Final Exam: Plant Tax Lecture

ALL of Plant tax exam 1 + Tracheophytes, seed plants / gymnosperms, Angiosperms, Reinforcement & Reproductive character displacement and role in speciation, Plant Groups & Key traits of each

Draw the heterosporous lifecycle

what is the difference between homospory & Heterospory?

Homospory: produces ONE type of spore → develops into a bisexual gametophyte

Heterospory: produces TWO types of spores (microspores + megaspores) → develop into male & female gametophytes separately

what are the differences in gametophyte development between homosporous and heterosporous?

homo: develops bisexual gametophyte

hetero: develops into separate male and female gametophytes

define endospory

Endospory: gametophyte develops inside the spore wall (protected & dependent)

define megasporophyll

Megasporophyll: leaf/structure that bears megasporangia

define megasporangium.

Megasporangium: structure that produces megaspores

define megasporocyte

Megasporocyte: diploid cell (2n) that undergoes meiosis to form megaspores

define megaspore

Megaspore: haploid (n) spore → develops into female gametophyte

define megagametophyte

Megagametophyte: female gametophyte (produces eggs)

define microsporophyll

Microsporophyll: leaf/structure that bears microsporangia

define microsporangium

Microsporangium: structure that produces microspores

define microsporocyte

Microsporocyte: diploid cell (2n) that undergoes meiosis to form microspores

define microspore

Microspore: haploid (n) spore → develops into male gametophyte

define microgametophyte

Microgametophyte: male gametophyte (produces sperm; e.g., pollen grain)

What is the adaptive significance of endosporic development?

Gametophyte develops inside the spore wall, which protects it from desiccation and environmental stress, reduces exposure to hazards, and allows retention on the parent sporophyte for added protection and nutrient support. This also promotes reduced, dependent gametophytes and is an important evolutionary step toward the seed habit (especially in heterosporous plants).

What are synapomorphies of euphyllophytes?

Megaphylls (true leaves) + highly branched vascular systems (leaf gaps present)

What are typical unifying traits of monilophytes (ferns & relatives)?

Sporophyte dominant, megaphylls (fronds), sporangia on leaves, often sori, circinate vernation (fiddleheads)
(exceptions exist, e.g., some lack typical fronds or sori)

what is a seed?

A mature ovule containing an embryo (young sporophyte), stored nutrients, and a protective seed coat → allows dormancy, protection, and dispersal

what are the 5 steps in the evolution of a seed?

1. Heterospory (micro + megaspores)
2. Reduction to one functional megaspore (others degenerate)
3. Retention of megaspore in megasporangium (on parent)
4. Endospory (female gametophyte develops inside)
5. Integument formation (protective layer → ovule/seed)

what is an integument?

Protective tissue layer surrounding the ovule → becomes the seed coat

What is pollen?

Male gametophyte that delivers sperm to the ovule (no water needed)

what is exospory?

Gametophyte develops outside the spore wall (free-living)

Gymnosperm (Pinus) life cycle — male function?

Pollen (microgametophyte) produced in microsporangia of pollen cones → dispersed by wind → lands on ovule → forms pollen tube to deliver sperm

Gymnosperm (Pinus) life cycle — female function?

Megaspore forms in ovule → develops into megagametophyte (with eggs) → fertilization occurs → zygote → embryo → seed develops on cone scale

draw the Gymnosperm (Pinus) life cycle with male and female parts included.

What are the functions of seeds?

Protection of embryo, nutrient storage, dormancy, dispersal, and increased survival in harsh environments

what are the 4 groups of gymnosperms?

Cycads, Ginkgos, Conifers, Gnetophytes

Characteristics of Cycads?

Palm-like, large compound leaves, dioecious, motile sperm, tropical/subtropical, often symbiotic N-fixing roots

Characteristics of ginkgos?

Single species (Ginkgo biloba), fan-shaped leaves, deciduous, dioecious, motile sperm, very pollution tolerant

Characteristics of conifers?

Woody trees/shrubs, needle or scale leaves, usually evergreen, non-motile sperm, wind pollination, dominant in cold/dry climates

Pinaceae vs. Cupressaceae — leaf shape?

Pinaceae: needle-like (often in bundles/fascicles)
Cupressaceae: scale-like or small needles

Pinaceae vs. Cupressaceae — pollen morphology?

Pinaceae: winged pollen (air sacs)
Cupressaceae: non-winged pollen

Pinaceae vs. Cupressaceae — ovulate cone shape?

Pinaceae: woody, elongated cones
Cupressaceae: smaller, often round/berry-like cones

Pinaceae vs. Cupressaceae — mycorrhizal status?

Pinaceae: ectomycorrhizal
Cupressaceae: typically arbuscular (or variable)

Role of vascular cambium in woody plants?

Produces secondary xylem (wood) inward and phloem outward → increases girth

Role of cork cambium in woody plants?

Produces cork (protective outer layer) → reduces water loss and protects from damage

What are the 6 unique characteristics of angiosperms?

Flowers, fruits (enclosed seeds), double fertilization, endosperm formation, vessel elements in xylem, reduced gametophytes

draw out the angiosperm (flowering plants) lifecycle.

What is an ovule and how does it relate to megagametophytes in other groups?

Ovule = megasporangium + integuments; contains the megagametophyte (embryo sac). Unlike other groups, it is fully enclosed in the ovary and highly reduced

What is double fertilization? What cells are fertilized and what forms?

Double fertilization is a process unique to angiosperms where two sperm cells are involved in fertilization. After pollination, the pollen tube delivers two sperm into the ovule. One sperm fertilizes the egg cell, forming a diploid (2n) zygote, which develops into the embryo. The second sperm fuses with two polar nuclei in the central cell, forming a triploid (3n) endosperm, which serves as nutritive tissue that supports the developing embryo.

What are the evolutionary origins of anthers and pistils?

Anthers = modified microsporophylls (male structures)
Pistils (carpels) = modified megasporophylls that enclose ovules

What is the androecium?

Male reproductive whorl (all stamens)

What is an anther?

Pollen-producing structure

What is a filament?

Stalk that supports the anther

What is the gynoecium?

Female reproductive whorl (carpels/pistils)

what is a pistil?

female structure = stigma + style + ovary

what is the stigma?

sticky surface that recieves pollen

what is a style?

tube connecting stigma to ovary

what is the ovary?

encloses ovules; develops into fruit

what is an ovule?

structure containing egg; becomes seed after fertilization.

what is the calyx?

all sepals (outer whorl)

what are sepals?

protect flower bud

what is the corolla?

all petals

what are petals?

often colorful; attract pollinators

what is the perianth?

calyx + corolla (non-reproductive parts)

what is a stamen?

male structure = anther + filament

what is a pedicel?

flower stalk

what is a complete flower?

has sepals, petals, stamens, and pistil

what is an incomplete flower?

Missing one or more of these: sepals, petals, stamens, and pistil.

what is difference between perfect & imperfect flower?

perfect = both male and female parts are present

imperfect = has only male or female parts. not both.

difference between actinomorphic and zygomorphic?

actinomorphic = radial symmetry (multiple planes of symmetry present)

zygomorphic = bilateral symmetry (one plane of symmetry present)

what are the 3 fruit types, and explain the definition of each. give examples of each as well.

simple = from one ovary of one flower ex) tomato, peach, cherry, apples, legumes

aggregate = from multiple ovaries of one flower ex) strawberry, raspberry, blackberry

multiple = from many flowers fused together ex) pineapple, fig, mulberry

what are the common fruit dispersal strategies?

Wind (light/winged), animals (fleshy or hooked), water (buoyant), explosive/mechanical (bursting)

Monocots vs. eudicots — key differences?

Monocots: 1 cotyledon, parallel veins, fibrous roots, flower parts in 3s, scattered vascular bundles

Eudicots: 2 cotyledons, netted veins, taproot, flower parts in 4s/5s, vascular bundles in ring

What traits do basal angiosperms share with monocots & eudicots?

Flowers, enclosed ovules, double fertilization, but often have less specialized traits (e.g., many floral parts, spiral arrangement)

What is reproductive character displacement? Why is it important?

Traits related to reproduction (flower shape, timing, pollinators) diverge more in areas where similar species coexist to prevent hybridization → reinforces reproductive isolation and promotes speciation

Key traits of: Apiaceae (umbelliferae)

Umbel/compound umbel inflorescence, hollow stems, aromatic, schizocarp fruit, inferior ovary

Key traits of: Apocynaceae

Milky latex, opposite/whorled leaves, 5 fused petals, often toxic (dogbane), epipetalous stamens

Key traits of: Araceae

Spadix + spathe, often large tropical leaves

Key traits of: Arecaceae

large palmate / pinnate leaves (palms), unbranched trunks, large compound leaves

Key traits of: Aspleniaceae

Ferns, sori elongated / linear along veins

Key traits of: Asteraceae

Composite heads (disc + ray florets), “flower = many flowers”, involucral bracts, achene fruit

Key traits of: Berberidaceae

bulbous pistil, simple leaves, basal angiosperm, spiny shrubs

Key traits of: Betulaceae

Monoecious trees, toothed leaves, dense male catkins, nut or samara fruit

Key traits of: Boraginaceae

Rough/hairy plants, scorpioid cyme, 5 fused petals, 4 nutlets

Key traits of: Brassicaceae

4 petals in cross shape, 6 stamens (4 long, 2 short), silique fruit

Key traits of: Calycanthaceae

Aromatic shrub, many tepals, basal angiosperm-like flower structure

Key traits of: Caryophyllaceae

Opposite leaves, swollen nodes, 5 petals, capsule fruit, petals are pinked to various severities

Key traits of: Cornaceae

Opposite leaves with arcuate venation, cyme/head inflorescence, drupe fruit,

Key traits of: Cupressaceae

Scale-like leaves, woody cones (sometimes berry-like), conifer

Key traits of: Cyperaceae (sedges)

Triangular solid stems, 3-ranked leaves, reduced flowers in spikelets

Key traits of Dryopteridaceae

Fern with round sori and indusia, “wood ferns”

Key traits of: Equisetaceae

Jointed stems, silica, whorled leaves, strobili (horsetails)

Key traits of: Ericaceae

Acidic soils, evergreen shrubs, urn-shaped flowers, poricidal anthers

Key traits of: Euphorbiaceae

Milky latex, cyathium inflorescence, often highly reduced flowers

Key traits of: Fabaceae

Legume fruit, compound leaves, nitrogen-fixing roots, 10 stamens

Key traits of: fagaceae

Acorns/nuts, monoecious trees, loose male catkins, lobed leaves

Key traits of: Geraniaceae

Beak-like fruit, 5 carpels, 10 stamens (2 whorls)

Key traits of: Iridaceae

Sword-like leaves, 3-merous flowers, inferior ovary, 3 stamens

Key traits of: Juncaceae (rushes)

Grass-like, round solid stems, 6 tepals, capsule fruit

Key traits of: Lamiaceae

Square stems, opposite leaves, aromatic, zygomorphic flowers, 4 nutlets, gynobasic style

Key traits of: Lauraceae

Aromatic trees, simple leaves, 2 whorls of 3 tepals, drupe fruit

Key traits of: Liliaceae

Monocot with 6 tepals, 6 stamens, bulbs common

Key traits of: Malvaceae

Mucilage, hibiscus-type flowers, stamens fused into column

Key traits of: Magnoliaceae

Large flowers, many spiraled parts, basal angiosperm traits, cone-shaped receptacle

Key traits of: Nymphaceae

Aquatic plant, floating peltate leaves, many petals/stamens, berry fruit

Key traits of: Onagraceae

4 petals, inferior ovary, hypanthium tube, evening primrose type, chicken-foot stigma

Key traits of: Ophioglossaceae

Simple leaf + fertile spike (adder’s tongue fern)

Key traits of: Orchidaceae

Zygomorphic flowers, labellum, pollinia, column (gynostemium), epiphytes

Key traits of: Osmundaceae

Fern with distinct fertile fronds (royal ferns)