BIOL120 Lectures 10–16: Plants, Algae & Land-Plant Evolution

Vocabulary flashcards covering major concepts from BIOL120 Lectures 10–16, including plant ecology, algal diversity, land-plant evolution, and reproductive strategies.

Plants as Habitats

Plants provide physical structure, shelter and food that underpin terrestrial ecosystems.

Plant Blindness

The human tendency to overlook or undervalue plants and their importance.

Ecosystem Services

Benefits humans obtain from ecosystems, including provisioning, regulating, supporting and cultural services.

Provisioning Services

Ecosystem products such as food, fibre, medicine, timber and biofuels supplied by plants.

Regulating Services

Plant-mediated processes that moderate climate, sequester CO₂, control erosion and regulate water.

Supporting Services

Underlying functions—habitat structure, soil formation, nutrient cycling and biodiversity maintenance—provided by plants.

Cultural Services

Non-material plant benefits such as aesthetics, spiritual value and traditional gatherings (e.g., Bunya Pine festivals).

Photosynthesis Equation

6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂ (in the presence of sunlight).

Agro-biodiversity

The variety of crop and livestock species, breeds and cultivars used in agriculture.

Artificial Selection

Human-directed breeding that produced crops like broccoli, cabbage and kale from wild mustard.

Carbon Farming

Land-use practices (e.g., agroforestry, cover crops) that increase plant productivity and soil carbon.

Plant–Soil Feedback

Reciprocal interactions where plants influence soil microbes and nutrients, which in turn affect plant growth.

Mycorrhizae

Mutualistic associations between plant roots and fungi that enhance nutrient exchange; found in 80–90 % of species.

Hemi-parasite

Parasitic plant that photosynthesises but taps host xylem for water (e.g., mistletoe).

Holoparasite

Non-photosynthetic parasitic plant (e.g., dodder) completely dependent on host for nutrients.

Epiphyte

Plant that grows on another plant for support but is not parasitic.

Liana

Woody vine that uses other plants for vertical support in forests.

Transpiration

Evaporative water loss from leaves that cools air and drives nutrient uptake.

Carbon Sink

Ecosystem (e.g., forest, wetland) that absorbs more CO₂ than it releases.

Algae

Functional term for diverse aquatic, photosynthetic protists; polyphyletic.

Phytoplankton

Microscopic, free-floating algae that perform up to 50 % of global primary productivity.

Mixotroph

Organism capable of both photosynthesis and heterotrophic nutrition.

Photosynthetically Active Radiation (PAR)

Light wavelengths (≈400–700 nm) usable for photosynthesis.

Chlorophyll a

Universal primary pigment and electron donor in oxygenic photosynthesis.

Chlorophyll b

Accessory pigment in green algae and land plants that broadens light capture.

Chlorophyll c

Accessory pigment found in red algae, brown algae, diatoms and dinoflagellates.

Carotenoid

Orange-brown accessory pigments providing light capture and photoprotection (e.g., fucoxanthin).

Phycocyanin

Blue accessory pigment in cyanobacteria that absorbs orange/red light.

Phycoerythrin

Red pigment in red algae that absorbs green/blue light for deeper-water photosynthesis.

Primary Endosymbiosis

Origin of chloroplasts when a eukaryote engulfed a cyanobacterium.

Secondary Endosymbiosis

Engulfment of a photosynthetic eukaryote by another eukaryote, creating plastids with 3–4 membranes.

Plastid

Double-membrane organelle containing its own genome; includes chloroplasts and chromoplasts.

Nucleomorph

Remnant nucleus of an engulfed algal cell found in some secondary plastids (e.g., chlorarachniophytes).

Dinoflagellate

Alveolate algae with cellulose plates and two flagella; major plankton and HAB agents.

Harmful Algal Bloom (HAB)

Rapid algal proliferation (often dinoflagellates) producing toxins such as PSP.

Diatom

Silica-walled stramenopile algae supplying ~45 % of oceanic primary production.

Frustule

Two-valved silica shell of a diatom.

Biological Carbon Pump

Export of organic carbon to sediments via sinking algal remains (e.g., diatom frustules).

Golden Algae

Chrysophytes with golden carotenoids; many are mixotrophic and form resistant silica cysts.

Brown Algae (Phaeophyta)

Large marine stramenopiles (kelps) rich in fucoxanthin and alginic acid.

Fucoxanthin

Brown carotenoid giving kelps and diatoms their colour.

Holdfast

Root-like basal structure anchoring a brown alga to substrate.

Stipe

Stem-like support in large brown algae.

Blade

Leaf-like photosynthetic surface of kelps.

Red Algae (Rhodophyta)

Archaeplastid lineage with phycoerythrin; includes nori and coralline algae.

Coralline Algae

Calcium-carbonate-depositing red algae that reinforce coral reefs.

Agar

Polysaccharide from red algae used as microbiological medium and food thickener.

Carrageenan

Red-algal polysaccharide used to gel and thicken foods like chocolate milk.

Green Algae

Chlorophytes and charophytes sharing chlorophylls a & b with land plants.

Charophyte

Green-algal lineage most closely related to land plants.

Embryophyte

Land plant; synapomorphies include multicellular embryo and alternation of generations.

Sporophyte

Diploid plant generation that produces spores via meiosis.

Gametophyte

Haploid plant generation that produces gametes via mitosis.

Alternation of Generations

Life cycle with separate multicellular haploid and diploid stages.

Sporopollenin

Tough polymer in spore and pollen walls that resists desiccation.

Bryophyte

Non-vascular land plants: liverworts, mosses, hornworts; gametophyte-dominant.

Rhizoid

Hair-like structure anchoring bryophytes; lacks vascular tissue.

Seta

Stalk of a moss sporophyte supporting the capsule.

Capsule

Spore-producing sporangium at tip of moss seta.

Tracheid

Lignified water-conducting cell in vascular plants.

Xylem

Vascular tissue transporting water and minerals upward.

Phloem

Vascular tissue transporting sugars and other organics.

Microphyll

Small leaf with a single, unbranched vein; characteristic of lycophytes.

Megaphyll

Larger leaf with branched venation found in most vascular plants.

Homospory

Production of one type of spore that develops into a bisexual gametophyte.

Heterospory

Production of microspores (male) and megaspores (female).

Megaspore

Large spore that develops into a female gametophyte.

Microspore

Small spore that develops into a male gametophyte.

Seed

Multicellular structure containing embryo, food supply and protective coat.

Ovule

Megasporangium plus integuments that becomes a seed after fertilisation.

Integument

Protective layer(s) surrounding the ovule; develops into seed coat.

Pollen

Male gametophyte of seed plants enclosed in a resistant wall.

Gymnosperm

Seed plant with “naked” seeds borne on cones (e.g., conifers, cycads).

Angiosperm

Flowering plant whose seeds develop inside ovaries (fruits).

Double Fertilisation

Fusion of one sperm with egg (zygote) and another with polar nuclei (endosperm) in angiosperms.

Endosperm

Triploid nutritive tissue formed during double fertilisation in angiosperm seeds.

Monocot

Angiosperm clade with one cotyledon, parallel veins and fibrous roots (e.g., grasses, lilies).

Eudicot

Large angiosperm clade with two cotyledons, net venation and taproots (e.g., roses, oaks).

Carpel

Female flower organ composed of stigma, style and ovary.

Stamen

Male flower organ consisting of filament and anther.

Simple Fruit

Fruit derived from a single carpel (e.g., pea pod).

Aggregate Fruit

Fruit formed from multiple separate carpels of one flower (e.g., raspberry).

Multiple Fruit

Fruit formed from an inflorescence of many flowers (e.g., pineapple).

Accessory Fruit

Fruit whose fleshy parts include non-ovary tissue (e.g., apple).

Pollination Syndrome

Suite of floral traits adapted to a specific pollination vector.

Anemophily

Wind pollination strategy featuring small, unscented flowers and abundant dry pollen.

Dioecy

Condition where individual plants bear only male or only female flowers.

Heterostyly

Floral polymorphism (pin/thrum) promoting cross-pollination by varying style and anther heights.

Protandry

Male flower parts mature before female parts to reduce self-fertilisation.

Protogyny

Female parts mature before male parts to reduce self-fertilisation.

Endozoochory

Seed dispersal via ingestion and defecation by animals.