bio 2 - protists and fungi ch 29 (post)

the four kingdoms within domain eukarya are:

Protista, Fungi, Plantae, and Animalia

protists

microscopic and unicellular; found in all the supergroups

• can be colonial or multicellular

• found in all six supergroups

• easier to identify them as eukaryotic that is not a plant, animal, or fungus

• some are disease causing but many have significant ecological importance such as aquatic photoautotrophic protists that make oxygen

• main types: plant like (algae) animal like (protozoa) and fungus like (molds)

• endosymbiotic theory

endosymbiotic theory

suggests that mitochondria may have resulted when a nucleated cell engulfed aerobic bacteria

• Chloroplasts may have originated when a nucleated cell with mitochondria engulfed cyanobacteria

protists bridge the gap between ____ and _____

eukaryotic cells and multicellular organisms

general characteristics of protists

• Structurally diverse

• Most single-celled

  • exceptions are kelp, volvox, and spirogyra

• high level of complexity

  • some have unique organelles

• Sometimes grouped according to how they acquire nutrients

• Protists reproduce sexually and asexually

  • Mostly asexually - only sexually when in unfavorable conditions

• can form spores or cysts in unfavorable environmental conditions

eukaryotic supergroups

• Archaeplastida

• Chromalveolata

• Rhizaria

• Excavata

• Amoebozoa

• Opisthokonta

archaeplastida - eukaryotic supergroups

• photosynthetic organisms with chloroplasts (plastids) derived from endosymbiotic cyanobacteria

• A number of colonial forms occur among chlorophytes

examples of archaeplastida

volvox, spirogyra, red algae, and green algae

colony

loose association of independent cells

chromalveolata - eukaryotic supergroups

types of organisms: Dinoflagellates, apicomplexans, ciliates, diatoms, golden brown algae, brown algae, water molds

• proposed that alveolates and stramenopiles were common ancestors

• Represent a very large, diverse group of protistans.

• Photosynthetic

• Different lineage from the green and red algae

What word refers to unicellular eukaryotes that are typically heterotrophic consumers?

protozoans

When black bread mold sexually reproduces, what kind of spore does it make?

zygospore

Where are the spore-producing structures located on a mushroom?

on the underside of the cap

What kind of algae has silica in its cell walls?

diatoms

rhizaria - eukaryotic supergroups

organisms with fine and threaadlike pseudopods (temporary, arm-like cytoplasmic extensions used by eukaryotic cells or locomotion and feeding)

• types of organisms: Cercozoans, foraminiferans, radiolarians

foraminiferans and radiolarians - supergroup rhizaria

they have fine, threadlike pseudopods and a skeleton called a test made of calcium carbonate

• Fossilized shells can be used to date sedimentary rock

• Their presence is used as an indicator of oil deposits on land or sea

excavata - eukaryotic supergroups

sometimes referred to as flagellates

types of organisms: Euglenozoans, diplomonads, parabasalids, flagellates

amoebozoa - eukaryotic supergroups

protozoans that move by pseudopods which form when the microfilaments contract and extend as the cytoplasm streams toward a particular direction. usually live in aquatic environments

• types of organisms: Amoeba, slime molds

opisthokonta - eukaryotic supergroups

animals, fungi, and several closely related protists

types of organisms: Animals, fungi, choanoflagellates

phagocytosis

form of endocytosis where immune cells (phagocytes) engulf and destroy large particles

• often termed "cell eating"

sporangia

an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular

choanoflagellates - supergroup opisthokonts

• Animal-like protists closely related to sponges

• Single-celled and colonial forms

• Filter feeders; resemble choanocytes that line the inside of sponges

• Each one has a single, posterior flagellum surrounded by a collar of microvilli

• Beating of flagellum creates a water current through the collar, where food is taken in by phagocytosis

fungi!

domain Eukarya, supergroup Opisthokonta, kingdom Fungi

• structurally diverse group of heterotrophs

• release enzymes into their external environment and digest food outside of the body

• some are parsitic

• some are saprotrophs that decompose dead plants, animals, and microbes

• important to recycling inorganic nutrients

• degrade cellulose and lignin

• six groups: microsporidia, chytrids, zygospore, sac, and club

• nonmotile - move toward a food by growing toward it

• glycogen is used as an energy reserve

• no chloroplasts

evolution of fungi

• ancestry to protists

• closer related to animals than to plants

• do not fossilize well

• likely originated when organisms began to colonize land

• lots of questions about its evolution

hyphae

body of a fungus composed of many of these filaments

• gives mycelium a large surface area to facilitate absorption of nutrients

what is a mass of hyphae called for fungi?

mycelium

what are septa?

cross walls that separate hyphae into chains of cells in fungi

• these sorts of hyphae are septate

• xxx have pores to allow cytoplasm to pass from cell to cell

• non septate fungi have no cross walls and hyphae are multinucleated

what are the cell walls of fungal cells comprised of?

chitin

fungi windblown spores - reproduction

used as a method of adaptation to dry land

• spores are haploid reproductive cells that develop into a new organism without the need to fuse with another cell

  • spores germinate into new mycelia

• sexual reproduction occurs by the conjugation of hyphae from different mating types

  • Haploid nuclei may not immediately fuse

  • Eventually, the nuclei fuse to form a zygote

  • Zygote undergoes meiosis to produce haploid spores

fungal diversity

classified by mode of sexual reproduction

• Microsporidians

• Chytrids (Chytridiomycota)

• Zygospore fungi (Zygomycota)

• Sac fungi (Ascomycota)

• Club fungi (Basidiomycota)

• AM fungi (Glomeromycota)

saprotrophs

organisms that obtain nutrients by breaking down dead and decaying organic matter through extracellular digestion

sporangium

a capsule that produces spores

yeast

unicellular fungi, many are sac fungi

• most reproduce by budding

budding

reproduction that is unequal binary fission

• A small cell gets pinched off and grows to full size

• Asexual reproduction occurs as food sources run out, producing spores

club fungi

phylum Basidiomycota

• Their characteristic sexual reproductive structure is called a basidium where + and - nuclei join which produces spores by meiosis

  • Contained within a basidiocarp which develops after + and - hyphae gone

  • forms at fusion of + and - hyphae

includes: puffballs, stinkhorns, smuts, and rusts

Symbiotic Relationships of Fungi with Lichens

Associations between fungi and cyanobacteria or green algae

• Efficient at acquiring nutrients and moisture

• Are primary colonizers because they produce organic matter and soil that supports plants

• take three characterstics forms: crustose (compact) fruticose (shrublike) and foliose (leaflike)

• Lichens can reproduce asexually by releasing fragments with hyphae and an algal cell

Lichen body

has three layers—fungi form top and bottom layers and protect middle layer of photosynthetic cells

• Fungal portion offers protection and delivers minerals and water

• Cells of photosynthetic partner give the fungus nutrients

fungal diseases of humans

• cause disease in those humans with a weakened immune system

• Mycoses - serious disease usually superficial

  • dermatophytes - fingus causing tinnea - athletes foot

  • fingworm - causes infected area to be inflammed

  • Candida albicans causes a wide variety of fungal infections

    • thrush is an infection that occurs in the mouth of newborns and people living with AIDS

systemic mycoses

fungal infections that affect internal organs (mainly the lungs) - in immunocompromised individuals, fungi can spread through the bloodstream

• Several fungal diseases are considered AIDS-defining

• death is possible as multiple organ may be infected

• normal immune systems have no trouble responding but in serious cases they start with  respiratory symptoms, which include coughing, chest pain, hoarseness, or blood in sputum

examples of systemic mycoses

• Histoplasma capsulatum - A common soil fungus often linked to bird droppings

• Can cause a lung disease known as histoplasmosis - Resembles tuberculosis

• Cryptococcus neoformans - Found in soils infected with pigeon or chicken droppings

• Coccidioides immitis - Found in desert areas; causes valley fever

• Black mold, Stachybotrys chartarum - Sick building syndrome

antifungal drugs

work for topical medication but not for systemic infections

amoeba v paramecium

Amoeba and Paramecium are both single-celled, eukaryotic microorganisms found in aquatic habitats, but they differ significantly in structure and locomotion

• Amoebas have an irregular, ever-changing shape and move using temporary projections called pseudopodia (false feet)

• Paramecium has a fixed, slipper-shaped form, uses hair-like cilia for fast movement, and has a more complex structure, including two nuclei