Chapter 20

Protists

Student Notes

20-1 The Kingdom Protista

Objective

• Explain what a protist is

20-1 Homework

• Define each vocabulary word in a complete sentence

• Write out each key concept.

Food for Thought

• What do you do when you get hungry?

• You probably go in search of food.

• Different organisms have different ways of obtaining the nutrients they need to live.

1. How does an animal obtain food?

2. How does a plant obtain food?

3. Predict how a microorganism described as “plantlike” might behave.

20–1 The Kingdom Protista

A. What Is a Protist?

B. Evolution of Protists

C. Classification of Protists

A. What Is a Protist?

B. Evolution of Protists

• Protista - Greek for “the very first”

• First eukaryotic organism on earth

C. Classification of Protists

• Due to diversity of group

– Heterotrophs

– plantlike protists

– funguslike protista

Concept Map

are classified by

which includewhichwhich which

Protists

Animallike FunguslikePlantlike

ParasitesTake in food from the environment

Produce food by photosynthesis

Obtain food by external digestion

Decomposers

Homework for 20-1

• All 5 questions on page 496

• Page 523: answer questions # 1, 11, 26

• Each question in at least 3 complete sentences.

Homework for 20-1

20-2 Animallike Protists: Protozoans

Objective

• Describe the major phyla of animallike protists.

• Explain how animallike protists harm other living things.

20-2 Homework

• Write out all key concepts.

• Define each vocabulary word in at least one complete sentence.

On the Move

• Think about the last time you watched a puppy at play, a fish in an aquarium, or a squirrel in the park.

• They don’t stay still for long - how do they get where they are going?

1. List five different ways in which animals can move from place to place.

2. What structures do these animals have that enable them to move?

3. What structures might a microorganism need in order to move?

20–2 Animal-like Protists: Protozoans

A. Zooflagellates

B. Sarcodines

C. Ciliates

D. Sporozoans

E. Animal-like Protists and Disease

F. Ecology of Animal-like Protists

A. Zooflagellates

• many live in lakes and streams

• Most reproduce asexually - binary fission

B. Sarcodines

– pseudopods

• amebas -

• Foraminifers

–

• Heliozoan - group means “sun animal”

Food vacuole

Nucleus

Contractile vacuole

Pseudopods

Figure 20-4 An Amoeba

Anal pore

GulletOral groove

TrichocystsLysosomes

Food vacuoles

Contractile vacuole

Micronucleus

MacronucleusCilia

Figure 20-5 A Ciliate

C. Ciliates

• phylum Ciliophora named for cilia

1. Internal Anatomy

– best know ciliated - genus Paramecium

– two types of nuclei

• macronucleus –

• micronucleus –

2. Conjugation

Macronucleus

Micronucleus

Conjugation

Macronucleus

Micronucleus

Conjugation

Macronucleus

Micronucleus

Conjugation

Macronucleus

Micronucleus

Conjugation

D. Sporozoans

• move independently

• parasitic

E. Animal- like Protists and Disease

1.Malaria

2.Other Protistan Diseases

F. Ecology of Animal- like Protists

• What is role of Trichonympha?

Plasmodium undergoes several stages of development in mosquito’s body

Section 20-2

Figure 20-7 The Life Cycle of Plasmodium

Mosquito bites human, injecting saliva that contains Plasmodium sporozoites

Plasmodium sporozoites

Sporozoites infect liver cells

Liver

Infected liver cells burst, releasing Plasmodium cells that infect red blood cells

Plasmodium cells

Red blood cells

Infected red blood cells burst, releasing Plasmodium cells; some can infect other red blood cells, and others can infect mosquitoes

Anopheles mosquito bites infected human and picks up Plasmodium cells

20–2 Homework

• Answer all 5 questions on page 503

• Page 523 questions #2-4, 12-14, 20

• Answer each question in at least 3 complete sentences.

20–2 Homework

20–3 Plantlike Protists: Unicellular Algae

Objective

• Describe the function of chlorophyll and accessory pigments in algae

• Describe the major phyla of unicellular algae

• Summarize the ecological roles of unicellular algae

20–3 Homework

• Write all key concepts.

• Define each vocabulary word in a complete sentence.

What’s in a Name?• Pyrrophyta and Chrysophyta

1. Using a dictionary, look up the prefixes pyrro- and chryso-, as well as the root -phyta. What do these terms mean?

2. Use the information you found in the dictionary to find out the meaning of Pyrrophyta and Chrysophyta.

3. Based on the meaning of their names, what characteristics might the protists in each of these phyla have?

20–3 Homework

• Define each vocabulary words in at least one complete sentence.

• Write out all key concepts.

20–3 Plantlike Protists: Unicellular Algae

A. Chlorophyll and Accessory Pigments

B. Euglenophytes

C. Dinoflagellates

D. Chrysophytes

E. Diatoms

F. Ecology of Unicellular Algae

A. Chlorophyll and Accessory Pigments

Blooms

– Contain sensory pigments

B. Euglenophytes

• closely related to animallike flagellates

C. Dinoflagellates

• half are photosynthetic

D. Chrysophytes

• yellow-green and golden-brown algae’s

E. Diatoms

• phylum Bacillariophyta

F. Ecology of Unicellular Algae

• phytoplankon

– small photosynthetic organism

1. Symbiotic Algae

– unicellular algae that form relationship with other organisms

• dinoflagellates feed on the waste products of coral animals

2. Algae Blooms

– many protists absorb organic material directly for food

– alga blooms

• many protists absorb organic material directly

Gullet

Chloroplast

NucleusEyespotFlagella

Section 20-3

Euglena

Carbohydrate storage bodies

Pellicle

Contractile vacuole

1. Why do you think Sargassum and other similar protists are called seaweed?

2.Compare and contrast Sargassum to another type of brown algae you have read about in this chapter.

3. How are they different?

20–3 Homework

• Answer all question on page 509

• Page 523 questions #5-6, 15-17, 21

• Answer all question in at least 3 complete sentences.

20–3 Homework

20–4 Plantlike Protists: Red, Brown, Green Algae

Objective

• Describe the major phyla of multicellular algae

• Explain how multicellular algae reproduce

• Identify some human uses of algae

20–4 Homework

• Define each vocabulary word in at least one complete sentence.

• Write out all key concepts.

20–4 Plantlike Protists: Red, Brown, and Green Algae

A. Red Algae

B. Brown Algae

C. Green Algae

D. Reproduction in Green Algae

E. Human Uses of Algae

A. Red Algae

• phylum Rhodophyta meaning “red plant”

• Important marine alga

B. Brown Algae

• phylum Phaeophyto - “dusky plants”

• most marine -

• largest is giant kelp - can grow > 60 meters

• most common Fucus or rockweed

C. Green Algae

• phylum Chlorophyta --> “green plant”

• ancestor of both living alga and mosses

1. Unicellular Green Algae

2. Colonial Green Algae

3. Multicellular Green Algae

E. Human Uses of Algae

• Rich in vitamin C and iron

Diploid

Haploid

FERTILIZATION

MITOSIS MEIOSIS

Gametes fuse

MITOSIS

GametesFemale

gametophyte

Male gametophyte

Spores

SporophyteZygote

Ulva Life Cycle

MEIOSIS

Haploid

Diploid

Release of haploid cells

Zoospores

Mature cell

Pairing of plus and minus gametes

Zygote

Figure 20-17 The Life Cycle of Chlamydomonas

A Protist Problem

Some protists can harm living things by causing diseases.

Imagine that you live on an island where the main source of food for the inhabitants is a single type of plant.

Protists have caused the majority of the crop of that plant to become diseased and inedible.

Predict the effect the disease will likely have on the following:

1. food supply

2. lives of the inhabitants

3. island ecosystem

4. island economy

Homework 20-4

• Answer all 5 question on page 515

• Page 523 questions #7-8, 18-19

• Answer all question in at least 3 complete sentences.

20-5 Funguslike Protists

Objective• Compare and contrast funguslike protists and fungi

• Describe slim molds and water molds.

• Summarize the ecological roles of funguslike protists

20-5 Homework

• Define each vocabulary words in at least one complete sentence.

• Write out all key concepts.

20–5 Fungus-like Protists

• heterotrophs -

A. Slime Molds

• found in damp places rich in organic matter

1. Cellular Slime Molds -

– reproduce rapidly

2. Acellular Slime Molds

– begin life cycle as ameba-like cells

B. Water Molds

• phylum oomycota

C. Ecology of Fungus-like Protists

• both slime and water molds are important as recycler of organic matter

D. Water Molds and the Potato Famine

SEXUAL REPRODUCTION

Antheridium

ASEXUAL REPRODUCTION

OogoniumNuclei (N)

Sexual fusion

Meiosis occurs within antheridium

and oogonium.

Zoosporangium

Flagellated spores

Mycelium (2N)

Section 20-5

The Life Cycle of a Water Mold

Hypha

Germination and mitosis

Diploid

Haploid

Spores(2N)

Haploid (N)

Diploid (2N)

Fruiting body Spores

Migrating colony

Emerging amoebas

Aggregated amoebas

MEIOSIS

FERTILIZATION

Zygote

Section 20-5

Figure 20-22 The Life Cycle of a Cellular Slime Mold

MEIOSIS

FERTILIZATION

ZygoteGerminating spore

SporesMature

sporangiumYoung sporangium Mature

plasmodium

Feeding plasmodium

Haploid (N) Diploid (2N)

Section 20-5

Figure 20-23 The Life Cycle of an Acellular Slime Mold

Homework 20-5

• All 5 question on page 520

• Page 523 question #9-10, 23-25

• Answer all questions in at least 3 complete sentences.

Homework 20-5