Bio 181 exam 3

The main characteristic all fungi have

double cell wall with chiten

Fungi’s sources of energy

• Dead plants and animals ( Decomposers)

• Alive plants, animals, and bacteria

• Materials

Haploid-Dominant lifestyle

Fungi spend most of their life in the haploid stage of the lifecycle

The only unicellular fungi that reproduces asexually

Microsporoida

Polar Tubes

Used by microsporida to inject themselfs into living cells and reproduce by fission

The fungi with motile cells live in freshwater habitats

Chytridiomycete

Motile cells

Spore cells that have flagella that can swim

chytridomycetes life cycle

zygomycetes

Has zygospores, are coenocytes, and only sexually reproduce in stressful situations 

Zygomycetes life cycle

Plasmogamy

Union of cytoplasm without the fusion of nuclei

Kayrogammy

the union of nuclei to create a zygote

What zygospores are not

zygospores are not alteration of generations

Glomeromycota 

Are coenocytic and have arbuscules 

Arbuscules

Structures that live inside plant cell walls, provides essential nutrients to plants and gains carbon from the plants.

Basidiomycota

Fungi that form Basidium and are ectomycorrhizal

Ectomycorrhizal

Penetrate plant wall cells but foes not live in plant cells

Basidium 

The reproductive structure of a basidiomycota 

Basidiomycota life cycle

Dikaryotic

contains two genetically distinct haploid nuclei

Heterokaryotic

contains two or more genetically different nuclei within a single cytoplasm

Ascomycetes

Make an Ascus, a spore producing body

Mesoproterozoic 

boring billion, no environmental events, resulted in little species richness 

Neoproterzoic

Period of massive change, warming, and cooling events, with the gradual beginnings of freshwater lakes and pools

What the Neoproterozoic period resulted in

High species diversity, selective pressures, and some organisms transitioning to land.

Bio and chemical weathering and their importance

Withering by either acid rain or bacteria and fungi that process rock

Helped create soil and allowed plants to transition to land 

Neo protozoic period, allopatric or sympatric speciation?

Allopatric, separated species are either divided by layers of ice and rock or through the creation of freshwater revisors

Hyphae

each of the branching filaments that make up the mycelium of a fungus

Fungi’s transition to land

Some fungi used rocks from land as a source of carbon and nutrients, and formed a symbiotic relationship with early plants (they create soil and trade nutrients)

Non-Vascular Plants

Plants that lack vascular tissues, such as lignin, which acts as a reinforcement to keep water inside. But do have water-conducting cells, such as xylem.

What are the four characteristics that all land plants have

• waxy cuticle

• UV radiation protection

• Vascular Tissue and Structural Support

• Reproduction in dry conditions - Haploid-diplontic

What plants use for gas exchange because of the waxy cuticle 

Stomate

Haplotic Lifestyle

When the multicellular phase is haploid, originally in green algae

Why does a haplotic lifestyle not work on land?

In a haplontic life cycle, haploid gametes are released and must swim in water to find and fuse with other gametes to form a diploid zygote. On land, this is an inefficient and unreliable method of reproduction. The evolution of a protective, drought-resistant diploid sporophyte allows for the airborne dispersal of spores, freeing reproduction from the constant need for a moist environment.

Haplo-diplontic lifestyle

Both haploid and diploid stages can be multicellular, allowing spores to disperse through air instead of water

Basic Plant life style

Sporophytes do meiosis to make spores

spores do mitosis to make gametes

gametophytes do mitosis to make gametes

gametes do fertilization to make sporophytes

Antheridia

The part of the gametophyte that makes spores

Archegonium

Part of the gametophyte that makes the egg, and where the egg is fertilized

Bryophyte lifecycle

Sporangium

The diploid phase and the sporophyte part of the bryophyte

What do zygospores (in zygnematophyceae and zygomycota) have in common with plants?

They have similar chemical and structural components found in spores of bryophytes and lycophytes, possible consequence of Snowball Earth as it allows them to survive extreme temperatures

Sister taxa to plants

zygnematophyce - have a very diffrent life cycle to land plants

The differences of lycophytes than bryophytes   

• Sporophyte-dominant lifestyle

• Lignified vascular tissue with xylem and phloem (vascular tissue in plants that conducts sugars and other metabolic products)

• can be both exosporic and endosporic 

• Can be homosporous or heterospores 

Sporophyte dominate lifestyle

A plant that spends most its life in its diploid form

lignified vascular tissue allows for

Allows plants to grow bigger, water can conduct through the veins more easily

Exosporic

Archegonia and archegonia develops outside the spore

exospores

archegonia and archegonium develops inside the spore 

Sporangium

where sporangium’s are held for lycophytes and ferns

homosporous

a plant that produces only one type of spore, which then develops into a gametophyte capable of producing both male and female gametes

Heterosporous

plants that produce two different types of spores: smaller, male microspores and larger, female megaspores

heterosporous life cycle

Sporophytes have megasporophylls that produce megasporangia that contain megaspore mother cells (all 2N) that undergo meiosis to produce megaspores (1N) Sporophytes have microsporophylls that produce microsporangia that contain microspore mother cells (all 2N) that undergo meiosis to produce microspores (1N) Megaspores grow via mitosis into megagametophytes that contain archegonia that produce eggs (all 1N) Microspores grow via mitosis into microgametophytes that contain antheridia that produce sperm (all 1N) Sperm are released from antheridia and swim down the neck of an archegonium to fertilize the egg (all 1N) to produce a zygote (2N)

Homosporous lycophyte life cycle

What does branched veins allow for?

it allows for bigger leaves and plants as the veins can reach further

What are key synapomorphies shared by all green plants?

Double-membraned chloroplasts, chlorophyll a & b, carotenoid pigments, sugar stored as starch, and cell walls with cellulose and pectin.

Why are green plants considered monophyletic while green algae are paraphyletic?

Because green plants include all descendants of a common ancestor, whereas “green algae” excludes land plants even though they share that ancestor.

What is the evolutionary significance of Streptophyta?

Streptophyta share specialized metabolic pathways (like photorespiration) and gave rise to land plants, unlike Chlorophyta which remained primarily aquatic.

What evolutionary pattern links fungi and plants over time?

• Origin of terrestrial fungi → origin of terrestrial green algae

• Origin of AMF (arbuscular mycorrhizal fungi) → origin of land plants

• Origin of EMF (ecto-mycorrhizal fungi) → diversification of land plants

• Diversification of EMF → diversification of flowering plants

What were the six major challenges early plants faced on land?

• Acquiring water for photosynthesis and reproduction

• Drought stress

• High irradiance and oxidative stress

• Freezing temperatures

• Anchoring to substrates

• Building self-supporting structures in air

Why is Zygnematophyceae considered the closest living relative to land plants?

they share stress-response and hormone-signaling genes found in all land plants. Genes for multicellularity and terrestrial pre-adaptation.

What structural and chemical features make zygospores key to land adaptation?

Zygospore walls contain sporopollenin and lipid droplets, similar to land plant spores and pollen, providing UV and desiccation protection.

How did fungi contribute to the success of land plants?

Early terrestrial fungi broke down rocks, decomposed bacteria, and created primitive soils—preparing land for plant colonization.

What does Prototaxites tell us about early terrestrial ecosystems?

It was a giant (over 20 ft tall) ascomycete-like organism dominant 500 MYBP, showing fungi’s major role before vascular plants diversified.

Adaptations for plants to live on land

Adaptations:

• Development of protective spores (zygospores) with thick, sporopollenin-rich walls for UV and desiccation resistance

• Formation of mutualistic relationships with fungi (e.g., mycorrhizae) for nutrient uptake and soil stabilization

• Acquisition of genes for stress tolerance and hormone signaling from soil bacteria

• Evolution of stronger cell walls and structural support mechanisms

• Enhanced water regulation and stress response pathways for life outside aquatic environments