chapter 21: protists and fungi section 21-4: fungi
TRANSCRIPT
Chapter 21: Protists and
FungiSection 21-4: Fungi
What are Fungi?O Heterotrophs – produce enzymes
that digest food outside their bodies, then absorb the nutrients
O Most feed on decaying material in the soil, some are parasitic
O Cells walls made of chitin – also found in exoskeletons of insects
O More closely related to animals than plants
Structure and FunctionO Yeasts are the only unicellular fungiO Mushrooms and other fungi are
larger, with bodies made up of cells forming long, slender branching filaments called hyphae
Structure and FunctionO Cross walls divide the hyphae into
compartments, each containing 1 or 2 nuclei
O Openings in cross walls allow cytoplasm and organelles to move
O Body of mushroom called fruiting body – reproductive structure of a fungusO Grows from mycelium – mass of branching
hyphae below soilO Clusters of mushrooms can have same
mycelium
ReproductionO Reproduce asexually, primarily by
releasing spores adapted to travel through air or water
O Breaking off hypha or budding also
ReproductionO Most reproduce sexually - life cycle
of the bread mold Rhizopus stolonifer
Sexual ReproductionO 2 mating types - + and 1O Genetic and fossil evidence shows
eukaryotes evolved from prokaryotes, more closely related to Archae than Bacteria
O Split may have come as early as 2.5 byaO Protist group now includes as many as
300,000 speciesO Most remained unicellular – except
those leading to plants, animals, and fungi