Fungi
They are heterotrophs that absorb nutrients from their environment by secreting enzymes
They include lichens, yeasts, molds, mushrooms and more
They contain cell walls made of chitin
Most multicellular fungi contain hyphae
Hyphae are tiny tube like filaments that form a network
Hyphae grow through and in the fungi's food
The interconnected network of hyphae is called mycelium
The mycelium has a root like appearance as both are made to maximize the surface area for absorption
Mycelium is very densely packed1 cc of soil can contain enough hyphae to stretch out to 1 kilometer when laid end to end
Types of fungi
Based on their diet, fungi can be broadly classified into the following types:
Decomposers:
They derive nutrition from non-living organic matter
They are one of very few organisms that can break down the lignin present in the bark of trees
They can also breakdown proteins into amino acids
Mutualists:
Group of fungi that are in a symbiotic relationMutualist or give and take relation or provide and derive relation with other creatures, mainly vascular plants
Many of them contain specialised hyphae called haustoria
Haustoria tangle themselves with roots of plants and help facilitate exchange with the host
They help absorb nutrients, especially phosphates, by being more efficient at breaking them down than the roots
They then get sap as payment for their work
This relation is also called mycorrhizaeGreek for fungus root
Almost all vascular plants have mycorrhizal fungi in their roots
They are useful in agriculture
Predators:
They derive nutrition by capturing prey with their hyphae and digesting it
Nematophagous fungi are fungi that specialize in trapping and digesting nematodes
Parasites:
They derive nutrition from hosts with out killing them
Plant parasitic fungi also contain haustoria and use it to take nutrition
Some fungi, like ophiocordyceps unilateralis , can even alter the behavior of their hosts
Some parasitic fungi are also known to infect other fungi, including other parasitic fungi
Reproduction:
They propagate themselves using huge amounts of spores
They can reproduce sexually or asexually
Sexual reproduction:
When mycelium from one fungus sends pheromones that are picked up and bound to receptors in another fungus
This compels the mycelium to send its hyphae to each other
Upon meeting, the cytoplasms of their cells fuse without fusing the nucleiAlso called the plasmogamy stage
This is followed by the fusion of the 2 nucleiAlso called the karyogamy stage
This is followed by meiosis leading to spore formation
Some fungi produce spores in sac-like structures called asci, present in fruiting bodiesspore producing structures called ascocarps
Some fungi release spores into the wind, others in the water, others on other organisms
Mating types:
Some fungi can only reproduce with fungi of compatible mating typesPresent in species that produce gametes with the same morphology, because of this the organisms cannot be classified into male or female
The mating type is represented by "+" or "−" or with numbers
This is distinct from biological sex and is thought to be the ancestor of distinct sexes
Successful reproduction occurs in fungi of different mating types
Asexual reproduction:
Some fungi undergo asexual reproduction
This can occur via spore formation or through fragmentation
Spores are formed through filaments like structure
Filaments are formed through mitosis and are visible, they are known as molds
In unicellular yeast, asexual reproduction can occur through cell division or bud formation