Bio Ch 23
Terms in this set (65)
Alternation of generation
Life cycle, typical of land plants, in which a diploid sporophyte alternates with a haploid gametophyte.
Flowering land plant; the seeds are borne within a fruit.
Sperm-producing structures, as in the moss life cycle.
Directional term that refers to the tip of a filament or branch of a plant.
A nonvascular land plant—including the mosses, liverworts, and hornworts—in which the gametophyte is dominant.
Ovule-bearing unit that is a part of a pistil.
Reproductive structure in conifers made up of scales bearing sporangia; pollen cones bear microsporangia, and seed cones bear megasporangia.
Member of a group of cone-bearing gymnosperm land plants that includes pine, cedar, and spruce trees.
Seed leaf for embryo of a ﬂowering plant; provides nutrient molecules for the developing plant before photosynthesis begins.
Waxy layer covering the epidermis of plants that protects the plant against water loss and disease-causing organisms.
Having unisexual ﬂowers or cones, with the male ﬂowers or cones conﬁned to certain land plants and the female ﬂowers or cones of the same species conﬁned to other different plants.
In ﬂowering plants, one sperm nucleus unites with the egg nucleus, and a second sperm nucleus unites with the polar nuclei of an embryo sac.
Flowering plant group; members have two embryonic leaves (cotyledons), net-veined leaves, vascular bundles in a ring, ﬂower parts in fours or ﬁves and their multiples, and other characteristics.
Member of a group of land plants that have large fronds; in the sexual life cycle, the independent gametophyte produces ﬂagellated sperm, and the vascular sporophyte produces windblown spores.
Reproductive organ of a ﬂowering plant, consisting of several kinds of modiﬁed leaves arranged in concentric rings and attached to a modiﬁed stem called the receptacle.
Flowering plant structure consisting of one or more ripened ovaries that usually contain seeds.
Haploid generation of the alternation of generations life cycle of a plant; produces gametes that unite to form a diploid zygote.
Member of phylum Ginkgophyte; maidenhair tree.
Type of woody seed plant in which the seeds are not enclosed by fruit and are usually borne in cones, such as those of the conifers.
Seed plant that produces two types of spores—microspores and megaspores. A plant that produces only one type of spore is homosporous.
A plant that produces only one type of asexual spore.
Chemical that hardens the cell walls of land plants.
Large leaf with several to many veins.
One of the two types of spores produced by seed plants; develops into a female gametophyte (embryo sac).
Small leaf with one vein.
One of the two types of spores produced by seed plants; develops into a male gametophyte (pollen grain).
Flowering plant group; members have one embryonic leaf (cotyledon), parallel-veined leaves, scattered vascular bundles, ﬂower parts in threes or multiples of three, and other characteristics.
Having male ﬂowers or cones and female ﬂowers or cones on a single plant.
Bryophyte that is typically found in moist habitats.
In plants, the place where one or more leaves attach to a stem.
Bryophytes, such as mosses and liverworts, that have no vascular tissue and either occur in moist locations or have special adaptations for living in dry locations.
In ﬂowering plants, the enlarged, ovule-bearing portion of the carpel that develops into a fruit; female gonad in animals that produces an egg and female sex hormones.
In seed plants, a structure that contains the female gametophyte and has the potential to develop into a seed.
Flower stalk; expands into the receptacle.
A ﬂower part that occurs just inside the sepals; often conspicuously colored to attract pollinators.
Vascular tissue that conducts organic solutes in plants; contains sieve-tube members and companion cells.
Multicellular, photosynthetic, eukaryotes that increasingly became adapted to live on land.
In seed plants, structure that is derived from a microspore and develops into a male gametophyte.
In seed plants, a tube that forms when a pollen grain lands on the stigma and germinates. The tube grows, passing between the cells of the stigma and the style to reach the egg inside an ovule, where fertilization occurs.
In gymnosperms, the transfer of pollen from pollen cone to seed cone; in angiosperms, the transfer of pollen from anther to stigma.
Area where a ﬂower attaches to a ﬂoral stalk.
Root like hair that anchors a plant and absorbs minerals and water from the soil.
Root like underground stem.
Mature ovule that contains an embryo, with stored food enclosed in a protective coat.
Vascular plants that disperse seeds; the gymnosperms and angiosperms.
Seedless vascular plant
Collective name for club mosses (lycophytes) and ferns (pteridophytes) Characterized by windblown spores.
Outermost, leaﬂike covering of the ﬂower; usually green in color.
Structure that produces spores.
Asexual reproductive or resting cell capable of developing into a new organism without fusion with another cell, in contrast to a gamete.
Modiﬁed leaf that bears a sporangium or many sporangia.
Diploid generation of the alternation-of-generations life cycle of a plant; produces haploid spores that develop into the haploid generation.
In ﬂowering plants, the portion of the ﬂower that consists of a ﬁlament and an anther containing pollen sacs where pollen is produced.
In ﬂowering plants, portion of the carpel where pollen grains adhere and germinate before fertilization can occur.
Small openings between two guard cells on the underside of leaf epidermis through which gases pass.
Elongated, central portion of the carpel between the ovary and stigma.
Plant that has xylem and phloem.
Transport tissue in plants, consisting of xylem and phloem.
Cluster of branches, or other plant structures, that occurs in a circular pattern.
Vascular tissue that transports water and mineral solutes upward through the plant body; it contains vessel elements and tracheids.
1. What is meant when it is said that a plant alternates generations?
meaning that an organism has two alternating forms in the course of its life cycle. the sporophyte (2n) is so named for its production of spores by meiosis. A spore is a haploid reproductive cell that develops into a new organism without the need to fuse with another reproductive cell. In the plant life cycle, a spore undergoes mitosis and becomes a gametophyte. The gametophyte (n) is so named for its production of gametes. In plants, eggs and sperm are produced by mitotic cell division. A sperm and egg fuse, forming a diploid zygote that undergoes mitosis becoming the sporophyte embryo, and then the 2n generation. Two observations can be made. First, meiosis produces haploid spores. This is consistent with the sporophyte being the diploid generation and producing spores, which are haploid reproductive cells. Second, mitosis occurs as a spore becomes a gametophyte, and mitosis occurs again as a zygote becomes a sporophyte. The occurrence of mitosis at these times deﬁnes the two generations.
2. What features do all seed plants have in common?
SEED PLANTS (gymnosperms and angiosperms)
Leaves are megaphylls; dominant sporophyte produces
heterospores that become dependent male and female
gametophytes. Male gametophyte is pollen grain and female gametophyte occurs within ovule, which becomes a seed.All seed plants have vascular tissue and seeds to reproduce. In addition they all have body plans that includes leaves, stems, and roots.
3. List and describe 3 phyla of gymnosperms.
a) Conifers: (such as pine, spruce, and cedar) cone bearing and evergreen;
b) cycads: (such as Zamia pumila, Cycas revoluta) and cone bearing, evergreen and wind pollinated;
c) ginkgoes: (a single species, the ginkgo) cone bearing, deciduous ;
d) gnetophytes: (strange plants such as Welwitschia, Ephedra and Gnetum) cone bearing and insect pollinated.
4. How do monocots and eudicots differ?
Flower parts in threes or multiples of three
Pollen grain with one pore
Usually parallel venation
Scattered bundles in stem
Fibrous root system
Flower parts in fours or fives or multiples of four or five
Pollen grain with three pores
Woody or herbaceous
Usually net venation
Vascular bundles in a ring
5. Discuss how pollen is formed.
Pollen is produced within the anthers (microsporangia or pollen sacs) of the flower.Within the pollen sacs, meiosis produces four microspores. Each microspore becomes a pollen grain.
6. Discuss how the mature female gametophyte is formed.
In an ovule (megasporangium) within an ovary, meiosis produces four megaspores. Inside the ovule of an ovary, three megaspores disintegrate, and only the remaining one undergoes mitosis to become a female gametophyte. The ovule now contains the mature female gametophyte (embryo sac), which typically consists of eight haploid nuclei embedded in a mass of cytoplasm. The cytoplasm differentiates into cells, one of which is an egg and another of which contains two polar nuclei.