diverse and widespread and are essential for the well-being of most terrestrial ecosystems because they break down organic material and recycle vital nutrients
(Armillaria ostoyae), a fungus that covers over 2,500 acres and is growing through the earth and roots of trees on the Malheur National Forest in eastern Oregon Age estimated to be 1,900 years, weight could be hundreds of tons
Fungi as heterotrophs
they dont ingest their food but secrete exoenzymes that break down complex molecules, and then they absorb the smaller compounds. this is why these organisms are ecologically successful.
type of fungi, aka saprobes.. they're everywhere, but common on forest floor.
about thirty percent of fungi.. absorb nutrients from living host and are responsible for about 80 percent of plant disease
these are the root tip fungi and plants that help in nutrient scavenging and recieve carbon from the plant
three diverse lifestyles of fungi
decomposers, parasites, mutualistic symbionts
two most common body structures of fungi
multicellular filaments and single cells(yeast)
tiny filaments used for absorption
networks of branched hyphae adapted for absorption
cell walls of fungi are made of this
morphology of multicellular fungi
enhances ability to absorb nutrients.
hyphae divided into cells by septa with pores allowing cell to cell movement
mutualy beneficial relationships between fungi and plant roots.. since fungi are more efficient at absorbing minerals, they help plants get established through roots. Fungi increases uptake and rates of mineral absorption and the plant provides fungus with food in the form of sugar.
ektos-out.. form sheaths of hyphar over a root and grow into extracellular spaces of root cortex.. this results in plant roots that are thicker, more branched and lack hairs. 10% of plant species have this and theyre usually woody.
endos- in.. extend hyphae through cell walls of root cells and into tubes formed by invagination of the root cell membrane. theyre also called arbusular mycorrhizae.. its found in 85% of plant species including crops
reproduction of fung
spores are produced sexually or asexually
the union of two parent mycelia.. hyphae were attracted to each other by the releasing of signaling molecules called pheromones. they meet and fuse.
signaling molecules that attract hyphae together
means different nuclei.. this occurs in many fungi where the haploid nuclei from each parent don't fuse right away but coexist in the mycelium
means two nuclei.. occurs sometimes when the haploid nuclei pair off two to a cell
nuclear fusion, where the haploid nuclei fuse to produce diploid cells. the diploid phase is shortlived, undergoes meiosis and produces haploid spores.
asexual reproduction of fungi
usually grow as mold on bread, fruit and other food
clusters of bead like structures in the SEM that are conidospores at the end of aerial hyphae
asexual, by simple cell division or budding
yeast as model organisms
budding yeast and fission yeast..rapid doubling(every 2 hours), genes can be knocked out easily, first eukaryotic genome sequence, performs many of the same physiological processes as animals
some don't have a known sexual stage, some are classified based on fruiting bodies or spores.. also called deuteromycetes