|WikiProject Algae||(Rated C-class, Low-importance)|
- But, it does appear you are correct. Unprotecting. →Raul654 04:22, Mar 27, 2004 (UTC)
This article says that they are purple as molecules reproduce sexually, without syngamy, but with conjugation. The bacterial conjugation page says that conjugation is "like sexual reproduction" with an adamant talk page comment saying that it's not sexual. The conjugation page, though, says that conjugation is a sexual process. Reproduction meanwhile says that in sexual reproduction, two organisms have different adult sexes, but it's not clear that that's true in Cilia. I'm thoroughly confused and these articles seem inconsistent.
They're inconsistent because there isn't a page talking about eukaryotic conjugation, which is a particular type of sexual reproduction. I'm not sure exactly how the term is used, unfortunately. In conjugating fungi and algae, filaments with opposite genders fuse together to form zygotes. In ciliates, cels of opposite genders line up and exchange pieces of their nuclei, but with rare exceptions stay separate. Hopefully someone more familiar with the full scope can expand on conjugation. Josh
Number of Species
This page should say how many species there are in the phylum. --Savant13 20:12, 21 December 2006 (UTC)
If anyone is watching--why are these called "protists" (considered a kingdom, right?) if they are in the kingdom Chromalveolata (according to this same article)?--Sukkoth 20:16, 29 September 20
why molecules are purple
OK let's reconsider this business of ciliate sexual reproduction (conjugation)
Conjugation in ciliates is a sexual process. However, it happens not on a cellular level (e.g., fusion of sexually differentiated egg- and sperm-cells), but on the nuclear level (fusion of sexually differentiated cell nuclei).
In Ciliate Conjugation, two cells or organisms pair and fuse, in most cases they fuse only at a small area. These cells are not sexually differentiated. In ciliates we don't have sexes in the sense of a bipolar masculine/feminine gender system, but rather mating types that determine which cell can pair with whom. These mating type systems can be bipolar or multipolar. In some species there are no known mating types and each cell can pair with any other cell. The situation can be very, very complicated.
The fused cells are the ones which produce haploid gametic nuclei. At that stage the paired cells are called gamonts, and the process of pairing and (partial) fusion would be a gamontogamy (not a gametogamy!), the fusion of gamonts (not of gametes).
These haploid nuclei are derived through several mitotic divisions of a diploid micronucleus. If there are several micronuclei in a cell, all undergo the initial divisions, but in any case only one haploid nucleus will survive which divides into 2 sexually differentiated haploid nuclei, called pronuclei. To indicate their differentiation, one nucleus is described the “stationary nucleus” and the other one “migratory nucleus”; terms that are well chosen.
The entire migratory nucleus from each gamont (= from each conjugation partner) then migrates through the fusion area into the opposing partner cell and fuses with the stationary nucleus that remained in its original cell. This process of fusion (syngamy) is analogous to fertilization in higher organisms. In each conjugation partner a (diploid) synkaryon or zygotic nucleus is formed. In the simplest case, this synkaryon will divide mitotically and one nucleus will develop into a new macronucleus and the other will be the new micronucleus. (During the entire process the old macronucleus gradually degenerates.)
This is the simplest textbook case, but the postzygotic development can be quite complicated.
I this a sexual process? It certainly is! We have 2 sexually differentiated entities, a stationary and a migratory pronucleus! Is it reproduction? Yes, in the sense that it leads to a recombination of genetic material. But … There is no increase in the number of individuals involved. Ciliate conjugation starts with 2 cells and it ends with 2 cells. In rare cases there is actually a reduction in number of individuals.
Gene scrambling section
Hello. Shouldn't the text read: "Ciliates are unicellular eukaryotes with two types of nuclei: the somatic “macronucleus” and the germline “micronucleus”." instead of "Ciliates are unicellular eukaryotes with two types of nuclei: the somatic “micronucleus” and the germline “macronucleus”."? Thanks. --kupirijo (talk) 10:46, 13 December 2011 (UTC)
Three minor changes, one significant edit
- Linked to osmotrophy article on Wikipedia
- Removed Suctoria from the entry on predatory ciliates (the list of ciliate predators is very long, and to name just one group is misleading)
- Added parasitism to feeding strategies, and mentioned the only human pathogen, Balantidium coli
- Edited the Reproduction section to remove a confusing false distinction (one that appears fairly often in biology texts, as well as the Encyclopedia Britannica entry on Ciliate -- protozoan). As written, the text stated that ciliate conjugation is an alternative form of reproduction, in contrast to binary fission. In fact, all ciliate reproduction is by fission, an asexual process. Conjugation and autogamy, which typically precede fission, are sexual phenomena, and not modes of reproduction. From Denis Lynn's The Ciliated Protozoa: "[T]hough there are a number of types of fission , the only kind of reproduction in ciliated protozoa is asexual, textbook statements notwithstanding (i.e., conjugation , for example, is a sexual phenomenon but not sexual reproduction). " I've amended the section heading from "Reproduction" to "Reproduction and Sexual Phenomena."