protists

Protists

Protozoa

• Move independently• Heterotrophic – obtain nutrients by ingesting

small molecules or cells.• Food vacuoles – where food is broken down

in.• Zooplankton – organisms that are the primary

source in aquatic ecosystems.

Reproduction

• Binary fission – division into two identical individuals.

• Multiple fission – division into more than two identical individuals.

• Conjugation – sexual reproduction, protozoa pair and exchange genetic material.

Classification

• Four Phyla:• Sarcodina – pseudopodia– Amoeba, radiolaria, naegleria

• Ciliophora – cilia– Paramecium, tetrahymena, blantidium

• Zoomastigina – flagella– Giardia, trypanosoma, leishmania, trichonympha

• Sporozoa – no locomotion, some parasitic– Plasmodium, toxoplasma

Tetrahymena

Plasmodium

Trichonympha

Naegleria

Giardia

Adaptations• Eyespot – detect changes in the quantity and

quality of light.• Some protozoan sense physical and chemical

changes or obstacles in their environment.• Cyst – dormant form, hardened external

covering, metabolic activity stop. Allow them to survive harsh conditions.

• Conditions are favorable protists emerge from cyst.

Evolution

• First prokaryotes evolved 3.5 billion years ago.• 1.5 billion years ago first eukaryotic organisms

evolved.• Protozoa descended from these early

eukaryotes.• Endosymbiosis

Fungi

• Objectives:– Describe the origin and evolution of fungi– Compare fungi with other eukaryotic organisms.– Describe how fungi obtain nutrients.– Distinguish between a hypha and a mycelium.

Characteristics

• Most fungi are:• Molds – tangled masses of filaments of cells.

• Yeasts – unicellular organisms, circular.• Hyphae – filaments of fungi.• Chitin – cell walls of hyphae. (unique to fungi)

Armillaria

• Lives underground• Occupies a space of 861,000 ft2

Ingestion

• Fungi secret enzymes to break down food then absorb the digested nutrients through their cell wall.

• Most fungi are saprophytic – live on organic compounds that they absorb from dead organisms in the environment.

Structure of Fungi• Mycelium – mat of hyphae visible to the

unaided eye.• In some fungi hyphae is divided by cross

section called septa. • Coenocytic – hyphae of species that do not

have septa.

Three Phyla of Fungi

• Zygomycota – coenocytic hyphae, spores.– Penicillium, mucor, rhizopus

• Basidiomycota – septate hyphae, reproduce sexually.– Puccinia, ustilago (mushrooms)

• Ascomycota – septate or unicellular hyphae, budding, spores– Yeast, morel

Molds

-fuzzy growth, spore-producing.-the hyphae of molds grow into the food, digesting it as they grow.

Ex.) athlete’s foot, used in making cheese, bread mold, dutch elm disease, penicillin (antibiotic fights bacteria),

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Mushrooms Cap – where the spores are contained.

Stalk – where the cap grows from.

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Yeasts, Truffles

- Single-celled fungi.

- Grows on: sap of plants, animal tissues, shower curtains, human skin.

- Used in food: bread, beer

- Reproduces by budding.19

Fungi as a Food

• Truffles• Very expensive.

• Fungus in man’s face

• Homework: worksheet

• Bonus: bring in pond water, carageenan label