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Protista

The “Leftovers” Kingdom

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General Characteristics

All contain a nucleus in each cell Most live in watery environments Most are single-celled organisms Most live as individual cells but many live

as a colony ( a number of relatively independent cells of the same species that are attached to one another)

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General Characteristics

Evolved ~ 1.5 billion years ago Some are autotrophs, some are

heterotrophs and some can be either Three general categories

Animal-likePlant-likeFungus-like

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Animal-like Protists

Also called protozoa (= first animals)

Characteristics of: Nucleus No cell wall Heterotrophs Most can move

4 types:SarcodinesCiliatesZooflagellatesSporozoans

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Sarcodines

Characterized by extensions of the cell membrane and cytoplasm known as pseudopods (pseudopod = false foot)

Pseudopods are used to capture and engulf particles of food and to move from one place to another

Sarcodines Feed by the process of phagocytosis

6Illustration modified from public domain image http://commons.wikimedia.org/wiki/File:Amoeba_fagocitose.jpg

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Sarcodines – with Shells

Many sarcodines have shells (also called tests)

The shells must have openings that allow the pseudopods to extend out

These shells are part of limestone, marble and chalk

Two examples of shelled sarcodines are foraminiferans and radiolarians

Sarcodines -Foraminiferans

Although they are unicellular, these shelled ameboids can be seen without a microscope.

They typically are less than 1mm in diameter, but some found on the deep ocean floor*, may reach 20 cm in diameter**.

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FYI: *Commonly found on the Abyssal plains, at depths of up to 6.6 miles. ** Among the largest known unicellular organisms.

Foraminifera "Star sand" Hatoma Island – Japan

Photo by Psammophile http://en.wikipedia.org/wiki/File:2085f_Japon_Hatoma.jpg

Their shells are made of calcium carbonate or organic materials.

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Sarcodines – Foraminiferans

Tests of foraminifera extracted sand from the beach of Ngapali (Myanmar)

Photo by: Psammophile http://en.wikipedia.org/wiki/File:Foraminif%C3%A8res_de_Ngapali.jpg

SEM micrographs of four benthic foraminiferans from the USGS

(Public Domain: http://en.wikipedia.org/wiki/File:Benthic_foraminifera.jpg )

FYI: Benthic means bottom dweller.

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Sarcodines – Foraminiferans

Live Ammonia tepida benthic foraminiferan

collected from San Francisco Bay. Phase-contrast photomicrograph by Scott Fay, UC

Berkeley, 2005.http://en.wikipedia.org/wiki/File:Ammonia_tepida.jpg

Ammonia beccarii , benthic forams collected in 2011 on the edge of the

Belgian part of the North Sea.Photo by: Hans Hillewaert

http://en.wikipedia.org/wiki/File:Ammonia_beccarii.jpg

Sarcodines - Radiolarians

Radiolarians are zooplankton that have a mineral skeleton containing silica

Their skeletons can be very elaborate.

They range in size from 0.1-0.2 mm in diameter. Illustration by Ernst Haeckel, 1904, Public Domain http://

en.wikipedia.org/wiki/File:Haeckel_Spumellaria.jpg

11FYI: Plankton are organisms that float in the ocean.

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Sarcodines - Radiolarians

Various RadiolariaPhoto by: Luis Fernández García http://commons.wikimedia.org/wiki/File:Radiolaria_varios.jpg

REM(Reflection Electron Micrograph) of a RadiolarianPhoto by Hannes Grobe/AWI http://commons.wikimedia.org/wiki/File:Radiolaria_hg.jpg

Skeleton of a polycystine radiolarianPublic Domain: NASA

http://en.wikipedia.org/wiki/File:Radiolarian.png

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Sarcodines – Amebas (or Amoeba)

Reproduce by binary fission (the same as bacteria) – one cell divides into two

Respond to light and certain chemicals by moving away

Because they live in fresh water they have a special structure, the contractile vacuole, that pumps excess water out of the cell. Water diffuses in by osmosis and must be actively pumped out or the cell would burst.

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Sarcodines - Ameba

1. Cytoplasm

2. Nucleus

3. Contractile Vacuole

4. Cell Membrane

5. Food Vacuole

6. Pseudopods

Racette

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Sarcodines - Amebas

Amoeba proteusPhoto by Cymothoa exigua

http://commons.wikimedia.org/wiki/File:Amoeba_proteus.jpg

Chaos carolinensis

a species of giant ameba (up to 5mm)Photo by: Dr.Tsukii Yuuji

http://pl.wikipedia.org/wiki/Plik:Chaos_carolinense.jpg

Ameba Videos

Ameba in motion https://www.youtube.com/watch?v=7pR7TNzJ_pA

Ameba feeding

https://www.youtube.com/watch?v=W6rnhiMxtKU

https://www.youtube.com/watch?v=x1ErCyZCFw8

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Ciliates

All have cilia – small hair-like projections on the outer surface of the cell

Cilia do three things Act like tiny oars to help these organisms

moveSweep food particles towards themselvesAct as tiny sensors

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Ciliates Have two nuclei

Large nucleus (Macronucleus) controls cell functions

Small nucleus (Micronucleus) controls the process of conjugation

Conjugation – two ciliates (same species) temporarily join and exchange part of their DNA

Conjugation is followed by binary fission

Ciliate undergoing binary fissionPhoto by TheAlphaWolf

http://en.wikipedia.org/wiki/File:Unk.cilliate.jpg

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Ciliates - Paramecium

Paramecium caudatumPhoto by Deuterostome

http://en.wikipedia.org/wiki/File:Paramecium_caudatum_Ehrenberg,_1833.jpg

Paramecia, illustrated by Otto Müller, 1773.

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Ciliates - Paramecium

Pellicle – the cell membrane and underlying structures that give the organism its shape; without the pellicle a paramecium would look like a hairy ameba

Gullet – a funnel-like structure that captures food into food vacuoles

Oral Groove – guides food to the gullet Anal Pore – empties wastes out of the cell

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Ciliates - Paramecium

Have contractile vacuoles to pump out water; look a bit like a flower

Video: https://www.youtube.com/watch?v=mTXRcbjuYGU

Part of a photo by Barfooz http://commons.wikimedia.org/wiki/File:Paramecium.jpg

C.V.

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Ciliates - Paramecium

Illustration modified from Public Domain image http://commons.wikimedia.org/wiki/File:Paramecium_sp.jpg

Other Ciliates

Blepharisma japonicumPhoto by Frank Fox  (www.mikro-foto.de) on http://

en.wikipedia.org/wiki/Blepharisma

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Tetrahymena thermophilaPhoto Source: Ciliate Genome Sequence Reveals Unique Features of a Model Eukaryote. Robinson R, PLoS Biology Vol. 4/9/2006, e304. doi:10.1371/journal.pbio.0040304 (Creative Commons License)

VorticellaPhoto by Frank Fox  (www.mikro-foto.de) at

http://commons.wikimedia.org/wiki/File:Mikrofoto.de-Vorticella_7.jpg

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Other Ciliates - Stentor

A composite image of Stentor roeseli This work has been released into the public domain by its author, Protist Image Database

http://en.wikipedia.org/wiki/File:Stentor_roeseli_composite_image.jpg

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Zooflagellates

Flagellates are protists that move by means of a flagellum, a long, whip-like structure. They may be animal-like, plant-like or fungus-like.

Zooflagellates are animal-like flagellates.

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Zooflagellates

Usually have 1-8 flagella, depending on the species

Many live inside the bodies of animals (they are symbiotic).Some are mutualistic – for example those that

live in the gut of the termite and digest woodMany are parasitic – Examples include

Typanosoma sp. (causes African Sleeping Sickness) and Giardia

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ZooflagellatesGiardia

Public Domain: Centers for Disease Control and Preventionhttp://en.wikipedia.org/wiki/File:Giardia_lamblia_SEM_8698_lores.jpg

Trypanosoma evansiPhoto by Alan R Walker

http://commons.wikimedia.org/wiki/File:Trypanosoma-evansi.jpg

 False color SEM of Trypanosoma brucei (found in the gut of the

tsetse fly host)Photo by Zephyris

http://commons.wikimedia.org/wiki/File:TrypanosomaBrucei_ProcyclicTrypomastigote_SEM.jpg

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Sporozoans

All are parasites that feed on the cells and body fluids of their host animals

Many have complex life cycles with more than one host

Each forms a spore during some part of their life cycle that enables it to be passed from host to host

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Sporozoans - Plasmodium Several different species of Plasmodium

cause the disease malaria.

They are transmitted only by Anopheles mosquitos.

FYI: According to the WHO, there were an estimated 207 million cases of malaria in 2012 (uncertainty range: 135 – 287 million) and an estimated 627 000 deaths (uncertainty range: 473 000 – 789 000). Ninety percent of all malaria deaths occur in sub-Saharan Africa, 75% of whom were children under the age of five.

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Plasmodium Life Cycle

Mosquito bites human injecting spores

Spores travel to the liver

Infect liver cells, multiply and burst out

Sporozoans infect red blood cell and multiply

Red blood cells burst releasing sporozoans that then infect more RBCs

Mosquito bites human and drinks infected blood

Sporozoans develop in the mosquito’s gut

Each sporozoan divides to form many spores

Spores move to the mosquito’s mouth

Female Anopheles albimanus mosquito, transmits malaria in Central America

Mosquito Photo Credit: James Gathany, CDC http://en.wikipedia.org/wiki/File:Anopheles_albimanus_mosquito.jpg

Liver and Blood cell diagrams part of Public Domain image from NIHhttp://sw.wikipedia.org/wiki/Picha:MalariacycleBig.jpg

In Human Host

In Mosquito Host