lec exam 3 (mostly fungi, but also angiosperms)

current/new angiosperm categories

• basal angiosperms

• Magnoliids

• Monocots

• eudicots.

why did we get rid of old angiosperm categories

they were paraphyletic :(

if it has three small lineages that were earliest/first in angiosperm history, which angiosperm category is it? is it basal angiosperms, Magnoliids, Monocots, or eudicots?

Basal Angiosperms

Basal Angiosperm species (4)

•  Amborella trichopoda (a single shrub species)

•  water lilies

• star anise

• star anise relatives

vessel elements

efficient cells that conduct water

is it common or rare for angiosperms to have vessel elements?

common

defining characterisitic of basal angiosperms

they don’t have vessel elements (most angiosperms do)

what is Amborella trichopoda and describe it

• a single shrub species

• a woody basal angiosperm

what about Basal Angiosperm structure could tell u abt its evolution/lineage

no vessel elements → common ancestor could be a woody shrub with small flowers and simple water-conducting cells (not sure where the rest came from but simple water conducting cells prob came bc vessel elements help u conduct water efficiently)

who has pollen tubes, angiosperms (flowers) or gymnosperms (mainly pines)

both

mangnoliid species

• Magnolias

• Laurels

•  black pepper plants

if an angiosperm category has 8500 species, is it it a basal angiosperms, Magnoliids, Monocots, or eudicots?

magnoliids

if an angiosperm category includes both woody and herbaceous species, is it a basal angiosperms, Magnoliids, Monocots, or eudicots?

Magnoliids

magnoliid and basal angiosperm commonality

 spiral arrangement of floral organs

which angiosperm category are Magnoliids most related to? is it basal angiosperms, Magnoliids, Monocots, or eudicots?

eudicots and monocots

if an angiosperm category Include both woody and herbaceous species, is it basal angiosperms, Magnoliids, Monocots, or eudicots?

Magnoliids (could be wrong, but the other categories don’t openly say this so)

monocot examples

Orchids
grasses (maize, rice, wheat)

palms

if it represents about one-quarter of angiosperm species (~72,000 species), which angiosperm category is it? is it basal angiosperms, Magnoliids, Monocots, or eudicots?

monocot

if the Vascular tissue is scattered, is it a monocot or eudicot

monocot

if the Veins are usually netlike, is it a monocot or eudicot

eudicot

if the pollen grain has one opening, is it a monocot or eudicot

monocot

if the pollen grain has three openings, is it a monocot or eudicot

eudicot

if the vascular tissue is usually arranged in a ring, is it a monocot or eudicot

eudicot

if the Floral organs are usually in multiples of three, is it a monocot or eudicot

monocot

tap root

main root

root type with no main root

fibrous roots

if Floral organs are usually in multiples of four or five, is it a monocot or eudicot

eudicot

eudicot examples

• legume family (peas, beans) 

• the rose family (strawberry, apple)

• many familiar flowering trees (oak, walnut, maple)

if it has more than two-thirds of angiosperm species (~210,000 species), is it a monocot or eudicot

eudicot

alteration of generations/generalized plant life cycle

1. multicellular haploid gametophyte

2. fertilization

3. multicellular diploid spirophyte

4. meiosis

5. gametophyte development

fertilization (plant life cycle step 2)

haploid gametes fuse into a diploid zygote

what’s a sporophyll

modified leaf bears sporangia

gametophyte development (plant life cycle step 5)

haploid spores → mitotic division → new multicellular gametophyte

multicellular diploid sporophyte (plant life cycle step 3)

mitotically dividing zygote → multicellular diploid sporophyte

mulitcellular haploid gametophyte (plant life cycle step 1)

mitosis makes gametes (egg + sperm)

meiosis (plant life cycle step 4)

mature sporophytes produce haploid spores

who called the origin of angiosperms an "abominable mystery"

charles darwin

why are the origin of angiosperms an "abominable mystery"

Bc they suddenly appeared in the fossil record around 100 million years ago

new time frame for angiosperm appearance

Cretaceous period (140 million years ago)

angiosperm terrestrial dominance

• mid-Cretaceous

• angiosperms replaced conifers and gymnosperms around the world

• mass extinctions at the end of the Cretaceous only helped the angiosperms expand/dominate even more

fossil impact on the "abominable mystery"/sudden appearance idea

angiosperms appeared + diversified steadily thru out a 20 million year period, so they didn’t just come out of nowhere

early fossils with angiosperm features

Archaefructus, it could have been aquatic tho

ancestral angiosperm traits

• Bennettitales: extinct, had flower-like structures but no carpels or flowers

• early angiosperms were prob woody shrubs w small flowers and simple water-conducting cells (basal angiosperm)

are fungi heterotrophs or autotrophs

heterotrophs

how do fungi eat

• by absorption: their hydrolytic enzymes break complex molecules into smaller organic compounds

• then they absorb it

• sometimes they can use the enzymes to penetrate host cell walls and then absorb nutrients

fungi cell wall

chitin

fungi ecological role

• break down organic material

• recycle nutrients

• parasites

• mutualists

how does chitin strengthen feeding by absorption

structural rigidity (goes against osmotic pressure, not sure where this pressure comes from)

most common fungal body structures

• multicellular filaments

• single cells (yeasts)

structure of non-septate hypha (Coenocytic hypha)

• fungi has continuous cytoplasmic mass

• the mass has 100s or 1000s of nuclei

• comes from repeated division of nuclei without cytokinesis (the supercells are back)

fungi with no septa

coenocytic fungi

what are hypha/hyphae

tiny filaments that make up fungus’ body

what are hypha/hyphae made of

tubular cell walls

what do the tubular cell walls (that make up hypha filaments) do

• surround plasma membrane

• surround cytoplasm

what do hyphae do

• secrete enzymes that break down organic matter

• absorb released nutrients

septate hypha

fungi w septa

what are septa

hyphae divided into cells by cross-walls (or maybe the septa are the cross walls themselves??) idk

septa size

usually big enough for ribosomes, mitochondria, and even nuclei to flow between cells

stolon

Hyphae that spread over the surface of the substrate

Mycelium

• intervoven mass

• infiltrates material of fungus’ food

mycelium structure impact on fungi feeding

• makes it more efficient bc it uses surface-to-volume ratio

Haustoria

hyphae where some fungi can extract nutrients from plants

arbuscules

hyphae that lets fungi exchange nutrients w plants

fungi as parasites in humans + animals

•  ringworm

• athlete's foot

• coccidioidomycosis

• systemic infections

Mycorrhizae mutualism (what does each party get)

plants got phosphate ions and other minerals, fungi got nutrients

Endophytes (fungi impact)

• fungi that live in leaves or other plant parts (mutualism)

• protect plants from herbivores by making toxins

• can increase heat tolerance

• can increase drought tolerance

• can increase heavy metal tolerance

• usually ascomycetes, sometimes mucoromycetes

Fungus-Animal Mutualism

• when fungi help animals digest

• they can also give nutrients to insects (ex: leaf-cutter ants)

lichens (what does each party get)

• mutualism

• green algae/cyanobacteria gets structure, protection, water, and minerlas

• fungus (usually gets carbon compounds

what are lichens important for

cleared surfaces

can fungi produce sexually or asexually

both

how do fungi reproduce

a lot of spores

how are fungi spores spread

wind or water

when do fungi spores germinate

when conditions are favorable

besides germinate, what else do fungi spores do when conditions are favorable

produce new mycelia

plasmogamy meaning

fusion of cytoplasms (of 2 mycelia w diff mating types)

2 options for what plasmogamy could lead to

option 1: heterokaryotic stage

option 2: dikaryotic stage

heterokaryotic stage (n+n)

genetically different haploid nuclei coexist (in the fused mycelium)

dikaryotic stage

nuclei pair off (2 to a cell)

what happens after plasmogamy

karyogamy (can be hours, days, or centuries later)

karyogamy meaning

fusion of haploid nuclei

what does karyogamy cause

transient diploid (2n) cells (zygotes)

what happens to the transient diploid cells (zygotes) after karyogamy

• meiosis → genetically diverse haploid spores

if it involves plasmogamy and karyogamy, is the fungi reproducing sexually or asexually?

sexually

if it involves meiosis, is the fungi reproducing sexually or asexually?

sexually

if it involves mitosis, is the fungi reproducing sexually or asexually?

asexually

how do fungi reproduce asexually

• mitosis → haploid spores → visible mycelia

what are visible mycelia from mitotically-made haploid spores called

molds

how do yeasts reproduce asexually

option 1: ordinary cell division

option 2: budding

substrate

place where fungi can grow (ex: overripe peach)

favorable conditions for fungi spore germination

• moist place

• food (sugars, amino acids)

what’s usually the only diploid stage in most fungi

karyogamy

 closest living relatives of fungi

nucleariids

what are nucleariids (and what do they eat)

• single celled protists (amoebas)

• they feed on algae and bacteria

how did ppl find the closest living relatives to fungi

molecular evidence

Microsporidians structure

• highly reduced mitochondria 

• small genomes

• no flagellated spores, unlike other basal fungi

what do basal fungi usually have that Microsporidians don’t

flagellated spores

what are Microsporidians

unicellular parasites of protists and animals, including humans

microsporidian spore

• unique

• use harpoon-like organelle to infect host cells

monophyletic group with Fungi, animals, and their protistan relatives (including nucleariids) (does this include microsporidians too??)

opisthokonts

what are microsporidians classified as

fungi (for now, needs more data)