Post on 31-Dec-2015
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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