protists and fungi
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Protists and fungi. Chapters 19 and 20. Origin of Eukaryotic Cells. Endosymbiotic Theory The eukaryotic cell probably originated as a community of prokaryotes 2 billion years ago. - PowerPoint PPT PresentationTRANSCRIPT
PROTISTS AND FUNGIChapters 19 and 20
Origin of Eukaryotic Cells Endosymbiotic Theory
The eukaryotic cell probably originated as a community of prokaryotes 2 billion years ago.
The nucleus and endomembrane system of organelles probably evolved from infoldings of the plasma membrane of ancestral prokaryotes.
Mitochondria and chloroplasts probably evolved from symbiotic prokaryotes that took up residence inside larger prokaryotic cells.
If prokaryotes were the first cells, how did eukaryotes evolve?
Connection to Evolution
Plasma membrane Cytoplasm
Ancestral prokaryote Cell with nucleus and endomembrane system
Endoplasmic reticulum NucleusNuclearenvelope
Aerobic heterotrophicprokaryote
Somecells
Ancestral host cell Photosyntheticeukaryotic cell
MitochondrionPhotosyntheticprokaryote
MitochondrionChloroplast
KINGDOM PROTISTA
DOMAIN EUKARYA
Domain Eukarya Kingdom Protista Characteristics of a Protist:
Often characterized by what they are NOT Not animals, plants, or fungi Diverse group of 200,000 organisms Cell type: EUKARYOTES Mode of Nutrition: Heterotrophs and
autotrophs Habitat: water or moist soil; some live in
animals causing disease
Categorizing Protists
1) Animal-like (Protozoans)2) Plantlike (Algae)3) Fungus-like (Slime mold &
mildew)
Protozoa Animal-like heterotrophs
Four Phlya: Phylum Ciliophora: Use cilia for motion Phylum Sarcodina: Use pseudopods for
motion Phylum Apicomplexa: Use spores for
motion Phylum Zoomastigina: Use flagella for
motion
Kingdom Protista Phylum Ciliophora AKA: Ciliates Use short, hair-like projections to move
through fluids and move food particles into the cell
7000 species of ciliates Abundant in oceans, lakes, and rivers Example: Paramecium caudatum
Kingdom Protista Phylum Sarcodina Animal-like protists that use pseudopods
for feeding and locomotion Pseudopod: false foot; a temporary
extension of cytoplasm that surrounds and envelops smaller organisms, forming a food vacuole
Example: Amoeba
AKA: Sporozoans Produce spores
(reproductive cells) during their life cycle
Parasitic and move as their hosts move
Hosts transmit the spores to new hosts
Example: Plasmodium (malaria)
Kingdom Protista Phylum Apicomplexa
AKA: Zooflagellates Use flagella to move Cause American and African sleeping
sicknesses Example: Trypanosoma
Infects a tsetse fly which transmits disease to humans
Kingdom Protista Phylum Zoomastigina
Algae Plant-like protists because they contain photosynthetic
pigments Found in bodies of water Can be unicellular or multicellular Unicellular Phyla:
Phylum Bacillariophyta: Diatoms Phylum Pyrrophyta: Dinoflagellates Phylum Euglenophyta: Euglenoids Phylum Chrysophyta: Chrysophytes (colonies)
Multicellular Phyla: Phylum Phaeophyta: Brown Algae Phylum Chlorophyta: Green Algae Phylum Rhodophyta: Red Algae
Kingdom Protista Plant-like Examples
Diatoms Unicellular Photosynthetic autotrophs using chlorophyll
(green pigment) and carotenoids (golden pigment)
Store food as oil, which is less dense that water
Float near the surface of water where they can absorb energy from the Sun for photosynthesis
Kingdom Protista Plant-like Examples
Dinoflagellates Unicellular Have two flagella at right angles to one
another Cause the organism to spin as they move
through the water Some are photosynthetic autotrophs and
others are heterotrophs Some use red pigment for photosynthesis,
which cause red tides during blooms Produce dangerous toxins
Kingdom Protista Plant-like Examples
Green Algae Unicellular and multicellular Use chlorophyll for photosynthesis Have cell walls and store food as
carbohydrates Most are found in freshwater
Kingdom Protista Fungus-Like Examples
AKA: Slime molds Similar to fungus:
Use spores to reproduce Feed on decaying organic
matter and absorb nutrients through their cell walls
Different from fungus: Fungi cell walls contain
chitin, a complex carbohydrate.
Slime mold cell walls contain cellulose.
Protists are mainly unicellular. How did multicellular organisms evolve?
Connection to Evolution
Evolution of Multicellular Organisms Multicellular organisms probably evolved
from colonial protist cells becoming specialized
Multicellular life has diversified over hundreds of millions of years
Unicellularprotist
1
Colony
2
Early multicellular organism withspecialized, interdependent cells
Locomotorcells
Food-synthesizingcells
Somaticcells
3
Later organism thatproduces gametes
Gamete
Evolution of Multicellular Organisms
Multicellular life first arose over a billion years ago All life was
aquatic until almost 500 million years ago
Multicellular organismscolonize landDiverse multicellular algae, fungi,and animals, all living in the sea
Mass extinctions
Earliest animals; manymulticellular algae
Oldest known fossils ofmulticellular eukaryotes(small algae)
Earliest multicellular eukaryotes?
Age
of f
ossi
ls in
mill
ions
of y
ears
PREC
AM
BR
IAN
ER
APA
LEO
ZOIC
ERA
KINGDOM FUNGI
DOMAIN EUKARYA
Characteristics of Fungi Diverse – over 100,000 species
have been identified Some are mutualistic organisms Others are parasites
Some are predators
Others are decomposers of dead organisms
Characteristics of Fungi Type of cell: eukaryote Mode of nutrition: heterotroph Number of cells:
Most are multicellular Yeasts are unicellular
Cell structure: cell wall composed of chitin
Unique Fungi Characteristics Hyphae: long chains of
cells; threadlike filaments that make up the body of the fungus
Mycelium: netlike mass of hyphae; sometimes underground
Fruiting body: fungus seen above ground; example-mushroom
Structure of a Fungus
Nutrition in Fungus All fungi are heterotrophs, but there are three
types of fungi that differ in how they obtain nutrients. Saprophytic fungi: DECOMPOSER
Feed on dead organisms or organic wastes Return nutrients to the food chain
Parasitic fungi: absorb nutrients from the living cells of a host organism
Mutualistic fungi: WORK TOGETHER Example: Soybean root fungus receives sugar from the
soybean root and helps the root to increase water and mineral uptake.
Phyla of Fungi
1 2 3 4
1. Chytrids are closely related to protists. The are unicellular. Earliest fungi.
2. Common molds are multicelluar and composed of stolons on the surface and rhizoids that penetrate the surface.
3. Club fungi are the most commonly recognized fungus. They are multicellular.
4. Yeast is unicellular, but most members are multicellular.
Ecology of Fungi Lichens consist of fungi living
mutualistically with photosynthetic organisms.
Lichens are associations of algae or cyanobacteria with a network of fungal hyphae. The fungus receives food in exchange for
housing, water, and minerals. Lichen serve as bioindicators or
environmental changes.
Parasitic Fungi Parasitic fungi cause disease
Dutch elm disease Corn smut Athlete’s foot
Beneficial Fungi Numerous fungi are beneficial Many are important in the decomposition
of organic material and nutrient recycling
Fungi are also important as food Mushrooms are the fruiting bodies of
subterranean fungi Yeasts (unicellular fungi) are essential for
baking and beer and wine production Fungi are used to ripen
certain cheeses
Beneficial Fungi Penicillin – First antibiotic to be
discoveredStaphylococcusaureus Penicillium
Zone ofinhibitedgrowth