What is the dominant stage of a gymnosperm life cycle?
The dominant stage in gymnosperms is sporophyte. Gymnosperms, like all vascular plants, have a life cycle that is sporophyte-dominant. The answer among the options given above is 'sporophyte'.
What is the classification of gymnosperms?
The gymnosperms are classified into four separate divisions, viz. the Coniferophyta, Gnetophyta, Cycadophyta and Ginkgophyta. Of these, the Coniferophyta represents the largest group. Similar to other evolved plants, alternation of generations are present in the life cycle of gymnosperms.
What is the time period between pollination and fertilization in gymnosperms?
Thus, the time period between pollination and fertilization in gymnosperms is quite long, about a year. This newly formed sporophyte is enclosed in a seed in the form of an embryo. When favorable conditions arrive, the scale bearing the seeds separate and the seeds are dispersed by means of wind and rain.
How are Gnetophyta distinguishable within the gymnosperms?
The gnetophyta are distinguishable within the gymnosperms because they have vessel elements, a system of channels mostly found in the angiosperms, which transport water within the plant.
Which stage is dominant stage in?
The gametophyte comprises the main plant (the green moss or liverwort), while the diploid sporophyte is much smaller and is attached to the gametophyte. The haploid stage, in which a multicellular haploid gametophyte develops from a spore and produces haploid gametes, is the dominant stage in the bryophyte life cycle.
In which period gymnosperms were present in the form of dominant vegetation?
Section Summary. Gymnosperms are heterosporous seed plants that produce naked seeds. They appeared in the Paleozoic period and were the dominant plant life during the Mesozoic.
What is the dominant phase in the life cycle of gymnosperms and angiosperms?
Thus, the correct answer is 'Sporophyte. '
When were gymnosperms dominant?
Gymnosperms dominated the landscape in the early (Triassic) and middle (Jurassic) Mesozoic era. Angiosperms surpassed gymnosperms by the middle of the Cretaceous (about 100 million years ago) in the late Mesozoic era, and today are the most abundant plant group in most terrestrial biomes.
How gymnosperms became the dominant plant group?
Gymnosperms became the dominant group during the Triassic. In these, pollen grains and seeds protect against desiccation. The seed, unlike a spore, is a diploid embryo surrounded by storage tissue and protective layers. It is equipped to delay germination until growth conditions are optimal.
Is the sporophyte dominant phase in?
In gymnosperms, pteridophytes and angiosperms, the sporophytic phase is dominant.
Which generation is dominant in sporophyte?
sporophyteThe sporophyte is the dominant generation, but multicellular male and female gametophytes are produced within the flowers of the sporophyte. Cells of the microsporangium within (more...)
What are the steps in gymnosperms reproduction?
In gymnosperms, when the nuclei of the two sperm meet the egg cell, one nucleus dies and the other unites with the egg nucleus to form a diploid zygote. The fertilized egg undergoes mitosis to begin the development of a new sporophyte generation—the multicellular embryo of the seed.
What is the life cycle of a gymnosperm?
Gymnosperm Life Cycle. Gymnosperms reproduce with an alteration of generations, meaning their reproductive cycle has both haploid and diploid phases. As in all other vascular plants, gymnosperms have a sporophyte dominant life cycle (the sporophyte is the diploid multicellular stage, which comprises the body of the plant, i.e., a leafy tree).
What is a gymnosperm?
Gymnosperms are a group of plants which produce seeds that are not contained within an ovary or fruit. The seeds are open to the air and are directly fertilized by pollination. “Gymnosperm”, from the Greek, gymnos, “naked” and sperma, “seed”, develop their seeds on the surface of scales and leaves, which often grow to form cone or stalk shapes, ...
What is the closest relative of Gymnosperm?
Ginkgo. The closest relatives to the cycads, Gingko is a genus of gymnosperm of which Gingko biloba is the sole extant species. Gingkos are large, slender, shade-intolerant trees, growing up to 160ft with distinctive fan-shaped leaves. They are deep rooted and resistant to damage from wind and snow.
What is the name of the plant with a single, stout, cylindrical, woody trunk?
The appearance of the cycads (division Cycadophyta) typically constitutes a single, stout, cylindrical, woody trunk and a crown of large, hard and stiff, evergreen compound leaves, which grow directly from the trunk in a rosette formation. The cycads are dioecious, meaning that each individual plant is either all male or all female.
What is the male cone?
The male cone, called the microsporophyll, is a small, spongy, leaf-like organ which bears the microsporangium. The microsporangium contains the male microspores, which undergo meiosis to generate the male gametophyte, pollen. The pollen grain contains the pollen tube cell and the generative cell (which contains two sperm, although one dies).
What is the phase of a gametophyte?
The gametophyte phase is relatively short, and sees gametes produced on the reproductive organs , which are usually cones. The female ovulate cone, or megasporophyll, bear the megasporangium, diploid cells, which undergo meiosis to produce four haploid spores. Of these haploid spores, only one survives as the megaspore.
What is the name of the tissue that surrounds the zygote?
The nuclei of the female and the male gametophytes then fuse to create a diploid zygote. The endosperm, a haploid nutritional tissue, is released from the endosperm mother cell, and surrounds the zygote to form a seed.
What is the life cycle of a gymnosperm?
Life Cycle of Gymnosperms. In the life cycle of gymnosperms, the dominant sporophyte phase alternates with the short gametophyte phase. The sporophyte plant produces spores, while the gametophyte bears gametes. Leaf through this article to get an insight about gymnosperm life cycle in detail.
What are the different types of gymnosperms?
Of these, the Coniferophyta represents the largest group. Similar to other evolved plants, alternation of generations are present in the life cycle of gymnosperms. Two different forms that alternate each other are the spore bearing plant (sporophyte) and gamete bearing structure (gametophyte). The former is the dominant one and lasts for a longer period than the gametophyte phase in the gymnosperm life cycle. For simple understanding, you can study the life cycle of spruce or pine.
How do gymnosperms get pollinated?
The production of sperm cells and egg cells is followed by pollination process. Pollination of gymnosperms takes place by means of winds and natural agents. Over here, the pollen grains containing the sperm cells are carried to the female gametophyte of the ovulate cones by wind or insects.
What is the sporophyte phase?
Sporophyte: Spore-bearing Phase. The sporophyte phase represents the adult, photosynthetic, diploid gymnosperm plant that produces the male cones (or pollen cones) and the female cones (ovulate cones). The former is usually smaller than the latter one. They develop in the same plant (monoecious) or different plants (dioecious).
How long does it take for a gymnosperm to fertilize?
Thus, the time period between pollination and fertilization in gymnosperms is quite long, about a year. This newly formed sporophyte is enclosed in a seed in the form of an embryo.
How many gymnosperms are there?
The evolution of gymnosperms can be traced back to the Paleozoic era, during which they were found abundantly. At present, there are approximately 700-900 living gymnosperm species. They are basically woody, large-sized and bear evergreen foliage. The leaves are reduced, of which many gymnosperms have needle-shaped leaves.
How long does it take for pollen to go to the female gametophyte?
In the mean time, pollen grains germinate to form pollen tubes, which take about a year and make their way to the female gametophyte for fertilization.
Gymnosperm Life Cycle
Gymnosperms have a dominant sporophyte generation. The main sex organs are the cones. In the male cones, sperm are formed, while eggs are formed in the ovules of female cones. The sperm can sit for a long period of time, but the pollen (sperm) can then travel by air to the female cone, making its way to the ovule.
Examples of Angiosperms
The dominant stage in the Angiosperm's life cycle is the sporophyte stage In the male gametophytes, pollen (sperm) is produced, and eggs are formed in the female. The haploid pollen travels to the female, undergoing fertilization forming a diploid zygote and developing into an embryo.
Parallel Evolution
Parallel Evolution is when 2 things co-evolve alongside each other. One example of parallel evolution is plants and insects. Specifically flowering plants, insects evolved with them to rely off their pollen to create food for themselves and to live.
