bio 102 2

what sizes can protists be?

from microscopic single celled organisms to enormous multicellular ones

why aren’t protists plants?

their gametes and zygotes are not protected from drying

why aren’t protists fungi?

they don’t have chitin in their cell wall

why aren’t protists animals?

they don’t have embryotic development

why are protests hard to classify?

diverse: could be split into as many as a dozen kingdoms, vary in morphology

what variation in morphology exist among protists?

most are unicellular but even unicellular ones have an amazingly high level of complexity

protists life cycle

most are free living but some are parasitic, asexual reproduction is common, sexual reproduction may occur when conditions deteriorate, some simple but many are complex

why are protists ecologically important?

photoautotrophic forms produce oxygen & function as producers in both fresh & many are symbionts (coral reefs & photoautotrophic protists in coral tissues)

how do protists transport?

three ways: paramecium, amoeba, & euglena

paramecium

waves hair like appendages called cilia to propel itself

amoeba

uses lobe like pseudopodia to anchor itself to a solid surface and pull forward

euglena

whiplike tail called flagellum

protists metabolism

photoautotrophs, heterotrophs, & mixotrophs

mixotrophs

obtain nutrition by photoautotrophic or heterotrophic routes, depending on whether sunlight or organic nutrients are available.

phagocytosis

form of metabolism

engulfment of food particle → digestion using hydrolytic enzymes and lysosome → expulsion of undigested materials from cell

protists reproduction

some use binary fission, some budding, and some through sexual repoduction (many switch back and forth)

budding

buds go on to divide and grow to protist size

sexual reproduction

meiosis and fertilization, only switch to sexual reproduction when environmental changes occur (induces genetic diversity so only used when change is needed)

protists habitat

tend to like moisture (water, damp soil, snow) because they can’t stop gametes and zygotes from drying otherwise

can be inside organisms

diversity of protists (types)

algae, zooflagellates, amoeboids, ciliates, dinoflagellates, slime molds

algae definition & types

photosynthetic protist

green algae/phylum chlorophyta, red algae/rhodophyta, brown algae/phaeophyta, yellow green/chrysophyta

green algae/phylum chlorophyta

• inhabit a variety of environments including oceans, freshwater, snowbanks, tree bark, and turtles backs

• symbionts w/ fungi, plants, or animals

• morphology varies: some are unicellular (can be filamentous or colonial), some are multicellular (sea lettuce)

red algae/rhodophyta

• economically important

• multicellular

• warmer sea water environment

how is red algae economically important?

dentistry, cosmetics, carrageen emulsifying agent in chocolate, sushi seaweed

brown algae/phaephyta

• 1,500 species

• colder water environment

• not unicellular or colonial

• some are small with simple filaments, some are multicellular exceeding 200 meters in size

• chlorophylls a & c

• fucoxanthin (carotenoid pigment) gives the color

• excess food stored as a carb called laminarin

chrysophyia/yellow green

• cell wall is in two valves with the larger valve as a lid

• silica in cell wall

• diatomaceous (diatoms) eath used as a filtering agent and for soundproofing and polishing

where are plants thought to be derived from?

chlorophyta because of their cell walls and cellulose, they possess chlorophyl a & b, store excess food and starch

how may the first eukaryote been introduced?

endosymbiosis

original ancestral prokaryote undergoing membrane proliferation → compartmentalization of cellular function → establishment of endosymbiotic relationships with either an aerobic prokaryote or a photosynthetic prokaryote, to form mitochondria and chloroplasts

how were diatoms made?

(secondary endosymbiosis) 2 endosymbiotic events: heterotrophic eukaryote consumed by bacterium → this cell consumed by a second cell

zooflagelates

• colorless heterotrophs

• most are symbiotic and many are parasitic

• cause various diseases

diseases zooflagellates cause

• trpanosoma/african sleeping sickness & chagas disease

• giardia lamblia: digestive system, cysts, cause severe diarrhea

• trichomonas vaginalis: sexually transmitted protist infects urogenital o

amoeboids/phylum rhitopoda

• move and ingest food with pseudopods

• use phagolysosomes to digest their food (phagocytize food)

disease amoeboid causes

entamoeba histolytica: colon parasite that causes dysentery

ciliates/phylum ciliophora

• hundreds of cilia beat in a coordinated rhythm

• most are holozoic

• binary fission

• 2 nuclei: micronucleus (contains genes to reproduce & create new macronucleus, comes in if micronucleus dies), macronucleus (day to day to transcribe genes, not stable)

holozoic

eat their food whole

dinoflagellates

• diverse in shape

• encased in a cellulose armor, 2 flagella that fit between plates

• 2 perpendicular flagella cause spinning, creating bioluminescence

slime molds definition and types

feeds like fungi and make spores, but no cell wall and they have flagellated cells. both form sporangium which produces spores.

• plasmodial and cellular

plasmodial

multinucleated, diploid mass covered in slime → easily have areas that create sporangium

cellular

body in form of individual amoebal cells, aggregate into pseudoplasmodium → sporangium

protists as primary producers

photosynthetic organism base to fix CO2 and pull up water and minerals (algae)

how is half of the worlds photosynthesis conducted?

protists such as dinoflagellates, diatoms, or multicellular algae

whats one way protists are primary producers of nutrition?

symbiotic mutualistic relationships (protists & nutrients for coral polyps)

protists as decomposers

protist saprobes are specialized to absorb nutrients from nonliving organic matter such as dead organisms or their wastes

role of saprobic protists

returning inorganic nutrients to the soil and water

what do saprobic protists make possible?

allows new plant growth, which in turn generates sustenance for other organisms along the food chain

without them, all life would cease to exist because all organic carbon would stay in dead organisms

parasitic protists

significant number of protists are pathogenic parasites that must infect other organisms to survive and propagate

(some cause disease and some prey on plants)

mushroom parts

mushroom, mycelium, hyphae, & mycorrhiza

mushroom

fruiting body of the fungus (spores act like seeds)

mycelium

the main structure of the fungus

hyphae

long, thin strands that tangle together to make mycelium

mycorrhiza

where hyphae attach to plant roots

where to fungus live?

diversity of habitats, from seawater → skin. most like moist environments, mostly forests

characteristics of fungi

multicellular eukaryotes, heterotrophic, mostly saprobes, some are parasitic, mutualistic relationships with plants and others, biggest organism on earth because of their roots

what heterotrophic process do fungi use?

release a digestive enzyme and create a nutrient slurry which the fungus consumes

saprobes=

decomposers

decomposing process

release elements from decaying matter and make them available to other living organisms

how do fungi decomposers get their nutrients?

from their hyphae which invades and decays organisms (shelf & bracket fungi from trees)

evolution of fungi

plants, animals, and fungi are evolutionarily related to protists. animals and fungi are more related than plants & fungi.

flagellated unicellcular protists most likely common ancestor between animals and fungi.

structure of fungi

thallus, hyphae, cell walls, glycogen, rhizoid, sporangiophore, and sporangium

thallus

the body of fungi. usually a multicellular mycelium, however, yeasts are unicellular

hyphae

thread-like parts that grow from the tip and help with absorption.

contribute to classification of septate or non septate

septate

hyphae with cross walls

non septate

multinucleated

cell walls

have chitin, similar to an insect exoskeleton

glycogen

the material how excess food is stored (same as animals)

rhizoid

“roots” anchors the fungi to their substrate for nutrition

sporangophore

specialized hyphae & stalk of sporangium

sporangium

enclosed unit where spores are formed

growth of fungi

reproduction

can produce asexually or sexually (same as protists, asexual in optimal conditions)

how do fungi reproduce asexually?

the mycelium breaks off to produce, creating sporangium and releasing spores

how do fungi produce sexually?

male and female cells fuse but not the nucleus and are herero/dikaryotic (plasmogamy) → nuclei fuse (karyogamy, makes diploid) → creates zygote → meiosis to make cells (halves genetic material) → germination which creates a mycelium → the mycelium then follows the process of asexual reproduction (creates spores & releases them)

3 stages of sexual reproduction

haploid hyphae, dikaryotic, and diploid zygote

haploid hyphae

plasmogamy

dikaryotic (heterokaryotic)

karyogamy

diploid zygote

meiosis - asexual reprodction

how do unicellular yeasts reproduce?

budding

types of fungi

zygomycota, chytridiomycota, sac fungi, & club fungi

zygomycota

zygospore fungi, phylum zygomycota, sapotrophs, black bread mold (Rhizopus stolonifer)

chytridiomycota

phylum chytridiomycota, primitive (about 500 million years ago), release digestive enzymes → digestive flora ruminates, were placed in the protista kingdom for a long time

sac fungi

• phylum ascomycota

• about 60000 species

• most are sapotrophs (digest cellulose, lignin, of collagen)

• septate hyphae

• morels & truffles, many plant diseases (powdery mildew)

sexual sac fungi reproduction

ascus finger-like sac develops during sexual reproduction, haploid hyphae fuse to make diploid nucleus, mitosis & meiosis produces 8 ascospores (multicellular)

asexual sac fungi reproduction

yeast reproduced by budding, small bulge forms on the side of the cell, nucleus gets pinched off

mold sac fungi

aspergillus

a group of green molds used to produce soy sauce by fermentation of soy beans, used to produce citric and gallic acids, species of penicillium (talaromyces) creates penecillin

yeasts sac fungi

saccharomycus cerevisae are added to grape juice to make wine, some yeasts ferment and produce ethanol and CO2, used in genetic engineering experiments, candida albicans causes fungal infections (oral thrush common in newborns and AIDS patients)

club fungi

• phylum basidiomycota

• 22000 species

• familiar toadstools/mushrooms/bracket fungi/puffballs/stinkhorns

• some can be deadly or poisonous

• plant diseases such as the smuts and rust

• mycelium composed of septate hyphae

mychorrhizae

the mutualistic relationships between soil fungi and the roots of most familiar plants

earlist fossil plants have mycorrhizae associated with them

two types of mychorrhizae

ectomycorrhizae or endomycorrhizae

how mychorrhizae works?

80-90% of plant species have mycorrhizal partners

fungal mycelia use their extensive network of hyphae and large surface area to channel water and minerals from the soil into the plant, in exchange the plant supplies the products of photosynthesis to fuel the metabolism of the fungus

endophytes

fungi that live inside tissue without damaging the host plants. endophytes release toxins that repel herbivores or create resistance to environmental stress factors (microorganisms, drought, heavy metals in soil)

lichens

example of mutualism

fungus (usually ascomycota or basidiomycota phyla) lives in close contact with a photosynthetic organism (alga or cyanobacterium)

lichen layers

upper cortex of fungal hyphae provides protection, algal zone is where photosynthesis occurs, medulla of fungal hyphae, lower cortex which provides protection, and potentially rhizane to anchor thallus to substrate

forms of lichen

crust like, hair like, or leaflike

fungi and other types of mutualism

parasitism, pathogens, and commensalism

parasites and pathogens harm (pathogens by disease), & commensalism

parasites and economic/environmental damage

fungi that cause tissue decay and eventual death for most, ruin crops and bring famine

responsible for food spoilage and rotting of stored crops

fungal infections

ringworm (red ring on skin) trichophyton violaceum (superificall mycoses on the scalp, histoplasma capsulatum (ascomycete that infects airways and causes influenza like symptoms)

what is an ancestor to the plantae kingdom?

green algae

evolution of of seedless plants

transition from water → land (made there be constraints)

strategies to adjust to land

• waxy cuticle to protect leaves & stem from desiccation

• protective flavonoids and other pigment to prevent photodynamic damage from UVB

• poisonous secondary metabolites such as alkaloids to deter predators

• sweet and nutritious metabolites for animals to aid in pollination and dispersing pollen grains and seeds

• nonvascular → vascular to add structural support, capture sunlight.

problems & how they were solved with waxy cuticle

prevents the intake of CO2

stomata- intake of CO2, holes/doors inside of the plant open during photosynthesis