Botany

Systematics The study of biological diversity and its evolutionary history.

Phylogeny The hypothetical evolutionary history/relationship among organisms.

Taxonomy The science of classification and naming organisms.

Systematics vs taxonomy Taxonomy focuses on naming/classifying; systematics also emphasizes evolutionary relationships.

Why is systematics important? It lets us describe, document, name, compare, conserve, and communicate about biodiversity.

How do you “do” systematics? Collect/observe organisms, compare traits, use DNA/morphology, build phylogenies, classify, and name species.

Why do species names matter? Names create a shared language so scientists know exactly which organism is being discussed.

Type specimen A reference specimen that anchors the scientific name of a species.

Holotype The single main specimen originally chosen to define a species.

Isotype A duplicate of the holotype collection, common in botany.

Lectotype A specimen selected later to serve as the type when no holotype was chosen or the holotype is lost.

Paratype An additional specimen cited in the original description that supports the species description but is not the main type.

Holotype vs lectotype Holotype = original main type; lectotype = chosen later as the main type.

Paratype vs lectotype Paratype = extra supporting specimen; lectotype = later-selected name-bearing specimen.

Domain The broadest taxonomic rank; examples are Bacteria, Archaea, and Eukarya.

Kingdom A major group within a domain; examples include Plantae, Animalia, and Fungi.

Phylum A rank below kingdom grouping organisms with major shared ancestry/body plan.

Class A rank below phylum and above order.

Order A rank below class and above family.

Family A rank below order and above genus; often groups related genera.

Genus A rank below family that groups very closely related species.

Species The most specific rank; a distinct evolutionary/reproductive/morphological lineage.

Taxonomic rank order Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Taxonomic rank memory trick Dear King Philip Came Over For Good Soup.

Bryophytes Nonvascular land plants such as mosses, liverworts, and hornworts; gametophyte-dominant.

Pteridophytes Seedless vascular plants such as ferns and horsetails; sporophyte-dominant but reproduce by spores.

Gymnosperms Seed plants with naked seeds not enclosed in fruit; examples include conifers, cycads, ginkgo, and gnetophytes.

Angiosperms Flowering plants with seeds enclosed in an ovary that becomes fruit.

Dicots Older traditional group of flowering plants with two cotyledons; not all “dicots” form one true clade.

Eudicots A major true clade of angiosperms; usually have two cotyledons and tricolpate pollen.

Dicot vs eudicot Dicot = older broad category; eudicot = true evolutionary clade containing most former dicots.

Monocots Angiosperms with one cotyledon, parallel veins, scattered vascular bundles, flower parts often in 3s, and monosulcate pollen.

Eudicot traits Two cotyledons, net venation, vascular bundles in a ring, flower parts often in 4s or 5s, and tricolpate pollen.

Sporophyte The diploid 2n generation that produces spores by meiosis.

Gametophyte The haploid n generation that produces gametes by mitosis.

Which generation dominates in bryophytes? The gametophyte generation.

Which generation dominates in vascular plants? The sporophyte generation.

Major land plant life cycle trend Shift from gametophyte dominance to sporophyte dominance.

Key innovation A novel trait that allows a lineage to exploit a new resource or adaptive zone.

Adaptive radiation Rapid diversification of a lineage into new ecological roles or adaptive zones.

Charophycean algae Closest living relatives of land plants.

Early land plant innovations Meristematic growth, spores, waxy cuticle, gametangia, and protected embryos.

Vascular plant innovations Xylem, phloem, lignin, roots, shoots, leaves, and sporophyte dominance.

Seed plant innovations Pollen, ovules, seeds, and reduced gametophytes.

Gymnosperm key innovation Seeds and pollen allowed reproduction with less dependence on free water.

Angiosperm key innovations Flowers, carpels, fruits, double fertilization, and enclosed seeds.

Carpel Structure unique to angiosperms that encloses ovules/seeds.

Angiosperm meaning “Seed in vessel,” because seeds are enclosed in carpels/ovaries.

Flower A reproductive structure made of modified leaves on a shortened stem.

Complete flower A flower with all four whorls: calyx, corolla, androecium, and gynoecium.

Incomplete flower A flower missing one or more floral whorls.

Perfect flower A flower with both male and female reproductive structures.

Imperfect flower A flower missing either stamens or carpels.

Calyx The sepals collectively; usually protects the flower bud.

Corolla The petals collectively; often attracts pollinators.

Androecium The male flower parts collectively; all stamens.

Gynoecium The female flower parts collectively; all carpels/pistils.

Stamen Male floral structure made of anther and filament.

Anther Part of the stamen where pollen is produced.

Filament The stalk of a stamen.

Pistil Female floral structure made of stigma, style, and ovary; may be one carpel or fused carpels.

Stigma Pollen-receptive surface.

Style Neck-like structure connecting stigma to ovary.

Ovary Swollen lower part of the pistil containing ovules.

Ovule Structure that develops into a seed after fertilization.

Fruit Mature ovary that helps protect and disperse seeds.

Darwin’s Abominable Mystery Darwin’s concern about the apparently rapid origin and diversification of flowering plants.

How can the Abominable Mystery be explained? Angiosperm diversification may be explained by flowers, fruits, pollinator coevolution, dispersal, reproductive isolation, and adaptive radiation.

Major angiosperm evolutionary trends Reduction and fusion of flower parts; increased protection of the ovary.

Trend in perianth parts Indefinite to definite number of parts; spiral to whorled/radial insertion; fusion; loss/reduction; radial to bilateral symmetry.

Trend in androecium Decrease in number of stamens and fusion into sheaths or bundles.

Trend in gynoecium Apocarpy to syncarpy and superior ovary to inferior ovary.

Apocarpy Distinct, separate carpels.

Syncarpy Fused carpels.

Hypogyny Superior ovary; ovary sits above other floral parts.

Epigyny Inferior ovary; ovary enclosed below/within receptacle tissue.

Radial symmetry Flower can be divided into mirror-image halves in multiple planes.

Bilateral symmetry Flower can be divided into mirror-image halves in only one plane.

Why is bilateral symmetry important? It can make pollination more precise by forcing pollinators into a specific position.

Early angiosperm flower traits Radial symmetry, perfect flowers, superior ovary, many free parts, and poorly differentiated tepals/stamens/carpels.

Tepals Perianth parts not clearly differentiated into sepals and petals.

Species A group of organisms that are distinct genetically, morphologically, reproductively, or evolutionarily from other groups.

Speciation The evolutionary process by which one species splits into two or more species.

Morphological species concept Species are separated by detectable physical/morphological discontinuities.

Morphological species concept strength Useful when reproductive, genetic, or ecological data are unavailable.

Morphological species concept problem Physical traits may not match genetic or reproductive isolation; homoplasy can mislead.

Homoplasy Similar-looking traits that evolved independently and do not indicate close relationship.

Biological species concept Species are groups of interbreeding populations reproductively isolated from other groups.

Biological species concept strength Focuses on reproductive isolation and gene flow.

Biological species concept problem in plants Hybridization, asexual reproduction, and lab crosses may not reflect natural reproduction.

Phylogenetic species concept A species is the smallest diagnosable evolutionary lineage with ancestry/descent.

Phylogenetic species concept strength Emphasizes evolutionary history and diagnosable synapomorphies.

Phylogenetic species concept problem Requires discrete characters and struggles with hybridization/reticulate evolution.

Should we doubt plant species? Not completely; plant species can be messy, but many are real reproductively independent lineages.

Why are plant species boundaries messy? Polyploidy, asexual reproduction, hybridization, gene flow, and taxonomic over-splitting can blur boundaries.

What did the plant species reading conclude? Many plant species are biologically real; about 70% of taxonomic plant species correspond to reproductively independent lineages.

Phenotypic cluster A group of organisms that look similar based on measured traits.

Reproductively independent lineage A lineage mostly reproductively isolated from other lineages.

Gene flow Movement of genes between populations through reproduction.

Reproductive isolation Barriers that reduce or prevent gene flow between populations.

Isolating mechanisms Factors that limit gene flow between populations.

Do isolating mechanisms need to be absolute? No; they only need to reduce gene flow enough to allow divergence.

The road to speciation Mutation, recombination, isolation, genetic drift, hybridization, and polyploidy.

Geographic isolation Populations are physically separated, limiting gene flow.

Ecological isolation Populations adapt to different ecological conditions or habitats.

Premating isolation Barriers that prevent pollen transfer or mating before fertilization.

Postmating isolation Barriers after pollen transfer/mating, including incompatibility or hybrid problems.

Temporal isolation Species flower or become receptive at different times.

Ethological isolation Different populations attract different pollinators because of pollinator behavior.

Mechanical isolation Floral architecture prevents pollen transfer between species.

Gametic incompatibility Pollen fails to germinate, or pollen tube fails before fertilization.

Hybrid inviability Hybrid does not survive or does not reach reproductive age.

Hybrid sterility Hybrid survives but cannot produce functional gametes.

Hybrid breakdown F2 or later-generation hybrids are weak, inviable, sterile, or disease-susceptible.

Theoretical sequence of isolating mechanisms Geographic isolation first, then ecological/environmental isolation, then premating barriers, then postmating barriers.

Which isolating barriers are strongest? Premating reproductive barriers are often strongest.

Why are postmating barriers costly? Energy has already been invested in fertilization or offspring before failure occurs.

Allopatric speciation Speciation through geographic separation.

Allopatric memory trick Allo = apart.

Sympatric speciation Speciation in the same geographic area, often through polyploidy or ecological shifts.

Sympatric memory trick Sym = same place.

Parapatric speciation Neighboring populations diverge while still touching at their edges.

Parapatric memory trick Para = beside.

Peripatric speciation A small isolated edge population becomes a new species.

Peripatric memory trick Peri = perimeter/edge.

Founder effect model One or a few individuals disperse, become isolated, and diverge genetically/phenotypically.

Hybridization Mating between different varieties, populations, or species.

Introgression Movement of genes from one species/variety into another through repeated backcrossing.

How can hybridization lead to speciation? Hybrids may become reproductively isolated from both parent species and form a new lineage.

Possible outcomes of hybridization Species merger, stable hybrid zone, transfer of adaptations, reinforcement of reproductive barriers, or birth of new hybrid lineages.

Destructive role of hybridization Species merge and distinct lineages may be lost.

Neutral role of hybridization Stable hybrid zones persist without fully merging or producing new lineages.

Creative role of hybridization Hybridization transfers adaptations, reinforces barriers, or produces new hybrid lineages.

Stable hybrid zone Area where hybrids keep forming but selection and gene flow maintain a stable boundary.

Polyploidy Condition where an organism has more than two complete sets of chromosomes.

Why polyploidy can cause rapid speciation Polyploids often cannot successfully interbreed with diploid ancestors because of meiotic imbalance.

Autopolyploidy Chromosome doubling within one species.

Autopolyploid memory trick Auto = self.

Allopolyploidy Chromosome doubling after hybridization between two species.

Allopolyploid memory trick Allo = other.

Auto vs allopolyploidy Autopolyploidy uses one species’ genome; allopolyploidy combines genomes from two species.

Why polyploidy matters in angiosperms It creates reproductive isolation, genetic redundancy, new variation, and sometimes new species quickly.

Heterosis Hybrid performance exceeds parental values.

Gene redundancy Extra gene copies allow duplicate genes to be silenced or evolve new functions.

Examples of allopolyploid groups Brassica, Tragopogon, Triticale, Polystichum, and some ferns.

Pollination Transfer of pollen from microsporangia to stigma in angiosperms or to ovule in gymnosperms.

Fertilization Fusion of sperm and egg to form an embryo/new sporophyte.

Wind pollination Ancestral in gymnosperms; some angiosperms are secondarily wind-pollinated.

Animal pollination Derived and very important in angiosperm diversification.

Why do pollinators visit flowers? They seek rewards such as nectar, pollen, oils, waxes, shelter, heat, or mating sites.

Attractants Flower signals that advertise to pollinators, such as color, scent, shape, nectar guides, timing, and heat.

Rewards Benefits flowers provide pollinators, such as nectar, pollen, oils, waxes, shelter, or warmth.

Attractant vs reward Attractant = advertisement; reward = payment.

Nectar Sugary energy reward for pollinators.

Pollen Protein-rich food reward for pollinators.

Oils/waxes Specialized rewards collected by some pollinators.

Trick pollination Flowers deceive pollinators instead of rewarding them, such as mimicry or trapping.

Bee-pollinated flower traits Showy, colorful, fragrant, nectar guides, and landing platforms.

Butterfly-pollinated flower traits Showy, colorful, fragrant, often long tubes or spurs, usually no nectar guides.

Moth-pollinated flower traits Large, white/pale, fragrant, often tubes or spurs, active/open at night.

Fly-pollinated flower traits Often maroon/brown and foul-smelling like rotting flesh.

Bird-pollinated flower traits Often red/orange, tubular, and large nectar rewards.

Bat-pollinated flower traits Nocturnal, large, colorful or white, with copious nectar or pollen.

Wind-pollinated flower traits Small, numerous, often unisexual, absent/non-showy perianth, produced in mass.

Outbreeding Sexual reproduction between different individuals; also called outcrossing, allogamy, or xenogamy.

Outbreeding advantages Increases genetic variability, evolutionary potential, and adaptation to changing conditions.

Outbreeding disadvantages Can destroy well-adapted genotypes and relies on pollination, dispersal, and establishment.

Inbreeding/selfing Sexual reproduction within an individual.

Selfing advantage Assures reproduction when mates or pollinators are scarce.

Selfing disadvantage Reduces genetic variation and can cause inbreeding depression.

Inbreeding depression Reduced fitness caused by increased expression of harmful recessive alleles.

Dichogamy Different timing of male and female floral function.

Protogyny Female function first; stigma receptive before anthers release pollen.

Protandry Male function first; anthers release pollen before stigma is receptive.

Hercogamy Spatial separation of anthers and stigmas.

Self-incompatibility Genetic system preventing self-fertilization.

Dioecy Staminate and carpellate flowers occur on different plants.

Monoecy Staminate and carpellate flowers occur on the same plant.

Outbreeder morphology Many large, colorful, scented flowers; nectar guides; nectaries; anthers far from stigma; many pollen grains.

Inbreeder morphology Few small, mono-colored, unscented flowers; little/no nectar; anthers near stigma; fewer pollen grains.

Allautogamy A mixed breeding system using both outcrossing and selfing.

Chasmogamous flowers Normal open flowers that can outcross.

Cleistogamous flowers Closed flowers that self-pollinate.

Asexual reproduction Reproduction without meiosis or fertilization.

Vegetative reproduction Asexual reproduction through structures like rhizomes, bulbs, corms, or plantlets.

Apomixis Seed production without fertilization.

Dispersal Movement of spores, pollen, fruits, seeds, or other propagules away from the parent plant.

Diaspore The plant part that gets dispersed.

Why disperse? To colonize habitat, track environmental change, avoid relatives/competition, avoid pathogens/herbivores, and avoid inbreeding.

Abiotic dispersal vectors Wind, water, and gravity.

Biotic dispersal vectors Animals such as birds, mammals, and ants.

Endozoochory Internal animal dispersal, usually through fruit eating and seed passage.

Ectozoochory External animal dispersal, usually by seeds/fruits sticking to fur or feathers.

Frugivory Fruit eating; animals get food and may disperse seeds.

Janzen-Connell idea Seeds near parent plants suffer more from competition, pathogens, or herbivores, so dispersal away from parents can improve survival.

Coevolution Reciprocal evolutionary change between interacting species.

Interspecific interaction Interaction between different species.

Mutualism Interaction where both species benefit.

Antagonism Interaction where one species benefits while the other is harmed.

Commensalism Interaction where one benefits and the other is mostly unaffected.

Plant-pollinator coevolution Plants evolve floral traits and pollinators evolve traits/behaviors that match those flowers.

Plant-herbivore coevolution Plants evolve defenses; herbivores evolve ways to overcome them.

Plant-pathogen coevolution Plants evolve resistance; pathogens evolve ways to infect.

Plant-seed disperser coevolution Plants evolve fruits/rewards; animals evolve feeding/dispersal behavior.

Mycorrhizal interaction Fungi help plants absorb nutrients; plants provide sugars to fungi.

Specialist A species relying on one or very few partner species.

Generalist A species interacting with many possible partner species.

Red Queen hypothesis Species must keep evolving just to keep up with interacting species.

Evolutionary arms race Back-and-forth coevolution, such as plant toxins vs herbivore detoxification.

How coevolution explains the Abominable Mystery Interactions with pollinators, dispersers, and herbivores may have promoted rapid angiosperm diversification and specialization.

Cosmopolitan species A species found across much of the world.

Endemic species A species naturally restricted to a particular region.

Narrow endemic A species with a very small geographic range.

Refugia Places where species survive unfavorable climate periods.

Thermal refugia Cold microhabitats that let species persist during warming.

Why refugia matter They preserve populations and genetic diversity through climate upheaval.

Floristic region at WWU Rocky Mountain Floristic Region in the class framework.

Floristic province at WWU Vancouverian Province, the more specific coastal Pacific Northwest province.

Region vs province Region = larger plant geography category; province = smaller, more local subdivision.

Vancouverian Province traits Cool, wet, ocean-influenced climate with conifer forests, mosses, ferns, and species like Douglas-fir, western hemlock, and western red cedar.

Direct climate change effects on plants Heat stress, drought stress, altered growing season, changed snow/frost timing, CO2 changes, and fire.

Indirect climate change effects on plants Pollinator shifts, new competitors, herbivore/pathogen changes, soil changes, and disturbance changes.

Phenology Seasonal timing of life events such as flowering, leaf-out, and fruiting.

Phenological mismatch Climate change shifts timing so plants and pollinators/seed dispersers no longer match.

Five plant responses to climate change Tolerate new conditions, shift locally, migrate elsewhere, adapt genetically, or go extinct.

Habitat tracking Species shift distribution to stay within suitable climate/habitat conditions.

Likely plant response to warming Many species shift poleward, upslope, or toward cooler/moister refugia.

Why mountain plants are at risk They may move upslope until there is no higher habitat left.

Escalator to extinction Upslope movement under warming eventually leaves mountaintop species with nowhere to go.

Widespread species under climate change Often have broader tolerance, more populations, and more chance to shift range.

Narrow endemics under climate change Often have small ranges, specific habitat needs, poor dispersal, and higher extinction risk.

Olympic alpine endemic climate result Five Olympic alpine endemics were projected to lose 85–99% of suitable habitat by 2080.

Why Olympic alpine endemics are vulnerable They live in isolated high-elevation habitats with limited room to move and strong dispersal barriers.