chapter 19- Plants Flashcards
what is the evidence that plants are closely related to green algae?
they both have chlorophyll a, use of starch as a storage carbohydrate, cell walls are made of cellulose, and similar life cycles that feature alternation of generations. DNA sequences also support this hypothesis
How does vascular tissue adapt plants to land?
vascular tissues (xylem and phloem) transports water/nutrients throughout the body, which helps roots, stems, and leaves to develop specialized functions. lignin in xylem add strength that supports the plants to grow tall
Describe the reproductive adaptations of plants
nonvascular plants and seedless vsc plants have swimming sperm, so the sperm can reach egg only in moist conditions
seed plants, pollen allows reproduction to occur over great distances and in the absence of a film of water. seeds allow for dormancy stage and provide food for the developing embryo
angiosperms, flowers promote efficient pollination, and fruits aid in seed protection and dispersal
Describe the three main groups of bryophytes
Liverworts have flattened, lobed gametophytes
Hornworts have tapered, horn-shaped sporophytes and flat gametophytes
Mosses are compact bryophytes with structures resembling stems and leaves
Describe the relationship between bryophyte gametophytes and sporophytes
A haploid gametophyte develops from a haploid spore. Once they mature, they begin producing mitosis. sperm from gametophyte swims in water to egg cell in female gametophyte. fertilization occurs, making the zygote within the female. the diploid zygote is the 1st cell of the sporo gen. the sporophyte divides mitotically, forming a stalk that grows out of the gameto tissue. cells in the sporophyte undergo meiosis to produce haploid spores that are the 1st cells of a new gameto gen.
Describe the four groups of seedless vascular plants
Club mosses, spike mosses, and other lycopods have similar leaves resembling scales or needles
whisk ferns have highly branched stems that typically lack leaves. they also have rhizomes but lack roots.
horsetails grow from rhizomes as well, they have aerial, bushy stems that bear spores at their tips.
True ferns have fronds that grow from rhizomes, the undersides of the fronds bear spores.
How do seedless vascular plants reproduce?
A fern frond is part of the diploid sporophyte generation. on the underside of the frond are sporangia. Cells in sporangia undergo meiosis, releasing haploid spores that germinate and develop mitotically into small, heart-shaped gametophytes. then the gametophyte produce eggs and sperm cells by mitosis. sperm swims to an egg and fertilize. the fertilized egg develops into a diploid sporophyte, which soon dwarfs into tiny gametophyte
Compare and contrast seedless vascular plants and bryophytes
Plants in both groups are tied into water by swimming sperm that requires water to reach the eggs. neither groups has pollen, seeds, flowers or fruits. seedless vascular plants however, have xylem and phloem, which bryophytes don’t have
What are the characteristics of gymnosperms?
they have vascular tissue, pollen, naked seeds that are not enclosed in fruits
what are the four groups of gymnosperms?
cycads, ginkgos, conifers, and gnetophytes
What is the role of cones in conifer reproduction?
cells in male cones undergo meiosis, producing microspores that develop into pollen grains (male gametophytes). cells on female cone scales undergo meiosis, producing megaspores that develop into egg-producing female gametophytes. pollination, fertilization, and seed development occur on the female cone’s scales.
what happens during and after pollination in gymnosperms?
during pollination, a pollen grain is delivered to a female gametophyte in an ovule on a cone scale. the pollen grain germinates, forming a pollen tube that grows into the ovule, toward the egg cell. during fertilization, a haploid sperm nucleus unites with the haploid egg cell, producing a diploid zygote. the zygote grows into an embryo, which will be packaged inside a seed.
What are the two largest clades of angiosperms?
eudicots and monocots
In what ways are the life cycles of angiosperms similar to and different from those of gymnosperms?
similarities include the conspicuous sporophyte stage and the presence of pollen and seeds.
unlike gymnosperms, angiosperms produce flowers and fruits. the major difference is that angiosperm life cycles include double fertilization, which produces a zygote and a triploid endosperm cell. the endosperm provides nutrients for the developing embryo.
What is the relationship between flowers and fruits?
flowers are the structures that produce pollen and egg cells. after fertilization in the ovary, parts of the flower develop into the fruit which encloses in the seeds
