Chapter 11Protists
Protista (Protists)
Some are too tiny to be seen without a microscope while others are meters long
Some are like animals, plants or fungi
General Characteristics
All are eukaryotic, have nuclei
Most are single celled but some are multi cellular
Scientists believe more complex organisms originated from protists
Protists
Producers- get food through photosynthesis
Consumers- get food from other sources
Grouped by how they get food into 3 groups
Funguslike Protists
Get food from dead organic matter
Secrete juices into the food source and absorb the digested nutrients
Reproduce like fungus
Slime Mold
Thin masses of living matter
Colorful, shapeless globs of slime
Live as single celled organisms, but congregate in times of stress
Slime molds
Live in cool, shady moist places in the woods and fresh water
Eat bacteria, yeast, small bits of decaying plants and animal matter
Unfavorable Conditions
Slime molds develop stalk-like structures with rounded knobs at the top (spores)
The spores can survive a long time without nutrients until conditions improve
Water Molds
Most are small and single celledLive in water, moist soil or other organismsDecomposers or parasitesCaused the Great Potato Famine
Plantlike Protists
Producers
Algae (alga) have chlorophyll (pigment for photosynthesis) and other pigments
Almost all live in water
Seaweed or Kelp
Multicellular algae
Live near the shore
Can grow to be
meters in length
Phytoplankton
Single celled algae
Usually float near the surface
Produce most of the world’s oxygen
Divided into phyla based on color and cell structure
Algin and Carageenan
2 substances extracted from algae used in many foods
Including ice cream , salad dressing, jelly beans and instant pudding
Volvox
An example specimen of green algae
Single celled but live in colonies
You will see in lab
Diatoms
Single celled, unusual shapes
Found in salt and fresh water
Contain silica (a glass-like substance) and cellulose
Used in tooth paste and silver polish
Dinoflagellates
Single celled, live primarily in salt water, Have 2 flagella, whip-like strand used for movementSome are red and produce a poison which can cause red tides If fish eat enough of the poison, they can be toxic to humans
Euglenoids
Single celled, live in fresh water, characteristics of plants and animalsUse photosynthesis and consume foodHave one flagella (whip-like tail) and contractile vacuoles
Animal-like Protists
Protozoa
Grouped into 4 categoriesAmoebalike protists
Flagellates
Cilliates
Spore forming protists
Amoebalike protists
Soft jelly-like, contractile vacuolesMove with psuedopodia (false feet)Feed by engulfing foodInclude Foraminiferans and Radiolarians (amoeba like with shells)
Flagellates
Flagella for movementParasitesGiardia lamblia found in water, affects hikers when drinking untreated waterAnother lives in the guts of termites to help them digest the cellulose in wood
Cilliates
Most complex protozoans
Covered in tiny hair-like projections called cillia
used for movement and feeding
Best known is Paramecium
Spore-Forming Protists
Parasites, no cillia or flagella present so they can’t move on their own
Have complicated life cycles
Malaria caused by Plasmodia vivax
Reproduction of Protists
Asexual – one parentFission- dividing of parent into 2 organismsEuglena and Amoeba
Sexual – 2 parentsConjugation – swap DNA and then divideParamecium
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