eukaryotes (perform photosynthesis
for their food supply)
AND
Pediastrum
• A “Pond alga”
• Form colonies of individual cells
• Contribute to the pond scum
AND
Ulva
• “Sea lettuce”
• Edible chlorophyte
• Have blades and holdfast
• Form true multicellular bodies by cell division and differentiation
Fungal Structures
• Multicellular fungi
• Hyphae- Network of tiny, connected filaments that collectively make up the mycelium of a fungus
Mycelium- Mass network of hyphae in a fungus
Arbuscules- branching hyphae that allow
fungi to exchange nutrients
with living plants
• Mycorrhizae (“fungus roots”)
• Mutually beneficial relationships between fungi and plant roots