Plant Diversity, Morphology, and Reproduction

Comprehensive practice flashcards defining foundational vocabulary across green plant evolution, morphology, physiological transport, life cycles, and reproductive adaptations.

Development of multicellularity

Unicellular → colonial → multicellular with DOL.

DOL

Division of labor.

Multicellularity: early change

Cell-cell communication / extracellular matrix.

Multicellularity: later change

Partial soma-germ division of labor → full DOL.

Sexual reproduction trend

Isogamy → anisogamy → oogamy.

Isogamy

Gametes are similar.

Anisogamy

Gametes are different in size.

Oogamy

Egg and sperm are differentiated.

Haploid

n.

Diploid

2n.

Meiosis

Produces the haploid stage.

Fertilization

Gametes (n) combine to make the diploid stage.

Fertilization ploidy

n + n = 2n.

Mitosis

Keeps the same ploidy while cells grow/divide.

Five traits needed to colonize land

Spores with sporopollenin, alternation of generations, multicellular embryo, cuticle, mycorrhizas.

Sporopollenin

Resistant spore coating; a “pre-adaptation” for land.

Spores with tough outer wall

Sporopollenin.

Cuticle

Waxy outer layer.

Cuticle advantage

Helps prevent water loss / drying out.

Why does water bead up on a leaf?

Wax in the cuticle.

Multicellular embryo

Multicellular 2n embryo.

Mycorrhizas

Symbiosis of plant roots with fungi.

Alternation of generations

A multicellular haploid gametophyte and multicellular diploid sporophyte.

Land plant tree

Chara → liverworts → mosses → hornworts → lycophytes → monilophytes → gymnosperms → angiosperms.

Spore-dispersed seedless plants

“Bryophytes,” lycophytes, ferns & allies.

Seed-dispersed plants

Gymnosperms and angiosperms.

“Bryophytes”

Liverworts, mosses, and hornworts.

Liverworts

Gametophyte dominant; sporophyte tiny and dependent.

Mosses

Gametophyte dominant; sporophyte small and dependent.

Moss evolutionary change

3-D growth, differentiated sporophyte, stomata.

Hornworts

Long-lived sporophyte.

Vascular plants

Sporophyte dominant & independent; vascular tissue, stems; multicelled apical meristem.

Stem with vascular tissue

Enabled a large increase in sporophyte height.

Lycophytes

Sporophyte dominant & independent; vascular tissue, stems, multicelled apical meristem.

Lycophyte structures

Roots and microphylls.

Lycophyte gametophyte

Gametophyte small & independent.

Monilophytes

Ferns & allies.

Monilophyte structures

Megaphylls and roots.

Ferns

Sporophyte dominant; gametophyte small & independent.

Fern reproductive structure

Sori.

Gymnosperms

Sporophyte dominant; gametophytes tiny & dependent.

Gymnosperm traits

Secondary growth; gametophyte retained; seeds in cones; megaphylls.

Angiosperms

Sporophyte dominant; gametophytes tiny & dependent.

Major land-plant trend

Sporophyte becomes dominant/reduced dependence on the gametophyte.

Bryophyte dependence on water

Growth & sex need water.

Lycophytes and monilophytes

Sex needs water.

Gymnosperms and angiosperms

Sex enclosed in cone or flower; does not need water.

Alternation of generations: sporophyte

Sporophyte is 2n.

Alternation of generations: gametophyte

Gametophyte is n.

Sporophyte produces

Spores.

Spores are produced by

Meiosis.

Spore grows into

Gametophyte.

Spore to gametophyte

Mitosis.

Gametophyte produces

Gametes.

Gametes are produced by

Mitosis.

Gametes combine by

Fertilization.

Fertilization produces

Zygote.

Zygote ploidy

2n.

Zygote to sporophyte

Mitosis.

Alternation of generations sequence

Sporophyte 2n → meiosis → spores n → mitosis → gametophyte n → mitosis → gametes n → fertilization → zygote 2n.

Life-cycle question 1

Is the haploid stage multicellular?

Life-cycle question 2

Is the diploid stage multicellular?

Ancestral unicellular life cycle

Haploid multicellular? No. Diploid multicellular? No.

Diploid-dominant life cycle

Haploid multicellular? No. Diploid multicellular? Yes.

Haploid-dominant life cycle

Haploid multicellular? Yes. Diploid multicellular? No.

Alternation of generations life cycle

Haploid multicellular? Yes. Diploid multicellular? Yes.

Chara life cycle

Haploid-dominant.

Chara diploid stage

The zygote is the only diploid cell.

Fucus reproductive mode

Oogamous.

Fucus life cycle

Diploid-dominant.

Plants respond to diverse environmental conditions

Responses can involve morphology of structures or physiology of processes.

Morphology of structures

Leaves, shoots, roots, stems: size, shape, color, number.

Physiology of processes

Photosynthesis, respiration, transport.

Physiology can change

Division of labor of cells; tissue types and arrangements; specialized processes.

Hydrophyte example

Water lily.

Hydrophyte leaf

Stomata on top surface; big air spaces.

Xerophyte example

Oleander.

Xerophyte leaf

Multi-layer epidermis + wax; recessed stomata + hairs.

Epiphytes

Plant-on-plant interactions; not parasites.

Nutrient-poor soils

Leaves can become passive and active traps.

Cuscuta

Dodder; parasitic plant.

Mistletoe dispersal

Fruit eaten by birds → sticks to beak → wiped off on a new host.

Rafflesia

Parasite to the max; develops inside stem of host.

Parasitic plant strategies

Growth toward, dispersal to, or development inside a host.

Water potential & transpiration

Diffusion; evaporation; cohesion/adhesion/tension.

Transpiration direction

High water potential → low water potential.

Transpiration energy cost

Does not cost the plant energy.

Vascular tissue

Xylem and phloem.

Xylem

Dead; water & minerals.

Phloem

Alive; sugars, hormones, etc.

Xylem transport

Transpiration of water + minerals.

Phloem transport

Pressure flow.

Phloem source

Substance such as sugar is pumped in.

Phloem sink

Substance such as sugar is pumped out.

Xylem vs phloem

Xylem carries water and minerals through transpiration; phloem moves sugars from source to sink using pressure flow and ATP-dependent pumping.

First vascular plants

Stems with central vascular cylinder.

Vascular bundles in a ring

Secondary growth with BVC.

Monocot vascular bundles

Scattered.

Monocots and BVC

Loss of BVC; no secondary growth.

BVC

Bifacial vascular cambium.