Next: What am I??Next: What am I??

One large, multinucleated cell with no cell

walls…

Revisiting the ProtistsRevisiting the Protists

Kingdom (?) ProtistaKingdom (?) Protista

60,000 known species of 60,000 known species of mostlymostly unicellular unicellular eukaryotes eukaryotes

Other eukaryotes that are Other eukaryotes that are not not Fungi, Plants or Fungi, Plants or Animals also includedAnimals also included

The The “Protista “Protista Problem”Problem”

It’s a It’s a paraphyletic paraphyletic

taxon!!taxon!!

Ecological Roles- ProtistaEcological Roles- Protista

Can divide the Protists into Can divide the Protists into three categories:three categories:

1. Protozoa1. Protozoa- - Animal-like, Animal-like, injestiveinjestive

2. Absorptive protists2. Absorptive protists – – fungus-likefungus-like

3. Photosynthesitc 3. Photosynthesitc protists-protists- algae algae

The Absorptive Protists: A Closer The Absorptive Protists: A Closer LookLook

The Plasmodial Slime Mold Life CycleThe Plasmodial Slime Mold Life Cycle

The Dictyostelida- Cellular The Dictyostelida- Cellular Slime MoldsSlime Molds

Feeding stage consists of Feeding stage consists of solitary cells functioning solitary cells functioning individuallyindividually

When food is low, cells follow When food is low, cells follow chemical trails to form an chemical trails to form an aggregate (pseudoplasmodium)aggregate (pseudoplasmodium)

Cells in the aggregate maintain Cells in the aggregate maintain their membranestheir membranes

Haploid organisms!Haploid organisms! Most have no flagellated stagesMost have no flagellated stages

Dictyostelid CinemaDictyostelid Cinema(Cellular Slime Molds)(Cellular Slime Molds)

Let’s Watch!

The Dictyostelida- Cellular Slime MoldsThe Dictyostelida- Cellular Slime Molds

http://dictybase.org/Multimedia/development/development.html

Next: Thinking Next: Thinking About About Real Real

FungiFungi

General CharacteristicsGeneral Characteristics

The Fungi: Structural OrganizationThe Fungi: Structural Organization

Sexual Reproduction in Sexual Reproduction in FungiFungi

In sexually reproducing fungi, the union In sexually reproducing fungi, the union occurs in two stages:occurs in two stages:

1. 1. Plasmogamy-Plasmogamy- fusion of the fusion of the parents’ parents’ cytoplasmcytoplasm

2. 2. Karyogamy-Karyogamy- fusion of haploid fusion of haploid nuclei of nuclei of the two parentsthe two parents

During the time lag (minutes to centuries!) During the time lag (minutes to centuries!) the mycelium is a the mycelium is a heterokaryonheterokaryon

Occasionally the haploid nuclei pair off, two Occasionally the haploid nuclei pair off, two to a cell. This mycelium is to a cell. This mycelium is dikaryotic.dikaryotic.

EvolutioEvolution of the n of the FungiFungi

Zygomycete Life Cycle

Famous Famous ZygomycotaZygomycota

The black bread mold, The black bread mold, RhizopusRhizopus

The dung fungus, The dung fungus, PilobolusPilobolus

EvolutioEvolution of the n of the FungiFungi

The Ascomycota (Sac Fungi)The Ascomycota (Sac Fungi)

30,000+ species from 30,000+ species from marine, freshwater, and marine, freshwater, and terrestrial habitatsterrestrial habitats

Unicellular yeasts to Unicellular yeasts to large elaborate morels!large elaborate morels!

Many live with algae as Many live with algae as lichens, may also form lichens, may also form mycorrhizae with plants, mycorrhizae with plants, or between cells in or between cells in leaves!leaves!

Ascomycetes

The Basidiomycota- Club FungiThe Basidiomycota- Club Fungi

~30,000 fungi ~30,000 fungi including including mushrooms, shelf mushrooms, shelf fungi, puffballs, fungi, puffballs, and rusts & smutsand rusts & smuts

Important Important decomposers decomposers (lignin!), also form (lignin!), also form mycorrhizamycorrhiza

Most vascular plants are associated Most vascular plants are associated

with with mycorrhizae.mycorrhizae.Photo: ectomycorrhizal fungi (Photo: ectomycorrhizal fungi (HebelomaHebeloma and and LactariusLactarius species) around the bases of birch trees; helios.bto.ed.ac.uk species) around the bases of birch trees; helios.bto.ed.ac.uk

EctomycorrhizaeEctomycorrhizaeEctomycorrhizae occur in almost all tree species in

temperate and boreal forests. Short growing seasons in these areas limit decomposition and create nitrogen

stress. The fungi release peptidases (exoenzymes) that break down proteins, releasing N-containing compounds.

EndomycorrhizaeEndomycorrhizae

Endomycorrhizae are found in ~80% of all plants, especially in warm/tropical grasslands

and forests. They help supply phosphorus to the plants.

Lichens-Lichens-Symbiotic association of millions of algae or Symbiotic association of millions of algae or

cyanobacteria within a mesh of fungal cyanobacteria within a mesh of fungal hyphae (most commonly ascomycetes)hyphae (most commonly ascomycetes)

Ecological Adaptations in the Ecological Adaptations in the FungiFungi