Protists KEY CONCEPT Kingdom Protista is the most diverse of all the kingdoms.
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Transcript of Protists KEY CONCEPT Kingdom Protista is the most diverse of all the kingdoms.
Protists
KEY CONCEPT Kingdom Protista is the most diverse of all the kingdoms.
Protists
Protists can be animal-like, plantlike, or funguslike.
• Protists are eukaryotes that are not animals, plants, or fungi.
Protists
• Animal-like protists consume other organisms.
– heterotrophs – single-celled
Protists
• Plantlike protists are photosynthetic.
– single-celled, colonial, or multicellular– no roots, stems, or leaves
Protists
• Funguslike protists decompose dead organisms.
– heterotrophs – can move, whereas fungi cannot
Protists
Protists are difficult to classify.
• Protista is one kingdom in the domain Eukarya.
Protists
• Protist classification will likely change.
– Some protists are not closely related.– Molecular evidence supports reclassification.
Protists
KEY CONCEPT Animal-like protists are single-celled heterotrophs that can move.
Protists
Animal-like protists move in various ways.
• Animal-like protists are often called protozoa.
macronucleus
food vacuole
oral groove
micronucleus
contractile vacuole
cilia
Protists
• Protozoa with flagella are zooflagellates.
– flagella help zooflagellates swim – more than 2000 zooflagellates
Protists
• Some protists move with pseudopods.– change shape as they move – amoebas
Protists
– foraminifera
• Some protists move with pseudopods.– change shape as they move – amoebas
Protists
• 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
Protists
Paramecia have contractile vacuoles to expel excess water. To avoid an obstacle, they back up, and move away in an avoidance reaction.
Protists
Some ciliates remain attached to a surface. Stentor is an example.
Protists
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
Protists
Trypanosoma
Protists
Giardia
Protists
Trichonympha lives with termites, digests wood. • Both species benefit, so this is called mutualism.
Protists
Algae are plantlike protists.Plantlike protists can be single-celled or multicellular.
• Photosynthetic plantlike protists are called algae.
colonycolony
daughter colonydaughter colony
Protists
Volvox daughter colonies leaving the mother colony.
Protists
• 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
Protists
• Euglena moves toward the light, which is known as a positive phototropism.
• Has a red eyespot, which is light sensitive
Protists
• Dinoflagellates are mostly marine plantlike protists.
DinoflagellatesDinoflagellates
– have two flagella – may be bioluminescent – have stiff protective plates – can cause red tide
Protists
Noctiluca scintillans
Protists
• Diatoms are plantlike protists with glasslike shells.
– shells made of silica – produce large amounts of oxygen
Protists
More diatoms
Protists
• 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.
Protists
Red algae is used to make agar, food thickener, and medicine capsules.
Protists
Spirogyra : a type of green algae
Protists
Slime molds and water molds are funguslike protists.
• Slime molds have both funguslike and animal-like traits.– decomposers, like fungi – can move, like animals
Protists
• Slime molds can be plasmodial or cellular.
– Plasmodial slime molds are giant cells with many nuclei.– Cellular slime molds contain independent cells.
Protists
• Water molds are freshwater, funguslike protists.
– one type of water mold caused Great Potato Famine
of Ireland in the 1800’s – made of branching strands of cells – can be parasites of plants or fish