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    The Life Cycle of Hornworts

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    ador kumar
    (1) Hornworts are small plants that grow in damp areas and have a complex life cycle involving sporophytes and gametophytes. (2) The life cycle begins with haploid spores that grow into leafy gametophyte plants which produce sex organs - antheridia contain sperm and archegonia contain eggs. (3) Fertilization occurs between the sperm and eggs, forming a zygote that grows into the sporophyte stage. (4) The sporophyte resembles horns and produces haploid spores that continue the cycle by growing into new gametophytes.

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    The Life Cycle of Hornworts

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    ador kumar
    105 views4 pages
    (1) Hornworts are small plants that grow in damp areas and have a complex life cycle involving sporophytes and gametophytes. (2) The life cycle begins with haploid spores that grow into leafy gametophyte plants which produce sex organs - antheridia contain sperm and archegonia contain eggs. (3) Fertilization occurs between the sperm and eggs, forming a zygote that grows into the sporophyte stage. (4) The sporophyte resembles horns and produces haploid spores that continue the cycle by growing into new gametophytes.

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    The Life Cycle of Hornworts _ Study.com

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    (1) Hornworts are small plants that grow in damp areas and have a complex life cycle involving sporophytes and gametophytes. (2) The life cycle begins with haploid spores that grow into leafy gametophyte plants which produce sex organs - antheridia contain sperm and archegonia contain eggs. (3) Fertilization occurs between the sperm and eggs, forming a zygote that grows into the sporophyte stage. (4) The sporophyte resembles horns and produces haploid spores that continue the cycle by growing into new gametophytes.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    105 views4 pages

    The Life Cycle of Hornworts

    Uploaded by

    ador kumar
    (1) Hornworts are small plants that grow in damp areas and have a complex life cycle involving sporophytes and gametophytes. (2) The life cycle begins with haploid spores that grow into leafy gametophyte plants which produce sex organs - antheridia contain sperm and archegonia contain eggs. (3) Fertilization occurs between the sperm and eggs, forming a zygote that grows into the sporophyte stage. (4) The sporophyte resembles horns and produces haploid spores that continue the cycle by growing into new gametophytes.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
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    12/4/2019 The Life Cycle of Hornworts | Study.

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    The Life Cycle of Hornworts

    You've heard of ferns, tulips, oak trees, but hornworts? Hornworts are a plant that belong to the same group as
    mosses and liverworts, and they have a complex lifecycle. This lesson explores that life cycle.

    Hornwort De ned
    Let's compile a list that includes things with horns. You've got bulls, orchestras, Vikings and a plant
    called a hornwort. Upon closer inspection, however, it appears hornworts don't have horns at all,
    or they do they?

    Things with horns

    Hornworts are plants that belong in the same group as mosses and liverworts. They are found in
    damp or humid areas around the world, produce spores and are owerless and seedless.
    Hornworts also do not have true roots, leaves or stems.

    Hornwort growing on a tree

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    12/4/2019 The Life Cycle of Hornworts | Study.com

    They get the common name 'hornwort' because their sporophytes looks like horns. Sporo-what?
    Don't worry, we'll delve into that de nition, among others, when we go over the life cycle of the
    hornwort.

    Life Cycle
    The life cycle of a hortwort is fairly complex (and quite di erent from your life cycle), so we will
    need to break it down a bit.

    Spore to Gametophyte
    A hornwort start as a haploid spore, which just means a spore that contains one set of
    chromosomes. Sometimes you will see a haploid represented by an n. You can contrast that with
    diploid organisms that contain two sets of chromosomes (one from each parent). Most of your
    cells, in case you are wondering, are diploid, and diploid is often represented by 2n.

    The colored sticks represent chromosomes

    The plant that grows from this haploid spore is called a gametophyte. The gametophyte hornwort
    is green or blue-green and the entire plant looks like a leafy clump. The gametophyte undergoes
    photosynthesis (meaning it makes its own food from sunlight, water and carbon dioxide).

    Once this plant reaches adult size, it will produce the plant's sex organs. Depending upon the
    species, the male and female sexual organs can be produced on the same gametophyte plant, and
    other times they can be produced on two separate plants.

    Sex Organs and Fertilization


    The female sex organs of the hornwort are called archegonia (plural) and the male sex organs are
    called antheridia (also plural). The archegonia have eggs and the antheridia have sperm (which,
    fun fact, has two tails). If you've studied plants before, the term 'anther' may sound familiar. It is
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    12/4/2019 The Life Cycle of Hornworts | Study.com

    the male part of a owering plant, so I always remember antheridia is the male part of a hornwort
    by recalling anther is the male reproductive structure in owers.

    The sperm leaves the antheridia and swims to the archegonia, where fertilization takes place and a
    zygote forms. A zygote is a diploid cell produced when haploid sperm and egg unite. Hornworts
    like wet areas, and this helps the sperm swim to its egg-destination.

    Sporophyte
    The zygote eventually becomes the sporophyte, which is the part of the plant that will produce
    haploid spores.

    A hornwort with immature sporophytes

    The sporophyte is the reason a hornwort is called a hornwort (remember it kind of looks like a
    horn)? The sporophyte is attached to the gametophyte and depends on the gametophyte for food.
    The sporophyte contains spores, which will be released and will eventually grow into more
    gametophyte plants. To remember this, think spores come from the sporophyte.

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