From owner-population-bio@net.bio.net Tue Jan 05 22:00:00 1993 Path: biosci!uwm.edu!zaphod.mps.ohio-state.edu!cs.utexas.edu!sun-barr!ames!saimiri.primate.wisc.edu!usenet.coe.montana.edu!news.u.washington.edu!carson.u.washington.edu!johnreed From: johnreed@carson.u.washington.edu (John Reed) Newsgroups: sci.bio,bionet.plants,bionet.population-bio Subject: Plant riparian population genetics Message-ID: <1if7ugINNeg@shelley.u.washington.edu> Date: 6 Jan 93 18:21:04 GMT Organization: University of Washington, Seattle Lines: 20 Xref: biosci sci.bio:1585 bionet.plants:815 bionet.population-bio:365 NNTP-Posting-Host: carson.u.washington.edu Newsgroups: sci.bio,bionet.plants,bionet.population-bio Subject: Plant riparian population genetics Summary: Followup-To: Distribution: Organization: University of Washington, Seattle Keywords: Hi, I am doing research on the population genetics of black cottonwood (Populus trichocarpa) in some river valleys in the Cascade Mountains. I have searched for references on population genetics of plants (trees are preferable) in a linear spatial system (a river or stream), but have had virtually no luck in finding any. It seems to me that the genetics of such a system may be different than a typical 2-d system. I would appreciate any leads on references or studies you may know of concerning population genetics of plants in a riparian setting. Thanks John Reed (E-mail: johnreed@u.washington.edu) From owner-population-bio@net.bio.net Wed Jan 06 22:00:00 1993 Path: biosci!uwm.edu!zaphod.mps.ohio-state.edu!rpi!usenet.coe.montana.edu!news.u.washington.edu!carson.u.washington.edu!johnreed From: johnreed@carson.u.washington.edu (John Reed) Newsgroups: bionet.population-bio Subject: Plant riparian population genetics Message-ID: <1ihsooINNt6n@shelley.u.washington.edu> Date: 7 Jan 93 18:28:40 GMT Organization: University of Washington, Seattle Lines: 20 NNTP-Posting-Host: carson.u.washington.edu Newsgroups: sci.bio,bionet.plants,bionet.population-bio Subject: Plant riparian population genetics Summary: Followup-To: Distribution: Organization: University of Washington, Seattle Keywords: Hi, I am doing research on the population genetics of black cottonwood (Populus trichocarpa) in some river valleys in the Cascade Mountains. I have searched for references on population genetics of plants (trees are preferable) in a linear spatial system (a river or stream), but have had virtually no luck in finding any. It seems to me that the genetics of such a system may be different than a typical 2-d system. I would appreciate any leads on references or studies you may know of concerning population genetics of plants in a riparian setting. Thanks John Reed (E-mail: johnreed@u.washington.edu) From owner-population-bio@net.bio.net Wed Jan 06 22:00:00 1993 Path: biosci!uwm.edu!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!cbnewsk!cbnewsj!att-out!cbfsb!cbnewsg.cb.att.com!djd From: djd@cbnewsg.cb.att.com (david.j.daulton) Newsgroups: sci.bio,bionet.plants,bionet.population-bio Subject: Re: Plant riparian population genetics Message-ID: <1993Jan7.215342.22845@cbfsb.cb.att.com> Date: 7 Jan 93 21:53:42 GMT References: <1if7ugINNeg@shelley.u.washington.edu> Sender: news@cbfsb.cb.att.com Organization: AT&T Lines: 12 Xref: biosci sci.bio:1605 bionet.plants:819 bionet.population-bio:367 Regarding populus tichocarpa, I read that this is one of the "balsam poplars", and one of the most fragrant plants to have in one's garden. Specifically, it is supposed to smell really good when the buds first open in the spring. So, I sent off for one, but when it arrived, no smell. I tried keeping it in a pot, but it died during the winter. Before I order another, was the book wrong, and this is not fragrant plant, or did it arrive after its fragrant phase, or did the nursery send me the wrong tree? Dave Daulton, Columbus, Ohio From owner-population-bio@net.bio.net Thu Jan 07 22:00:00 1993 Path: biosci!uwm.edu!ogicse!news.u.washington.edu!stein.u.washington.edu!toby From: toby@stein.u.washington.edu (Toby Bradshaw) Newsgroups: sci.bio,bionet.plants,bionet.population-bio Subject: Re: Plant riparian population genetics Message-ID: <1iigkrINNda@shelley.u.washington.edu> Date: 8 Jan 93 00:07:55 GMT References: <1if7ugINNeg@shelley.u.washington.edu> <1993Jan7.215342.22845@cbfsb.cb.att.com> Organization: University of Washington, Seattle Lines: 25 Xref: biosci sci.bio:1608 bionet.plants:820 bionet.population-bio:368 NNTP-Posting-Host: stein.u.washington.edu In article <1993Jan7.215342.22845@cbfsb.cb.att.com> djd@cbnewsg.cb.att.com (david.j.daulton) writes: >Regarding populus tichocarpa, I read that this is one of the "balsam >poplars", and one of the most fragrant plants to have in one's garden. >Specifically, it is supposed to smell really good when the buds first open >in the spring. So, I sent off for one, but when it arrived, no smell. > >I tried keeping it in a pot, but it died during the winter. Before I order >another, was the book wrong, and this is not fragrant plant, or did it >arrive after its fragrant phase, or did the nursery send me the wrong >tree? P. trichocarpa ("black cottonwood") is a member of the section Tacamahaca ("balsam poplars"). The yellow, sticky bud resin is the smell of spring in the Pacific Northwest, and can be quite strong near a big stand. P. balsamifera has a stronger, less pleasant (to me) smell. I wouldn't recommend planting either species near a dwelling with sewers or septic tanks, as the Populus are notorious for clogging them with a profusion of greedy roots. Toby Bradshaw | Department of Biochemistry | Will make genetic linkage maps and College of Forest Resources | for food. University of Washington, Seattle | toby@u.washington.edu | From owner-population-bio@net.bio.net Thu Jan 07 22:00:00 1993 Path: biosci!uwm.edu!wupost!spool.mu.edu!agate!doc.ic.ac.uk!uknet!daresbury!news From: benz@GSF.DE (Joachim Benz) Newsgroups: bionet.population-bio Subject: estimation of phenotypical variability Message-ID: <1993Jan8.104350.927@gserv1.dl.ac.uk> Date: 8 Jan 93 10:39:59 GMT Sender: list-admin@daresbury.ac.uk Distribution: bionet Lines: 99 Original-To: pop-bio@uk.ac.daresbury X-Mailer: ELM [version 2.3 PL11] For a colleague of me (Anja Oetmann, email: oetmann@gsf.de) I forward this request: >--------------------------------------------------------------------- > Our project aims to measure and to describe the present phenotypical > variability of german indigenous populations of a wide-spread grass > species (population in biological sense). We are interested in variation > within and between populations as well as in the total variability of each > character. >! The object is to minimize the number of sites that covers the >! over-all variance and further to preserve this variance through IN SITU >! conservation. > The problem is how to consider/eliminate the existing correlations > between several characters before starting mathematical analyses. > >Data: >===== > > * 100 sites, each divided in 3 subpopulations covering > spaced heterogeneity of the sites > * total plant number: 18 000 > * 13 variables for each plant were observed: > 5 measures: 30 values/subpopulation > 1 measure: 60 values/subpopulation > 7 estimations (in german: Bonituren): 60 scores/subpopulation > * Data of 1 year and 1 experimental site (spaced plants) > > >STRATEGY TO SOLVE THE PROBLEM: >============================= > 1. Estimation of the univariate variability of one subpopulation > We define the term variability of a specific variable as follows: > > VB = [ VBL .... VBH ] > i,j,l i,j,l i,j,l > > with: VBL = MEAN -STDEV > i,j,l i,j,l i,j,l > VBH = MEAN +STDEV > i,j,l i,j,l i,j,l > (assumption: the distributions are symetric) > i = index of variables [1, ..., 13] > j = index of subpopulations [1,2,3] > l = index of sites [1, ..., 100] > > 2. Estimation of the univariate variability at one site > > VBS = [ VBMIN .... VBMAX ] > i,l i,l i,l > > with: VBMIN = MIN(VBL ,VBL ,VBL ) > i,l i,1,l i,2,l i,3,l > VBMAX = MAX(VBH ,VBH ,VBH ) > i,l i,1,l i,2,l i,3,l > > 3. Estimation of the univariate variability over all sites > > VBG = [ VBGMIN .... VBGMAX ] > i i i > > with: VBGMIN = MIN(VBMIN ,l=1,...,100) > i i,l > VBGMAX = MAX(VBMAX ,l=1,...,100) > i i,l > > 4. Selection of sites > Select a minimal number of sites, that the cover of the total > variabilties in all variables by the selected sites becomes a > maximum. > >But there is a serious problem we have no solution at the moment. >Between the variables the covariances are not 0. PCA we can't use as an >intermediate step to come to uncorrelated variables because the assumption >of one density function doesn't hold. On the other hand we assume if we > --- >carry out the optimization with the original variables we will get a too >strong influence of highly correlated variables in the results. > >Any suggestions and discussion are appreciated. > > >Thanks in advance .... -- Sincerely, Joachim Benz University of Kassel Faculty of Agriculture (FB 20) Nordbahnhofstr. 1a D-3430 Witzenhausen (FRG) Phone: (+49)-5542-503-560 Fax: (+49)-5542-503-588 email: benz@gsf.de C=de; A= ; P=gsf; S=benz (X.400) From owner-population-bio@net.bio.net Sun Jan 10 22:00:00 1993 Path: biosci!ASRR.ARSUSDA.GOV!jkirkbride From: jkirkbride@ASRR.ARSUSDA.GOV ("JOSEPH H. KIRKBRIDE") Newsgroups: bionet.population-bio Subject: Documentation explaining IOPI Message-ID: <9301111341.AA06752@net.bio.net> Date: 11 Jan 93 12:33:00 GMT Sender: daemon@net.bio.net Distribution: bionet Lines: 681 From: AS8250::WINS%"david@rsbs13.anu.edu.au" 22-DEC-1992 22:55:59.21 To: JKIRKBRIDE CC: Subj: What is IOPI Return-Path: Received: from anu.anu.edu.au by asrr.arsusda.gov with SMTP ; Tue, 22 Dec 92 21:55:34 EDT Received: from life.anu.edu.au by anu.anu.edu.au (4.1/SMI-4.1) id AA11828; Wed, 23 Dec 92 14:53:38 EST Errors-To: zellweger@cjb.unige.ch Received: from (localhost) by life.anu.edu.au (4.1/SMI-4.1) id AA05407; Wed, 23 Dec 92 14:51:15 EST Date: Wed, 23 Dec 92 14:51:14 EST Message-Id: <9212230349.AA09317@rsbs13.anu.edu.au> Comment: IOPI project discussion list. Originator: iopi@life.anu.edu.au Errors-To: zellweger@cjb.unige.ch Reply-To: david@rsbs13.anu.edu.au (David Green) Sender: iopi@life.anu.edu.au Version: 5.5 -- Copyright (c) 1991/92, Anastasios Kotsikonas From: david@rsbs13.anu.edu.au (David Green) To: jkirkbride@asrr.arsusda.gov Subject: What is IOPI Scanned from Taxon 41(May1992): 390-392. Content-Length: 11060 IOPI NEWS == ======= Edited by Herve M. Burdet Conservatoire et Jardin Botaniques, Ville de Geneve, Case Postale 60,CH-1292 Chambesy, Switzerland. What is IOPI? [the International Organization for Plant Information] ============= This new organisation came into being on September 20th, 1991, at a meeting at the Australian National Botanic Gardens, Canberra, hosted by the Australian Biological Resources Study. Forty-nine botanists from eleven countries participated. The genesis of the new internation al organisation lay in discussions arising from an initial proposal by Kew to establish, with a consortium of major herbaria, a computerized taxonomic database - the Species Plantarum Project (SPP) - and those held at Delphi, under the auspices of TDWG, in October 1990, to consider the establishment of a Global Plant Species Information System (GPSIS). At a subsequent meeting at Kew in November 1990 in connexion with SPP, it became obvious that both proposals had a common interest in establishing a world checklist of vascular plants as soon as possi- ble. It was equally clear that this would involve a major, co-operative, truly international effort and that the project would be extremely expensive. An interim Council was established to expedite the proposal. This met at Kew under the successive chair- manships of Professor Prance (June 27th) and Mr Alex George (June 28th and 29th), Professor Lucas acting as Secretary, as agreed in November. To quote from the minutes of the meeting: "There was general agreement that a new organization which could combine and replace SPP and GPSIS, as presently constituted, by a single organization, would prevent duplication, possible undesirable competition, and would greatly facilitate the success of the project. A unified will is essential to make it work on an international scale" Mr. George, on behalf of the relevant Australian organizations, then offered to host a meeting to consider this proposal in Canberra where a meeting of TDWG - whose act ivities would be particularly relevant to aspects of the proposal - had already been arranged. There was a very thorough and wide-ranging discussion at Canberra of the pros and cons of the proposal and how it would impact on existing institutional taxonomic activities; of how it would relate to other ongoing projects, such as those of IAPT; of the kind of support it might attract from taxonomic institutions and elsewhere and indeed, of whether the proposal was a viable proposition. At the end of two days full discussion there was overwhelming support for the proposal to establish a new organization. A Constitution was agreed and working arrangements proposed to achieve, as the first task, a Checklist of the vascular plants of the world. The Constitution of IOPI sets out succinctly the objectives of the organization, namely: 1. to promote and prepare, as expeditiously as possible, a series of integrated, dispersed, computerized databases, summarizing the basic taxonomic information (b earing in mind the basic requirements of freedom of taxonomic research and opinion), and biological and other attributes (in particular, information relating to their utilization and conservation) of all kinds of plants* in the world; * Plants to be interpreted as those organisms covered by the International Code of Botanical Nomenclature. 2. to document the data in such ways as shall make them most readily accesible to users of all kinds, in all regions, and in such formats as shall seem most expedient to the governing body of IOPI; 3. thereafter, to maintain the data in an up to date form and continue to render them accessible in accordance with (1) and (2) above. To assist in gaining international recognition for IOPI, the Constitution also includes establishing of an association with IAPT, TDWG, CODATA, IUCN, UNEP and UNESCO, including their representation, ex officio, on the Council of IOPI. To date, IAPT, TDWG, IUCN and UNEP have agreed to such an ass ociation, and the matter is under consideration by CODATA and UNESCO. Preliminary recognition of IOPI as an international scientific association or commission by IUBS has been granted with a view to ratification of full recognition and representation at their next general assembly in 1994. Setting out objectives is the easiest part of the task, achieving them will be more difficult for several reasons. Firstly, the available expertise necessary is scattered all over the world and many of the pract itioners are already fully engaged on existing taxonomic tasks. IOPI will have to depend upon the goodwill and voluntary collaboration of many institutions, together with finding the means (where essential) to provide additional assistance, whether for basic taxonomic work or modifications of present practice, so that existing and ongoing knowledge can contribute to the world database. Moreover, for many regions and several taxonomic groups even the most basic data are lacking or very limited. It wil l be important for IOPI to raise funding to assist such regions to develop taxonomic work both for their own information as well as a contribution to world knowledge. It is important to realize that IOPI will act primarily as a trustee of the knowledge in the proposed world database and to facilitate the acquisition and availability of knowledge about plants and their attributes as an international service. Lastly, but of immense importance, IOPI will need to work through international collaborat ion and to ensure that such funding activities as it may promote compete minimally, or not at all, with the fund-raising efforts of other taxonomic institutions and individuals. Because the objectives of IOPI are wider than the purely taxonomic, although in the first instance that is the area of overriding importance, the founders of IOPI believe that sources can be tapped which will meet the non-taxonomic competitive criterion. To implement this approach a number of actions were agreed. Firstly, an international Foundation Council was established to get the project started. A Council fully in accordance with the Constitution is to be elected by postal ballot of members in 1992 to become effective from the next plenary meeting of IOPI to be held in Xalapa, Mexico, in Autumn 1992 (in association with a TDWG meeting). Secondly, a World Plant Checklist Committee having a wide regional representation was seen as a prime necessity. Dr. David Hunt of Kew was asked to establish and lead it. This b ody will co-ordinate and promote the range of activities necessary to achieve a working checklist in an initial target period of 5 years. Inter alia it will have to organize commitments and contributions from different participants and establish regional groups so that participants can keep in touch both with each other and with the project as a whole. Thirdly, the Checklist Committee will be supported by four international Working Groups. One will develop a Taxonomic Resources Network (TRN, chair ed by Nancy Morin, St Louis) to assess what is already available, identify regional and taxonomic gaps and provide information to others in the project. A second will be concerned with Dataset Definition and Standards (DDS, chaired by Frank Bisby, Southampton), for work allied to that already being carried out by TDWG. It is expected that this group should be able to provide a minimum dataset with appropriate definitions of acceptable standards early in 1992. The Information System Design group (ISD, chaired by Catherine Zellweger, Geneva) will first examine the question of basic transfer formats in current use, as advised by TRN in collaboration with DDS. But its major task will be to develop an adequate and effective system for the final Checklist so that it will be possible to integrate other data, taxonomic and non-taxonomic, into it. K. Beese (Brussels) has been asked to form an additional User working group to look into what other kinds of data should be incorporated into the taxonomic ch ecklist and with what priority. Lastly, the Products and Editing group (PE, chaired by Herve Burdet) will be concerned with the form of the final products as well as the editing en route. As has already been said, IOPI will have to depend greatly on the voluntary participation of institutions and individuals world-wide, and most of the financing of basic taxonomic work will be that available to each participant in the course of normal work. However, if the project is to be truly developed and in tegrated internationally, then some central funding will have to be found to cover the running costs of maintaining communications and the like, as well as for assisting with travel when no other source is available. A Finance working group (chaired by J. Scott Petersen, US.D.A., Beltsville) has therefore been established both to seek support and supporters for all financial aspects of the work. While this group will, of course, actively seek general funds for central activities, it will also try to respond to, and promote, the needs of other groups within the project. For instance the Checklist Committee will have to meet at least once before the next full meeting of IOPI and ISD would like to hold a number of small workshops involving people from different parts of the world. Geneva has most generously offered to prepare, circulate, and meet the cost of an IOPI Newsletter (to be edited by Herve M. Burdet) and this should greatly aid communication. However, until the first Newsletter is p roduced, further detailed information about IOPI can best be obtained from its Secretary, Alex George, Australian Biological Resources Study, GPO Box 636, Canberra, ACT 2601, Austral From owner-population-bio@net.bio.net Tue Jan 12 22:00:00 1993 Path: biosci!agate!spool.mu.edu!caen!batcomputer!cornell!uw-beaver!news.u.washington.edu!carson.u.washington.edu!johnreed From: johnreed@carson.u.washington.edu (John Reed) Newsgroups: bionet.population-bio Subject: Plant riparian population genetics Message-ID: <1ivtktINNqi6@shelley.u.washington.edu> Date: 13 Jan 93 02:09:33 GMT Organization: University of Washington, Seattle Lines: 18 NNTP-Posting-Host: carson.u.washington.edu Hi, I am doing research on the population genetics of black cottonwood (Populus trichocarpa) in some river valleys in the Cascade Mountains. I have searched for references on population genetics of plants (trees are preferable) in a linear spatial system (a river or stream), but have had virtually no luck in finding any. It seems to me that the genetics of such a system may be different than a typical 2-d system. I would appreciate any leads on references or studies you may know of concerning population genetics of plants in a riparian setting. Thanks -------------------------------------------------------------------------- John Reed College of Forest Resources, AR-10 University of Washington Seattle, WA 98195 Internet: johnreed@u.washington.edu -------------------------------------------------------------------------- From owner-population-bio@net.bio.net Sat Jan 16 22:00:00 1993 Path: biosci!agate!dog.ee.lbl.gov!hellgate.utah.edu!fcom.cc.utah.edu!rogers From: rogers@anthro.utah.edu (Alan R. Rogers) Newsgroups: bionet.population-bio Subject: Re: Plant riparian population genetics Message-ID: <1993Jan17.223642.8934@fcom.cc.utah.edu> Date: 17 Jan 93 22:36:42 GMT References: <1ihsooINNt6n@shelley.u.washington.edu> Sender: news@fcom.cc.utah.edu Organization: U of Utah Dept of Anthropology Lines: 85 In article <1ihsooINNt6n@shelley.u.washington.edu>, johnreed@carson.u.washington.edu (John Reed) writes: |> Newsgroups: sci.bio,bionet.plants,bionet.population-bio |> Subject: Plant riparian population genetics |> Summary: |> Followup-To: |> Distribution: |> Organization: University of Washington, Seattle |> Keywords: |> |> Hi, |> I am doing research on the population genetics of black cottonwood |> (Populus trichocarpa) in some river valleys in the Cascade Mountains. I |> have searched for references on population genetics of plants (trees are |> preferable) in a linear spatial system (a river or stream), but have had |> virtually no luck in finding any. It seems to me that the genetics of |> such a system may be different than a typical 2-d system. I would |> appreciate any leads on references or studies you may know of concerning |> population genetics of plants in a riparian setting. |> Thanks |> John Reed |> (E-mail: johnreed@u.washington.edu) |> There are lots of articles on genetic population structure in 1-d habitats, but not much of it is specifically about plants. However, the theoretical literature ought to apply equall to plants and animals. The relevant subjects are "linear stepping stone models" and "circular stepping stone models". Here are a few references that I happen to have online. @book{Maruyama:77, author = "Maruyama, Takeo", year = 1977, title = "Stochastic Problems in Population Genetics", address = "New York", publisher = "Spring\-er-Ver\-lag" } @Article{Carmelli:TPB-9-329, author = "Carmelli, D. and L.L Cavalli-Sforza", year = 1976, title = "Some Models of Population Structure and Evolution", journal = TPB, volume = 9, pages = "329--359" } @incollection{Karlin:EB-4-61, author = "Karlin, S.", year = 1982, title = "Classifications of Selection-Migration Structures and Conditions for a Protected Polymorphism", pages = "61--204", editor = "M. K. Hecht and B. Wallace and G. T. Prance", booktitle = "Evolutionary Biology", volume = 4, address = "New York", publisher = "Plenum" } @Article{Kimura:G-49-561, author = "Kimura, M. and G. H. Weiss", year = 1964, title = "The Stepping Stone Model of Population Structure and the Decrease of Genetic Correlation with Distance", journal = "Genetics", volume = 49, pages = "561--576" } @Article{Rogers:AN-135-398, author = "Rogers, Alan R.", title = "Group Selection by Selective Emigration: The Effects of Migration and Kin Structure", journal = AmNat, year = "1990", volume = "135", pages = "398--413", } -- Alan Rogers WORK PHONE : (801) 581-5529 Dept. of Anthropology HOME PHONE : (801) 486-6013 Univ. of Utah INTERNET: rogers@anthro.utah.edu Salt Lake City, UT 84112, USA From owner-population-bio@net.bio.net Wed Jan 20 22:00:00 1993 Path: biosci!uwm.edu!rpi!utcsri!torn!news.ccs.queensu.ca!qucdn!promislo From: PROMISLO@QUCDN.QueensU.CA Newsgroups: bionet.molbio.evolution,bionet.population-bio Subject: growth curve sex.dimorphism Message-ID: <93021.115126PROMISLO@QUCDN.QueensU.CA> Date: 21 Jan 93 16:51:25 GMT Organization: Queen's University at Kingston Lines: 5 Xref: biosci bionet.molbio.evolution:735 bionet.population-bio:373 I am in search of recent comparative studies on sexual dimorphism of growth curves in mammals. Any suggestions? Thanks, Daniel Promislow (Direct reply to promislo@qucdn.queensu.ca would be appreciated) From owner-population-bio@net.bio.net Fri Jan 22 22:00:00 1993 Path: biosci!NET.BIO.NET!kristoff From: kristoff@NET.BIO.NET (David Kristofferson) Newsgroups: bionet.population-bio Subject: BIOSCI/bionet Frequently Asked Questions Message-ID: <9301231000.AA28603@net.bio.net> Date: 23 Jan 93 10:00:02 GMT Sender: kristoff@net.bio.net Distribution: bionet Lines: 16 New users of BIOSCI/bionet may want to read the "Frequently Asked Questions" or "FAQ" sheet for BIOSCI. The FAQ provides details on how to participate in these forums and is available for anonymous FTP from net.bio.net [134.172.2.69] in pub/BIOSCI/biosci.FAQ. It may also be requested by sending e-mail to biosci@net.bio.net (use plain English for your request). The FAQ is also posted on the first of each month to the newsgroup BIONEWS/bionet.announce immediately following the posting of the BIOSCI information sheet. Sincerely, Dave Kristofferson BIOSCI/bionet Manager kristoff@net.bio.net From owner-population-bio@net.bio.net Sat Jan 30 22:00:00 1993 Path: biosci!agate!spool.mu.edu!sdd.hp.com!caen!umeecs!quip.eecs.umich.edu!bagchi From: bagchi@quip.eecs.umich.edu (Ranjan Drzzzzt! Bagchi) Newsgroups: comp.theory.dynamic-sys,bionet.population-bio,sci.fractals Subject: Examples needed Message-ID: <1993Jan31.224819.2673@zip.eecs.umich.edu> Date: 31 Jan 93 22:48:19 GMT Sender: news@zip.eecs.umich.edu (Mr. News) Organization: University of Michigan EECS Dept., Ann Arbor, MI Lines: 29 Xref: biosci comp.theory.dynamic-sys:110 bionet.population-bio:375 sci.fractals:766 Hi. I'm having a hell of a time finding an example of a chaotic attractor in a 3-species predator-victim system with either Lotka-Volterra characteristics, or logistic characteristics. I do have (from Hastings and Powell, 1991) an example of a chaotic attractor in a system type-II functional response: dx/dt = x(1-x) - f1(x)y dy/dt = f1(x)y - f2(y)z - d1y dz/dt = f2(y)z - d2z fn(u) = a_n u/(1 - b_n u) with constants -- d = ( 0.4 0.01) a = (5 0.1) b = (3 2.0) I don't see why I'm having a problem pushing this into a logistic or simple lotka-volterra model, but I'm either getting populations that crash or exponential. help?? -rj -- Ranjan Bagchi Ranjan.Bagchi@umich.edu oo oooo o oo ooo oo oo oo o o oooo ooo o o oooooooo