Endosymbiosis

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KingdomProtista

Eukaryotic

heterotrophic or autotrophic

Single-Celled

Have a Nucleus

Disease causing pathogens

Generally aquatic

Multicellular

Mixotrophs

Overiew;Protist Clip

Can be “grouped” by Method of

Nutrition

Animal-like“protozoa”

Plant-like“algae like”

Fungi-like

Heterotrophic Autotrophic Absorption

Plant-Like

Animal-Like

Fungi-Like

3- (Forams)4-

5-

2-(Rhizopoda)

Animal-Like

Classified

based on

Means of

Locomotio

n

5 5 importaimportant phylant phyla

1-

Ciliophora• The Ciliophora (ciliates), a diverse protist

group, is named for their use of cilia to move and feed.

Stentor Paramecium

Move by Cillia

Move by Cillia

Paramecium

Helps regulate water level

Locomotion

•Fresh or salt water

•Most Ciliates are free-living

Waste Removal

Oral Groove

macronucleus controls the everyday functions of he cell

micronuclei -required for sexual processes

• Ciliated generally reproduce asexually by binary fission of the macronucleus, rather than mitotic division.

• The micronuclei (with between 1 and 80 copies) are required for sexual processes that generate genetic variation.

• The sexual shuffling of genes occurs during conjugation, during which micronuclei that have undergone meiosis are exchanged.

• In ciliates, sexual mechanisms of meiosis and syngamy are separate from reproduction.

Paramecium Conjugation

Sporozoa• Parasites of

animals• Nonmotile• Release spores• Cause malaria

Plasmodium falciparum

•strictly parasitic protozoans that are usually immobile

Malaria Clip

• Plasmodium, the parasite that causes malaria, spends part of its life in mosquitoes and part in humans. Clip

• The incidence of malaria was greatly diminished in the 1960s by the use of insecticides against the Anopheles mosquitoes, which spread the disease, and by drugs that killed the parasites in humans.– However, resistant varieties of the mosquitoes and

the Plasmodium species have caused a malarial resurgence.• About 300 million people are infected with malaria in the

tropics, and up to 2 million die each year.

-transmitted by the bite of an Anopheles mosquito

Cryptosporidiosis

• diarrheal illness• acute short-term

infection but can become severe and non-resolving in children and immunocompromised individuals

Cryptosporidium

Toxoplasmosis

Toxoplasma gondii.

•Illness is usually minor•If weakened immune system, could be fatal

Zooflagellates• Move with flagella• Some mutalistic w/termites• Others are

parasites• Trypanosoma

transmitted by the tsetse fly causes African sleeping sickness

TermitesSymbiosis

Trichonympha

• Giardia lamblia, a parasite that infects the human intestine.

• 2 nuclei, multiple flagella• The most common method of acquiring

Giardia is by drinking water contaminated with feces containing the parasite in a dormant cyst stage

Rhizopoda• Amoebas

• Move by pseudopods

• Engulf food by phagocytosis

Move by PseudopodsMove by Pseudopods

Clip

Foraminifera• Porous shells called “tests”

– test-a technical term for internal shells

– Hardened CaCO3

• Pseudopodia extend through the pores

• Some species are geologically short-lived and some forms are only found in specific environments. Therefore, a paleontologist can examine the specimens in a small rock sample like those recovered during the drilling of oil wells and determine the geologic age and environment when the rock formed.

•Eukaryotes

•Most unicellular,

but some

multicellular

•Autotrophic –

contain chlorophyll

& make food by

photosynthesis

Plant-Like

Found in freshwater, marine, and moist soil habitats

•Range in size from microscopic to seaweeds hundreds of feet in length 10

algae

Chlamydomonas

Volvox

Spirogyra

Plant

-like

Protis

t Clip

• Phytoplankton (including planktonic eukaryotic algae and prokaryotic cyanobacteria) are the bases of most marine and freshwater food chains.

Phyla1. Euglenophyta

– Euglenoids2. Dinoflagellata

– Dinoflagellets3. Bacillariophyta

– Diatoms4. Chrysophyta

– Golden Algae5. Chlorophyta

– Green Algae6. Phaeophyta

– Brown Algae7. Rhodophyta

– Red Algae

Algae

Red Algae

Diatoms Golden Algae

Green Algae

EuglenophytaEuglenoids

1, 2 or 3 flagella

Pellicles- protein strips- outside of their membrane

Mixotrophic

Eyespot permits phototaxis

• -Euglena, a single celled mixotrophic protist, can use chloroplasts to undergo photosynthesis if light is available or live as a heterotroph by absorbing organic nutrients from the environment.

Euglenophyta

Unique glucose polymer, paramylon, as a storage molecule

Euglena

Detects light

Most live in freshwater, but some live in moist soil & the digestive tracts of certain animals

•Contractile vacuole to pump out excess water •Chloroplasts to make food by photosynthesis•Can be heterotrophic in the absence of light

Dinoflagellata

The dinoflagellates are abundant components of the phytoplankton that are suspended near the water surface.Dinoflagellates and other phytoplankton form

the foundation of most marine and many freshwater food chains.

Clip

Two flagella sit in perpendicular grooves and produce a spinning movement.

Some are bioluminescent

Some produce nerve toxins

Some dinoflagellates are heterotrophic.

Most dinoflagellates are unicellular, but some are colonial. Each dinoflagellate species has a characteristic shape, often reinforced by internal plates of cellulose.

• Dinoflagellate blooms, characterized by explosive population growth, cause red tides in coastal waters.

• The blooms are brownish-red or pinkish-orange because of the predominant pigments in the plastids.

They release a neurotoxin into the

environment. Shellfish concentrate this

toxin and it can kill people who eat the

contaminated shellfish.

Also produce massive invertebrate and fish

kills.These toxins can be deadly to humans as

well

Bacillariophyta• Diatoms

• Two silica (SiO2) shells that overlap like a shoe box.

DiatomsDiatoms

Chrysophyta• Golden algae (Chrysophyta), named for the

yellow and brown carotene and xanthophyll pigments, are typically biflagellated.

• Some species are mixotrophic and many live among freshwater and marine plankton.

• At high densities, they can form resistant cysts thatremain viable for decades.

While most are unicellular, some are colonial.

Chlorophyta• Green algaeGreen algae are named for their grass-green

chloroplasts.– These are similar in ultrastructure and pigment

composition to those of plants.– The common ancestor of green algae and plants

probably had chloroplasts derived from cyanobacteria by primary endosymbiosis.

– Believed to be the ancestors of plants

• Most of the 7,000 species of chlorophytes live in freshwater.– Other species are marine, inhabit damp soil

or snow, or live symbiotically within other eukaryotes.• Some chlorophytes live symbiotically with fungi to

form lichens, a mutualistic collective.

• Chlorophytes range in complexity, including:– Biflagellated unicells that resemble gametes

and zoospores.– Colonial species and filamentous forms.– Multicellular forms large enough to qualify as

seaweeds.

• Large size and complexity in chlorophytes has evolved by three different mechanisms:(1) The formation of colonies of individual cells

(Volvox)(2) the repeated division of nuclei without cytoplasmic

division to form multinucleate filaments (Caulerpa).

Volvox Caulerpa

Ulva-sea lettuce

(3) The formation of “true” multicellular forms by cell division and cell differentiation (Ulva).

Life Cycle of Chlamydomonas

(Alternation of Generations)

SyngamySyngamy-the -the union of two union of two gametes to form gametes to form a zygotea zygote

Chlorophyta

Clip

Phaeophyta• Brown algae (Phaeophyta)

are the largest and most complex algae.– Most brown algae are multicellular.– Most species are marine.

• Brown algae are especially common along temperate coasts in areas of cool water and adequate nutrients.

• They owe their characteristic brown or olive color to accessory pigments in the plastids.

• The life cycle of the brown alga Laminaria is an example of alternation of generations.

• The diploid individual, the sporophyte, produces haploid spores (zoospores) by meiosis.

• The haploid individual, the gametophyte, produces gametes by mitosis that fuse to form a diploid zygote.

Clip

• The largest marine algae, including brown, red, and green algae, are known collectively as seaweeds.

• Seaweeds inhabit the intertidal and subtidal zones of coastal waters.– This environment is

characterized by extreme physical conditions, including wave forces and exposure to sun and drying conditions at low tide.

Structural and biochemical adaptations help seaweeds

survive and reproduce at the ocean’s margins

• Seaweeds have a complex multicellular anatomy, with some differentiated tissues and organs that resemble those in plants.– These analogous features include the thallus or

body of the seaweed.– The thallus typically consists of a rootlike holdfast

and a stemlike stipe, which supports leaflike photosynthetic blades.

• Some brown algae have floats to raise the blades toward the surface.– Giant brown algae, known as kelps, form forests in

deeper water.– The stipes of these plants

may be 60 m long.

Holdfast of a kelp

Kelp Forest

•Many seaweeds are eaten by coastal people, including Laminaria (“kombu” in Japan) in soup and Porphyra (Japanese “nori”) for sushi wraps.•A variety of gel-forming substances are extracted in commercial operations.

–Algin from brown algae and agar and carageenan from red algae are used as thickeners in food, lubricants in oil drilling, or culture media in microbiology.

Rhodophyta• Unlike other eukaryotic algae, red algae have

no flagellated stages in their life cycle.• The red coloration visible in many members is

due to the accessory pigment phycoerythrin.– Coloration varies among species and depends on the

depth which they inhabit.

• The plastids of red algae evolved from primary endosymbiosis of cyanobacteria.

• Red algae (Rhodophyta) are the most common seaweeds in the warm coastal waters of tropical oceans.– Others live in freshwater, still others in soils.

• Some red algae inhabit deeper waters than other photosynthetic eukaryotes.– Their photosynthetic pigments, especially

phycobilins, allow some species to absorb those wavelengths (blues and greens) that penetrate down to deep water.• One red algal species has been discovered off the

Bahamas at a depth of over 260m.

• Most red algae are multicellular, with some reaching a size large enough to be called “seaweeds.”– The thalli of many

species are filamentous.– The base of the thallus

is usually differentiated into a simple holdfast.

Fungi-Like

•Includes slime molds & water

molds•Multicellular, heterotrophic

•Little tissue specialization

•Usually small & live in moist or

watery habitats

•Act as decomposers breaking

down dead organic matter

Slime molds

water molds17

1.1. AcrasiomycotaAcrasiomycota• Cellular Slime Molds

2.2. MyxomycotaMyxomycota• Plasmodial Slime

Molds

3.3. OomycotaOomycota• Water Molds, Downy

Mildews, White Rust

Plasmodial Slime Molds

Phyla•Cellular Slime Molds

Mildews Water Molds

Slime molds •Feed by

absorption- -break down dead organic matter•May be saprophytes or parasites •Make a

reproductive structure or

fruiting body that produces spores •Often found on

decaying wood or leaves

Myxomycota

Acrasiomycota

Cellular Slime Mold Life Cycle• The cellular

slime molds (Dictyostelida) straddle the line between individuality and multicellularity.– The feeding stage

consists of solitary cells.

– When food is scarce, the cells form an aggregate (“slug”) that functions as a unit.• Each cell retains

its identity in the aggregate.

dominant stage -haploid stage

Acrasiomycota

MyxomycotaMyxomycotaplasmodial slime molds

• The plasmodial slime molds are brightly pigmented, heterotrophic organisms.

• The feeding stage is an amoeboid mass, the plasmodium, that may be several centimeters in diameter.– The plasmodium is

not multicellular, but a single mass of cytoplasm with multiple nuclei.

– When food is scarce stalks bearing capsules form.

MyxomycotaMyxomycota

water molds

Phytophthora

infestans

caused

blight in

potatoes

(Irish Potato

Famine in

19th

century)

•Aquatic water molds are parasites on fish forming furry growths on their gills •May act as decomposers in water of dead plants & animals •May be pathogenic to plants•Form hyphae like fungi•Coenocytic- many nuclei w/in one cell

OomycotaOomycota

• In the Oomycota, the “egg fungi,” a relatively large egg cell, is fertilized by a smaller “sperm nucleus,” forming a resistant zygote.

Phytophthora

infestans caused

blight in

potatoes (Irish

Potato Famine in

19th century)

•White rusts and downy mildews are parasites of terrestrial plants.

–They are dispersed by windblown spores.–One species of downy mildew threatened French vineyards in the 1870s and another species causes late potato blight, which contributed to the Irish famine in the 19th century.

Phytophthora infestans

• Water molds are important decomposers, mainly in fresh water.– They form cottony masses on dead algae and

animals.– Some water molds are parasitic, growing on the

skin and gills of injured fish.

Water molds

Human Diseases Caused by Protist

African Sleeping Sickness

Malaria

Giardiasis Cryptosporidosis

Toxoplasmosis Chagas

Protista

Algae are a source of food in the aquatic ecosystem and produce oxygen

Sushi

African sleeping Sickness Malaria

Plant Pathogen

Red TidesSometimes used in

ice cream, pudding and

soups.

Chemical derived from algae can be

used to treat stomach ulcers

Termite Guts

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