Puberty: Human Males and Females

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Disorders of Female Reproductive system
Some of the few disorders of the Female Reproductive system are as
i.Sterility: Inability of the females to conceive due to inadequacy in structure or function of the genital organs.
ii. Menstrual Irregularity: this may be amenorrhoea (absence of menstruation) excessive or prolonged bleeding of the uterus (hypermenorrhoea) or dysmenorrhoea (painful menstruation).
iii. Breast cancer: Usually affects women over the age of 30. Its incidence increases after women attain menopause. Once detected, the standard treatment involves removal of the breast (mastectomy)
iv. Ovarian cysts: these are fluid-filled tumors of the ovary. Sometimes during pregmancy, such cysts rupture and regress. In old women, ovarian cysts are surgically removed.
v.Cervical cancer: It is a relatively slow-growing cancer. It can be treated with radiation or surgery if it has been detected.

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Ovule: Structure, Types, and Embryo sac

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Embryo sac and its Development
The first cell of the female gametophyte is the functional megaspore. It grows largely along the micropyle-chalazal axis and is mostly chalazal. The nucleus undergoes three mitotic divisions and forms eight nuclei. Out of the Eight nuclei, 4 are present at the micropylar end and 4 at the chalazal end. One nucleus from each group comes in the center to form 2 polar nuclei. The remaining three nuclei at the micropylar end make up the egg apparatus, whereas the remaining three nuclei at the chalazal end make up three antipodal cells. The mature female gametophyte or embryo sac is the entire structure with two polar nuclei, three antipodals, one egg, and two synergids. the Monosporic 8- nucleate embryo sac or polygonum type of embryo sac arises from a single megaspore and has 8 nuclei

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Pollination: Definition, Types, and Agents

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Pollination:Definition
Pollen grains are transmitted from the Anther to the Stigma during pollination. When pollen grains land on ovule, it is known as Direct pollination e,g Gymnosperms, and some primitive Angiosperms. When pollen grains land on Stigma and form a pollen tube it is known as Indirect pollination e,g Angiosperms. Pollination’s function in fruit and seed production has been recognised since ancient times. The Arab and Assyrian kings used to perform a special religious ceremony in which the female inflorescence of the date palm was touched by the male inflorescence to ensure good fruiting. However, Thomas Millington, towards the end of the 17th century, provided the scientific underpinning for this method.

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Flower: Definition, Types, and Functions

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Types of Flower
1. Complete Flower: If all the four whorls are present in the flower it is called Complete Flower (Gynoecium, Androecium, corolla, calyx).
2. Incomplete Flower: If any one of the four whorls are absent in Flower it is called Incomplete Flower (Gynoecium, Androecium, corolla, calyx)
3. Bisexual Flower: If a flower contains both male and female reproductive parts it is called Bisexual Flower.
4. Unisexual Flower: If Flower has only one reproductive part then it is called Unisexual Flower.
Pistillate Flower: If the only female part is present
Staminate Flower: If the only male part is present i.e. Androecium the flower is called Staminate Flower.
5. Dichlamydeous Flowers: If a flower contains both Calyx and Corolla it is known as Dichlamydeous Flower. It is most common in plants.
6. Monochlamydoeus Flower: If a flower contains only one whorl, the whorl which is present is known as perianth and this is seen in the case of monocot families e,g Liliaceae
7. Achlamydeous Flower: If Calyx and Corolla are absent in flower it is called Achlamydeous Flower.

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Reproduction: Life Span, Types and Features

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Life Span
The time between an organism’s birth and death is referred to as its life span. It is a specific trait and it is as long as several thousand years and as short as a few minutes. The life span of mango is about 200 years and the life span of peepal is 2500 years.No individual lives forever but an exception is a single-celled organism i.e they are immortal.

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Gymnosperms: Cycadopsida, Gnetopsida, Coniferopsida, and Pro-Gymnosperms

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Pro-Gymnosperms
Some palaeozoic era fossils from the Devonian and Carboniferous periods were previously assumed to belong to Pteridophytes, but are now thought to be closer to gymnosperms, but not fully gymnosperms. Beck in 1960 identified linkages between two such fossils, archaeopteris fern-like fronds and callixylon gymnosperm-like trunks, these members were classed as the progymnospermopsida, a class of gymnosperms. Progymnosperms are thought to be the origin of both Cycadales and Coniferales by some Palaeobotanists. After the discovery of Rhynie flora and Pteridosperms, Stewart views the discovery of progymnospermopsida to be a watershed event that has improved our understanding of vascular plant evolution more than any other.

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Gymnosperms: Definition, Characteristics, and Examples

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Gymnosperms:Definition
The term Gymnosperm was first used by Scientist Theophrastus in his book ‘Enquiry into plants’. The word Gymno means nacked and Sperma means seed. Due to the presence of nacked seeds, they are also called Nacked seed-bearing plants. the Gymnosperms are called Phaenerogams with ovaries. Gymnosperms are woody plants that can range in size from enormous trees to little shrubs. Sequoia sempervirens is as tall as a 36 story building. Perhaps the smallest Gymnosperm is a Cycad, Zamia pygmea whose fronds are only 4 or 5 cm long. Sequoiadendron giganteum, on the other hand, is the largest and oldest.

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Bryophytes:Economic Importance

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Peat
Sphagnum often grows in acidic marshes where there’s little decay. Over thousands of years, the dead sections of Moss and other marshy plants are slowly carbonized, compacted, and fossilized, resulting in a dark spongy material known as peat.
It is compressed, dried, and moved from blocks. Peat is employed pretty much as good manure to beat soil alkalinity and it increases water retention similarly to aeration of the soil.

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Bryophytes: Definition, Characteristics, and Reproduction

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Bryophytes:Definition
The term Bryорhytа wаs given by Brоwn. The study оf bryорhytes is known аs Bryоlоgy аnd therefоre the fаther оf bryоlоgy is Hedwig. The Bryорhytа соmes frоm the Greek wоrd Bryоn meаns Mоss аnd Рhytоn meаns рlаnts.It’s а group оf рrimitive рlаnts оf class Embryорhytа. These рlаnts оссuрy а griр intermediаte between the green thаllорhytes аnd рteridорhytes. The grоuр is reрresented in аbоut 960 generа аnd 24000 sрeсies оссurring in mоst раrts оf the wоrld wherever there’s suffiсient mоisture tо sustаin рlаnts. Bryорhytes аre referred tо аs Аmрhibiаns оf the Рlаntаe beсаuse they require wаter fоr fertilizаtiоn.

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