Post on 24-Feb-2016
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Characteristics of Fungi In partners or as a group – what
characteristics define a fungus (pl)? If you said:
EukaryoticHeterotrophic, but do not have an internal
digestive system (have external digestion)Non vascular (no root system)Reproduce sexually and asexually
You’d be right!
Wait...Fungi aren’t plants?Plants
Have a root system
AutotrophsCell wall
composed of cellulose
FungiNon-vascular
systemHeterotophicCell wall is
composed of chitin
Structure of FungiSome fungi are
single-celled They are called
yeastsValuable
economically – can you think why?
Structure of FungiMost fungi are
multi-cellularBody of a fungi
generally occurs below ground
Body = mycelium = a branching, mesh-like network of hyphae
Structure of Fungi cont.An individual filament is called a
hypha (hyphae (pl))One long continuous multicellular
structure
Structure of Fungi cont. So what is a
‘mushroom’?It is the spore
producing reproductive structure of a fungus, which is called the fruiting body
Made of hyphae that are densely packed together
Fungal NutritionFungi release enzymes into their
surrounding Enzymes break down the food externallyFungi then absorb the nutrients that have
been released by the enzymes through its cell membrane
One way of classifying fungi is through the four different ways that they obtain nutrients
Fungal Nutrition1. Parasitic
Fungi absorbs nutrients from the living cells of a host organism
Results in death of the host
Fungal Nutrition2. Predatory
Soil fungi whose mycelia have specialized structures for trapping prey
Fungal Nutrition3. Mutualistic
Fungi that have partnerships with other organisms (e.g. Plants, protists or animals)
Both organisms involved in the partnership benefit from the relationship
Fungal Nutrition4. Saprobial
Fungi that feed on dead or decaying organic matter
i.e. They are decomposers
Very important in nutrient recycling
Learning CheckWhat is mycelium and where is it
found?When you see a mushroom growing
from a dead log, which part of the fungus are you observing?
Fungal Classification 5 Major Phlya
Phylum Chytridiomycota (chytrids) Phlyum Zygomycota (zygomycetes) Phylum Deuteromycota Phylum Ascomycota (ascomycetes) Phylum Basidiomycota (basidiomycetes)
Based on differences in reproduction and the structure of the fruiting body they produce
Fungi Imperfecti (Deuteromycota)
Not known to reproduce sexually Generally types of moulds E.g. Penicillium mould; mould in blue
cheese
Chytrids (P. Chytridomycota) Mostly unicellular Aquatic species (marine or freshwater) Spores have flagella (motile) Parasitic or saprophytes
Zygospore Fungi (P. Zygomycota) Multicellular and mostly terrestrial (soil) Include familiar bread and fruit moulds Generally reproduce asexually
Zygospore Fungi (P. Zygomycota) Reproduce sexually in
unfavourable conditions to produce zygospores Diploid structure (2n)
that develops after two haploid (n) hyphae of opposite types combine their nuclei. Thick wall develops around nuclei to protect it.
Sac Fungi(P. Ascomycota) Largest fungi group Develop small finger-like
sacs called asci (contain spores) during sexual reproduction (similar to creation of zygospores)
Saprophyte and parasites Includes yeasts, which
reproduce by budding
Club Fungi (P. Basidiomycota) Includes ‘mushrooms’,
puffballs, and stinkhorns
Most are decomposers, some form symbiotic (mutualistic) relationship with plants
E.g. lichen
Club Fungi (P. Basidiomycota)
Fruiting bodies release spores called basidiospores from basidia (club-shaped hypha)
Reproduction Asexual
Budding – a smaller cell develops while attached to a parent cell. Eventually, small cell is pinched off of parent cell to produce a new individual
Reproduction Asexual
Fragmentation – a piece of mycelium breaks and forms a new individual
Spore production Sexual reproduction - also involves spore
production and often the creation of a fruiting body above ground
Fig3.21 (hand-out)
The Importance of Fungi Fungi are:
Decomposers – one of the most important groups for recycling materials along with Bacteris
Form symbiotic relationships – esp. with plants. Without these relationships plant growth and productivity would be reduced
Food source (e.g. Blue cheese, mushrooms) and used in food production (bread, beer)
The Importance of Fungi Fungi are:
Sources of antibiotics (medicine) (e.g. Penicillin). The discovery of antibiotics revolutionized health care worldwide.
Biocontrol – use fungi that target insects to control crop pests (e.g. Chinese caterpillar fungus; control of California potato beetles). This is cheaper and less damaging to the environment than using chemical pesticides
The Importance of Fungi Fungi
Cause animal and plant disease (e.g. Every year 10 – 50% of world’s fruit harvest is destroyed by fungi!) (e.g. Athlete’s foot, ringworm)
Food spoilage (mould)
Meet the worlds largest organism
http://www.scientificamerican.com/article.cfm?id=strange-but-true-largest-organism-is-fungus
Honey mushrooms – give an inkling of what is below.