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Kingdom Protista (“K. Fruit Salad”)• 100,000 living species, 35,000 fossilized members• Ancestors to metazoans: plants, fungi, animals• Low specialization, high complexity• Two distinguishing features from Moneran

ancestors:– Compartmentalized cell structure– Increased genomic size

Protistans are NOT monophyletic

Note: These groups only represent a sample of protist diversity; many other lineages are not shown on the tree.

Why Dr. R. has a Love/Hate relationship with K. Protista

General Protistan Characteristics

1. habitat diversity2. free-living or symbiotic3. aerobic metabolism4. pellicle support structure5. 9+2 structure in cilia and flagella6. asexual and sexual reproduction7. cyst forming potential8. not specialized but highly complex

Ciliates

Multinucleated

Macro: metabolic and developmental issues

Micro: Sexual reproduction

High intracellular specialization:“Mouth, anus, excretion, locomotion, reproduction, behavior”

A ciliated protozoanFig. 11.18

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Ciliophora: Conjugation and Genetic Recombination

RhizopodaThe Ameba• Amoebas,

simplest pseudopod users

• Free-living and parasitic

• Can form cysts• Reproduce

asexually• Phagocytosis

Fig. 11.26

Actinopoda: Heliozoans and Radiolarians• Axopodia• Heliozoans : FW,

unfused silica or chitin

• Radiolarians: marine, fused silica

• Radiolaria ooze

Radiolarian skeleton

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Foraminifera (Forams)• Most are marine• Porous,

multichambered shell of CaCO3

• 90% of described species are fossils

• Deepsea species• 1/3 of seafloor- One

species of Foram

Chalk, limestone, etc

Fig. 11.27b

Pyrophyta (Dinoflagellates)• Marine phytoplankton• Unicellular, some colonial

• cellulose plates with perpendicular flagella• chlorophyll a, c, carotinoids• starch• Dinoflagellate blooms, red tides. PSP and Pfiesteria

Red Tides

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Swimming with bioluminescent dinoflagellates Apicomplexa (Sporozoa): The life history of Plasmodium, the cause of

malaria.

leading cause of death for humans~ 3 million/year!

What happens with climate change? The problem of the Myxozoa

““BuddenbrockiaBuddenbrockia””

Diatoms- class Bacillariophyta

• Unicellular• Centric and Pennate• Shell (Frustule) walls made of

Silica (SiO2)– Epitheca and hypotheca

• Reproduction (asexual and sexual)

• Auxospores• Diatomaceous/Siliceous Ooze

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Diatom Reproduction

a slime mold Figure 28.30 The life cycle of a cellular slime mold (Dictyostelium)

The Macroscopic Algae

• Plant evolution begins in the sea• Single celled Multicelled colonies

– But still have very little specialization between cells

• Three divisions of algae- all can be seen in tide pools

– Rhodophyta- Red Algae– Phaeophyta- Brown Algae– Chlorophyta- Green Algae

The 3 groups of Algae

• Rhodophyta- Red Algae– Chl. a, other accessory

pigments, storage is Floridean starch

• Phaeophyta- Brown Algae– Chl. a & c, other pigments,

storage is Laminarin• Chlorophyta- Green Algae

– Chl. a & b, other pigments, storage is Starch

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Algae structurePneumatocysts:N2, O2, and Co2 gasSingular and large, or small and many

Phaeophyta and the Evolutionary Adaptations of Seaweeds to a Physically

Stressful Environment• Multicellular with a minor degree of

specialization• Structural adaptations of thallus:

holdfast, stipe, blades, gas bladders (pneumatocysts)

• Chemical adaptations:– Cellulose walls w/ polysaccharides– may incorporate calcium carbonate

• 3 Reproductive Cycles: Haplontic(zygotic), Diplontic (gametic) or Alternation of Generations (diplohaplontic,sporic cycle)

Kelp Beds and Forests

• Found in cold, temperate regions only.• Large brown algae= kelp.• Kelps obtain nutrients from water, so

depend on turbulence to renew waters to avoid depletion.

• Form extensive 3-D habitat with several vertical layers= High species diversity

Rhodophyta: distant relatives to Phaeophyta…a separate kingdom?

• No flagellated stage• mostly marine, tropical• Chlorophyll a, carotinoids,

phycobilins (phycoerythrin)– Primary endosymbiosis

• storage = floridean starch• cell walls are cellulose with agar

and carageenan• Broad coastal distribution• Alternation of generations is

common, rely on water currents

Chlorophyta: share a common ancestor with terrestrial plants

• Cyanobacteria and primary endosymbiotic theory…Chlorophyll a, b, carotinoids,

• Marine, FW, soil, freeliving and symbiotic

• Diverse body plans, colonial, multicellular

• storage=starch• cell wall = cellulose• Ulva: isomorphic alt of gen

– Biflagellated gametes– conjugation

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The life cycle of Laminaria: an example of alternation of generations Kingdom Fungi

• Decomposers make the world go round• Recycle nutrients from the dead to the

living• Symbiosis with roots allow nearly all plants

to absorb nutrients and water better.• Food Source, Drugs, Baking, Wine/Beer• Are Heterotrophs

Fungi and Bacteria- the decomposers• Long evolutionary history• 400 mya- 25 ft high fungi?• On land before large trees

and vertebrates

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Decomposers

Fungi Diversity

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Stinkhorn

Mycorrhizae- Important symbiosis with plant roots Lichens- Symbiotic associations of Fungi and Algae

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