20-1 The Kingdom ProtistaProtists are ______________ that are not members of the Plant, Animal, or Fungi Kingdoms. The Kingdom Protista may include more than 200,000 species. Most, but not all, protists are __________________.

One way protists can be classified is by how they obtain nutrition: ________________ are animal-like protists. ___________________ are plant-like protists. ___________________ and parasites are fungus-like protists. (Note: also heterotrophic)

The first eukaryotic organisms on Earth were _____________. The theory of ___________________ suggests that mitochondria and chloroplasts in eukaryotic cells may have descended from ________________________ that lived inside larger cells.

Evolution of Protists

Chloroplast

20–2 Animal-like Protists: ProtozoansThere are four _________ of ___________-like protists. They are classified by their means of _______________________:

1. Zooflagellates (P. Zoomastigina)

2. Sarcodines (P. Sarcodina)

3. Ciliates (P. Ciliophora)

4. Sporozoans (P. Sporozoa)

Ciliates (Ciliophora)

_____________ use cilia for feeding and movement. Cilia are short _____________ projections that propel a cell or surrounding fluid. One type of ciliate is a ________________. In a paramecium, the cilia are grouped into rows and bundles, and beat in a regular pattern. ___________________ are bottle-shaped structures found just below the surface of the cell membrane that are used for defense.

Paramecia possess two types of nuclei: The _______nucleus keeps multiple copies of most genes that the cell needs in its day-to-day existence. The _______nucleus contains a copy of all of the cell's genes.

Cilia sweep food particles into the _______________. The gullet traps the particles and forces them into food vacuoles. The food vacuoles fuse with lysosomes which contain digestive _______________. Once the material in the food vacuole is digested, the waste material empties through the anal pore.

In fresh water, water moves into the paramecium by __________________. Excess water is collected in contractile vacuoles, cavities in the cytoplasm that are specialized to collect water. Once full, they ______________________, pumping water out of the organism.

Ciliates(Ciliophora)

Ciliates reproduce _______________ by mitosis and _____________. When placed under stress, paramecia may engage in _____________ which allows them to exchange ______________ material with other individuals and increase genetic _________________.

Ciliate Conjugation

Two paramecia attachthemselves to each other.___________ produces four ____________ micronuclei, three of which disintegrate.

The remaining micronucleus in each cell divides again by _____________.

Conjugation is _______ a form of reproduction. In large populations, conjugation helps produce and maintain genetic ______________.

Exchange ofmicronuclei

Macronuclei disintegrate

New macronuclei form

Macronucleus

Micronucleus

MEIOSIS

Genetically identical paramecia

Disintegration & MITOSIS

The two cells exchange ___ micronucleus from each pair which __________.

The ________________ disintegrate, and each cell forms a new macronucleus from its _________________.

Zooflagellates (Zoomastigina)

Animal-like protists that swim using ________ are called zooflagellates. Most zooflagellates have one or two flagella, although a few species have many. Most zooflagellates reproduce ____________ by mitosis and cytokinesis (_______________ _______________).

STD

•Sand Fly vector•Infects skin and/or internal organs

•Tsetse Fly vector•African Sleeping Sickness

Sarcodines (Sarcodina)Sarcodines include: Foraminiferans, Amoebas & Heliozoans (“sun animals”).

Nucleus

Food vacuole

Contractile vacuolePseudopods

________________ are animal-like protists that have ______________, temporary cytoplasmic projections used for feeding or movement. _________ are flexible, active cells with thick pseudopods that extend out of the central mass of the cell. Cytoplasm ___________ into the pseudopod, and the rest of the cell follows. This type of locomotion is known as _______________ movement. Amoebas reproduce by mitosis and cytokinesis (______________ ______________).

Sporozoans (Sporozoa)

________________ do not move on their own—they are _________ on a wide variety of organisms, including worms, fish, birds, humans and other mammals. Many sporozoans have _________ life cycles that involve more than one _______. They reproduce by _______________, which attach to a host cell, penetrate, and live within it as a parasite.

Possibly all mammals, including humans, can become infected with Toxoplasma. One source of infection is the ingestion of material contaminated with sporulated oocysts excreted by cats. For example, children of crawling and dirt-eating ages are believed to be at higher risk for infection. Toxoplasmosis can also be acquired through the ingestion of undercooked meat containing tissue cysts or tachyzoites. In fact, most infections in the United States and Europe among adults are probably acquired from undercooked meat. Mutton and pork are more common sources than beef.Toxoplasma can also be transmitted from mother to fetus, often with dire consequences. Congenital transmission can only occur during an acute infection (ie, sporozoites) acquired during pregancy. Mothers with a chronic infection acquired before the pregnancy are not at a risk for transmitting Toxoplasma.

Sporozoites

Animal-like Protists and Disease

Some animal-like protists cause serious diseases, including _______ and African sleeping sickness. Malaria is one of the world’s most serious infectious diseases, killing as many as ___ million people each year. The sporozoan _______________, which causes malaria, is carried by the female Anopheles ________________.

The Sexual Phase A female Anopheles mosquito bites a human infected with malaria and picks up Plasmodium gamete cells. Gametes fuse to form zygotes, meioses occurs, and sporozoites are produced and migrate to salivary gland.

Infected mosquito bites another human, injecting saliva that contains Plasmodium sporozoites.

The Asexual Phase Sporozoites infect liver cells and multiply asexually.

Infected liver cells burst, releasing Plasmodium cells called merozoites.

Merozoites infect red blood cells and reproduce asexually.

Infected red blood cells burst, releasing merozoites that infect other red blood cells. Some cells release gametes that can infect mosquitoes.

Animal-like Protists and Disease

1. African ___________ Sickness

2. ___________ Dysentery

3. ___________

Trypanosoma brucei

Tsetse fly

Note abundant large amebic trophozoites (Entamoeba histolytica) with clear bubbly cytoplasm. 40X

Ecology of Animal-like Protists

Many animal-like protists are essential to the living world. •Some live ____________ with other organisms (parasitic/mutualistic)•Some recycle nutrients from dead organic matter (______________).•Some live in water, where they are eaten by tiny animals, which in turn serve as food for larger animals (1º ____________________).

The protist Trichonympha lives within the digestive systems of ______________. It breaks down _____________, allowing termites to digest wood.

20–5 Funguslike Protists

Like fungi, funguslike _____________ are _________________ that absorb nutrients from dead or decaying organic matter. Unlike most true fungi, funguslike protists contain centrioles. They also lack the ____________ cell walls of true fungi.

Slime Molds

Slime molds are funguslike protists that play key roles in recycling organic material. At one stage of their life cycle, slime molds look just like _______________. At other stages, they form moldlike clumps that produce ____________, almost like fungi.

Fruitingbody Spores Emerging

amoebas

Fruiting body

Aggregatedamoebas

Migrating colony

Solitary cell

Zygote

Most _________________ slime molds are free-living cells not easily distinguishable from soil ______________. In nutrient-rich soils, these amoeboid cells _______________ produce diploid zygotes. When food is scarce, the cells asexually produce ____________. The amoeboid cells emit chemicals to attract others of the same species. Cells gather into a _____________ that functions like one organism. The colony moves slightly, then stops to produce a fruiting body or ____________, a slender reproductive structure that produces spores. The spores are scattered from the fruiting body, each producing one cell.

Cellular Slime Molds (Acrasiomycota)

______________ slime molds begin as amoeba-like zygotes. When they aggregate, their cells fuse to produce _______________ “super cell-like” structures known as _______________. Fruiting bodies, or sporangia, arise from the plasmodium producing haploid _________ by meiosis. The spores scatter and germinate into flagellated cells which fuse to produce _____________, amoeba-like zygotes.

Spores Germinating

Maturesporangium Young

sporangiumMature

plasmodium

Feedingplasmodium

Zygote

Fertilization

Acellular (Plasmodial) Slime Molds (Myxomycota)

Water Molds (Oomycota)

_______________, or water molds thrive on dead or decaying organic matter in water and some are plant ______________ on land. Like true fungi, water molds produce thin filaments known as __________. Unlike true fungi, they have cell walls made of _____________ and produce ________________ spores. During asexual reproduction, portions of the hyphae develop into ____________________, which are spore cases. Each produces __________________ spores that swim in search of food, then develop into hyphae, which grow.

FERTILIZATION

SEXUAL REPRODUCTION

ASEXUAL REPRODUCTION

MEIOSIS

Mycelium (2N)

Zoosporangia Flagellated Spores (2N)

Hypha Germination and mitosis

Antheridium(male nuclei)

Oogonium (egg cells)

Zygotes (2N)

_______________ reproduction occurs in specialized structures formed by the ___________. The _________________ produces male nuclei. The _________________ produces female nuclei. Fertilization occurs within the oogonium, and the spores that form develop into new organisms.

Zoosporangia

FlagellatedZoospores (2N)Mycelium

(2N)

Oogonium Malenuclei (N)

Antheridium Egg cells (N)

Fertilization

Zygotes (2N)MEIOSIS

FERTILIZATIONWater Molds (Oomycota)

Ecology of Funguslike Protists

Slime molds and water molds _____________ organic material. After organisms die, their tissues are broken down by slime molds, water molds, and other _________________. Some funguslike protists can harm living things. Land-dwelling water molds cause a number of __________ diseases, including mildews and blights. A water mold was responsible for the Great ______________ Famine in the 1800s.

20-3 Plantlike Protists: Unicellular Algae

Plantlike protists contain _______________, carry out photosynthesis, are commonly called _________ and are sometimes classified with plants.

Chlorophyll and accessory _____________ allow algae to harvest and use the energy from ______________. Some algae have evolved different forms of chlorophyll—a, b, and c—that absorb different ________________ of light. Accessory pigments absorb light at different wavelengths than chlorophyll, giving algae a variety of _____________.

One trait used to classify algae is the type of photosynthetic ____________ they contain. The four ________ of unicellular algae are:

1. Euglenophyta

2. Chrysophyta

3. Bacillariophyta (Diatoms)

4. Dinoflagellata

Plantlike Protists

Synedra

Synura

Euglena

Ceratium

Euglenophytes (Euglenophyta)

Gullet Flagella

Eyespot

Pellicle

Contractilevacuole

Carbohydratestorage bodies

Chloroplast

Nucleus

Euglenophytes are plantlike protists that have two _____________ but no cell ________. Two flagella emerge from a gullet. The longer of the flagella spins so it ________ the organism rapidly through the water. Near the gullet is a reddish pigment known as the ________, which helps find sunlight to power photosynthesis.

Euglenas can also live as ________________. Euglenas store carbohydrates in small storage bodies. Instead of a cell wall, they have an intricate cell membrane called a _____________, which folds into ridges, each supported by microtubules.

Euglenas reproduce _____________ by binary fission.

Members of the phylum _________________ are a diverse group of plantlike protists that have _________-colored chloroplasts. The cell walls of some chrysophytes contain the __________________ pectin rather than cellulose, some both. Chrysophytes store food in the form of ________ rather than starch. They reproduce both asexually and sexually. Most are ____________, but some form threadlike colonies.

Bacillariophyta (____________) produce thin, delicate cell walls rich in ____________ (Si)—the main component of glass. The walls are shaped like the two sides of a __________ dish or flat pillbox, with one side fitted snugly into the other.

Chrysophytes (Chrysophyta) & Diatoms (Bacillariophyta)

About half of the ___________________ arephotosynthetic; the other half live as ________________.Dinoflagellates have two flagella that fit in ______________between two thick plates of ______________ that protect the cell. Most dinoflagellates reproduce _______________ by binary fission. Many are _____________________ and when agitated, give off light as a warning to predators. These species produce a ___________ which can kill fish and humans that eat shellfish during a “________ tide”.

(Pyrophyta)

Ecology of Unicellular Algae

Plantlike protists are important to freshwater and marine __________ because they make up the ________ of the food web in many aquatic ecosystems. _________________ constitute the population of small, photosynthetic organisms found near the surface of the ocean. They carry out half of ___________ photosynthesis and provide nourishment for many organisms.

Ecology of Unicellular Algae

Many protists are vital in ______________ sewage and other wastes. When waste is excessive (_______________), algae may grow into enormous masses known as ______________, which deplete the water of nutrients. Their __________________ robs water of oxygen, killing fish and invertebrate life.

20-4 Plantlike Protists: Colonial/Multicellular AlgaeThe three __________ of algae that are largely multicellular are:

1.red algae (_______________)

2.brown algae (_______________)

3.green algae (_________________)

Red Algae (Rhodophyta)

Red algae are able to live at great _____________ due to their efficiency in harvesting light energy. Red algae contain chlorophyll a and reddish accessory pigments called ________________ which absorb blue light, enabling red algae to live deep in the ocean.

Brown algae contain chlorophyll a and c, as well as a brown accessory pigment, __________________, which absorbs blue-green to yellow-green light. Brown algae are the __________ and most complex of the algae. All are ___________________ and most are marine, commonly found in cool, shallow coastal waters of temperate or arctic areas.

Brown Algae (Phaeophyta)

Fucoxanthin

Blades

Bladder

Stipe

Holdfast

Fucus (Kelp), a common brown alga.

__________________ the alga to rocks.

A flattened ______________ structure.

Leaflike structures(AKA _____________)

_______-filled bladders keep the alga ____________ and upright.

Green Algae (Chlorophyta)

Green algae share many characteristics with ___________, including their photosynthetic pigments and cell wall composition. The ancestors of modern land plants looked like certain species of living green algae, _________________. Green algae live in fresh and salt water, and moist land areas. Many species live most of their lives as single cells. Others form _________________, groups of similar cells that are joined together but show few _________________ structures. A few are __________________ and have specialized structures.

Charophyceans are named after the stonewort, Chara.

Reproduction in Green Algae

Pairing of plus andminus gametes

Zygote

Release of haploid cells

In suitable living conditions, this haploid cell reproduces asexually, producing cells called zoospores by mitosis.

If conditions become unfavorable, Chlamydomonas can also reproduce sexually.

zoospores

The zygote grows a thick protective wall that can survive conditions that otherwise would kill it.

The life cycles of many algae include both a diploid and a _________ generation. Switching between haploid and diploid stages during a life cycle is known as _____________ of generations. Many alga also shift between sexual and asexual reproduction. The unicellular Chlamydomonas spends most of its life in the _____________ stage.

Reproduction in Green Algae

The life cycle of the green alga Ulva involves alternation of _________________. One generation are __________________, haploid, gamete-producing Ulva. When male and female gametes fuse, they produce a diploid zygote which grows into the next generation _________________, a diploid, spore-producing Ulva.

Male gametophyte

Gametes Female gametophyte

Gametes fuse

Zygote

Sporophyte

Spores

Mitosis Meiosis

Fertilization

Mitosis Mitosis

Ecology & Human Use of Algae

Algae produce half of Earth’s _____ through photosynthesis.

Algae is found in sushi, ice cream, and other foods.

______________ from algae are used to make plastics, waxes, transistors, deodorants, paints, lubricants, and artificial wood.

_________ thickens nutrient mixtures in scientific labs.