The protists are the most basal eukaryotes

-Every eukaryrote that is not a plant, animal, of fungus is a protist (negative definition)

-Phylogeny not well resolved

-Evolved mitochondria and chloroplasts

-Evolved sex

-Evolved multicellularity

Chapter 21 Key points:

Fungi were the first to colonize land

What are the characteristics of fungi?

How are fungi classified?

What are the roles of fungi?

Which would you rather colonize?

Fungal associations with cyanobacteria allowed colonization of land

Lichens

-Form “symbiotic” relationship with cyanobacteria

-Fungi digests rock, supplies minerals to cyanobacteria

-Cyanobacteria fixes CO2 into food source

-Result in break down of rock into soil, lichens become organic matter

Fungi are a “true” multicellular organism - not much specialization but cell activities are highly coordinated

Cells are connected, share cytoplasm

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Cells are arranged in filaments called hyphae

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Filaments can make elaborate structures

Fungi are heterotrophs

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Most cells are in contact with environment

Secrete digestive enzymes, absorb minerals and nutrients from surrounding

Filamentous structure allows sharing of resources, can grow according to environment

What are the pros and cons of classification based on characteristics of reproduction?

Fungi are classified by details of reproduction

All can reproduce asexually and sexually

Fungi are decomposers

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Important in decay of wood - lignin, cellulose are difficult to break down

Fungi are pathogens and predators

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Can feed on living organisms

Major problem for plants

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Oyster mushrooms secrete chemical cue that attracts nematode worms, then anesthetizes and digest them

Fungi have commercial uses

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Yeast

- General term for ~250 species of secondarily signle celled fungi

- Used in alcohol production, baking

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Reproductive structures (mushrooms) are a major food source

- Penicillin is derived from fungus

Fungal symbiotic association with plant roots (mycorrhyizae) was pivotal in plant evolution

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Effect of mycorrhizae on soy bean plant growth

Augment root structure of plants

Assist in uptake of minerals

Receive food from plant

First fossil plants had mycorrhizae, likely aided terrestrial colonization

Chapter 21 Key points:

Fungi were the first to colonize land - Lichens

What are the characteristics of fungi? - Heterotrophic, multicellular, filamentous

How are fungi classified? - Based on details of reproduction

What are the roles of fungi? - Decomposers, pathogens, commercial, symbiotic