“KINGDOM” PROTISTA - Bakersfield College 3A/Bio 3A... · “KINGDOM” PROTISTA Professor Andrea Garrison ... –P/S protists have plastids ... –Used in reproduction (sexual

“KINGDOM” PROTISTA

Professor Andrea Garrison Biology 3A

Illustrations ©2014 Cengage Learning unless otherwise noted

Protista

• Domain Eukarya

• Very diverse

• Unnatural grouping (polyphyletic)

• Everything that isn’t animal, plant or fungi

Protista 2

Protista

• Described by Leeuwenhoek in 1760s • Typically unicellular

– Complex cell structure – Some multicellular – Some colonial

• Autotrophic, heterotrophic or both – P/S forms often called algae

• Varied lifestyles: all require moisture – Seawater, freshwater, soil, decaying organisms, parasitic – Microscopic protists in lakes/oceans make up phytoplankton

• Food source for zooplankton and rest of food chain

• Some pathogenic – Amoebic dysentery, sleeping sickness, malaria

3 Protista

Protista

• Reproduction asexual or sexual or both – Asexual

• Binary fission

• Budding

• Colonies – May show division of labor

– Sexual • Meiosis, resulting gametes fuse

– Both • Elaborate life cycles specific to that group

Protista 4

Protista

• Cell structure – Cell wall, shell of mineral or organic matter, or

pellicle

– Most have mitochondria • Some with very reduced mitochondria

– P/S protists have plastids • Chloroplasts

– Chl a, and chl b or chl c

– Accessory pigments

• Other plastids contain pigments or store P/S products

Protista 5

Protistan Plastid Evolutionary Scenario

Protista 6

Protistan Plastid Evolutionary Scenario

Protista 7

Protista

• Many freshwater spp have contractile vacuole – Maintain osmotic

balance – Absent in marine,

parasitic forms, isosmotic w/ environment

• Many have food vacuoles – Intracellular digestion,

wastes expelled

Protista 8

Protista

• Metabolism usually aerobic

• Excretion and respiration via diffusion across cell membrane

Protista 9

Protista

• Locomotion – Motile during at least

part of life cycle • Flagella

• Cilia

• Pseudopods – Temporary cytoplasmic

extensions of cell membrane

– Locomotion

» Amoeboid movement

– Feeding

Protista 10

Protistan Classification

Protista 11

SAR

Protistan Classification

• State of flux, not well understood (differs from text)

• Based on DNA data, structure

• 4 “supergroups” which also include the rest of Eukarya – Excavata

– SAR

– Archaeplastida

– Unikonta

Protista 12

BIKONTA

SAR

Arc

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pla

stid

a

Met

amo

nad

a

UNIKONTA

ARCHAEPLASTIDA EXCAVATA

Eugl

eno

zoa

Alv

eola

ta

Rh

izar

ia

Stra

men

op

ila

Am

oeb

ozo

a

Op

isth

oko

nta

p. 592

Protistan Classification

Protistan Classification

• 4 supergroups may eventually become kingdoms or suprakingdoms

• We will look at examples of each group

Protista 14

Excavata

• Parasitic, free-living species may be autotrophs or heterotrophs

• Feeding “groove” (excavate; ex=from, cavatum=cavity) in many, with flagellum in groove

• Reduced mitochondria in many – Mitochondrial genes incorporated into nuclei

• Locomotion via unique flagella – Crystalline or spiral rod inside

Protista 15

Excavata

• 3 clades

– Euglenozoa

– Diplomonada

– Parabasala

Protista 16

Excavata

• Clade Euglenozoa

– Highly motile

– Most P/S

– Some heterotrophic, or can be mixotrophic (both autotrophic and heterotrophic)

Protista 17

Excavata

• Subclade Euglenida – Free-living, most freshwater – 2 flagella

• 1 anterior flagellum – Can pull or push

• 1 very reduced

– Most P/S • Can also absorb nutrients across

cell membrane

– Contractile vacuole – Spiral-grooved pellicle replaces

cell wall • Protein strips under cell

membrane

– Photosensitive eyespot • Stay positioned in optimum light

levels

Protista 18

Excavata

• Subclade Kinetoplastida – Parasites

– Kinetoplast inside mitochondrion • Large DNA-protein deposit

– 2 flagella • 1 may be attached to cell

membrane forming undulating membrane

– Ex: trypanosomes • African sleeping sickness,

Chagas disease, leishmaniasis

Protista 19

Excavata

• Clade Diplomonada

– Many parasitic (intestinal)

– Anaerobic

– 2 nuclei

– Multiple flagella

– Ex: Giardia sp. • Giardiasis

Protista; photo From Brooke, MM, Melvin, DM: Morphology of Diagnostic Stages of Intestinal Parasites of Man. Public Health Service Publication No. 1966, 1969, http://www.ncbi.nlm.nih.gov/books/NBK7889/figure/A4205/?report=objectonly

20

Giardia sp.

http://www.cdc.gov/parasites/giardia/images/giardia-banner.jpg

Excavata

• Clade Diplomonada

– Many parasitic (intestinal)

– Anaerobic

– 2 nuclei

– Multiple flagella

– Ex: Giardia sp. • Giardiasis

Protista; http://www.cdc.gov/parasites/giardia/pathogen.html 21

Excavata

• Clade Parabasala

– Many parasitic

– Anaerobic

– Undulating membrane attached to flagellum

– Trichomonas vaginalis • Trichomoniasis

Protista; http://www.cdc.gov/std/trichomonas/stdfact-trichomoniasis.htm 22

Trichomonas vaginalis

SAR

• Very diverse group, phylogeny controversial

• 3 clades

– Stramenopila

– Alveolata

– Rhizaria

Protista 23

SAR

• Clade Stramenopila

• P/S

• “Hairy” flagellum, usually a shorter smooth flagellum as well

• 3 subclades

– Bacillariophyta

– Chrysophyta

– Phaeophyta

Protista 24

SAR/Stramenopila

• Subclade Bacillariophyta

– Diatoms

– Marine and freshwater

– Primary P/S member of marine phytoplankton • Chlorophyll, fucoxanthin

and beta-carotene

– Covered by glassy silica shell • 2 halves; pill box

• Diatomaceous earth

Protista 25

SAR/Stramenopila

• Subclade Bacillariophyta

– Flagella in gametes only

– Mature forms move via secretion released through grooves in shell

Protista 26

SAR/Stramenopila

• Subclade Bacillariophyta

– Reproduction asexual and sexual

• Binary fission most frequent

Protista 27

SAR/Stramenopila

• Subclade Chrysophyta – Golden algae

– Freshwater or marine

– Mixotrophic • P/S

– Chlorophyll, carotenoids, fucoxanthin

• Heterotrophs when light too low

– Glassy silica plates or scales

– May “bloom” in spring or fall • Discolors water

Protista; photo: Frank Fox - http://www.mikro-foto.de; http://creativecommons.org/licenses/by-sa/3.0/de/legalcode

28

Dinobryon: sessile, colonial chrysophyte

SAR/Stramenopila

• Subclade Phaeophyta

– Brown algae (color from olive green to brown)

– All multicellular

• Range from few centimeters to over 30m+ (giant kelps)

– Autotrophs

– Chlorophyll and fucoxanthin

– Cell wall contain cellulose and alginic acid

• Algin harvested for thickener in ice cream, pudding, cosmetics

Protista 29

SAR/Stramenopila

• Subclade Phaeophyta – Large kelps look like plants

but different structure • Holdfast

– Looks like roots, but only anchor, no absorption

• Stipe – Looks like trunk, minimal

vascular tissue

• Blade – Looks like leaves

• Bladders – Hollow, gas-filled for

buoyancy

Protista—picture: Claire Fackler; NOAA Photo Library 30

SAR/Stramenopila

• Subclade Phaeophyta

– Reproductive cycle alternate haploid and diploid forms

Protista 31

SAR

• Clade Alveolata – Have alveoli (alvus = belly)

• Small flattened membrane vesicles just under cell membrane (=pellicle)

• Support membrane

– Tubular membranes inside mitochondria

– 3 subclades • Dinoflagellata

• Apicomplexa

• Ciliophora

Protista 32

SAR/Alveolata

• Subclade Dinoflagellata

– Autotrophs or heterotrophs • Many be mixotrophic

• Some have algal symbionts

– Plates (cellulose) form “shell” under membrane

– Flagella beat within grooves between plates • Make cells spin

• Chloroplasts (P/S forms) have chlorophyll and carotenoids

Protista 33

SAR/Alveolata

• Subclade Dinoflagellata

– Members of marine plankton

– Highly productive

Protista—picture: © Mona Hoppenrath; http://tolweb.org/Dinoflagellates/2445 34

SAR/Alveolata

• Subclade Dinoflagellata

– Some live as symbionts within other species • Jellies, sea anemones, corals,

some sea slugs

• Dino’s in coral

– use waste CO2 and nitrogenous wastes from coral

– Supply 90% of corals food

– Provide color to corals

Protista—picture: © Toby Hudson; http://commons.wikimedia.org/wiki/File:Coral_Outcrop_Flynn_Reef.jpg#mediaviewer/File:Coral_Outcrop_Flynn_Reef.jpg 35

SAR/Alveolata

• Subclade Dinoflagellata

– Bioluminescence

– Red tides • May be toxic to fish, sea

birds

Protista—picture: H. Hillewaert; http://en.wikipedia.org/wiki/Dinoflagellate 36

SAR/Alveolata

• Subclade Apicomplexa

– Animal parasites

– Absorb nutrients across membrane

– Apical complex present at one end of cell

• Protein filaments, microtubles, organelles

• Function in attachment, invasion of host

– Ex: Plasmodium (malaria); Toxoplasma (toxoplasmosis)

Protista 37

SAR/Alveolata

• Subclade Apicomplexa

– Complex life cycle

• Sexual and asexual components

Protista—picture from http://www.niaid.nih.gov/topics/Malaria/P

ages/lifecycle.aspx 38

p. 595

Life Cycle of Plasmodium

SAR/Alveolata

• Subclade Ciliophora – Marine, freshwater, soil – Cilia – Most heterotrophs

• Feed on bacteria and algae

Protista 40

SAR/Alveolata

• Subclade Ciliophora – Contractile vacuoles

– Gullet lined w/cilia for feeding • Food vacuoles • Waste vacuoles

– Trichocysts just under pellicle • Discharge threads when stressed

Protista 41

SAR/Alveolata

• Subclade Ciliophora – Two nuclei

• Macronucleus polyploid – Used in normal cell function

• Micronucleus diploid – Used in reproduction (sexual or asexual)

Protista 42

SAR/Alveolata

• Subclade Ciliophora – Asexual reproduction via binary fission

• Both nuclei replicated and divide via mitosis

– Sexual reproduction • Conjugation

– Cells pair up, form cytoplasmic bridge – Replicate and exchange micronuclei – 1 micronucleus forms macronucleus – Cells undergo binary fission

Protista 43

MEIOSIS

Sexual Reproduction

DIPLOID STAGE

HAPLOID STAGE

FUSION

Diploid micronucleus

Macronucleus

2 1

3

5

4

6 8 7

9

11

10

Figure 27-7, p. 593

Conjugation in Paramecium

SAR

• Clade Rhizaria

• Amoebas

• Stiff filamentous pseudopods

• Many have tests (hard shells)

• We’ll study 2 subclades

– Radiolaria

– Foraminifera

Protista 45

SAR/Rhizaria

• Subclade Radiolaria – 0.01mm to 1mm+

– Heterotrophs • May contain algal

symbionts

– Marine

– Glassy internal skeleton

– Pseudopods supported by microtubules

– Skeletons form sediments, harden into sedimentary rocks

Protista 46

SAR/Rhizaria

• Subclade Foraminifera – Forams

• 0.1 mm to 20 cm long

– Heterotrophs • Some with algal symbionts

– Pseudopods supported by needle-like spine

– Marine

– Some planktonic, most on sandy bottoms and rocks

– Calcium carbonate internal skeleton • Form marine sediments

Protista 47

Archaeplastida

• Closest relatives of land plants

• Plastids show no indication of secondary endosymbiosis

• 2 Clades

– Rhodophyta

– Chlorophyta

Protista 48

Archaeplastida

• Clade Rhodophyta – Red algae – Most marine, most free-living – Multicellular, most small (<1 ft)

• Filamentous or sheetlike forms • Some covered in calcium carbonate (coralline algae)

– Adhesive holdfast

Protista 49

Archaeplastida

• Clade Rhodophyta – Chlorophyll, phycobilins

• Phycobilins allow them to grow deeper than other algae (absorb blue light)

– Complex life cycles involving alternation of diploid sporophytes and haploid gametophytes

– Commercial use • Porphyra used for nori

• Gelidium used for agar

• Chondrus, Gigartina, Eucheuma used for carrageenan

Protista 50

Archaeplastida

Protista 51

• Clade Chlorophyta – Green algae

– Most freshwater; some symbionts • w/fungi (=lichen), sea

anemones, marine snails

– Most microscopic

– Very diverse species

Archaeplastida

• Clade Chlorophyta – Green algae – Most freshwater; some symbionts

• w/fungi (=lichen), sea anemones, marine snails

– Most microscopic – Very diverse species – Diverse life cycles

• Sexual, asexual, or alternate

– Chlorophyll, carotenoids – Nucleic acid sequences, pigments, chloroplasts, food

reserves most similar to land plants

Protista 52

Unikonta

• 2 Clades

– Amoebozoa

– Opisthokonts

• Closely related to Fungi and Animals

Protista 53

Unikonta/Amoebozoa

• Most of the amoebas and plasmodial slime molds

• We’ll study 2 subclades which aren’t plamodial slime molds

– Gymnamoeba

– Entamoeba

Protista 54

Unikonta/Amoebozoa

• Subclade Gymnamoeba

– Amoebas

– Marine and freshwater

– Most free-living

– Lobose pseudopods • unsupported by internal

structure

• Locomotion and feeding

• No fixed body shape

– Contractile vacuole

Protista 55

Unikonta/Amoebozoa

• Subclade Entamoeba – Parasitic

– Entamoeba histolytica • Amoebic dysentery

– Destroys cells lining intestine

– Ulcerations, cramps, bloody diarrhea, foul-smelling stools

– Cysts spread through contaminated food or water

– A leading cause of death in infants and small children in less developed nations

Protista; photo CDC.gov 56

Trophozoite with ingested RBCs

Unikonta/Opisthokonts

• Nucleariida

– DNA evidence indicates close relationship to Fungi

Protista; photo by NEON ja; https://creativecommons.org/licenses/by-sa/2.5/legalcode

57

Unikonta/Opisthokonts

• Choanoflagellida

– DNA evidence indicates close relationship to Animalia

Protista; photo lower left by DH Zanette;,public domain, https://en.wikipedia.org/wiki/Choanoflagellate#/media/File:Sphaeroeca-colony.jpg; photo upper right by Stephen

Fairclough, https://creativecommons.org/licenses/by-sa/2.5/legalcode; picture lower right by Wikipedia user Urutseg, https://creativecommons.org/licenses/by-sa/3.0/legalcode;

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