Fungi are multicellular eukaryotic heterotrophs that do not ingest their food but rather absorb it through their cell walls and cell membranes after breaking it down with powerful digestive enzymes.

Fungi may live as saprophytes (obtain nutrients from dead organisms), symbionts (work with a mutually reciprocal relationship with a host), or parasites and, together with bacteria, are the major decomposers in the environment.

Have cell walls made of chitin (same material is found in the skeletons of arthropods)

Are made up of many tiny filaments called hyphae tangled together into a thick net-like mass called a mycelium (is the vegetative part of a fungus consisting of a mass of branching threadlike hyphae that exists below the ground or within another substrate.). This structure is well suited to absorbing food as it has a very large surface area (10 cubic centimeters of soil may contain upwards of 1 kilometer of hyphae). The hyphae may be divided by cross walls or they may be coenocytic (lack cell walls)

Most fungi are able to reproduce both sexually and asexually

Sexual Reproduction: two hyphae of different mating types each form a gametangium (organ in which gametes are produced). The two gamatangia fuse and genetic material is exchanged.

Asexual Reproduction: Production of spores or fragmentation of hyphae (budding and cell division in yeast.

Fungi are classed according to their methods of reproduction and their basic structure which, due to recent molecular studies, places them closer to animals than plants.

Very closely related to the plant like protists

Form a white fuzz on aquarium fish or on organic matter sitting in water

Only phylum with flagellated spores during sexual reproduction.

Terrestrial fungi can grow on meat, cheese, and bread and also contain those fungi that can form mycorrhizae (A fungus that grows in association with the roots of a plant in a symbiotic or mildly pathogenic relationship)

Spores produced in sporangia (an enclosure in which spores are formed) during asexual reproduction.

Sexual reproduction occurs when two hypha from different mating types fuse together. Gametes are formed in gametangia and then fuse to form a thick walled, very resistant zygospore (a thick walled resting cell) which can be displaced by the wind and remain dormant until conditions become favorable.

Sexual reproduction involves the formation of a tiny sac called an ascus that produces ascospores.

Yeasts reproduce asexually by cell division and budding. Also sexually with the formation of ascospores (which is found in the form of dry powder in bakers yeast to make bread)

Contains over 30, 000 members including yeast, truffles, powdery mildews, and the fungi that form symbiotic associations with cyanobacteria or green algae to create lichen.

Asexual spores called conidia are produced at the tips of specialized hyphae called conidiophores (non motile spores)

Penicillium mold

Includes mushrooms and shelf fungi (which are the visible fruiting bodies of the fungi), puffballs, and the plant parasites called rusts and smuts.

Mushrooms are a mass of tightly packed hyphae with a cap that contains spore producing structures called basidia which line the gills of the cap. A single mushroom can produce a billion basidospores.

Mushrooms can form overnight when the cytoplasm of thousands of hyphae in the soil stream into the mushroom.

“Fairy Rings” form as the mycelia from the fungi spread out from a central location. As the younger hyphae on the outside extend out, the older parts die as nutrients are exhausted from the soil which forms the ring pattern. The mushrooms form on the outside of the mycelia forming the ring pattern

Unfortunately there is no rule to follow to tell the difference between a poisonous mushroom and a non-poisonous mushroom.

Imperfect is a botanical term referring to a lack of sexual reproduction.

Includes Fungi that cannot be placed into any other phyla. The fungi responsible for athlete’s foot, ringworm and other skin conditions fit into this phyla. These fungi are also responsible for several plant diseases.

Recall - Phylum Chrysophyta: Golden Protists Two algae in this phylum – yellow-green algae

and golden-brown algae.

Contain one or two gold-green chloroplasts

Some have flagella Reproduce both sexually and asexually and

although usually solitary, they can live in threadlike colonies

Very thin leaf like structures to allow for exchange of nutrients and gasses with environment – not concerned about drying out.

No specialized tissues for transport – diffusion all over body of plant

No need for stem like supporting structures – supported by the buoyancy of water

Because water absorbs much of the energy from the sunlight, algae have evolved different forms of chlorophylls a, b, c, and d – which absorb different parts of the light spectrum.

Algae also have evolved accessory pigments which absorb different wavelengths of light than chlorophyll absorbs.

Habitat

Aquatic or semi-aquatic

Found in fresh water (ponds, lakes streams etc)

Found in marine areas (floating, submerged, intertidal)

Terrestrial forms grow on many moist surfaces

Many unicellular types and some Multi cellular types

Filaments

Large “leafy” types

Thin – most cells are in contact (or close to) the environment

Multicellular – organisms with different kinds of cells each performing specific functions (vegetative cells, holdfast, sporangium, gametangium antheridium/oogonium (produce sperm/egg for algae) etc…) – division of labour

Alteration of generations – sporophyte and gametophyte plants – switching back and forth between the production of diploid and haploid cells.

Gametes fuse to form spores (sporophyte) which are dispersed to undergo meiosis to form new gametophytes.

Diffusion of raw materials into the cells

Some intracellular conduction (eg. Fucus) – movement of material between cells.

Flagella

Holdfast

Air bladder – brown algae

Asexual – binary fission, zoospores, fragmentation

Sexual

Isogamy – gametes are identical to each other and swim to each other

Oogamy – definite egg and sperm – sperm motile – egg not

◦ Spirogyra – movement of gamete through tube

◦ Any cell can form gametes specialized cells which form gametes

◦ Alteration of generations – more than one free living stage of the organism (saporophyte/gametophyte)

Chlamydomonas

• Single celled green algae in

ponds, ditches and wet soil –

have an eye spot to detect light.

• Large cup shaped chloroplast

with a pyrenoid (organelle) to

synthesize and store starch.

• No large vacuoles that are found

in land plants but rather

contractile vacuoles that are

found in the protists

• Cell wall that does not contain

cellulose.

Colonial Green Algae.

Gonium - colonial algae composed of 4 - 32 cells. While they are living together each cell functions independently.

Volvox – colonial algae from between 500 to 50000 cells connected by strands of cytoplasm allowing them to communicate (ie push/pull when they swim). Almost all cells are identical except for a few that are specialize for reproduction and produce gametes.

Spirogyra and Oedogonium – threadlike green algae.

• Form long threadlike colonies called filaments that have cells stacked on each other.

• Fresh water algae that can reproduce asexually through fragmentation.

• Oedogonium can reproduce sexually by producing two specialized reproductive cells. This species utilizes holdfast cells to anchor to the bottom of a lake.

Ulva – multicellular green algae that also utilize holdfast cells to anchor to the rocks on the coastline of marine environments.

Fucus (see tank), Giant Kelp

Utilizes alterations of generations and heterogamy

Spends most of its life in the haploid stage and reproduces asexually by mitosis in favorable conditions.

Can reproduce sexually in unfavorable condtions ◦ Haploid cells continue to undergo mitosis but produce

gametes instead of zoospores.

◦ Produce gametes that appear identical (isogamy). The gametes gather in large groups, pair, join flagella and spin in the water shedding their cell walls to fuse and form a diploid zygote (fusing of gametes = syngamy)

◦ When conditions are favorable again the zygote divides by meiosis and the flagellated haploid cells swim mature and reproduce asexually.

Utilizes alteration of generations in which the haploid and diploid stages are multicellular plants.

◦ Diploid plant – sporophyte (spore producer) ◦ Haploid plant – gametophyte (gamete producer)

Has two different types of gametophytes that produce

different gametes (heterogamy)

When the two gametes fuse it doesn’t rest but rather forms a diploid multicellular sporophyte.

Specialized cells reproduce asexually by meiosis and release haploid zoospores.

Zoospores divide by mitosis to form two different types of gametophyes.

Utilizes both alteration of generation and heterogamy.

The egg is large and cannot swim whereas the sperm is flagellated and swims

Resembles land plants in that it is missing the multicelluar haploid gametophyte. The diploid sporophyte plant is the only multicellular part of the life cycle.