Introductory Biology 2 - Quiz 2

Plant Taxonomy & Protist Lifecycles

Plasmodial Slime Molds

• diploid

• primarily sexual

• can be found growing through leaf mulch, rotten logs, & moist soil

• usually bright yellow or orange

• decomposers (feed on bacteria, fungi, and decaying organic matter)

1) Diploid plasmodium in growth stage.

2) Sporangia formation when environment is harsh.

3) Meiosis occurs (in sporangium)

4) Gametes (n) released in air.

5) Spores release motile cells (flagellated or amoeboid) that eventually fuse.

6) Zygote (2n) goes through mitosis without cytokinesis several times.

Cellular Slime Molds

• haploid

• primarily asexual (can be both)

• feeding stage consists of solitary cells

Sexual Reproduction:

1) Two haploid amoebas fuse

2) Zygote (2n) develops environmental shell, goes through meiosis

3) New haploid amoebas released

4) In low food conditions, amoebas aggregate

5) Form fruiting body

6) Spores produced and released

7) Amoebas emerge from spores.

Plants

• eukaryotic

• multicellular

• photosynthetic autotrophs (chlorophyll a + b, carotenoids, and xanthophylls)

• stores glucose as starch

• cellulose

• colonized lands 470 mya

Adaptations

• water (cuticle, stomata)

• gravity (cell walls, lignin, vascular tissue)

• transport of nutrients (xylem & phylem)

• zygote containment (archegonia)

• reproduction (wind/animals to transport sperm)

Alternation of Generations

where the gametophyte generation alternates with the sporophyte; in no-vascular systems, the dominant is the gametophyte (opposite for angiosperms)

• gametophyte is haploid and multicellular; sporophyte is diploid and multicellular

• gametophyte undergoes mitosis to produce gametes which will fuse to form a diploid zygote; the zygote will undergo mitosis, yielding the sporophyte

• sporophyte produces haploid spores via meiosis; these spores will germinate and give rise (via mitosis) to the gametophyte

• spores are cells that develop directly into the organism without the fusion of another cell

Bryophyte

• non-vascular plants (seedless)

• haploid dominant

• no structure

• small

• no true roots or leaves

• water and wind dependent

• zygote protected by archegonium

• includes mosses, liverworts, and hornworts

Phylum Bryophyta

• mosses

• stem-like appearance

• produces sexually

Phylum Hepatophyta

• liverworts

• probably the first land plants (primitive)

• flattened, leaf-like appearance

• can produce sexually or asexually

Phylum Anthocerophyta

• hornworts

• most closely related to vascular plants

Tracheophytes

• seedless vascular

• diploid dominant

• vascular tissue (structure; move water & minerals throughout)

• true leaves (spore producing; sporangia cluster into Sori)

Phylum Lycophyta

• club moss

• true leaves

• symbiotic to soil fungi

• rhizomes

• flagellated sperm

Phylum Monilophyta

• ferns, horsetail, and whiskferns

Ferns:

• roots, stems, leaves

• rhizones

• xylem has tracheids

• spores (sori) found on underside

• free-living gametophyte

• sperm and egg mature at different times

• dependent on water for reproduction

Horsetails:

• true roots, leaves

Whisk Ferns:

• no true roots, leaves

• appearance of a thin, green stem

Vascular Seeded Plants

• seeds (enclosed and protected)

• pollen

• sporophyte dominant; gametophyte reduces

• doesn’t need water for sperm transport

Gymnosperms

• unprotected seeds

• no vessel elements in xylem; only has tracheids

Phylum Coniferophyta

• conifers

• cooler climate

• woody cones

• modified leaves (pine needles)

• includes pines, firs, spruce, and cedars

Phylum Cycadophyta

• cycads

• look like palms

Phylum Ginkgophyta

• ginkgo trees

• one species (Ginklo biloba)

• deciduous (sheds leaves one at a time)

Phylum Gnetophyta

• gnetophytes

• once used in dietary supplements for weight loss

Angiosperms

• protected seeds

• flowering plants

• use flowers for reproduction

Phylum Anthophyta

• apple trees

• protected seeds

• monocot/dicot

• double fertilization (embryo and endosperm)

• xylem has vessel elements

• flowers (pollen transfer; coevolution)

Flower Anatomy

• petal

• sepal (calyx → all sepals: corolla → all petals)

Carpel:

• stigma

• style

• ovary

Stamen:

• anther

• filament