ProtistsProtists

Kingdom ProtistaKingdom Protista

(The hodge-podge Kingdom)(The hodge-podge Kingdom)

Section 20-1Section 20-1 Kingdom ProtistaKingdom ProtistaProtist = any organism that is not a plant, animal, fungus, or Protist = any organism that is not a plant, animal, fungus, or

prokaryoteprokaryote

- this kingdom is mostly unicellular, but includes many - this kingdom is mostly unicellular, but includes many multicellular organisms as well multicellular organisms as well

- this kingdom will be broken into several kingdoms based - this kingdom will be broken into several kingdoms based on DNA analysis and other factorson DNA analysis and other factors

- similar to the first eukaryotes- similar to the first eukaryotes

Classification of the Protists is based on Classification of the Protists is based on NutritionNutrition

A) heterotrophic = animallike protists = protozoa

B) autotrophic = plantlike protists

C) decomposers/parasites = funguslike protists

Endosymbiont HypothesisEndosymbiont Hypothesis – Lynn Margulis

- hypothesis that explains the evolution of the first eukaryotic cells from symbiotic prokaryotes

Animallike Protists = ProtozoansAnimallike Protists = Protozoans

- Unicellular heterotrophs

- Four phyla based on locomotion:

a. Zoomastigina – swim using flagella

b. Sarcodina – move with pseudopodia

c. Ciliophora – swim with cilia

d. Sporozoa – no locomotion

A.

B.

C. D.

Zoomastigina = Zooflagellates- most have one or two flagella

- most absorb nutrients through cell

membrane

- often decomposers or parasites

- reproduce primarily by mitosis

- Trypanosomes – African Sleeping Sickness

- Trichomonas vaginalis – most common protozoan infection in humans

Phylum Sarcodina – SarcodinesPhylum Sarcodina – Sarcodines- move and feed via pseudopods

- temporary cytoplasmic extensions

- ameboid movement

- surround and engulf food into food vacuoles, digested nutrients are used, and undigested materials exit through the cell membrane

- reproduce by mitosis and cytokinesis

- Amoebas are best known examples

- Foraminiferans

- sarcodines of warm oceans with calcium carbonate shells

- White Cliffs of Dover in England

Heliozoans

Ameba Feeding with PseudopodsAmeba Feeding with Pseudopods

Phylum Ciliophora – CiliatesPhylum Ciliophora – Ciliates- use cilia for locomotion and feeding

- very fast swimmers

- live in both fresh and salt water

- most are free-living

Internal Structures of Paramecium

- trichocysts – small defensive structures

- macronucleus – controls normal activities

- micronucleus – reserve copy of genes;

exchanged during conjugation

- gullet – oral groove into which food enters

- food vacuoles form around food and

lysosomes fuse with it to digest food

- wastes exit through anal pore

- contractile vacuoles keep water balance

Paramecium AnatomyParamecium Anatomy

Paramecium Conjugation- normally paramecia reproduce by mitosis and cytokinesis

- during stressful times they sometimes undergo conjugation

- exchange micronuclei with each other

- not reproduction because no new cells are formed, but it helps produce and maintain genetic diversity

Phylum Sporozoa – SporozoansPhylum Sporozoa – Sporozoans

- do not move on their own

- parasitic

- often have complex life cycles with more than one host

- reproduce by means of sporozoites

Animallike Protists and Disease

1. Malaria

- Plasmodium parasite kills up to 2 million people per year

- Female Anopheles mosquitoes are the vector

- mosquito’s saliva enters a person with sporozoites which get in person’s blood

- sporozoites enter liver and red blood cells- sporozoites enter liver and red blood cells

- when erythrocytes burst it causes severe chills and fever- when erythrocytes burst it causes severe chills and fever

- many strains of malaria have evolved resistance to the - many strains of malaria have evolved resistance to the drugs we use against the parasitesdrugs we use against the parasites

- best control is to control mosquitoes- best control is to control mosquitoes

sporozoitessporozoites

merozoites

male gametophyte in erythrocyte

2. African Sleeping Sickness 2. African Sleeping Sickness

- Zooflagellate - Zooflagellate TrypanosomaTrypanosoma

- spread by Tsetse flies- spread by Tsetse flies

- damage the nervous system and can cause death- damage the nervous system and can cause death

3. Amebic Dysentery3. Amebic Dysentery

- causes severe diarrhea and intestinal bleeding- causes severe diarrhea and intestinal bleeding

- - EntamoebaEntamoeba

- spreads by contaminated drinking water- spreads by contaminated drinking water

4. 4. GiardiaGiardia

- a flagellated protozoan that also causes diarrhea and - a flagellated protozoan that also causes diarrhea and digestive system problemsdigestive system problems

Ecologically many protists are important decomposers and Ecologically many protists are important decomposers and symbionts with other organismssymbionts with other organisms

- - TrichonymphaTrichonympha in termite guts digest cellulose in termite guts digest cellulose

Sec. 20 -3 Plantlike Protists – Unicellular AlgaeSec. 20 -3 Plantlike Protists – Unicellular Algae

- often classified based on the type of photosynthetic pigments they have

- have many different pigments to absorb the light that can penetrate into deep water (blue)

- have chlorophyll a, b, and c

- accessory pigments absorb wavelengths that chlorophylls can’t

Phylum Euglenophyta

- have two flagella, but no cell walls

- genus Euglena

- found in lakes and ponds

- eyespot allows them to swim toward light

- can live autotrophically or heterotrophically

Phylum Chrysophyta – Yellow-green + golden-brownPhylum Chrysophyta – Yellow-green + golden-brown

- means “golden plants”

- cell walls of pectin rather than cellulose

- golden algae often cause fish kills

Lake Wichita

Spring 2009

Phylum Bacillariophyta – DiatomsPhylum Bacillariophyta – Diatoms

- make shells of silicon (glass)

- shells of two parts like a petri dish

Phylum Pyrrophyta – DinoflagellatesPhylum Pyrrophyta – Dinoflagellates

- half are heterotrophic; half autotrophic

- most have two flagella and a shell of thick cellulose

- many are luminescent

- Pyrrophyta means “fire plants”

Ecology of Unicellular AlgaeEcology of Unicellular Algae

1. Phytoplankton1. Phytoplankton

- small photosynthetic organisms in the ocean- small photosynthetic organisms in the ocean

- perform about half of all photosynthesis on Earth- perform about half of all photosynthesis on Earth

- are the base of the food chain – all sea-life - are the base of the food chain – all sea-life depends on these autotrophsdepends on these autotrophs

2. Algal Blooms2. Algal Blooms

- happen when excess nutrients are in water and - happen when excess nutrients are in water and algae grow very rapidlyalgae grow very rapidly

- when nutrients are used up and the algae die, - when nutrients are used up and the algae die, their decomposition takes all of the oxygen out their decomposition takes all of the oxygen out of of the water which causes many other the water which causes many other organisms organisms to dieto die

- “Red tides” can make shellfish poisonous- “Red tides” can make shellfish poisonous

Plantlike Protists: Red, Brown, and Green AlgaePlantlike Protists: Red, Brown, and Green Algae- these groups are mostly multicellular

- most have cell walls and life cycles like plants

Phylum Rhodophyta = Red Algae

- can live at great depth (260 meters) due to their efficiency at harvesting light energy

- contain chlorophyll a and reddish accessory pigments called phycobilins which absorb blue light

- important in coral reefs

Phylum Phaeophyta = Brown AlgaePhylum Phaeophyta = Brown Algae

- contain chlorophyll a and c and the accessory - contain chlorophyll a and c and the accessory pigment fucoxanthinpigment fucoxanthin

- largest and most complex algae- largest and most complex algae

- mostly marine and often in cool, shallow- mostly marine and often in cool, shallow

coastal watercoastal water

- Kelp forests on west coast of U.S.- Kelp forests on west coast of U.S.

- - SargassumSargassum forms huge floating mats forms huge floating mats

on the oceanon the ocean

- many have air-filled bladders that - many have air-filled bladders that

help them floathelp them float

Phylum Chlorophyta – Green AlgaePhylum Chlorophyta – Green Algae

- ancestors of green plants- ancestors of green plants

- cellulose cell walls, contain chlorophyll a and b; - cellulose cell walls, contain chlorophyll a and b; and store food as starchand store food as starch

- most are aquatic, but some live on moist land- most are aquatic, but some live on moist land

- both unicellular, colonial, and multicellular- both unicellular, colonial, and multicellular

- Chlamydomonas- Chlamydomonas

- - unicellularunicellular

UlvaUlva - multicellular - multicellular

Volvox colonies

A thick-walled resistant zygote develops.

Meiosis and Germination

Haploid cell (- strain)

Haploid cell (+ strain)

Mitosis ASEXUAL

REPRODUCTION

More spores produced.

More spores produced.

ASEXUAL REPRODUCTION

–

+

SEXUAL REPRODUCTION +–

Cytoplasmic Fusion

Diploid Stage

Haploid Stage

Zygote (cross-section)

Nuclear Fusion

Gametes of differentmating types meet.

Life cycle of a species of Chlamydomonas

sporophyte (2n)

germinating spore (n)

10 cmgametophyte (n)

female gametes

male gametes

zygote

MeiosisDiploid StageHaploid Stage

Fertilization

Human Uses of AlgaeHuman Uses of Algae

- algal chemicals are used to treat stomach ulcers, - algal chemicals are used to treat stomach ulcers, high blood pressure, arthritis, and other health high blood pressure, arthritis, and other health problemsproblems

- many foods contain algae or algal products- many foods contain algae or algal products

- thickening agent in ice cream, salad dressing, - thickening agent in ice cream, salad dressing, puddings, and candy barspuddings, and candy bars

- industry uses algal chemicals to make plastics, - industry uses algal chemicals to make plastics, waxes, deodorants, lubricants, even artificial woodwaxes, deodorants, lubricants, even artificial wood

- agar is used in biology labs to grow bacteria on- agar is used in biology labs to grow bacteria on