just wondering how the moss, ferns and angiosperms life cycles are similar and different.
I really don't understand this reproductive stuff.
sim's
all three life cycles alternate between haploid and diploid. I don't know much here so i can't fill in much details.
differences
moss and ferns have sperm that swims
angiosperms have seeds and pollen...
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Sra
thanks that stuff confuses me.
I really don't understand it at all.
The life cycles of mosses, ferns, and angiosperms all involve alternation between a diploid (two sets of chromosomes) and haploid (one set of chromosomes) stage. This alternation is known as the haplodiplontic life cycle.
Let me break it down further:
1. Mosses: The life cycle of mosses starts with a haploid spore. This spore germinates and grows into a gametophyte, which is the haploid stage of the moss. The gametophyte produces both male and female reproductive structures called gametangia. The sperm (male gametes) are released from the male gametangium and swim through a film of water to fertilize the egg (female gamete) in the female gametangium. After fertilization, the diploid zygote is formed, which grows into the sporophyte. The sporophyte develops a capsule at its tip, which contains sporangia. Spores are produced in the sporangia through meiosis and are released to start the cycle again.
2. Ferns: Ferns also start with a haploid spore. The spore germinates into a gametophyte, which is a small and often heart-shaped structure. The gametophyte produces both male and female structures called antheridia and archegonia, respectively. The sperm are produced in the antheridia and move through water to reach the egg in the archegonia. After fertilization, the diploid zygote is formed, which grows into the sporophyte. The sporophyte develops fronds with clusters of sporangia on the underside. Spores are produced through meiosis within these sporangia and are released into the surroundings.
3. Angiosperms (flowering plants): The life cycle of angiosperms is a bit different. It starts with a diploid sporophyte, which is the familiar plant that we recognize. The flowers of angiosperms contain male reproductive structures called stamens, which produce pollen grains containing sperm cells. The female reproductive structure is called the pistil, which contains an ovary that houses the ovules. Pollination occurs when pollen lands on the stigma of the pistil. The sperm cells then migrate down the style to reach the ovules and fertilize the egg. This fertilization produces a diploid zygote, which develops into a seed inside the ovary. The seed can then mature and be dispersed to start a new plant.
In summary, all three groups have an alternation of generations between haploid and diploid stages. Mosses and ferns have swimming sperm for fertilization, while angiosperms have pollen and seeds for reproduction.