Chapter 21- Protists & Fungi

Honors Biology

I. Protist Classification

A. The 1st Eukaryotes1. Part of the kingdom Protista2. Placed in the kingdom Protista when they cannot be classified as a plant, animal or fungus3. Most are unicellular

a. Example of a multicellular protest: brown algae or kelp

4. It is very difficult to classify protists5. The ancestors of modern day protists gave rise to all plants, animals & fungi

II. Protist Structure & Function

A. Movement1. Amoeboid Movement

a. Move by changing their shape and using cytoplasmic extensions called pseudopodsb. ex. AmoebaAmoeboid Movement

Amoeba

2. Cilia & flagellaa. Protists that move using cilia are called ciliatesb. Protists that move using flagella are called flagellatesFlagella & Cilia Movement

Euglena

Paramecium

3. Passive Movementa. Nonmotileb. Depend on water or air currents to carry around their reproductive cells (spores)c. Ex. Plasmodium forms spores which are carried by mosquitoes & causes malaria

Plasmodium Life Cycle

B. Reproduction1. Cell Division

a. Asexual reproduction/ mitosisb. Allows rapid reproductionc. Identical cellsd. Limits genetic diversitye. Ex. Amoebas, paramecium, ciliates

2. Conjugation a. After conjugating, the protist will go through mitosisb. Not a type of reproductionc. Maintains or Increases genetic variationd. Promotes evolution

3. Sexual Reproduction: Alternation of generations

a. alternates between a haploid & diploid phaseb . Water mold produces sexually by forming male & female structures that produce gametes fertilization zygotec. Water mold reproduces asexually by producing spores in a structure called a sporangium

III. Ecology of Protists

A. Autotrophic Protists1. Very different, but all are photosynthetic2. Base of the food chain for aquatic life3. Phytoplankton- feeding fish and whales

4. red algae- support the coral reefs by providing nutrients from photosynthesis- provides the calcium carbonate needed to stabilize the growing coral reefs

5. brown algae- largest protist, provides shelter for many marine species, provides food

6. euglenas- recycle waste from sewage dischargea. If there is a large amount of waste, an algal bloom

may developb. Dinoflagellates cause a bloom called a “red tide”

when they release toxins into the water

B. Heterotrophic protists1. Amoebas

a. Capture their food in way very similar to endocytosis

b. Store their food in a food vacuolec. Digest their food rapidly

2. Ciliates- paramecium – pg. 612a. Use their cilia to sweep food into their gulletb. Digested by lysosomesc. Wastes removed through the anal pore

3. Slime Moldsa. Eats decaying matterb. Found in damp placesc. Play a key role in recycling nutrientsd. 2 life stages» Single amoeba-like cells» Group of cells come together and form a

structure know as plasmodium

4. Protists that Absorba. Water molds grown on dead matter and absorb

food molecules through their cell walls

C. Symbiotic Protists1. Mutualists

a. Both the protist & the host benefitb. Trichonympha lives in the digestive system of

termites and allows for the digestion of wood

2. Parasites and Diseasea. Intestinal Diseases»Water borne» Giardi: causes severe diarrhea & digestive

problems» Entamoeba: causes amebic dysentery, destroys

intestines & causes severe bleeding

b. African Sleeping Sickness» Caused by the protists Trypanosoma» Spread by the tsetse fly» Destroys blood cells and damages nerves cells» Causes nervous system damage and causes the

person to go into deep, fatal sleep

c. Malaria» Caused by Plasmodium»One of the world’s most serious diseases» Carried by a mosquito & humans

IV. Fungi

A. Characteristics1. Heterotrophic

a. Contain powerful enzymes that digest food outside their bodies

b. Then they absorb the nutrients2. Cell wall contains chitin3. Eukaryotic

B. Structure & Function1. Yeast are unicellular2. Most other fungi are Multicellular

a. Contain branching fibers called hyphaeb. The portion of the fungus that is above ground is

the fruiting bodyc. The mass of branching hyphae beneath the soil is

the mycelium ( root like structures)

C. Reproduction- pg. 6201. Asexual

a. Release spores into the wind & waterb. Budding or breaking off a hypha is also considered

asexual reproduction2. Sexual

a. Involves 2 different mating types» No male & female, just “+” and “-“

b. Hypha of opposite matting types meet & fuse to form a 2N zygospore

c. Zygospore goes through meiosis and produces haploid spores that can all make new mycelium

D. Major Phyla of Fungi1. Basidiomycota

a. Club fungib. Sexual spores found in a club shaped cell called a

basidiumc. Ex. Mushrooms, puffballs, earthstars, shelf fungi,

jelly fungi, rusts

2. Ascomycotaa. Sac fungib. Sexual spores are found in a sac-like structure

called an ascusc. Ex. Morels, truffles, Penicillium species, yeast

3. Zygomycotaa. Common moldsb. Tough zygospore produced during reproduction

that can stay dormant for long periodsc. Ex. Black bread mold, mycorrhizae on plant roots

4. Chytridomycotaa. Chytridsb. Only fungi with flagellated sporesc. Ex. Decomposers in lakes and moist soils

E. Ecology of Fungi1. Decomposers

a. Help ecosystems maintain homeostasis by recycling elements & breaking down dead organic matter

2. Parasitisma. Plant Diseases» Corn Smut»Wheat rusts»Mildews» Destroys approx. 15 % of the crops in temperate

climates

Corn SmutWheat Rust

Mildew

b. Animal Diseases» Cordyceps- infects living animals & digests the

cells and tissues until the animal dies» Candida albicans- yeast infection in humans,

thrush (mouth), athletes foot

3. Lichensa. mutualistic relationship with cyanobacteria or

algaeb. cyanobacteria or algae give the fungus energy

(glucose)c. fungus gives the cyanobacteria or algae water &

mineralsd. lichens are great indicators of pollution levels in an

environment due to their high sensitivity of air quality

4. Mycorrhizaea. Mutualistic relationship with plant rootsb. Fungal hyphae collect water & minerals and bring

them to the rootsc. Fungi releases enzymes that free nutrients in the

soild. The plants provide the fungus with energy from

photosynthesis