Biodiversity Test 4 Strong Familiarity Elon University - Kingston

I put the study guide into claude and it gave me 3 sets of flashcards, this is the last one. Do it til your eyes bleed.

Synapomorphies of monocots vs. eudicots

Monocots: 1 cotyledon, parallel veins, 3-part flowers, scattered bundles, fibrous roots, monosulcate pollen. Eudicots: 2 cotyledons, net veins, 4/5-part flowers, ringed bundles, taproot, tricolpate pollen

Monocot synapomorphies: one cotyledon, scattered bundles, parallel veins, floral parts in 3s, monosulcate pollen, fibrous roots. Eudicot: two cotyledons, ring of bundles, net veins, parts in 4s/5s, tricolpate pollen, taproot

Angiosperm life cycle: double fertilization

Pollen lands on stigma, grows a pollen tube down the style; one sperm fertilizes the egg (2n zygote) and the other fuses with two polar nuclei (3n endosperm)

Sperm 1 + egg = 2n zygote (embryo). Sperm 2 + 2 polar nuclei (central cell) = 3n endosperm. Unique to angiosperms.

Angiosperm alternation of generations

Sporophyte (2n) flower makes microspores (in anthers) and megaspores (in ovules) by meiosis; these form male (pollen) and female (embryo sac) gametophytes (n), which produce sperm and egg; fertilization yields the 2n seed/new sporophyte

Male gametophyte = pollen grain (tube cell + generative cell). Female gametophyte = embryo sac, typically 7 cells / 8 nuclei (egg, 2 synergids, 3 antipodals, central cell with 2 polar nuclei).

Flower parts and functions

Sepals (protect bud), petals (attract pollinators), stamen = anther (pollen) + filament; carpel = stigma (receives pollen), style (tube), ovary (contains ovules)

Pistil = carpel(s). Sepals together = calyx; petals = corolla.

Directed pollination hypothesis

Animals carrying pollen directly from one plant to another is more efficient than wind or random dispersal, so selection favored plants that attract animal pollinators; this led to the evolution of showy flowers, nectar, and specialized pollination

Pollinator-driven selection favored colors, scents, nectar, and floral shapes, driving angiosperm diversification and co-evolution.

3 mechanisms to ensure outcrossing in plants

(1) Dioecy (separate male and female plants), (2) temporal separation: male and female parts mature at different times, (3) self-incompatibility (chemical rejection of own pollen); also spatial separation of anthers and stigma (herkogamy)

Outcrossing increases genetic diversity and avoids inbreeding depression.

Modified leaves

Tendrils = climbing; cactus spines = defense and reduced water loss; needles = conifer water conservation; onions = fleshy storage leaves in a bulb; bracts = colorful pollinator attractors

Modified leaves: tendrils (climbing, e.g., peas), spines (cactus; reduce water loss and defend), needles (conifers), storage leaves (onion bulb), bracts (poinsettia).

Modified stems and roots

Rhizome: underground horizontal stem (ginger). Stolon: above-ground runner (strawberry). Tuber: swollen storage stem (potato). Prop/buttress roots: support (corn, tropical trees). Pneumatophores: upward gas-exchange roots. Root tubers: storage roots (sweet potato)

Rhizomes = underground horizontal stems; stolons = above-ground horizontal stems (strawberry runners); tubers = swollen underground stems (potato); buttress roots = flared roots at base of trunk.

Seed formation in monocots vs. eudicots

Eudicot seed (bean): endosperm absorbed by two fleshy cotyledons. Monocot seed (corn): one thin cotyledon, endosperm remains as the main food storage; protective coleoptile/coleorhiza around the shoot and root

Monocot: endosperm persists and the single cotyledon absorbs it; embryo has coleoptile and coleorhiza. Eudicot: endosperm absorbed into the two thick cotyledons, so mature seed has little endosperm (e.g., beans); embryo has hypocotyl, epicotyl, radicle.

Life cycles: cellular vs. plasmodial slime molds

Cellular: single amoebas eat bacteria, starve, aggregate into a multicellular slug, then form a fruiting body with spores; cells remain separate. Plasmodial: haploid spores germinate into flagellated cells or amoebas, which fuse into a diploid zygote that grows into a coenocytic plasmodium, which forms sporangia where meiosis makes spores

Cellular slime mold (Dictyostelium): individual amoebas feed on bacteria; when starved, they aggregate (cAMP signal) into a slug (pseudoplasmodium) which forms a stalked fruiting body; spores released, germinate into amoebas. Sexual cycle: two amoebas fuse into a macrocyst.

Lab 11: Shannon vs. Simpson's vs. Pielou's

Shannon = overall diversity (richness + evenness); Simpson's = dominance (probability two individuals are the same species; 1-D is diversity); Pielou's = evenness (how equal the abundances are, J = H'/ln S, ranging 0-1)

Shannon (H') measures diversity combining richness and evenness. Simpson's (D) measures dominance: probability two randomly chosen individuals are the same species; 1-D gives diversity. Pielou's (J) = H'/ln(S) measures evenness (0 to 1).

Lab 12: dermal, ground, and vascular tissue systems

Dermal = outer protective covering (epidermis); ground = pith and cortex (storage, photosynthesis, support); vascular = xylem (water) and phloem (sugar)

Dermal = epidermis (and periderm in woody plants). Ground tissue = parenchyma, collenchyma, sclerenchyma. Vascular tissue = xylem + phloem.

Lab 12: identifying cell types in cross-section

Vessel elements: large round open pores with thick walls. Tracheids: smaller, angular thick-walled cells. Sieve tube members: large thin-walled cells with sieve plates; companion cells: small dense nucleated cells beside them. Parenchyma: thin-walled round; sclerenchyma: very thick-walled

In a cross-section, xylem usually appears as the larger, thick-walled, open (empty) cells, and phloem as smaller, thin-walled cells next to it.

Lab 12: root and shoot cross-sections, monocot vs. eudicot

Eudicot root: xylem forms an X/star in the center, phloem between the arms. Monocot root: central pith, with xylem and phloem arranged in a ring around it. Eudicot shoot: ring of bundles; monocot shoot: scattered bundles

Root: eudicot has xylem in a central X or star shape, with phloem between arms (no pith); monocot root has a central pith surrounded by a ring of alternating xylem and phloem. Shoot as described earlier.

Lab 12: tree trunk cross-section layers

Center to outside: pith, heartwood, sapwood (growth rings), vascular cambium, phloem, cork cambium, cork (bark = all outside the vascular cambium)

Order from center outward: pith, primary xylem, secondary xylem (heartwood then sapwood), vascular cambium, secondary phloem, cork cambium, cork. Bark = everything outside the vascular cambium. Growth rings: light early wood, dark late

Lab 12: flower dissection, locating parts

Sepals (outer green), petals (colorful), stamen (anther on filament), pistil (stigma on top, style tube, ovary at base containing ovules)

Know the stalk/swollen-base ovary relationship: ovules are inside the ovary, which becomes the fruit.

Lab 13: Amoeba organelles and Physarum

Amoeba: single cell with nucleus, contractile vacuole (expels excess water), food vacuoles, pseudopodia. Physarum: yellow multinucleate plasmodium with branching veins and cytoplasmic streaming; sporangia on stalks

Physarum: yellow, fan-shaped network (plasmodium) with veins; cytoplasmic streaming visible. Amoeba: a single large cell with nucleus, contractile vacuole, food vacuoles, pseudopodia, ectoplasm and endoplasm.