practical 3 Flashcards
Difference between monoecious and dioecious
In monoecious plants, you only need one plant of a species to produce fruit. Dioecious species, on the other hand, have separate male and female plants
Lycopodiophyta: Club mosses and spike mosses
Visible free-living part of plant = diploid sporophytes, dominant sporophyte
Microphylls Function (microphyll vs megaphyll)
micro = (one vein) unlobed
mega = multiple veins
Sporophylls
Sporangia located in axils of microphyll leaves, cone or strobilus, primary apomorphy = sporangium that splits open “laterally dehisces”
Polypodiopsida: Equisetidae (Horsetails) Apomorphies (2)
- Stems with external ridges (and often hollow internal canals)
- Whorled microphylls (3+ microphylls per node)
Polypodiopsida: Equisetidae (Horsetails) morphologies (5)
- Rhizome system & true roots
- Silica-filled epidermal cells (makes them rigid and tough)
- Photosynthetic stems
- Strobili (cones) at tips of stems containing sporangiophores (rather
than sporophylls) - Unique spores: have appendages (elaters) that move with humidity
changes to assit with spore dispersal
Strobilus
Polypodiopsida: Ophioglossidae (Whisk ferns) (5)
- Genus Psilotum
- Rhizomes (underground modified stem)
- Dichotomously branching stems (one branch
forks into two) - Tiny microphylls along the stem
- Three-lobed sporangia = synganium
Polypodiopsida: Polypodiidae (Leptosporangiate ferns)
Have megaphylls, circinnate vernation = immature leaves are coiled then slowly unfurl, immature coiled leaves = fiddlehead or crozier, dominant phase = sporophyte
Leptosporangiate ferns apomorphies
- leptopsorangium = Develops from a single cell, outer sterile layer only one cell thick
- Annulus: group of specialized cells functioning in spore dispersal
- Sori = clusters of leptosporangia
Seed plants: Spermatophytes Apomorphies
- Eustele = stem in which xylem and phloem form vascular bundles arranged in a ring (Internal xylem = (primary xylem, external phloem = primary phloem)
- Vascular cambium = continuously growing ring of tissue
situated between the xylem and phloem (bisects the
vascular bundles), single cell ring, can produce secondary
xylem or secondary phloem - Secondary xylem = wood
- seeds
Cork cambium (function)
Produces layer of protective cork tissue, cork contains suberin: waxy, water resistant compound, protects vascular cambium from damage and desiccation
Anatomy of the embryo
Cotelydons: seed leaves, Radicle: embryonic root apical
meristem (located at lower tip of
hypocotyl)
Adaptive significance of seeds (4)
- Seed coat protects embryo from damage, desiccation, predation
- Dispersal
- Dormancy (ensures germination (embryonic growth) under ideal conditions)
- Provides energy for young plant
(nutritive tissue surrounding embryo provides energy for initial growth)
Adaptive significance of wood
Vascular cambium = structural support, allows for larger size
Cycadophytes: Cycads
Pinnately compound leaves, dioecious (male and female plants), Cones (strobili) = male produces pollen, female bears ovules
Ginkophytes: Ginko biloba
- Only extant member of group: Ginko biloba
- Fan shaped leaves
- Dioecious
Pinophytes: Conifers
- dioecious or monoecious
- Basic female cone structure and function: bracts, ovuliferous scales
- Basic leaf structure: linear, may have bundles of needles (fascicles)
Angiosperms = flowering plants apomorphies (3)
- Flowers with carpels
- Endosperm
- Embryo sac
Significance of the evolution of flowers
Diversification: increased reproductive efficiency (ability to attract pollinators), coevolution with pollinators, fruits: protect and feed developing seeds (Animal dispersal = more coevolution)
Flower parts and function (8)
- Stamens (“androecium”)
(male reproductive organs) - Carpels (“gynoecium”) = modified female sporophyll: tubelike to receive
pollen - Ovary: base of pistil(s), contains ovules, is a “fruit” once
mature - Stigma: receptive to pollen grains (tip of pistil)
- style: neck-like, pollen tubes go down into this to reach the
ovary - Perianth: series of modified leaves at base of androecium/gynoecium
- Outer calyx of sepals (often green and leaf like)
- Inner corolla of petals (often elaborate and scented)
Fruits Definition
a mature ovary formed by the carpel
fruit anatomy and function (2)
- Pericarp = mature ovary wall
- seeds
fleshy fruits
Berry (grape), Drupe (peach), Hesperidium (orange), Pome (apple), Aggregate fruit, Multiple fruit
non fleshy fruits
Indehiscent = Achene (sunflower seed), Samara (maple), Grain (wheat), Nut (walnut)
Dehiscent = Legume (peas), Capsule (iris)
