Protists

BiologyChapter 20

20-1: The Kingdom Protista

Protista: Greek: “the very first”

What is a Protist?

Most diverse kingdom Protist may be:

Unicellular or multicellular Microscopic or very large Autotrophic or heterotrophic

Protists are eukaryotes that are not members of the kingdom Plantae, Animalia, or Fungi

There is no “typical protist”

PROTISTS

ENDOSYMBIONT THEORY Early eukaryotes developed symbiotic

relationships with prokaryotic cells Prokaryotic cells lived inside

eukaryotic cells Over time, the smaller prokaryotic

cells evolved with the eukaryotic cells to become mitochondria and chloroplasts

Evolution of First Eukaryote(s)

Forces leading to eukaryote Increases in size Increases in complexity

Mechanisms Infolding of cell membrane Serial endosymbiosis of

membrane-bound organelles

Classification of Protist

3 basic types based on how they obtain their nutrients Protozoa

Animal-like All unicellular

Plantlike Resemble plants because they are autotrophs Do not have roots, stems, and leaves

Funguslike protist Resemble fungi because they decompose dead

organisms

PROTIST CLASSFICATION

Separated by feeding habits (nutrition) Autotrophic

Able to make own food Photosynthetic – 30-40% of all

photosynthesis worldwide is done by algae Heterotrophic

Must eat other material Unicellular May be predators, decomposers, or

parasites

PROTISTS

ANIMAL LIKE PROTISTS = PROTOZOA Classified by method of movement

PLANT LIKE PROTISTS = ALGAE Classified by pigment color

FUNGUS LIKE PROTISTS = MOLDS Classified by body form

Watch video on Protists

http://www.youtube.com/watch?v=-zsdYOgTbOk&feature=player_detailpage

20-2: Animal-like Protists: Protozoans

Protozoan: “first animals”

What is a Protozoan?

All are unicellular heterotrophs Feed on other organisms or dead matter

Typically reproduce asexually but can reproduce sexually

Grouped by method of movement (4) Zooflagellates: flagella Sarcodines pseudopods Ciliates: cilia Sporozoans :non-motile: do not move

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Protozoans

•classified by the 4 ways they move:1) CiliaCilia -

2) Flagellum(a)Flagellum(a) -

•Coordinated movement between individual cilia

•Back and forth wave motion

tiny beating hair-like structures

whip-like tail(s)

3) Pseudopodia -Pseudopodia -

Protozoans•classified by the 4 ways they move:

projection of cytoplasm that sticks out like a foot (“false foot”)

4) Sessile Sessile - No locomotion (_________)movement

Phylum Zoomastigina

Often called flagellates because they move using 1 or 2 flagella

Absorb food by diffusion through cell membrane

Live off of dead or decaying organic matter or some are parasites

Reproduce asexually by mitosis and cytokinesis

Sexually by meiosis

Trichonympha lives in the gut of termites and helps termite digest cellulose in wood.

symbiotic relationship: MUTUALISM

Trichonympha

One flagellate, Trypanosoma, causes African Sleeping Sickness

Every day, about 100 people die from the disease.

1) Infected Tsetse fly bites human,

2) Trypanosoma enters blood stream, causes lethargy, swollen lymph nodes,

3) effects central nervous system and causes death if not treated.

Every day, about 100 people die from the disease.

Trypanosoma

Giardia

Giardiasis: transmission by contaminated water Causes diarrea and vomiting ALWAYS BOIL WATER WHEN CAMPING: boiling

water will kill giardia

PHYLUM SARCODINA Live in moist places (most live in saltwater) irregular shape Amoeboid movement - move by pushing out

extensions of cytoplasm called pseudopodia (false foot)

Plasmolemma – elastic cell membrane NO cell wall Cytoplasm is divided into ectoplasm and

endoplasm Nucleus, contractile vacuole, food vacuole During extreme conditions some form cysts Example: Amoeba proteus

Amoeba proteus: quiz

Know all structures and their functions!

Endoplasm

Ectoplasm

Ameoboid movement

Click on the link below to watch ameoboid movement

http://www.youtube.com/watch?v=PsYpngBG394&feature=player_detailpage

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Amoeba proteus feeding sequence psuedopodia surround and engulf food particle process called phagocytosis

Watch video of amoeba feeding

http://www.youtube.com/watch?

v=W6rnhiMxtKU&feature=player_detailpage

Foraminferans and HelizoansShelled Sarcodines

Ciliates

Phylum Ciliophora Live in any aquatic habitat Use cilia for feeding and movement Examples

Paramecium Typically undergoes asexually but can

undergo conjugation (exchange of genetic material)

PHYLUM CILIOPHORA Ciliates – found in fresh and salt water;

usually free-living, most are larger than other protozoa

Pellicle, cilia, ectoplasm, endoplasm, food vacuole, contractile vacuole

Micronucleus (exchanged during conjugation)

Macronucleus (controls daily functions)

PHYLUM CILIOPHORA

TRICHOCYSTS – spindle shaped alternating between bases of cilia; used as anchor and to paralyze prey

Oral groove – shallow furrow on one side of cell used to gather food

Locomotion – cilia; avoiding reaction contact with unfavorable conditions and will move away

Reacts to contact, temperature, gravity, water currents, electric currents, acidity and other chemicals

Paramecium caudatumParamecium caudatum

Know each term in the diagram

Anal pore

Reproduction Mitosis every 6-12

hours Conjugation –

become sticky and adhere to each other at oral groove and exchange nuclear material

Example = paramecium

1

2

3 45

6

7

8

910

Quiz yourself

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Paramecium movement

•Unicellular, slipper-shaped•move by coordinated beating of many cilia

Watch a paramecium feeding

http://www.youtube.com/watch?feature=player_detailpage&v=zS0f82ZJtvk

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Paramecium: food to waste pathway

Undulating membrane in groove (ciliary)

Oral groove on surface

Macronucleusw/ micronuclei

behind

Cilia

Contractile vacuoles

Site of cell “anus”Food particles

Food vacuoles

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Paramecium reproduction

1. Binary fission (________)asexual

N =nucleus

F =Fission plane

2. Conjugation (________)sexual

•Paramecium reproduction

•Form structure called conjugation tube to exchange genetic material•Micronucleus is exchanged

Watch a paramecium reproducing

http://www.youtube.com/watch?v=K0ZP8VtxUZ0&feature=player_detailpage

Sporozoans

Most produce spores All are parasites Found in blood or intestines Example

Plasmodium Genus that causes malaria in humans Transmitted by female Anopheles

mosquitoes More than 300-500 million people have

malaria & 1.5-2.7 million die of malaria every year

Chloroquine: drug used to treat malaria BUT……..

Toxoplasma (not in book)

Cryptosporidium (not in book)

Can be a problem in public splash areas