Multicellular Eucaryotes most single cells take in food and oxygen and get larger size is usually achieved only by being rid of wastes by simple diffusion in and out of multicellular the cell ! cells can’t get too large without breaking in larger organisms there are more ways to solve these problems better to make lots of small cells than a eg. getting food: herbivores, carnivores, fluid feeders, few very large cells insectivores, etc multicellularity evolved many separate times among eg. getting oxygen: gills, book gills, lungs, tracheae, etc eukaryotes: !evolution of multicellularity is correlated with an seaweeds slime molds explosion of diversity in the fossil record fungi plants 3. multicellular organism becomes more resilient animals damage doesn’t kill you !must have been a clear advantage Advantages of Multicellular Life: !it can often be repaired 1. allows individual cells to become more specialized but there are some tradeoffs: for specific functions: Disadvantages of Multicellular Life: all cells don’t have to do everything 1. individual cells become completely dependent on eg. epithelial cells: cover, protect, support, etc each other eg. muscle cells: movements eg. vascular tissues: transport of nutrients and wastes and hormones ! can no longer survive on their own 2. allow much more variation in size & shape Fungi, Ziser, Lecture Notes, 2011.3 1 Fungi, Ziser, Lecture Notes, 2011.3 2 2. larger organisms need MUCH MORE food and Fungi - General oxygen like the bacteria, fungi are a largely invisible ! lots more cells to feed kingdom 3. as size increases need more elaborate ways to simplest of three complex multicellular eucaryotic supply each cell with nutrients and remove wastes kingdoms in terms of structure elaborate organ systems to collect and distribute nutrients and get rid of wastes no true tissues or organs (as in Plants and Animals) eg. vascular systems, etc over 100,000 species described !est to 1.5M 4. need method of coordination and control to get fungi are extremely abundant in some ecosystems all parts on the “same page” but not commonly seen: eg. hormones, nervous systems eg. top 20 cm (8”) of soil contains over 2 tons of microorganisms (mainly fungi)/acre 5. need some kind of support, especially on land, to counteract gravity (or ~ 2 tons of fungi and bacteria per acre (=5 metric tons per hectare (=2.47 acres))) 6. Dispersal becomes more of an issue eg. a teaspoon full of soil contains several miles of fungal filaments eg. most bacteria and protists have worldwide distributions most fungi are hidden and inconspicuous and only the relatively few large animals and plants have worldwide “fruiting bodies” are regularly seen: distributions eg. mushrooms, puffballs, morrels, shelf fungi, etc some of the largest fruiting bodies: eg. one species of shelf fungus (polypore) weighs 100 lbs (45 kg) Fungi, Ziser, Lecture Notes, 2011.3 3 Fungi, Ziser, Lecture Notes, 2011.3 4 eg. another shelf fungus in Southern England is 16 feet in The Origin of Fungi circumference and is estimated to weigh ~700 lbs (316 kg) Fungi and Plants are the only kingdoms that are eg. one species of giant puffball can grow to almost 9 feet mainly terrestrial diameter and weigh over 48 lbs (22kg) fungi appear in fossil record at about the same many are familiar with fungi only due to the diseases time and were associated with the first land and economic damage they cause: (some even take it personally): plants ! French Botanist=S Veillardi said fungi “are a cursed tribe, an The appearance of the Plant and Fungi Kingdoms invention of the devil, devised by him to disturb the rest of nature created by God.” probably occurred before animals moved onto land In Medieval times fungi were associated with witches, oldest fossil fungi are from ~400 MY ago wizards and magic molecular evidence suggests that fungi emerged ~0.5 - 1 BY ago fairy rings that appeared overnight were said to be the result of fairies dancing in a circle while but no true fossils until ~460 MY ago humans slept molecular evidence indicates some flagellate protozoan was ancestral to the fungi (and probably animals as well) the study of fungi was frowned upon by the Church and therefore our knowledge of the at the time (Devonian) that simple plants began group lagged behind other kingdoms until the producing woody trunks and creating the first 1800’s forests some of the largest fungi appear in the fossil record today fungi are known generally as “friends” rather than foes: ! featureless columns some over 15’ tall represent an extinct fungus = Prototaxitis providing bread & beer and numerous other foods recycling trash and organic matter ! probably fed off of microbial crust of bacteria, algae and lichens covering much of the more barren land of the 1 Million or so suspected species, only a handful are capable of causing disease Fungi, Ziser, Lecture Notes, 2011.3 5 Fungi, Ziser, Lecture Notes, 2011.3 6 Characteristics of Fungi the cells of most fungi have flexible cell walls 1. fungi have colonized all major habitats but are of chitin found mainly in terrestrial ecosystems like cellulose, this is a highly indigestible starch: a Nitrogen containing polysaccharide; similar but some are aquatic to exoskeleton of arthropods) a few are marine, others found in freshwaters most are aerobic a few inhabit seemingly inhospitable habitats a total lack of O2 prevents growth of most eg. inside glaciers fungi eg. acidic waters -but some yeasts can make energy anaerobically 2. fungi are the most resilient of land eukaryotes but will use oxygen when present -a few fungi that live in sewage or animal intestines many fungi are less sensitive to acidic pH’s, higher can also grow anaerobically salt (solute) concentrations, and to colder temperatures than are most bacteria 4. all fungi are nonmotile, they do not even produce motile sex cells eg. pH! range 2-9; optimum = 5.6 5. most, not all, fungi are multicellular eg. thrive in a wide range of temperatures some can thrive in freezing temps yeasts = general term for unicellular fungi !common in refrigerators molds = general term for multicellular fungi eg. thrive in high osmotic pressures !high sugar or salt concentrations, jellies, jams multicellular fungi remain much simpler in structure than higher plants and animals 3. cells of fungi are eukaryotic (have nucleus & various organelles; mitochondria, vacuoles, etc) ! no true tissues or organs cells are enclosed within cell walls Fungi, Ziser, Lecture Notes, 2011.3 7 Fungi, Ziser, Lecture Notes, 2011.3 8 except for yeasts, bodies consists of filaments when growing space is limited, the fungus infuses called hyphae the food with hyphae and assumes the shape of its food. in most the hyphae consist of chains of individual cells a mycelium can get quite large: but the cell walls do not completely separate ! fungi may be Earth’s oldest and largest adjacent cells organisms on earth ! essentially, all cells in hyphae are interconnected: eg. fungus growing beneath coniferous forest in Michigan acts as one long single celled filament 37 acres 11 tons of hyphae the hyphae form an interwoven mat = mycelium 1500 years old (mushroom growers call it “spawn”) of individual eg. Armillaria ostoyae (Washington State) feeding filaments (=hyphae) extending into 2.5 square miles – covers three counties their preferred food supply probably 1000’s of years old probably 100’s of tons mycelium represents the individual organism eg. an individual crustose lichen (a symbiosis between a fungus and algae is estimated to be up to 3,700 years hyphae grow very quickly old a single hyphal filament that grows and branches can grow 6. fungi are heterotrophs like animals over a half mile of hyphae in 24 hrs; in 2 days, 100’s of miles a. most are saprobes (decomposers) that feed the filamentous structure provides an extensive on dead organic matter surface area for absorption of nutrients: particularly good at digesting plant compounds the vegetative portion of most fungi are often such as cellulose and lignin hidden in the food they are eating ! very common on dead trees and rotting logs fungi are organisms with no clear shape: but same substances cause fungal attacks on clothing, always growing and changing paper,shoes, insulation, lumber Fungi, Ziser, Lecture Notes, 2011.3 9 Fungi, Ziser, Lecture Notes, 2011.3 10 also thrive on a great variety of other organic most of the mass of the fungus grows into the food it eats and absorbs nutrients compounds 2. rings and traps asbestos – that predatory soil fungi use to capture prey jet fuel rubber -some have adhesive ends leather th -some rings can constrict or swell in a 1/10 of a second -some prefer certain species as prey b. some fungi are parasites -once prey are “caught” hyphae penetrate the prey and digest and dissolve it then absorb nutrients eat living organic matter eg. hyphae of the common oyster mushroom, Pleurotus ostreatus some can switch between saprophytic and parasitic 3. parasitic hyphae (haustoria) some are parasitic in plants and animals, –hyphal tips of parasitic fungi that invade cells of host including humans -secrete enzymes to dissolved their way through cell walls and cell membranes ! about 300 known animal pathogens 4. reproductive hyphae ! most important cause of agricultural plant diseases - may form large visible “fruiting bodies” that produce sometimes get established in areas making it spores difficult to get agricultural crops to grow – usually the most visible part of the fungus body - reproductive hyphae produce either asexual or sexual spores c. a few are even predators 7. most fungi reproduce by sexual and asexual spores yeasts reproduce asexually by budding 8. fungi lack true tissues but hyphae have become specialized for a variety of functions: 1.