Chapter 25 - Fungi Flashcards
What mode of nutrition are fungi
They are heterotrophic, feeding by absorption
How do they absorb food
The break down organic materials and recycle important nutrients
What purpose do fungi serve
They are a food and may live in symbiotic relationships with plants
Who are fungi most closely related to when looking at DNA evidence
Unicellular nucleariiids
Who are animals most closely realated to
Unicellular choanoflagellates
What does DNA evidence suggest when looking at animals and fungi
They shared a common, flagellated, unicellular ancestor and multicellularity arose seperately in the two groups
How old is the oldest undisputed fungi fossil
460 million years
When did fungi probably colonize land
As one of the earliest colonizers they arose around 760 million years ago
What did fungi do when it colonized early land
Probably formed mutualistic relationships with early land plants
What are Chytrids
Decomposers, parasites, and mutalists in freshwater and terrestrial habitats
What hypothesis does molecular evidence support about Chytrids
They diverged early in fungi evolution
Why are Chytrids unique
They have flagellated spores called zoospores
What group do Chytrids belong to
Opisthokonta
Describe the diversity of zygomycetes
They exhibit great diversity of life histories
What organisms are classified as zygomycetes
Fast-growing molds, parasites, and commensal symbiots
What are zygomycetes named for
Their sexually produced zygosporania
What is a unique characteristic of zygosporangia
They can survive unfavourable conditions
What negative functions do fungi have
They can attack crops or be pathogenic
Are many fungi edible
Yes
Saprotroph
Organism that decomposes other organisms
What mode of nutrition do fungi use
They are heterotrophs, absorbing nutrients from outside their body
What do fungi use to break down molecules
They use enzymes
What does the versatility of the enzymes in fungi do for thefungi
They contribute to the fungi’s ecological success
What 3 lifestyles do fungi exhibit
Decomposers
Parasites
Mutualists
What do pine beetles spread
Blue stain fungus
What are hyphae
Multicellular filaments that make up one common body structure of fungi
What are yeasts
They are single celled common body structures of fungi
Do fungi grow as filaments, yeasts, or both
They grow as all three depending on the species
What does the morphology of multicellular fungi allow them to do
It enhances their ability to absorb nutrients
What are most fungi cell walls made of
Chitin, glucose polymers, and mannoproteins
What specialized hypae do some haustoria have and what does it let them do
Haustoria that allow them to penetrate host tissues
What are arbuscular mycorrhizal fungi
Fungi that extend hypae through cell walls of root cells
What are ectomycorrhizal fungi
Fungi that form sheaths of hypae over a rootand grow inot the space between cellls
How do fungi reproduce
Asexually and sexually, through spores
Can fungi produce spore from different types of life cycles
Yes
Are fungal nuclei normally haploid
Yes, with the exception of transient diploid stages formed during the sexual life cycles
What does sexual reproduction in fungi require
It requires the fusion of hypae from different mating types
What sexual signaling molecules do fungi use to communicate their mating type
They use pheromones
What is plasmogamy
The union of two parent mycelia
Do the haploid nuclei from each parent fuse right away
No, they coexist in the mycelium
What is a heterokaryon
It is a cell with separate nuclei
What happens with haploid nuclei in some cells
They pair off two to a cell, making them dikaryotic
How long can pass before karyogamy occurs in fungi
Days, hours, or even centuries
What is karyogamy
Nuclear fusion
What happens during karyogamy
The haploid nuclei fuse to produce diploid cells
Is the diploid phase short-lived or long in fungi
It is short lived
What process occurs in the diploid phase of fungi
Meiosis, producing haploid spores
The life cycle of black bread mold is fairly typical of what phylum
Zygomycota
Can fungi reproduce asexually
Yes
What kind of spores do molds produce and how
They produce haploid spores by mitosis, forming visible mycelia
What fungi other than molds can reproduce asexually
Yeasts
What kind of environments do yeasts inhabit
They inhabit moist environments
How do yeasts reproduce
Asexually through cell division, pinching “bud cells” from parent cells
Do molds and yeasts have known sexual cycles
No, many don’t
What are molds and yeasts with no known sexual cyckes called
Deuteromycetes or imperfect fungi
What is an example of a Zygomycete that can aim their sporangia towards a good environment
Pilobolus
What is a characteristic of some Zygomycete when thinking of their sporangia
Some can aim their sporangia to areas associated with good food sources
What group were glomeromycetes once considered to be a part of
Zygomycetes
Are glomeromycetes a separate clade
Yes
What structure do glomeromycetes for in a symbiotic relationship
Arbuscular mycorrhizae
Where do Ascomycetes live
In marine, freshwater, and terrestrial habitats
What are Ascomycetes commonly called
Sac fungi
What organisms (not specific) are included in ascomycetes
Plant pathogens
Decomposers
Symbionts
What is the phylum Ascomycota defined by
The production of sexual spores in saclike asci
Where are asci found
In fruiting bodies called ascocarps
Can Ascomycetes reproduce asexually
Yes
How do ascomycetes reproduce asexually
Using large quantities of conidia, asexual spores
Where are conidia formed
In the tips of specialized hyphae called conidiophores
What are Basidomycetes often called
Club Fungi
What are included in the group Basidomycetes
Mushrooms
Puffballs
Shelf fungi
What kind of lifestyles do Basidomycetes have
Mutualistic
Plant parasites
What is the phylum Basidiomycota defined by
A club like structure called a basidium
What stage of the lifecycle are basidium present in
The transient diploid stage
What does the life cycle of a basidiomycete usually include
A long lived dikaryotic mycelium
What do mycelium in basidiomycetes do when exposed to environmental stimuli
They reproduce sexually by producing elaborate fruiting bodies
What are the fruiting bodies in basidiomycetes called
Basidiocarps
What are the basidia in basidiomycetes a source of
Basidiocarps, commonly called sexual spores
In what pattern on the ground do basidiomycetes grow in
They radiate from a localized source to form a ring
What is lichen
A symbiotic relationship between a photosynthetic microorganism and a fungus
What group do most lichen fall into
Ascomyetes
What do fungi living in herbivore guts do
Help break down cellulose
Can fungi be parasites
Yes
Can fungi be symbiotic
Yes
