ProtistsChapter 20

Objective:11.0 Classify animals according to type of skeletal structure, method of fertilization and reproduction, body symmetry, body coverings, and locomotion.Examples: skeletal structure - �vertebrates, invertebrates;fertilization- external, internal;�reproduction -sexual, asexual;�body symmetry- bilateral, �radial, asymmetrical;body coverings- feathers, �scales, fur;locomotion- cilia, flagella, �pseudopodia

What is a Protist?Any eukaryote that is not an

animal, plant, or fungusMost are unicellular, but not

allCan be classified as animal-

like, plant-like, or fungus-like

Animal-like Protists (Section12-2)

Heterotrophs4 phyla, based on means of

movement: Zooflagellates – swim through their

aquatic environments using flagella Sarcodines – move via temporary

cytoplasmic projections called pseudopods Ciliates – use _________ for feeding and

movement Sporozoans – do not move on their own;

are parasites

ZooflagellatesCan generally absorb food

through their cell membranes Nutrients from decaying organic

matter in water From the bodies of other

organisms in which they liveReproduction can be asexual

by mitosis and cytokinesis, or sexual by meiosis.

SarcodinesPseudopods are used for feeding

and movement.EX: amoebasReproduce asexually by mitosis

and cytokinesis

Source: http://www.enchantedlearning.com/subjects/protists/amoeba.shtml

CiliatesCilia are short hair-like projections.The rapid beating of cilia propels

ciliates through water.Most ciliates contain two different

nuclei: Macronucleus – keeps multiple copies of the

genes Micronucleus – contains a “reserve” copy of

all the cell’s genesObtain food by using cilia to sweep food

into an indentation called the gulletReproduce asexually by _____ and _____, and

sexually by conjugation.

Paramecium

Source: http://rookc.pbworks.com/w/page/46197520/Paramecium

Sporozoans

Live as parasites on everything from worms to humans

Reproduce by sporozoites

Protists and Disease

Malaria – caused by the sporozoan Plasmodium; spread by mosquito bites

African sleeping sickness – caused by zooflagellate Trypanosoma; spread by tsetse fly bites

Amebic dysentery – caused by parasitic Entamoeba

Dysentery – flagellate Giardia

Plant-Like Protists: Unicellular Algae(Section 20-3)

Contain chlorophyll and carry out photosynthesis

Commonly called “algae”Seven major phyla, classified

according to a variety of cellular characteristics (types of chlorophyll or accessory pigments present): First 4 phyla are unicellular Last 3 contain many multicellular

organisms

1. EuglenophytesPlant-like, but have 2 flagella

(like ???) and no cell wallEyespot – cluster of reddish

pigment that helps organism find sunlight

Reproduce asexually by binary fission

Source:http://www.fcps.edu/islandcreekes/ecology/euglena.htm

2. Chrysophytes“yellow plants”Includes yellow-green and

golden-brown algaeChloroplasts contain bright

yellow pigment

3. DiatomsProduce thin, delicate cell

walls rich in silicon (Si) – the main component of glass.

Look like etched petri dishes

Source: http://deepbluehome.blogspot.com/2011/01/psychedelic-diatoms.html

4. DinoflagellatesAbout half are photosynthetic;

others are heterotrophs2 flagella, which wrap around

the the organism in groovesReproduce asexually by binary

fissionCan luminesce when agitated

Source:http://biology.unm.edu/ccouncil/Biology_203/Summaries/Protists.htm

Source:http://www.asknature.org/strategy/d851e35113506bcf0219e973da169c29

Ecology of Unicellular AlgaeCompose most of the

phytoplankton – plant microorganisms at the bottom of food chains

Algal blooms (“red tide”) – Protists can break down sewage in

waterExcessive waste creates large

populations of euglenophytes, which deplete nutrients in the water.

When they die, they can deplete oxygen supplies needed by other organisms.

Plant-like Protists: Red, Brown, and Green Algae (Section 20-4)

Mostly multicellularReproductive cycles similar to

plantsMany with cell walls and

photosynthetic pigments identical to plants

Red AlgaePhylum Rhodophyta (“red

plants”)Contain chlorophyll and reddish

accessory pigments called phycobilins, which can absorb blue light, allowing them to harvest light energy at great depths

Can actually be green, purple, or redish-black in color

Play a role in coral reef formationLack flagella and centrioles

Brown AlgaePhylum Phaeophyta (“dusky

plants”)Contain chlorophyll and c, as

well as a brown accessory pigment (fucoxanthin)

Dark yellow-brown colorEX: giant kelp

Source:http://landsat.gsfc.nasa.gov/news/news-archive/sci_0033.html

Green AlgaePhylum Chlorophyta (“?????”)Same photosynthetic pigment

and cell wall composition as plants

Contain chloroplast a and bLife cycles of many include

both a diploid and a haploid generation (“alternation of generations”)

Alternation of Generation

Source: http://moodle.rockyview.ab.ca/mod/book/view.php?id=58103&chapterid=21008

Fungus-like Protists(Section 20-5)

FungiBoth

Fungus-likeProtists

Cell walls made of chitin

Have centrioles

Heterotrophs;Absorb nutrients from dead/decaying matter

MoldsSlime Molds:

Cellular slime molds – individual cells remain distinct (separated by cell membranes) throughout life

Acellular slime molds – pass through a life stage in which cells fuse to form large cells with many nuclei

Water Molds: Thrive on dead or decaying matter in water

OR are plant parasites on land EX: white fuzz on a dead fish in the water