EUKARYA BACTERIA ARCHAEA Protists Plants Fungi Animals Protists more distinct from each other than plants, animals, and fungi are

Protists Mainly single celled eukaryotes (some are colonial, others multicellular) species in the genus Volvocales range from unicellular to colonial to multicellular.

Protists Often have a very complicated internal structure

Protists Forms –fungus-like –plant-like –animal-like –probably little to do with their evolutionary history

Fungus-like Protists Water molds and slime molds

Animal-like Protists classified according to how they move: –amoeba-like –ciliated – flagellated

Protists and Human Health and Welfare Many protists are responsible for human diseases, such as malaria.

–Giardia - causes diarrhea – Trypanosoma - causes sleeping sicknes

most single-celled, but some multicellular have chloroplasts include –Diatoms –Dinoflagellates (red tides) –Algae – green, red, brown Plant-like Protists

Diatoms

Figure 28.17x Diatom shell

Figure Diatoms: Diatom diversity (left), Pinnularia (left)

Diatom

Dinoflagellate

Dinoflagellates Importance: parasites on fish cause “red tides” contain toxins cause mass mortalities of aquatic organisms

Algae Classified as: –green (mostly freshwater) –red (marine) –brown (marine “kelps”)

Green Algae The green algae are the ancestors of plants.

Freshwater habitats

Chara

Volvox colony

Marine habitats

Ulva – “sea lettuce”

Codium © D. Stengel

Caulerpa

Red Algae

Brown Algae “kelp”

Why are algae important? Production of Oxygen Production of biomass: -the leading primary producers in oceans and basis for marine and freshwater food chains

Grazing protists Photosynthetic protists Protists and Human Health and Welfare

Also … algae serves as human food –Annual value is about US$6 billion

KELP FORESTS

CALIFORNIA California kelp forests considered most diverse in world

Kelp (Brown Algae) 1000 species, almost all marine most common in cold, temperate seas

Giant Kelps - largest of all algae Kelp Forests –one kelp can grow m in one season –can reach 45 m long –among most productive of all plant communities

Parts of a kelp –Gas-filled pneumatocysts –Rootlike holdfast to attach to substrate –Long hollow stem or stipe –Leaflike blades FUNCTION AND FORM

Kelp forests - Where do they occur? Cold, temperate water

The ecological role of kelp

Dampen wave action Reduce coastal erosion Support populations of fish and invertebrates Habitat for many species

Animals of the kelp forest

Sea urchins graze on kelp

Sea otters control urchin populations by eating them

Now in trouble - not so diverse

Kelp Harvesting Old methods –led to reduction of many small marine creatures including abalone –now restricted

Kelp Harvesting Now Currently >100 tons of kelp are removed off the California coast alone --- down from 170,000