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 Cells are arranged in filaments called hyphae Filaments can make elaborate structures

Fungi are heterotrophs 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 Digest dead organic matter, cycle nutrients Important in decay of wood - lignin, cellulose are difficult to break down

Fungi are pathogens and predators Can feed on living organisms Major problem for plants Oyster mushrooms secrete chemical cue that attracts nematode worms, then anesthetizes and digest them

Fungi have commercial uses Yeast - General term for ~250 species of secondarily signle celled fungi - Used in alcohol production, baking 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 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