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[the-chomsky-hash]

[I. First postulate under critique: the individual living being has the property of reproducing, and in doing this through sexuality - cont'd]

[B. In nineteenth century, this subordination, of sexuality to reproduction, and of reproduction to the individual, had to be viewed differently - cont'd]

[4. Taking a wider biological scale, we are exaggerated ferns. Constant diminution of sexuality. - cont'd]

b. [Contrary to Freud,] it is not society that has reduced, to the extreme, the part of sexuality that evolution had developed in us. In the archegoniates we are, it is the play of biological structures that reduced the moment of the sexual phase.

It needs very little—some groups of cells enclosed in our organism—for the rest of the sexual phase to be entirely resorbed. We are just gigantic sporophytes, and have kept only some gametophytic cells. Biologically, we are successful sporophytes that carry some stunted gametophytes.

– Michel Foucault, Sexuality, Reproduction, Individuality, 1969, (Extract from Notebook No. 8, Green: Sexuality, Reproduction, Individuality), translated by Graham Burchell

#foucault #philosophy

[cedar-glade]

Asterella tenella and Reboulia hemisphaerica are often mistaken for one or the other.

Here is Reboulia hemisphaerica, with dark purple margins around it’s thallus, this species is also known for a purple tinged abaxial surface. Spring is the ideal time to see this species vs the wet karst choss and sandy choss pocket species usually found in fairly small holes in rocks, Asterella tenella. This species, while small is a bit larger than the ladder and is often much more exposed on karst surfaces with moss, if the exposure becomes problematic, it can dry up while maintaining cellular rigidity, enveloping its sides and partially invaginating into a purple tube. This species is monoicous, (one house for both reproductive organs/ mono=1 ecium=home).  The archegonial receptacle, is raised while antheridia are a series/cluster of purple conical/tube like structures around the base of the archegonial receptacle. There are no splash/gemma cups on this species making it easy to differentiate from common polymorphic liverwort and the glandular sweet/great scented( *coughs*) liverwort also found in karst habitats. One other mention that is similar to this species is Preissia quadrata, obligate calciphile, this species has both archegonia and antheridia elevated on a stype/phore; pores are visible with handlense, macrocamera, or good vision.

Boone co. Cliffs, Ky

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Assertion : Water is not required for fertilization process in ferns. Reason : Malic acid of archegonial neck attracts antherozoids.

Assertion : Water is not required for fertilization process in ferns. Reason : Malic acid of archegonial neck attracts antherozoids.

(a)       If both the assertion and the reason are true and the reason is a correct explanation of the assertion (b)       If both the assertion and reason are true but the reason is not a correct explanation of the assertion  (c)        If the assertion is true but the reason is false (d)       If both the assertion and reason are false (e)       If the assertion is false but reason is…

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BBYCT-131 Biodiversity (Microbes, Algae, Fungi and Archegoniates) in English Solved Assignment 2020-2021

BBYCT-131 Biodiversity (Microbes, Algae, Fungi and Archegoniates) in English Solved Assignment 2020-2021

BBYCT-131 Biodiversity (Microbes, Algae, Fungi and Archegoniates) Solved Assignment 2020-2021 Course Code: BBYCT-131 Assignment Code: BBYCT-131/TMA/2020-2021 Maximum Marks: 100 Title Name BBYCT-131 Solved Assignment 2020-21 University IGNOU Service Type Solved Assignment (Soft copy/PDF) Course BSCG Language ENGLISH Semester 2020-2021 Course: B.SC(G) CBCS Session 2020-21 Short…

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Pengertian, Ciri-Ciri dan Siklus Hidup Lumut (Bryophyta)

Pengertian, Ciri-Ciri dan Siklus Hidup Lumut (Bryophyta)

Murid.Co.Id Pengertian, Siklus Hidup dan Perkembangan Lumut (Bryophyta), Lumut merupakan kelompok tumbuhan kecil yang tumbuh menempel pada berbagai jenis substrat. Substrat yang umum dapat di tumbuhi lumut adalah pada pohon, kayu mati, kayu lapuk, serasah, tanah dan batuan dengan kondisi lingkungan lembab dan penyinaran yang cukup. Kehidupan lumut dipengaruhi oleh faktor lingkungan seperti, suhu, kelembaban dan cahaya. Lumut yang hidup seperti pada pohon akan dipengaruhi oleh struktur permukaan kulit kayu atau tempat tersebut harus lembab dengan intensitas cahaya yang cukup (Ariyanti, 2008).

Artikel Lainnya :  Peranan Bryophytha : Ciri, Reproduksi, Karakteristik, Klasifikasi dan Pengertian

Lumut merupakan salah satu kelompok tumbuhan rendah dan bagian dari keanekaragaman hayati yang belum banyak mendapat perhatian (Windadri, 2009). Ada 24.000 spesies Bryophyta yang dikenal, dan semua tumbuhan lumut membutuhkan kondisi lingkungan yang lembab yang masuk kedalam siklus kehidupan tumbuhan tersebut. Divisi Bryophyta dibagi menjadi tiga kelas, yaitu lumut hati (Hepatophyta) dengan 9000 spesies dan 240 genus; lumut tanduk (Anthocerotopyhta)hanya 500 spesies; dan lumut daun(Bryopsida) memiliki 12.000-14.500 spesies dan 670 genus (Semple,1999).

Bryophyta termasuk salah satu bagian kecil dari flora yang belum banyak tergali juga merupakan salah satu penyokong keanekaragaman flora. Tumbuhan lumut tersebar luas dan merupakan kelompok tumbuhan yang menarik. Mereka hidup di atas tanah, batuan, kayu, dan kadang – kadang di dalam air. Lumut hati dan lumut daun yang hidup menyendiri biasanya tidak menarik. Namun dapat tampak bahkan menarik jika tumbuh berkelompok. Pada umumnya jenis tumbuhan ini kurang beradaptasi pada kondisi kehidupan daratan, dan sebagian besar merupakan tumbuhan yang hidup pada lingkungan lembab dan terlindung. Meskipun demikian, lumut tertentu khususnya lumut sejati (Bryopsida), dapat bertahan hidup pada musim kering. Pertumbuhannya mengalami peremajaan jika air tersedia kembali (Tjitrosomo, 1984).

Kelas Bryopsida terdiri dari ordo Archidiales, Polytrichales, Fissidentales, Dicranales, Funariales, Eubryales, Isobryales, Buxbaumiales, Hyponobryales dan Tetraphidales (Eddy,1988). Polytrichales merupakan lumut yang memiliki penyebaran yang luas di dunia beberapa yang telah dikenali sebanyak 19 genus dan lebih kurang 370 spesies (Schofield, 1927).

Secara ekologis lumut berperan penting di dalam fungsi ekosistem. Seperti lahan gambut sangat tergantung pada lapisan atau tutupan lumut. Sehingga keberadaan lumutsebagai penutup permukaan tanah juga mempengaruhi produktifitas, dekomposisi sertapertumbuhan komunitas di hutan (Saw dan Goffinet, 2000).

Richardson (1981 cit. Windadri dan Siti, 2005) melaporkan bahwa beberapa jenisanggota dari marga Polytrichum dimanfaatkan untuk memperindah taman di sekitar pura Saihoji di kaki Gunung Koinzan di sebelah barat Kyoto. Selain itu Polytrichum digunakan sebagai indikator terhadap kondisi asam serta memiliki mineral dan unsur hara yang kaya (Glime dan Saxene, 1991).

A. Pengertian lumut

Secara ilmu tumbuhan, lumut termasuk Bryophyta, atau tumbuhan non vaskuler. Lumut dapat dibedakan dari yang serupa liverworts ( Marchantiophyta atau Hepaticae) dengan multisellular mereka rhizoid. Lain perbedaan bukanlah universal untuk semua lumut dan semua liverworts, yang membedakan “batang” dan “daun-daun”, ketiadaan daun-daun yang terbagi-bagi atau berlekuk, dan ketidakhadiran daun-daun diatur dalam tiga golongan, semua menunjuk tumbuhan lumut. Sebagai tambahan terhadap kekurangan suatu sistem vaskuler, lumut mempunyai gametophyte-dominant siklus hidup, yaitu.sel haploid untuk kebanyakan siklus hidupnya. Sporophytes (diploid) berumur pendek dan dependen pada atas gametophyte.

Artikel Lainnya :  Ekosistem dan Komponen : Pengertian, Struktur, Fungsi, Tipe

Adapun ciri – ciri dari lumut ialah sebagai berikut :

a)    Lumut mempunyai klorofil sehingga sifatnya autotrof. Lumut tumbuh di berbagai tempat, yang hidup pada daun-daun disebut sebagai epifit. Jika pada hutan banyak pohon dijumpai epifit maka hutan demikian disebut hutan lumut. b)   Akar dan batang pada lumut tidak mempunyai pembuluh angkut (xilem dan floem). Pada tumbuhan lumut terdapat Gametangia (alat-alat kelamin) yaitu: Alat kelamin jantan disebut Anteridium yang menghasilkan Spermatozoid. Alat kelamin betina disebut Arkegonium yang menghasilkan Ovum c)    Jika kedua gametangia terdapat dalam satu individu disebut berumah satu (Monoesius). Jika terpisah pada dua individu disebut berumah dua (Dioesius). Gerakan spermatozoid ke arah ovum berupakan Gerak Kemotaksis, karena adanya rangsangan zat kimia berupa lendir yang dihasilkna oleh sel telur. d)   Sporogonium adalah badan penghasil spora, dengan bagian - bagian :Vaginula (kaki), Seta (tangkai), Apofisis (ujung seta yang melebar), Kotak Spora : Kaliptra (tudung) dan Kolumela (jaringan dalam kotak spora yang tidak ikut membentuk spora). Spora lumut bersifat haploid. e)    Lumut mengalami keturunan (metagenesis). Dalam daur hidupnya, lumut mengalami duafase kehidupan, yaitu fase gametofit (haploid) dan fase sporofit (diploid). Alat perkembangbiakan jantan berupa antheridium dan alat perkembangbiakan betina berupa arkegonium.

B. Siklus Hidup Lumut

Lumut (dan Bryophyta lain)  memiliki satu set kromosom (haploid, beebrapa kromosom hidup dalam sebuah salinan sel yang unik). Periode siklus hidup lumut secara lengkap, merusak kromosom, tetapi hal ini hanya pada sporofit.

Lumut hidup diawali dari sebuah spora haploid, yang bertunas untuk memproduksi sebuah protonema, yang menumpuk filamen atau thalloid (flat dan seperti thallus ).Ini merupakan tingkatan sementara dalam hidup lumut. Dari protonema tumbuh gametophore yang dideferensiasi menjadi tangkai dan akar/ leaves (mikrofil).Dari tangkai atau cabang berkembang organ sex lumut.Organ betina disebut archegonia (archegonium) dan terlindungi oleh kumpulan tangkai yang termodifikasi yang disebut perichaetum (plural, perichaeta).

Archegonia memiliki leher disebut venter dimana sperma jantan turun. Organ jantan disebut antheridia (singular antheredium) dan tertutup oleh modifikasi tangkai disebut perigonium (plural, perigonia).Lumut bisa menjadi dioicous atau monoicous.Pada lumut dioicous, kedua organ sex, jantan dan betina terlahir pada gametofit tanaman. Pada monoicous (juga disebut autoicous) lumut, mereka terlahir pada tanaman yang sama. Pada pengairan, sperma dari antheridia berjalan ke archegonia dan terjadi fertilisasi, mengawali produksi sporofit diploid. Sperma lumut adalah biflagellate, mereka memiliki dua flagella yang membantu sebagai daya pendorong.Tanpa air, fertilisasi tidak dapat terjadi. Setelah fertilisasi, sporofit mandul didorong keluar dari archegonial venter. Ini membutuhkan kira-kira seperempat sampai setengah tahun untuk sporofit untuk matang. 

Badan sporofit terdiri dari gagang panjang, disebut seta, dan capsule disebut operculum. Kapsul dan operculum terlapisi oleh kaliptra yang merupakan sisa archegonial venter. Kaliptra biasanya mengecil/berkurang ketika kapsul matang. Di dalam kapsul, sel-sel pereproduksi spora mengalami meiosis untuk membentuk spora haploid, dimana siklus dapat berjalan lagi. Mulut capsule biasanya dikelilingi oleh set gigi disebut peristome. Ini mungkin tidak terjadi pada beberapa lumut.Pada beberapa lumut, struktur vegetatif hijau disebut gemmae yang diproduksi pada tangkai atau cabang, yang bisa merusak dan membentuk kembali tanaman tanpa perlu melalui fertilisasi.Ini disebut dengan reproduksi asexual.  

C. Perkembangan Lumut

Perkembangan lumut secara singkat berlangsung sebagai berikut : spora yang kecil dan haploid, berkecambah menjadi suatu protalium yang pada lumut dinamakan protonema. Protonema pada lumut ada yang menjadi besar, adapula yang tetap kecil. Pada protoneme ini terdapat kuncup-kuncup yang tumbuh dan berkembang menjadi tumbuhan lumutnya. Tubuh tumbuhan lumut berupa tallus seperti lembaran-lembaran daun (hepaticae), atau telah mempunyai habitus seperti pohon kecil dengan batang dan daun-daunnya (pada musci), tetapi padanya belum terdapat akar yang sesungguhnya, melainkan hanya rizoid-rizoid yang berbentuk benang-benang atau kadang-kadang memang telah menyerupai akar. Pada tumbuhan inilah dibentuk gametangium.

Setelah sel telur dibuahi oleh spermatozoid yang bentuknya seperti spiral atau alat pembuka gabus tutup botol dengan dua bulu cambuk itu, maka zigot tidak memerlukan waktu istirahat dulu tetapi terus berkembang menjdi embrio yang diploid. Bagian bawah embrio dinamakan kakinya. Kaki masuk ke jaringan lumut yang lebih dalam dan berfungsi sebagai alat penghisap (haustorium). Embrio itu lalu tumbuh merupakan suatu badan yang bulat atau jorong dengan tangkai pendek atau panjang dan seperti telah telah disebut di atas disebut sporogonium.

Di dalam bagian yang bulat itu dibentuk spora, oleh sebab itu bagian tersebut juga disebut kapsul spora. Kapsul spora juga dianggap sinonim dengan sporogonium karena leher arkegonium amat sempit, maka sporogonium tidak dapat menembusnya dan bekas dinding arkegonium ikut terangkat dan merupakan tudung capsule spora. Mengingat bentuknya seperti tudung akar, pada ujung akar dan mungkin juga mempunyai fungsi yang sama sebagai pelindung, maka bekas dinding arkegonium itu juga dinamakan kaliptra. Jaringan dalam Kapsul spora dinamakan arkespora. Arkespora membentuk sel induk spora, dan dari satu sel induk spora dengan pembelahan reduksi terjadilah 4 spora yang berkelompok merupakan tetrade. Seringkali pada pembentukan spora itu ditentukan pula jenis kelaminnya. Dari spora itu, bergantung pada macam sporanya, akan utmbuh lumut yang berumah satu atau berumah dua. Spora itu membulat sebelum terpisah-pidah dan terlepas dari capsule spora.

Reproduksi lumut bergantian antara seksual dengan aseksualnya, reproduksi aseksualnyadengan spora haploid yang dibentuk dalam sporofit, sedangkan reproduksi seksualnya denganmembentuk gamet – gamet, baik gamet jantan maupun gamet betina yang dibentuk dalam gametofit.

Sumber : https://guruips.co.id/

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[the-chomsky-hash]

[I. First postulate under critique: the individual living being has the property of reproducing, and in doing this through sexuality - cont'd]

[B. In nineteenth century, this subordination, of sexuality to reproduction, and of reproduction to the individual, had to be viewed differently - cont'd]

4. In fact, taking a wider biological scale (the eukaryotes or even just the the archegoniates), we can show on the contrary [to the notion that sexuality, appearing late in evolution, constantly increases in importance,] that

the (gametophytic) sexual stage constantly contracts

the sporophytic stage increases

We are mushrooms upside down. We are exaggerated ferns. Constant diminution of sexuality.

a. There are individuals in whom meiosis has already occurred:

which are therefore composed of elements with n chromosomes

which are therefore entirely devoted to the production of gametes

which are immense sexual cell machines

In these, yes, sexuality is important. We are beings of involuted sexuality.

– Michel Foucault, Sexuality, Reproduction, Individuality, 1969, (Extract from Notebook No. 8, Green: Sexuality, Reproduction, Individuality), translated by Graham Burchell

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New Post has been published on Biology Dictionary

New Post has been published on https://biologydictionary.net/moss/

Moss

What is a Moss

Moss is a type of non-vascular plant, classified in the division Bryophyta in the kingdom Plantae. Moss, while typically associated with dark, damp environments, has actually adapted to occupy many drier, sunny regions. There are over 12,000 species of moss recognized, which span 8 classes and 23 different genera.

Examples of Moss

Bryopsida

The Bryopsida, the largest class of mosses, contains most of the recognized species. A typical species can be seen above. In this image the gametophyte form is seen, as the sporophytes have not developed. Moss in the class Bryopsida can be found all over the world and grows on nearly any available surface, from concrete to bare fields, given the right conditions. In all, there are over 11,500 species of moss in the class. Before genetic and anatomical evidence suggested the division of more classes, all species of moss were found within this class.

Andreaeobryopsida

The moss found in the class Andreaeobryopsida represents only a couple species. These moss species are endemic to only a few parts of Alaska and Western Canada. These moss plants have developed a unique tolerance to the climate in this region. This, plus differences in their genetics and the development of their spore capsules, led scientists to remove them from the Bryopsida and into their own unique class. Many of the other types of mosses have been divided into their own classes, eight in total. However, the large majority are still classified as Bryopsida.

Types of Moss

While there are not necessarily different types of moss, there are currently 8 recognized classes, which are distinguished by their genetics, anatomy, and physiology. Importantly, scientists look at their reproduction habits and structures to help identify and categorize the various moss groups. The eight different classes are listed below:

Takakiopsida

Sphagnopsida

Andreaeopsida

Andreaeobryopsida

Oedipodiopsida

Polytrichopsida

Tetraphidopsida

Bryopsida

As an example, the Sphagnopsida class holds the genus Sphagnum, which has important industrial uses. This moss, known for creating thick sheets of moss over large areas, can be commercially harvested as peat. The moss can be identified by the way it grows, which is in large flat sheets. Further, Sphagnum moss species have a unique way of spreading their spores. Instead of mildly cracking open the case surrounding the spores and letting them fall out, the moss in this class use a more explosive strategy. By compressing air in the chamber, pressure builds. The cells of the sporophyte continue this process until the operculum holding the spores back ruptures. This shoots the spores into the air, like a “party-popper” or overfilled balloon. This greatly increases the area the spores can reach and is unique to the class.

Life Cycle of Mosses

Like all plants, moss species show an alternation of generations, in which two different classes of individuals carry out separate parts of the reproductive process. In a system like this, one organism, the sporophyte, is a diploid organism which creates haploid spores through the process of meiosis. In the picture below, the tall stems with small structures at the top are the sporophyte.

However, after the sporophyte generation has released the spores, it dies off. The spores find a place to settle, and develop into a haploid organism, the gametophyte. This is the dominant structure of moss, what you typically see if the moss is not reproducing. This can be seen in the image at the base of the sporophyte, much shorter and seemingly a different species. The gametophyte is responsible for producing gametes, which are capable of fusing together. Look at the image below, of moss reproduction.

In the top left of the image, fertilization is occurring. Sperm and eggs, gametes, are produced in special organs of the gametophyte. The sperm are released into the environment, and travel to the archegonial head, which houses the egg. Once the sperm fertilizes the egg, the zygote is formed. The zygote will develop into the sporophyte, which actually grows out of the gametophyte. The sporophyte, again a diploid organism after the fusion of two haploid gametes, is responsible for undergoing meiosis, and starting the process over again.

Further, many moss species have the ability to reproduce asexually using bundles of cells called gemmae. These cells, produced on the gametophyte, fall off when exposed to running water. This allows them to be carried to a new location, where an entire new plant can be established. If you have ever seen moss growing below a drip of water, this is likely the route in which it got there. Sexual reproduction takes a lot of energy, and is generally good for diversifying the genetic pool. Asexual reproduction is much faster, and can happen every time it rains.

Within this life cycle, some moss species have the same sex represented on one gametophyte, while others have different gametophytes for different sexes. This is another way in which moss species can be distinguished and identified against each other.

Commercial Uses of Moss

The main commercial use of moss is as peat, a renewable fuel source. As the moss grows, it pushes down old moss and creates dense mats of biofuel. The peat can be burnt in a fire or stove, as it has been for centuries in many different countries. Peat moss can also be used as a fertilizer and growing medium for various commercially important plants and mushrooms. Even Scottish whiskey famously uses peat fires to smoke the malt, giving the whiskey a distinct flavor.

Moss is also becoming a more important and widespread landscaping plant. Several cultures, like the Japanese, have used moss for centuries as a way to decorate an outdoor space. Like a grass turf lawn, it is comfortable, pleasingly green, and easy to maintain. In more extreme uses, it can even be used as a base for a green roof, a new conservation technique aimed at reducing the urban heat effect.

In the past, moss has even had uses in the medical and consumer fields. Moss, when dried, is extremely absorbent. Even more absorbent than cotton. This lead to the use of moss in bandages for wounded soldiers. Some even claimed that the moss had antibacterial properties, which helped wounds heal. Further, moss has been used as a diaper alternative product in several countries. Moss, which is completely biodegradable, is said to outperform many plastic and cotton products used today.

Quiz

1. If moss can reproduce asexually, what is the benefit of reproducing sexually? A. It uses less energy B. It takes less time C. It recombines and diversifies the gene’s an organism can use

Answer to Question #1

C is correct. Sexual reproduction is a very common mode among animals for reproducing, but species like many bacteria produce almost exclusively asexually. Both modes have their merits, and moss takes advantage of both strategies to maximize its success.

2. You identify a new form of plant. It is small, with tiny leaves that resemble moss. You take a closer look at the stem under the microscope. There are small bundles of vascular tissue, clearly distinguished from the rest. You determine that this new species is: A. A moss B. Not a moss C. Impossible to tell

Answer to Question #2

B is correct. All moss species are non-vascular. While they use some of the same methods to transport and retain water, they do not have specialized vascular tissues. This new species is some sort of tiny, vascular plant.

3. A small insect, the springtail, is attracted to moss, and may be responsible for pollinating the moss plants. If an insecticide is developed which targets theses insects, how could the energy industry be affected? A. It cannot be affected by an insect B. The moss making peat could die, affecting energy consumers C. The moss would reproduce more, making energy cheaper

Answer to Question #3

B is correct. While it may seem like an outdated form of energy, peat is renewable and can also serve environmental purposes while it grows. Without an insect to help fertilize the plant, it may not be able to adapt to changing conditions and die off. While it is not likely to affect the market greatly due to its limited use, it could greatly affect many small industries and the people in them.

References

Hartwell, L. H., Hood, L., Goldberg, M. L., Reynolds, A. E., & Silver, L. M. (2011). Genetics: From Genes to Genomes. Boston: McGraw Hill.

McMahon, M. J., Kofranek, A. M., & Rubatzky, V. E. (2011). Plant Science: Growth, Development, and Utilization of Cultivated Plants (5th ed.). Boston: Prentince Hall.

Rubinstein, C. V., Gerrienne, P., de la Puente, G., Astini, R. A., & Steemans, P. (2010). Early Middle Ordovician evidence for land plants in Argentina (eastern Gondwana). New Phytologist, 188(2).

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