lab 8

alternation of generations

• all plants undergo this

• land plants have 2 multicellular generations:

  1) gametophyte (haploid N) produces gametes

  2) sporophyte (diploid 2N) produces spores

non vascular plants

• lack vascular tissue

• rely on water to transport their gametes (specifically sperm)

• gametophyte dominant (N) spend most of their life in this stage

• MOSS AND LIVERWORTS

hepaticophyta (liverworts)

• gametophyte dominant (n)

• pores along upper surface for gas exchange

• gemma cups contain gemmae for asexual reproduction

bryophyta (mosses)

• gametophyte dominant (N)

• the sporophyte grows as brownish stalks which produce the spores

seedless vascular plants

• vascular tissue (xylem and phloem)

• enables plants to develop true roots, stems, and leaves

• grow taller than non-vascular plants

• depend on water for dissemination of gametes

• sporophyte dominant (2n) stage

lycophyta (club mosses)

• sporophyte dominant (2n)

• vascular tissue allows to grow upright

• possess strobili (cones) which produce spores

psilotophyta (whisk fern)

• sporophyte dominant (2n)

• sporangium located on a structure called a synangia

sphenophyta (horsetails)

• sporophyte dominant(2n)

• strobili (cones) found at the tips of each stem

pteridophyta (ferns)

• sporophyte dominant (2n)

• individual sporangia typically on underside of leaves in collections called sori

• sori sometimes covered by an indusium

gymnosperms (seed plants)

• cycadophyta, ginkophyta, and coniferphyta

• vascular plants that have seeds

• sporophyte dominant (2n)

• seeds (female gamete) and pollen (male gamete) provide protection for reproductive cells

• secondary growth (bark and wood) makes these plants grow wide and tall

• NOT FLOWERS ONLY STROBILI

cycadophyta (cycads)

• Once prominent, not anymore in modern times

• have large strobili

• female strobilus = round & squat

• male strobilus= long & elongated

• pollen grains are on/ within cone

ginkgophyta (ginkgoes)

• only gymnosperm to cycle leaves with the season

• produces seeds that look like fruit but aren’t (only flowering plants have fruit)

• the fleshy seed coat is part of the sporophyte (2n)

• the gametophyte within (n) provides nutrition for developing embryo (2n)

coniferophyta (conifers)

• pine, firs, cypresses, junipers, & redwoods

• include the largest and longest lived plants in da world

• have strobili (cones)

Angiosperm (flowering plants)

• seed plants that possess flowers and fruit

• most recent group to evolve (65 mil ago)

• pollen grains mostly dispersed by pollinators

Anthophyta (flowering plants)

• structures include male and female which are stamen and carpels

• seeds develop within the ovary (within the carpel)

• when seed develops the ovary becomes the fruit of the plant