Protist diversity IIProtist diversity II
Level 1 Biological DiversityLevel 1 Biological Diversity
Jim ProvanJim Provan
Phylogeny of eukaryotesPhylogeny of eukaryotes
Diplomonads and ParabasalaDiplomonads and Parabasala
Amitochondriate:Amitochondriate:Originally believe to have Originally believe to have diverged before diverged before acquisition of acquisition of mitochondriamitochondria
Presence of nuclear gene Presence of nuclear gene homologues now suggests homologues now suggests that mitochondria have that mitochondria have been lostbeen lost
DiplomonadsDiplomonads have have multiple flagella and two multiple flagella and two separate nucleiiseparate nucleii
InfectiousInfectious
EuglenozoaEuglenozoa
Contain flagellaContain flagellaTwo main groups:Two main groups:
EuglenoidsEuglenoids::— Paramylon (glucose Paramylon (glucose
polymer) used as a polymer) used as a storage moleculestorage molecule
— Anterior pocket with one Anterior pocket with one or two flagellaor two flagella
KinetoplastidsKinetoplastids::— Contain a single large Contain a single large
mitochondrion and a mitochondrion and a unique organelle unique organelle (kinetoplast)(kinetoplast)
— Symbiotic / pathogenicSymbiotic / pathogenic
AlveolataAlveolata
Encompasses:Encompasses:Photosynthetic flagellates Photosynthetic flagellates ((dinoflagellatesdinoflagellates))
Parasites Parasites ((apicomplexansapicomplexans))
Group that move by cilia Group that move by cilia ((ciliatesciliates))
Have small, membrane-Have small, membrane-bound cavities under bound cavities under cell surfaces (cell surfaces (alveolialveoli))
DinoflagellatesDinoflagellates
Components of phytoplankton – may cause Components of phytoplankton – may cause red red tidestides
Most are unicellular, some are colonialMost are unicellular, some are colonial
Some are photosynthetic symbionts, some are non-Some are photosynthetic symbionts, some are non-photosynthetic parasitesphotosynthetic parasites
Plastids are brownish and contain chlorophylls Plastids are brownish and contain chlorophylls a a and and c c and a mix of carotenoids (including peridinin)and a mix of carotenoids (including peridinin)
Food stored as starchFood stored as starch
Chromosomes lack histones and are always Chromosomes lack histones and are always condensedcondensed
Have no mitotic stagesHave no mitotic stages
ApicomplexansApicomplexans
All parasites of animals:All parasites of animals:Infectious cells called sporozitesInfectious cells called sporozites
Apex of sporozites has organelles for penetrating host Apex of sporozites has organelles for penetrating host cellscells
Life cycles have both sexual and asexual reproduction, Life cycles have both sexual and asexual reproduction, often requiring more than one hostoften requiring more than one host
Several species of Several species of PlasmodiumPlasmodium cause malaria: cause malaria:AnophelesAnopheles mosquitoes serve as intermediate host mosquitoes serve as intermediate host
New, resistant forms of New, resistant forms of PlasmodiumPlasmodium are appearing are appearing
Little success in developing a vaccine:Little success in developing a vaccine:— PlasmodiumPlasmodium spends most of its life cycle in blood or liver cells spends most of its life cycle in blood or liver cells— Has the ability to alter its surface antigensHas the ability to alter its surface antigens
Life history of Life history of PlasmodiumPlasmodium
CiliatesCiliates
Species use cilia to move Species use cilia to move and feedand feed
Most solitary cells in fresh Most solitary cells in fresh waterwaterCilia are short and beat in Cilia are short and beat in synchronysynchronySubmembraneous system Submembraneous system coordinates beatingcoordinates beatingSome species move on leg-Some species move on leg-like like cirricirriOthers have rows of tightly Others have rows of tightly packed cilia which act as packed cilia which act as locomoter membranelleslocomoter membranelles
Among most complex of Among most complex of cellscells
Two types of ciliate nucleiTwo types of ciliate nuclei
Macronucleus:Macronucleus:Is large and has over 50 copies of the genomeIs large and has over 50 copies of the genome
Genes packaged into units, each with hundreds of copies of Genes packaged into units, each with hundreds of copies of just a few genesjust a few genes
Controls everyday functions by synthesising RNAControls everyday functions by synthesising RNA
Necessary for asexual reproduction – macronucleus Necessary for asexual reproduction – macronucleus elongates and splits instead of undergoing mitosiselongates and splits instead of undergoing mitosis
Micronucleus:Micronucleus:Small and present in 1-80 copiesSmall and present in 1-80 copies
Does not function in growth, maintenance or asexual Does not function in growth, maintenance or asexual reproductionreproduction
Functions in the sexual process of Functions in the sexual process of conjugationconjugation
Conjugation and genetic Conjugation and genetic recombination in recombination in ParameciumParamecium
StramenopilesStramenopiles
Includes several heterotrophic groups as well as a Includes several heterotrophic groups as well as a variety of photosynthetic protists (algae):variety of photosynthetic protists (algae):
OomycotaOomycota (water moulds etc.): (water moulds etc.):— HeterotrophicHeterotrophic— Ostensibly similar to fungi but have analogous hyphae, Ostensibly similar to fungi but have analogous hyphae,
cellulose cell walls (as opposed to chitin), prevalent diploid cellulose cell walls (as opposed to chitin), prevalent diploid stage and biflagellated cells (true fungi have no flagellated stage and biflagellated cells (true fungi have no flagellated stages)stages)
Heterokont algae:Heterokont algae:— DiatomsDiatoms have hydrated silica shells and generally reproduce have hydrated silica shells and generally reproduce
asexuallyasexually— ChrysophytesChrysophytes (golden algae) have carotene and xanthophyll (golden algae) have carotene and xanthophyll
accessory pigments and are mostly unicellularaccessory pigments and are mostly unicellular— PhaeophytesPhaeophytes (brown algae) are all multicellular and mostly (brown algae) are all multicellular and mostly
marinemarine
SeaweedsSeaweeds
Have differentiated tissues Have differentiated tissues and organs similar to and organs similar to plants:plants:
Analogous:Analogous:— Holdfast Holdfast root root— Stipe Stipe stem stem— Blade Blade leaf leaf
Commercially important:Commercially important:Food (Food (LaminariaLaminaria and and PorphyraPorphyra))
AgarAgar
ThickenersThickeners
LubricantsLubricants
Alternation of generations in Alternation of generations in algaealgae
Rhodophyta (red algae)Rhodophyta (red algae)
Have no flagellated Have no flagellated stagesstages
Accessory pigment: Accessory pigment: phycoerythrinphycoerythrin
Not always red: Not always red: dependent on depthdependent on depth
Mostly multicellularMostly multicellular
Diverse life cycles but Diverse life cycles but alternation of alternation of generations is commongenerations is common
Chlorophyta (green algae)Chlorophyta (green algae)
Two main groups:Two main groups:ChlorophyceaeChlorophyceae
CharophyceaeCharophyceae
Share a common Share a common ancestor with green ancestor with green plantsplants
Unicellular, colonial or Unicellular, colonial or multicellularmulticellular
Nearly all reproduce Nearly all reproduce sexually by way of sexually by way of biflagellated gametesbiflagellated gametes
Life cycle of Life cycle of ChlamydomonasChlamydomonas
Rhizopods (amoebas)Rhizopods (amoebas)
Simplest unicellular Simplest unicellular protistsprotists
No flagellated stagesNo flagellated stages
PseudopodiaPseudopodia used in used in feeding and movementfeeding and movement
All reproduction is asexualAll reproduction is asexual
Inhabit freshwater, marine Inhabit freshwater, marine and soil habitatsand soil habitats
Most are free living, Most are free living, although some are although some are parasiticparasitic
ActinopodsActinopods
Possess Possess axopodiaaxopodia, , slender form of slender form of pseudopodiapseudopodia
Increase surface area Increase surface area which helps floating and which helps floating and feedingfeedingSome prey may stick to Some prey may stick to axopodia and be axopodia and be phagocytosedphagocytosed
Two main groups:Two main groups:HeliozoansHeliozoans (primarily (primarily freshwater)freshwater)RadiolariansRadiolarians (primarily (primarily marine)marine)
Plasmodial slime moulds Plasmodial slime moulds (Myxomycota)(Myxomycota)
Cellular slime moulds Cellular slime moulds (Acrasiomycota)(Acrasiomycota)