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Ch 19: Kingdom Protista
Protists can be animal-like, plantlike, or funguslike.
•
Protists
are eukaryotes that are not animals, plants, or fungi.
Ch 19: Kingdom Protista
•
Animal-like protists
consume other organisms.
–
heterotrophs–
single-celled
Ch 19: Kingdom Protista
•
Plantlike protists
are photosynthetic.
–
single-celled, colonial, or multicellular–
no roots, stems, or leaves
Ch 19: Kingdom Protista
•
Funguslike
protists
decompose dead organisms. –
heterotrophs
–
can move, whereas fungi cannot
Ch 19: Kingdom Protista
Protists are difficult to classify.
•
Protista is one kingdom in the domain Eukarya.
Ch 19: Kingdom Protista
•
Protist classification will likely change. –
Some protists
are not closely related.
–
Molecular evidence supports reclassification.
Ch 19: Kingdom Protista
KEY CONCEPT Animal-like protists are single-celled heterotrophs that can move.
Ch 19: Kingdom Protista
Animal-like protists move in various ways.•
Animal-like protists
are often called protozoa.
macronucleus
food vacuole
oral groove
micronucleus
contractile vacuole
cilia
Ch 19: Kingdom Protista
•
Protozoa with flagella are zooflagellates.–
flagella help zooflagellates
swim
–
more than 2000 zooflagellates
Ch 19: Kingdom Protista
•
Some protists
move with pseudopods.– ��change shape as they move – amoebas
Ch 19: Kingdom Protista
–
foraminifera
•
Some protists
move with pseudopods.– ��change shape as they move – amoebas
Ch 19: Kingdom Protista
•
Some protozoa move with cilia.
macronucleus
food vacuole
oral groove
micronucleus
contractile vacuole
cilia
– cilia help protists
swim and capture food– more than 8000 ciliates
Ch 19: Kingdom Protista
Some animal-like protists cause disease.•
Protists
cause some well-
known infectious diseases. sporozoiteshuman liver
liver cells
developedparasites
red bloodcells
•
Malaria is caused by Plasmodium and spread by mosquitoes.
•
Sleeping sickness is caused by Trypanosoma and spread by flies.
•
A giardia
infection is caused by Giardia and spread through water.
Malaria Infection
Ch 19: Kingdom Protista
Plantlike protists can be single-celled or multicellular.•
Photosynthetic plantlike protists
are called
algae.
colonycolony
daughter colonydaughter colony
Ch 19: Kingdom Protista
•
Euglenoids
are a large group of plantlike protists.
pellicle
nucleus
chloroplast
eye spot
contractilevacuole
flagellum
– mostly photosynthetic – some heterotrophic – single-celled – one or two flagella
Ch 19: Kingdom Protista
•
Dinoflagellates
are mostly marine plantlike protists.
DinoflagellatesDinoflagellates
– have two flagella – may be bioluminescent – have stiff protective plates – can cause red tide
Ch 19: Kingdom Protista
•
Diatoms are plantlike protists
with glasslike shells. – shells made of silica – produce large amounts of oxygen
Ch 19: Kingdom Protista
•
Multicellular algae are classified by their pigments.
–
Green algae contain chlorophyll a and b.
–
Brown algae contain chlorophyll c.
–
Red algae contain chlorophyll a and phycoerythrin.
Ch 19: Kingdom Protista
Many plantlike protists can reproduce both sexually and asexually.
•
All algae can reproduce asexually. –
Multicellular algae can fragment.
–
Chlamydomonas divides into zoospores.
Ch 19: Kingdom Protista
•
Some algae produce sexually. – Some species alternate generations.–
Sexual reproduction can be triggered by environmental stress.
Ch 19: Kingdom Protista
Slime molds and water molds are funguslike protists.•
Slime molds have both funguslike
and animallike
traits.
–
decomposers, like fungi –
can move, like animals
Ch 19: Kingdom Protista
•
Slime molds can be plasmodial
or cellular.
– Plasmodial
slime molds are giant cells with many nuclei.– Cellular slime molds contain independent cells.