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
Protists
Chapter 20
What is a Protist?
 Any
eukaryote that is not an animal,
plant, or fungus
 Most are unicellular, but not all
 Can be classified as animal-like,
plant-like, or fungus-like
Animal-like Protists
(Section12-2)
 Heterotrophs
4
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
Zooflagellates
 Can
generally absorb food through
their cell membranes
 Nutrients
from decaying organic matter
in water
 From the bodies of other organisms in
which they live
 Reproduction
can be asexual by
mitosis and cytokinesis, or sexual by
meiosis.
Sarcodines
 Pseudopods
are used for feeding and
movement.
 EX: amoebas
 Reproduce asexually by mitosis and
cytokinesis
Source:
http://www.enchant
edlearning.com/subj
ects/protists/amoeba
.shtml
Ciliates
 Cilia
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 genes
 Obtain
food by using cilia to sweep food into
an indentation called the gullet
 Reproduce 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. Euglenophytes
 Plant-like,
but have 2 flagella (like ???)
and no cell wall
 Eyespot – cluster of reddish pigment that
helps organism find sunlight
 Reproduce asexually by binary fission
Source:http://www.fcps.edu/islan
dcreekes/ecology/euglena.htm
2. Chrysophytes
 “yellow
plants”
 Includes yellow-green and goldenbrown algae
 Chloroplasts contain bright yellow
pigment
3. Diatoms
 Produce
thin, delicate cell walls rich
in silicon (Si) – the main component
of glass.
 Look like etched petri dishes
Source:
http://deepbluehome.
blogspot.com/2011/0
1/psychedelicdiatoms.html
4. Dinoflagellates
 About
half are photosynthetic;
others are heterotrophs
 2 flagella, which wrap around the
the organism in grooves
 Reproduce asexually by binary
fission
 Can luminesce when agitated
Source:http://biology.un
m.edu/ccouncil/Biology_
203/Summaries/Protists
.htm
Source:
http://w
ww.ask
nature.
org/stra
tegy/d8
51e351
13506b
cf0219
e973da
169c29
Ecology of Unicellular Algae
 Compose
most of the phytoplankton –
plant microorganisms at the bottom of
food chains
 Algal blooms (“red tide”) –
 Protists
can break down sewage in water
 Excessive 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
multicellular
 Reproductive cycles similar to plants
 Many with cell walls and
photosynthetic pigments identical to
plants
Red Algae
 Phylum
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 formation
 Lack flagella and centrioles
Brown Algae
 Phylum
Phaeophyta (“dusky
plants”)
 Contain chlorophyll
and c, as well
as a brown accessory pigment
(fucoxanthin)
 Dark yellow-brown color
 EX: giant kelp
Source:http://landsat.gsfc.nasa.gov/news/newsarchive/sci_0033.html
Green Algae
 Phylum
Chlorophyta (“?????”)
 Same photosynthetic pigment and
cell wall composition as plants
 Contain chloroplast a and b
 Life cycles of many include both a
diploid and a haploid generation
(“alternation of generations”)
Alternation of Generation
Source:
http://moodle.rockyvi
ew.ab.ca/mod/book/v
iew.php?id=58103&c
hapterid=21008
Fungus-like Protists
(Section 20-5)
Fungi
Both
Cell
walls
made of
chitin
Fungus-like
Protists
Heterotrophs;
Absorb
nutrients from
dead/decaying
matter
Have
centrioles
Molds
 Slime
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