[1] [1] {\huge --Rhythms in organisms--} \\ An introduction for observing, experimenting, recording and analysing

-Rhythms in organisms-
An introduction for observing, experimenting, recording and analysing

Wolfgang Engelmann

Institut für Botanik
Physiologische Ökologie der Pflanzen
Universität Tübingen
Auf der Morgenstelle 1
D72076 Tübingen (FRG)

In memoriam Jürgen Aschoff, Erwin Bünning and Colin S. Pittendrigh

Tübingen, September 1999 1


III    Teaching about rhythms

10  Chronobiology for the interested layman
    10.1  Topics and project proposals for the interested layman and for adult education courses

11  Teaching chronobiology in advanced courses in schools
    11.1  Introductory literature
    11.2  Chronobiology topics for schools

12  Teaching at the universities, research projects

13  Didactic considerations and concepts
    13.1  Teaching aids
        13.1.1  Programs and their description
        13.1.2  Movies, video films, slides
        13.1.3  Instruments, -instructions, laboratory material, supply sources
        13.1.4  Rearing of experimental organisms, supply sources


Part 3
Teaching about rhythms


This part of the book is somewhat preliminary and will be worked at in the future. I consider it important, since the development of the field of biological rhythms depends on the young people coming in contact with it, and on the interest of the public.

In the first chapter of this part, books are listed and commented on which introduce the interested layman into the field. Proposals are made for projects in adult education courses and teaching material is mentioned.

In the next chapter projects for schools are described on two levels. The lower level is aiming at pupils and students who want to be introduced into the field and to back it up with observations, simple experiments and modelling. At the advanced level more elaborate projects are introduced and weight is put on own planning and execution of experiments. In this chapter reference is frequently made to methods described in part I and examples given in part II.

A third chapter is concerned with teaching this field at the university level, where I have much own experience. Lecture topics, seminar proposals and -styles, are briefly mentioned.

In the last chapter didactic considerations will be discussed.

Furthermore, instruments, recording systems, laboratory material, sources for material and organisms, handling and rearing of unicells, plants and animals which have been proposed to be used in this book are described.

Chapter 10
Chronobiology for the interested layman

There are a number of books which introduce into the area of chronobiology. Some of them are listed in the following section and their content is summarized. In a further section topics for small projects are proposed which interested laymen could tackle for instance in the frame of an adult education course. The chapter closes with hints for audio- and visual material.

The following books are useful as an introduction to chronobiology and their content is summarized briefly:

10.1  Topics and project proposals for the interested layman and for adult education courses

The following topics are useful for smaller projects :

[Movements in leaves and flowers:]Quite a number of plants show leaf movements, which are mostly adapted to the daily rhythm. In Leguminosae, Oxalidaceae and Maranthaceae special joints are formed which are responsible for the movement [103][113]. There are, however, also leaf movements in plants without special joints. Here daily periodic differences in growth between the upper and the lower side lead to movements.

Flowers might open and close in a diurnal manner. The movement can be brought about by turgor changes in the cells of the petal. Examples are the Kalanchoe petal movements we have heard about already (page pageref). The petals of water lillies do also move in a circadian way. Even cut stripes of the petals show this movement [].

Some flowers open at certain times of the day. This is especially impressive in Oenothera. The process of opening occurs in a few minutes. An interesting project is to determine the time of opening as a function of time of the year (and consequently as a function of daylength). The first flowers open in the begin of july, the last one in october or even november. Is the time of day at which they open influenced by temperature, clouds, wind? The flowers of morning glory Pharbitis open also at certain times.

The opening of flowers is often connected with fragrance . Other flowers such as Exaccum are open all the time, but the fragrance occurs rhythmically. One should also test whether perhaps the sensitivity of the human nose and not the fragrance of the flowers changes rhythmically. For this purpose fragrant substances can be smelled in different concentrations at different times of the day. The threshold value (lowest still recognizable concentration) should be constant, if the sensitivity of the nose does not change. Many petal movements or openings of flowers or fragrance productions of plants are connected with the attraction of insects, to ensure fertilization. This offers also the opportunity to identify the fertilizing insects.

[Rhythms in algae:] Use samples of water with algae from lakes, ponds, puddles and pools. To isolate species, the samples are diluted considerably, poored in test tubes and closed with a cotton plug. In this way one can succeed in having only individual cells in the diluted sample. After several division steps one ends up with a dense population. To determine the algae a microscope is needed. Use  [46] to find out the species. It is, however, easier to buy algae from a place were collected algae are kept, such as the Pringsheim collection of algae in Göttingen [].

The algal suspension in the test tube is observed every 3-4 hours and the density recorded. In many algae a substantial part of the population settles during the night at the bottom and during the day they are more or less uniformly distributed in the medium. The cause for it is in the case of Euglena a difference in beat activity of the flagellae respectively a loss of flagellae during the night. There are, however, also indications of diurnal vertical migrations based on a different density of the individual cell [46]. These events can be documented by photography or video pictures. In this way it is easier to compare the density differences in the various parts of the test tube.

Especially interesting would be studies on bluegreen algae (Cyanobacteria). It was only in the last years that diurnal and circadian rhythms were described in these prokaryotes [66]. These rhythms show up in photosynthesis, nitrogen fixation and carbohydrate . Other movements in Cyanobacteria are perhaps also controlled in a circadian manner. Cyanobacteria show vertical movements due to density differences. To determine Cyanobacteria see [15].

[Fairy rings in fungi:] In the woods one can often find fungal fructification bodies in a ringlike structure, so called fairy rings. They are formed because the mycelium which grew radially from a single spore fructifies simultaneously. Here we will study another kind of fairy ring which is often found in molds. We use an agar-fungal medium in a Petri dish of 10 cm diameter and keep the dish open for some time. They are then closed and controlled daily. Germinating spores of different species of molds form mycelia which grow radially. They are recognizable by their circular pattern. Some show a daily rhythm (testable by daily marks at the growth front of the mycelium), which might even be temperature independent [86]. The method is useful also to check for a periodic spore flight during the course of a day. To determine molds, use [,].
[Rhythmic events in insects:] In grasshoppers, crickets, cockroaches diurnal depositions of the chitin coat can be observed. An animal is killed with chloroform and the tibia of a leg cut off. It is embedded in a piece of elder pith or styrofoam (polyurethan?) and crosssectioned with a new razor blade. A pattern of layers can be seen under the microscope at about a 500 fold magnification (figure 10.1). It is especially well recognizable under polarized light. Use a polaroid foil (see sources of supply page pageref) in front of the microscope lamp. This pattern is brought about by chitin fibers arranged in preferrential directions. Processes which are connected with the development of insects are often controlled in a circadian way. Thus in some species egg deposition, larval shedding, pupation or eclosion of the adults from the pupal cast occur only at certain times of the day. This occurs of course in the individual animal only once. The rhythmic control can therefore be studied only in a population of animals (see page pageref). On the other hand rhythmic events are also observable in individual animals: running and flight activity, attraction of males by pheromones (e.g. in butterflies) or by light signals (e.g. in fireflies) are examples. In the eye of several arthropods one can observe pigment migration in a diurnal or circadian way. This protects the eye from too heavy light exposure  [49]. A time pitfall: The daily activity of Drosophila flies can be demonstrated in field experiments using a time trap. Deposit a glass vial with fermentizing banana in an area where Drosophila is found. Change every hour for a new one, close the old one and determine the species [] and number of flies using a binocular microscope. The number of flies caught depends in a characteristic way on the time of day for the different species.
[Daily rhythms in man:]The efficiency of our sense organs are modulated in a diurnal way. This can be shown for vision, hearing, smell and taste [95]. The capacity to perform is also not uniform throughout the day, as can be shown. On page pageref it was already referred to the diurnal rhythmicity of locomotion and of body temperature of man. The phase of these rhythms depends on the chronobiological phase type, i.e. whether somebody is more a morning or an evening type. Use the questionair on page pageref, to determine your phase type.


Figure 10.1: [
Chitin deposition rhythm]Rhythmic deposition of chitin layers in the tibia of a cockroach.

Chronobiological topics are also interesting for adult education courses and are used there. Scientist working in this field are usually willing to report about their work. Especially motivating are topics concerned with rhythms of man and their significance, such as shift work or flights to the east or west (`jetlag'). Proposals for own observations and projects can be offered such as the one on page pageref. Movies and references to literature enrich the program.

Adresses of groups working in the field of chronobiology  for Germany can be found in the internet under Roenneberg, University of München, Institute for physiological Psychology. In the USA is the Center of Biological Timing in Charlottesville, University of South Carolina. University calendars or Internet pages on research fields in universities are usefull. Publications of the groups help also to become familiar with the work done there.

Chapter 11
Teaching chronobiology in advanced courses in schools

Some books are mentioned which in addition to the one of the last chapter introduce into the area of chronobiology. Ten chronobiology topics for an advanced course at schools are proposed.

11.1  Introductory literature

As an introduction the following books and articles are suited:

A multimedia show will be composed which aims at motivating the student for this field. It will offer an overview of the different rhythms at different organisms from unicellulars to man.

11.2  Chronobiology topics for schools

Topics from the field of chronobiology are well suited for an advanced course at schools. In the following, ten units are described with content, time necessary to do them, and the kind of instruments needed.

[1st unit: Introduction:]A short introduction into the field offered by the teacher or by proposing literature. Observation of the lateral leaflet movement of Desmodium motorium. Determination of mean period length of an oscillation at different environmental temperatures with stop watch or watch with hand for seconds. Grafic representation of the results: Strong temperature dependence of the rhythms. Comparision of the results with those from the literature. Q10 of 2 (see Glossar). Mentioning of circadian movement of terminal leaflets. Aim: to demonstrate a short term oscillation and dependency of the period on temperature. Discussion: what is the physiological basis of these oscillations? Chemical processes? Can chemical processes exhibit oscillations? Gears: Stopwatch or clock with hand for seconds. Time needed: one hour.
[2nd unit: Chemical oscillations:]Observation of Belousov-Zhabotinsky-reaction (how to make it, see pageref or movie (page pageref). Differences to water waves. Demonstration of the Belousov-Zhabotinsky-reaction in time. Temperature dependency. Aim: To show that even chemical processes can oscillate. Discussion: The sequences of reaction is quite well known. Feedback and amplification as prerequisits for oscillations (see also unit 10).
[3rd unit: Sleep movements of bean plants:]In the following unit bean leaves are recorded and analyzed using the kymograph method or the described video system. The course of the leaf movement is studied in a natural day, in an artificial light-dark-cycle with 12 hours light and 12 hours dark, normal and inverted (i.e. dark during the day, light during the night) and under constant conditions. Aim: Circadian processes show freerun under constant conditions, but are synchronizable to 24 hours by a light-dark-cycle. Analysis of the experiment after a week. Instruments: Kymograph, video recording system with imaging (page pageref), fluorescence light, timer, air conditioned box. Time needed: One hour each to start the experiment and analyze the results, one week of recording.
[4th unit: banding in bread mold:]The banding of Neurospora is easy to demonstrate or to perform because of the simple (selfrecording) method [39]. A week later analysis of the experiments by the students. Determination of period length with a ruler. Aim: Demonstration of timing of reproductive and vegetative processes. Discussion: Hints to other similar events (see unit 6, control of semilunar rhythm). frq-mutations of Neurospora. Instruments: growth tubes made from 10 mm diameter glass tubes the ends of which are bended upward. Inoculation wire, explained in [39]. Time needed: One hour for medium (prepare in advance), half an hour for inoculation and marking.
[5th unit: Locomotor activity of cockroaches:]Locomotor activity of cockroaches in light-dark-cycle and in weak continuous red light. Evaluation after a week by the students. Aim: To demonstrate circadian rhythms in insects. Discussion: Insects as suitable objects for the localization of the control centers of rhythms. Instruments: Video-computer recording system with imaging program. Program to analyse the data. Time required: Setup of the recording system and putting animals into the recording dishes about one hour. One week recording. One hour for evaluation of the data.
[6th unit: Lunar rhythms:]Show two movies on moon dependend tidal rhythms: Clunio and grunion-story [97,]. Aim: Lunar- and tidal rhythms. Discussion: Significance of these rhythms for the biotope sea-coast. Increases chance for fertilization. Palolo worm as an example. Instruments: Movie projector. Movies from IWF in Göttingen. Time required: One hour.
[7th unit: Photoperiodism:]Measurement of daylength as a means to orientate during the course of the year. Short day plant Pharbitis nil, long day plant Lolium perenne. Evaluation of photoperiodic induction of flowers under the binocular by the students. Aim: Photoperiodism as the most precise method for an organism to determine the time of year. Discussion: How is the daylength measured? Instruments: Binocular, pair of forceps, preparation needle. Seeds (page pageref), concentrated sulfuric acid, Erlenmeyer flask, garden soil, flower pots. Time required: One hour for preparation and sowing, after one week photoperiodic induction in darkroom or box (timer!), after another week one hour for evaluation.
[8th unit: Rhythm of man:]Temperature rhythm and activity rhythm in man, chronobiological phase type. Fill out questionaire. Distribution of phasetype classes in the school class. Demonstrate daily rhythm of body temperature with extreme morning and evening types. Aim: Demonstration of diurnal rhythms in man. Other diurnal rhythms in man. Development of circadian rhythms in babies. Instruments: None. Questionair. Time required: One hour to fill out and evaluate the questionair.
[9th unit: Gravitropic pendulum:]Demonstration of the phenomenon during an one hour lesson. Demonstration and interpretation of curves. Aim: Exogenously induced oscillation, feed back principle. Discussion: How the gravitropic pendulum functions. Experiments in space. Instruments: Video-computer recording system with imaging program. Program to evaluate the data. Time required: One hour.
[10th unit: Models:]Simulation of oscillations with program `Modus'. Explain program and demonstrate the predator-prey model. Students in groups of two change parameters. Damping, increase in oscillation. Aim: Modells as tools for scientific work. Discussion: Predator-prey oscillations exemplified with the furs of snowhares and lynx sold to the Hudson Bay Company. Effect of other factors. Instruments: PC computer with mouse and colour monitor. Modus program and handbook. Time required: at least five hours.

Slides, movies, videos and suitable computer programs are mentioned in the last chapter of this part (`teaching aids').

Chapter 12
Teaching at the universities, research projects

Lectures, seminars, courses as introductions into chronobiology at universities, research projects, research groups.

The field of chronobiology can be offered in courses, seminars, colloquia and lectures. Details are found in the catalogue of lectures of the universities. See also page pageref.

I have experience of many years in teaching chronobiological topics. In a lecture cycle `adaptation of organisms to the time structure of the environment' I have covered in five terms the following topics:

The content of these lectures will be presented on the Internet (see page 10.1). Here are some short overviews of the content:

[Photoperiodism and annual rhythms:]Introduction, historical background, examples from the plant- and animal kingdom, significance, photoperiodic time measurement and circadian system, flower induction in short- and long day plants, models for photoperiodic reactions (external, internal coincidence, amplitude model), diapause, photoperiodic counter, photoperiodism and annual rhythms, mechanism of photoperiodic reactions, localization, annual rhythms in birds, mammals, plants and unicellulars, timing of annual rhythms.
[Rhythms in unicellulars:] Introduction, evolution and adaptation of circadian rhythms, circadian rhythms in prokaryotes, fungi, amoebae (Thalassomyxa), algae (Euglena, Chlorella, Chlamydomonas, Acetabularia, Gonyaulax), ciliatae (Paramecium), minimal systems (erythrocyts, seeds, Cyanobacteria), rhythmic cell division, recording and analysis, mechanisms and models, genetical aspects.
[Insect clocks:] Introduction, examples (cockroaches, crickets, butterflies, flies, mosquitoes, beetles), population rhythms (predator-prey interaction, eclosion rhythm), annual rhythms, photoperiodism and diapause, tidal- and lunar rhythms, sun compass orientation and time memory, circadian system, localisation of controlling centers, mechanism of circadian rhythms, genetical and molecular biological studies, models.
[Rhythms in higher plants:] Introduction, gravitropic pendulum, heliotropic movement, growth rhythms, movement of lateral leaflets of Desmodium, sleep movements of plants, pulvinus as a motor organ, synchronisation, flower clock Kalanchoe, transpiration rhythm, layer formation, deposition rhythms, CAM metabolism, photosynthesis rhythm, molecular biological methods.
[Rhythms of man:] Introduction, spectrum of rhythms, examples of circadian rhythms (temperature-, locomotor activity-, sleep-wake-rhythms), localisation of the circadian oscillators, influencing and perturbing the circadian system (diseases, shiftwork, jetlag), ontogeny.

One of the main obstacles in preparing these lectures was the lack of more recent books and review articles. Therefore one had to use quite often original papers, to select the most important findings and to try to cover the newest results of this rapidly expanding field.

Seminars are useful to introduce into the field of chronobiology. I have used different strategies and found the Epstein-method [44] useful. All the participants read the same publication at home and it is discussed in the seminar. The basic idea is, that an original paper reflects quite accurately the way of scientific working of a scientist. This strategy stresses mainly the methods used and the way of presenting the results, whereas the subject content of the publication is less important. In this way the learned is transferable to other fields in biology and natural sciences.

I have also offered seminars in which teaching aids were produced by the participants, and some of them are referred to in this part. This kind of seminar is especially interesting for students which want to become teachers.

Courses are the most effective teaching arrangements to get to know the field of chronobiology. At the university of Tübingen we propose projects which can be worked at in small groups. The students have 2 to 3 weeks time for the practical studies. They are, however, already familiar with the field and the methods by an introductory seminar. It is of much value to work on projects which have not been studied so far. The knowledge to work at the frontier of science balances the danger, that such a study might also lead to an unexciting result. It is, however, necessary to have the recording methods and other aids available. Otherwise too much time has to be invested which is then lacking for the studies themself. One reason to write this book was to offer the necessary prerequisites for this.

Often research studies in the field of chronobiology are started as a consequence of working with such a project in a course. A number of students become so motivated that they decide to continue the project in form of a diploma-, teachers examination- or even doctoral thesis.

How to find a topic or project has been described already before (page pageref). A list of groups working in the field of chronobiology is found on the Internet (page pageref). Lecture catalogues or lists of research activities at universities are of help as is the Internet. Using the publications of the research groups allow to get an overview of the work done in these groups.

Chapter 13
Didactic considerations and concepts

Learning objectivs are briefly mentioned. Afterward we will list aids for the teaching of chronobiology such as programs, movies, slides, instruments, laboratory material, supply sources and rearing of experimental organisms.

Didactic aspects are important in schools, adult education courses and universities. This applies for the field of chronobiology to the same extent as for other fields of natural sciences. I will mention here just briefly some high level teaching aims, which are essential, and refer to literature [118,].

Important teaching aims:

To reach these goals, a number of aids have to be offered such as

To offer learning- and working places and to provide resources is, especially for research work, the most elaborate task.

13.1  Teaching aids

As teaching aids the following should be available:

The aids described in the book and the supply sources are compiled in the following: 

13.1.1  Programs and their description

13.1.2  Movies, video films, slides

Movies from the catalogue for scientific movies of the `Institut für den wissenschaftlichen Film' (IWF) (Göttingen) (partly available in english versions also).

[Chemical oscillation:] 



[Nyctinastic movements:] 

[Rhythms in unicellulars and algae:] 

[Insect rhythms:] 

[Insects and pollination:] 

[Mammals, man:] 

[Tidal and lunar rhythms:] 

[Sun compass orientation:] 


13.1.3  Instruments, -instructions, laboratory material, supply sources

[Construction of a temperature box:]  To allow studies under constant temperature and in controlled light conditions, we propose the construction of an air conditioned box. This small room for constant conditions consists of a solid basis (plywood or chipboard), a 10 cm thick wall of polystyrene plates for thermal isolation and a plywood bench which is inserted into the box.
On the top of this bench is a window covered with plexiglass to allow light from three fluorescence tubes to enter. The fluorescence tubes are switched on and off by an electric timer. The fittings and ballasts of the lamps are also mounted on top. At the left side of the bench a tangential ventilator maintains permanent circulation of the air. Below the ventilator are two heat foils mounted (80 Watt efficiency each). The heating foils are controlled by a thermostate. Depending on the required temperature and precision a counter cooling has to be added. For this purpose a coiled copper tube (8mm diameter) can be mounted at the right side of the bench. Cooling water constantly flowes through the tube ( 12-140 C). The number of revolutions has to be reduced by adding a resistance (e.g. a 25 Watt incandescence lamp). Otherwise the air stream is too strong. The front wall contains a door, which allows handling in the box. Holes for air exchange as well as openings for e.g. a recording camera can be inserted with a knife. For required temperatures below the room temperature (lowest limit at about 150 C) the cooling copper tube has to be dimensioned larger or the flow of water has to be increased.
[Illumination:]Safety ligth with red or green fluorescence tubes. Filter and foils (Cinemoid or Rosco, Dedo Weigert Film GmbH, Karl Weinmair Str. 10, 80807 München). Slideprojectors as light sources. White fluorescence tubes. Electric timer to obtain light dark cycles (`photoperiods'). Measuring of light intensity with light measuring instrument, setting the intensity with grey foils. Polarized light using polarisation foil.
[Computer:]Description of advisable features see [37]. Framegrabber as an A/D-converter (digitizer) to connect a video-camera to the computer. Programs for recording see [37].
[Recording]of voltages, currents, resistances with the computer using special printed cards (analogue/digital converters)
[Temperature recorder:]Powerline independent apparatus for recording body temperature of man.
[Activity recorder]for counting rates (e.g. arm movement as a measure of locomotor activity).
[Video equipment with time laps]see [37]
[Recording system of W. Hellrung]for locomotor activities of animals with infrared lightbeam, multiplexer, interface and peripheric processor unit, radio controlled clock as time reference.
[Recording of eclosion rhythm]of Drosophila-flies with metal plate containing holes, soot method.
[Transpiration measurement]with humidity sensor of Driesen und Kern company, Wiesenweg 2, PF 1126, 2000 TANGSTEDT Tel. 04109 6633 Fax 0419 1359
[Aquarium pump]in aquarium supply shops
[flow meter] 
[Cages]Fly cage, tilting cage, hamster cages, food pellets, drink nippel, running wheels.
[Hand microtome]for cutting plant material or legs of insects.
[Cuvettes]for Kalanchoe flowers with polyurethan plates, for Oxalis- und clover leaves, spectral photometer cuvettes to record the locomotor activity of Drosophila.
[Koukkari-recording]method for leaf movements.
[Microscope]for anatomical work (pulvinus sections, petal structure of Kalachoe flowers)
[Temperatur recorder,]electronic. For recoding the temperature in chambers and boxes.

13.1.4  Rearing of experimental organisms, supply sources

Index (showing section)

abdomen, 9-3
abstract journal, 1-2
acid metabolism, 6-0
activity, 8-3
     conditions, 8-1
     data, 8-3
         collection of, 8-1
     locomotor, 2-2, 4-4, 8-3, 11-2
     locomotory, 8-1
     minimum, 8-3
     rhythm, 4-4, 8-0, 8-1, 11-2
actogram, 2-2, 3-6, 8-1
agar, 8-1
age, 8-3
agriculture, 9-1
aids, 12-0, 13-1
air conditioned
     box, 1-1, 8-1
     room, 13-1
air travel, 10-1
alcohol, 8-3
alertness, 8-3
algae, 10-1, 12-0
     naked, 7-1
Amphiprora, 7-1
amplitude, 3-2
amyloplast, 5-3
analysis, 1-1, 3-6, 5-4, 6-2, 8-1
     of experiment, 8-3
     program, 8-3
anatomy, 6-2
     day active, 8-1
     night active, 8-1
annual rhythm, 12-0
apex, 9-2
apparatus, 1-1
aquarium pump, 5-4
Arrhenius-plot, 5-2
arthropods, 10-1
attraction, 10-1
autocorrelation, 3-6
     day, 3-6
     smoothing, 3-4

baby, 11-2
banding formation, 11-2
bandpass, 3-6
bean, 5-5, 6-2, 11-2
Belousov-Zhabotinsky-reaction, 5-2, 11-2
binary data, 8-3
Biological Abstracts, 1-2
body temperature, 8-3
     temperature controlled, 13-1
bractea, 9-2
brome malonic acid, 5-2
bunker, 8-3
butterfly, 10-1

caffeine, 8-3
CAM-metabolism, 6-1
carbohydrate production, 10-1
     subject, 1-2
cave, 8-3
cell vacuole, 6-1
Cestrum, 6-1
chemical activities
     pattern formation of , 5-2
chemicals, 1-1
     coat, 10-1
     fibers, 10-1
Chlorella, 7-1
chronobiological phase type, 8-3, 11-2
chronobiology, 1-2, 11-2, 12-0
Cinemoid, 6-3
circadian, 0-0, 8-1
     rhythm, 7-0
circumnutation, 5-3
     circadian, 6-1
     endogenous, 1-3, 2-2, 8-1
     radio controlled, 2-2
clover, 5-5, 6-2
     leaf movement, 1-1
Clunio, 11-2
CO2, 5-4
cockroaches, 10-1, 11-2
coleoptile, 5-4
colloquium, 12-0
colour foil, 6-3
commentary, 2-1
communication, scientific, 1-2
computer, 2-1, 2-2, 5-3, 6-2, 6-3, 8-1
     model, 7-1
     program, 11-2, 13-1
     system, 8-1
content, 1-2
control, 1-1
     in time, 1-4
     scientific, 1-3
coordinates, x, y, 2-1
correlation, 8-3
cotton, 6-1
course, 12-0
     advanced, 11-2
Crassulaceae, 6-3
Crassulacean acid metabolism, 6-1
crickets, 10-1
     synchronous, 7-1
Current Contents, 1-2
     polynomial, 3-5
cuticula, 5-4
cuvette, 5-4
cyanobacteria, 7-0, 10-1

damping, 3-3
dark period, critical, 9-2
     physiological, 8-2
     logging, 5-4
     recorded, 8-3
daylength, 9-1, 9-2, 11-2
     critical, 9-3
     measurement, 0-0
     complex, 3-6
Desmodium, 1-1, 1-4, 3-3, 4-4, 5-5, 11-2
     movie, 1-1
     quadratic, 3-5
     standard, 1-1
     structural, 4-2
diapause, 9-1, 9-3
didactic aspects, 13-0
dielectricity constant, 5-4
dielectricum, 5-4
digitizer, 2-1, 6-2, 8-1, 8-2
diskette, 1-2, 2-2, 4-4, 5-4
     cell-, 12-0
drink nipple, 8-1
Drosophila, 1-1, 2-2, 8-0, 8-1, 8-2
     food, 8-1
     litoralis, 9-3
     per-mutant, 8-1
DSP-program, 4-3, 4-4
Dunaliella, 7-1

eclosion, 10-1
     rhythm, 8-0, 8-2
egg deposition, 10-1
encyclopedia, 1-2
endoplasmatic reticulum, 5-3
     free, 5-2
epidermis, 6-2, 6-3
Epstein methode, 12-0
Euglena, 10-1
eukaryote, 1-4
evening type, 8-3, 11-2
evolution, 5-4
Exaccum, 6-1, 10-1
exhaustor, 9-3
experiment, 1-1
     crucial, 1-1
     plan, 1-1
     planing and execution, 1-1
     crucial, 1-3

Fairy rings, 10-1
feedback, 11-2
     loop, 5-4
     model, 4-4, 13-1
ferroin, 5-2
fertilization, 10-1
figures, 1-1
     digital, 3-6, 5-3, 6-2
     program, 5-3
firefly, 10-1
flow meter, 5-4
flower, 6-1, 10-1
     induction, 12-0
     water lilly, 10-1
     light, 13-1
     tube, 6-3
fly, 9-3
     cage, 8-1
forceps, 8-2
     change in, 7-1
Fourrier analysis, 3-6
fragrance, 0-0, 1-1, 10-1
     production, 10-1
     rhythm, 6-0, 6-1, 6-3
freerun, 1-3, 6-2, 8-3, 11-2
     folding, 3-6
frq-mutation, 11-2
fructification, 10-1
fruitfly, 8-0
fur coloration, 9-1

generation, 4-4
Grafik, 6-3
graphic, 2-1, 3-3, 4-2, 5-3, 8-2, 8-3, 9-3
grasshopper, 10-1
     reaction, 5-3
gravity, 5-3
grey filter, 5-4
grey value, 2-1
growth, 10-1
Grunion, 11-2
guard cell, 3-3, 5-4

     cage, 8-1
     food, 8-1
     golden, 1-1
     pellet, 8-1
     sibirian, 9-1
     syrian, 8-0, 8-1
handbook, 1-2
heating, 13-1
     foil, 13-1
Hellrung-system, 8-1
horticulture, 9-1
housefly, 8-0
human, 8-0
     rhythm, 8-3, 11-2, 12-0
humidity sensor, 5-4
hyperpolarization, 3-3
hypocotyl, 5-3
     length, 5-3
hypothesis, 1-1
     alternative, 1-3

illumination, 2-1, 6-2
imaging, 2-2, 7-1, 8-1
     program, 2-1, 6-2
     system, 5-5, 6-3, 8-1, 8-2
index journal, 1-2
indifference type, 8-3
indolyl acetic acid, 5-3
     point of , 1-1
     light, 2-1
     light beam, 2-2, 8-1
inhibitor, 1-4
insect, 4-4, 6-3, 9-1, 10-1
     clocks, 12-0
instructions, 13-1
interface, 8-3
inverted, 11-2
Isabgol, 8-1

jetlag, 10-1
journal, 1-2
     chronobiology, 1-2

Kalanchoe, 6-0, 6-1, 6-3, 9-1, 10-1
kitchen cloth, 8-1
Koukkari method, 1-1

laboratory book, 1-1
Larvae, 8-1
larval shedding, 10-1
latency time, 5-3
layer deposition, 10-1
leaf movement, 2-1, 10-1
     Desmodium, 1-1
     lateral, 11-2
learning, 13-0
lecture, 12-0
     catalogue of, 12-0
Leguminosae, 5-5, 6-1, 10-1
light, 8-3
     additional, 9-1
     beam, 8-1
     intensity, 5-4, 6-3, 8-1
     polarized, 10-1
     red, 8-1
     change in, 8-1
     cycle, 7-1, 8-3, 11-2
light-dark cycle, 11-2
     guide, 1-2
     search, 1-2
lithium ion, 5-5, 6-3
localisation, 11-2
long day, 9-1
     plant, 11-2, 12-0
Lottka-Volterra model, 4-4
lunar rhythms, 0-0, 11-2
lynx, 4-4, 11-2

mammals, 9-1
manuscript, 1-2
Maranthaceae, 6-1, 6-2, 10-1
marriage, 8-3
mastermind, 1-1
maximum, 1-1
maximum entropy spectral analysis, 3-6
mean value, 1-1, 3-4
mechanism, 1-4
     of biological rhythm, 1-4
menstruation, 8-3
mesophyll, 6-3
     molecular genetical, 1-4
     of multiple hypotheses, 1-1, 1-3
     of strong inference, 1-1, 1-3
     recording, 2-0
     scientific research, 1-1
     time series analysis, 0-0
Mimosa, 5-5
minimal system, 1-4
minimum, 1-1
model, 1-4, 4-0
     dynamical, 4-1
     examples, 4-4
     program, 4-0
Modus-program, 4-2, 4-4
monography, 1-2
moonlight, 6-1
morning glory, 5-3, 10-1
morning type, 8-3, 11-2
motor cell, 5-5, 6-3
motor tissue, 6-2
moulds, 10-1
     bending, 5-3
movie, 0-0, 5-2, 7-1, 10-1, 11-2, 13-1
moving state, 7-1
multimedia show, 11-1
multiplexer, 2-2
Musca domestica, 8-1
mutant, 8-1
mycelium, 10-1

Neurospora, 11-2
night shift, 8-3
nipagin, 8-1, 9-3
nitrogen fixation, 6-1, 10-1
noise, 3-1, 3-3, 3-4, 3-6

oat seedling, 5-4
objectiv, 8-1
Oenothera, 10-1
organ, 7-0
organisation, 13-0
     chemical, 5-2, 11-2
     form, 3-2, 3-3
     in space, 5-2
ovaries, 9-3
Oxalidaceae, 6-1, 10-1
Oxalis, 6-2

Paloloworm, 11-2
Paramecium, 7-0
parameter, 2-1
pea, 5-5
     gravitropic, 4-4, 5-3, 11-2
performance, 8-3, 10-1
period, 1-1, 3-2, 3-6, 4-4, 5-3, 6-2, 6-3, 7-1, 8-1, 8-3
periodicity, 3-1, 3-5
     daily, significance, 0-0
periodogram analysis, 3-6
Petri dish, 8-1
pH rhythm, 6-1
Pharbitis, 5-3, 9-2, 10-1, 11-2
phase, 1-1, 3-2
     diagramm, 4-4
     position, 7-1
pheromone, 10-1
phosphoinositol cycle, 6-3
photo, 1-1
photoelectric methods, 8-1
     spectral, 8-1
photoperiod, 9-3
     induction, 6-1
     reaction, 6-1, 9-1
photoperiodism, 0-0, 6-1, 11-2, 12-0
photosynthesis, 5-4, 10-1
picture analyser, 2-1, 5-3
pigment migration, 10-1
pipette, 7-1
pixel, 2-1
     experimental, 1-1
     higher, 12-0
plasticine, 8-1
plate with holes, 8-2
polarisation foil, 10-1
pollination, 6-3
polyurethan disk, 6-2
population, 8-0
     rhythm, 4-4, 8-2, 12-0
potential, 3-3
     model, 4-2, 4-4, 11-2
primary leaf, 5-4
problem, 1-1, 13-0
     solving, 1-1
process, 4-3
processor, 2-2
program, 1-2, 3-0, 4-3, 5-3
project, 12-0, 13-0
prokaryote, 1-4, 7-0, 10-1
protocol, 1-1, 6-3
     notebook, 8-3
publication, 1-2
pulvinus, 1-4, 6-1
puparium, 8-2
pupation, 8-1, 10-1
pupils, 8-3

Q10 value, 1-1, 4-4, 5-2, 11-2
questionaire, 8-3, 11-2

     radical, 5-2
rearing, 8-1, 9-3
recording, 1-1, 8-1
     method, 1-1
     cuvette, 5-4
     device, 1-1
     method, 2-0, 12-0
     time, 2-1
red blood cell, 1-4
     length of, 11-2
repolarization, 3-3
report, 1-1, 5-2, 6-3, 7-1, 8-3
reproductive, 11-2
residue, 3-6
result, 1-2
     presenting, analysing, interpreting, 1-1
review, 1-2
rhizome bulbs, 6-2
     circadian, 7-1, 8-3
     man, 10-1, 12-0
     plants, 12-0
     several, 3-3
     ultradian, 5-4, 7-1
     unicellulars, 12-0
Robinia, 5-5
ROM-port, 8-1
run-test, 3-6
running wheel, 8-1
rutting season, 9-1

safelight, 2-1, 5-3, 8-2
salade, 9-1
sample, 1-1
     nonequidistant, 3-3
school, 8-3
Science Citation Index, 1-2
seed, 1-4, 5-3, 9-2
semilunar rhythm, 11-2
seminar, 12-0
     introductory, 12-0
shift work, 8-3, 10-1
short day, 9-1
     plant, 11-2, 12-0
     average, 3-6, 8-3
simulation, 7-1
singlet, 5-2
     movement, 6-3, 11-2
     sleep-wake cycle, 8-3
slide projector, 5-4
smoking, 8-3
smoothing, 3-4
     window, 3-4
snowhare, 4-4, 11-2
Solanaceae, 6-1
soot recording, 8-2
space experiments, 11-2
     analysis, 3-6
spore, 10-1
     deviation, 1-1
     error, 1-1, 5-2
stoma, 3-3, 5-4
subsidiary cell, 5-4
suction force, 6-3
     lump of, 8-1
sulfuric acid, 5-2, 5-3, 9-2
sun compass, 12-0
sunflower, 5-3
synchronisation, 7-0, 8-1, 11-2
system-dynamics method, 4-2

Tamarindus, 6-1
     adult education courses, 13-0
     aids, 12-0
     aims, 13-0
     at schools, 13-0
     universities, 13-0
telegraph plant, 1-1, 5-5
temperature, 1-1, 4-4, 5-2, 7-0, 7-1, 9-2
     body, 8-3
     compensation, 9-2
     dependency, 11-2
     minimum, 8-3
     recorder, 8-3
     rectal, 8-3
     rhythm, 11-2
testis, 9-3
     sampling rate, 8-1
tetraethylammoniumchloride, 6-3
textbook, 1-2
Thalassomyxa, 7-0, 7-1
theophylline, 8-3
thermodynamics, 5-2
     electronic, 1-1
Tibia, 10-1
tidal rhythms, 0-0, 11-2
tilting cages, 8-1
     diagram, 4-4
timelaps , 7-1
Timesdia, 3-6
timeseries, 3-3, 6-2
     analysis, 3-0, 6-3, 8-3
tissue, 7-0
traffic accidents, 8-3
transpiration, 5-4
     rhythm, 5-4
trend, 3-1, 3-3
     removal, 3-5
turgor, 6-3, 10-1
     mechanism, 1-4

ultradian, 5-1
unicellular, 2-2, 12-0
urin, 8-3

     cell-, 6-3
variability, 1-1
variable, 1-1
     independent, 1-1
vegetative, 11-2
ventilator, 13-1
vertical migration, 10-1
     diurnal, 10-1
Vicia, 3-3
     camera, 2-1, 5-3, 5-4, 6-2, 8-1, 8-2
     system, 11-2
voltage recorder, 5-4

wood sorrel, 6-2

     dry, 8-1

zeitgeber, 7-0, 7-1, 8-3
zero point adjustment, 5-4


Remark: in italics latin names and references to other entrances in the glossary

[agar]or agar-agar, gelatine like product (polysaccharide) of red seaweeds. Used as solidifying component for culture medium. Absorbs as much as 20 times its weight water.
[actogram]graphic presentation of locomotor activity of animals
[amyloplast]Organell (leukoplast) of plant cell, in which sugar is converted into starch
[apex]tip of shoot of higher plants from which all the tissue of the stem arises
[Arrhenius-equation]desribes effect of temperature on velocity of a chemical reaction. Basis for calculating reaction rate constants
[arthropod]member of the largest phylum of animal kingdom. Largest group of this phylum are insects. Furthermore chelicerata (spiders, scorpions, ticks, mites), crustaceae (shrimps, crabs, lobsters, crayfish, sand fleas) and trilobita. Bilaterally symmetrical, segmentated body with exoskeleton
[autocorrelation]measure of how strong a momentarious value correlates with a later one
[Avena sativa,]oat, cereal with edible, starchy grains, widely cultivated in temperated regions of the earth. Family Poaceae
[background noice]statistical deviations of recorded data
[bandpass filter]filter which passes frequencies between two border frequencies only
[Belousov-Zhabotinsky-reaction]an oscillating chemical reaction described by B. Belousov in 1958 and studied especially by A.M. Zhabotinskii
[binary]numerals used in the binary system are two distinct symbols only, 0 und 1. Used in computer devices
[bract(s)]modified leaves intermediate between the calyx (the outermost of the floral envelopes) and the normal leaves
[caffein]nitrogenous organic compound of the alcaloide group. Purin derivate trimethylxanthin. White powder. In tea, coffee, cacao and other plants
[CAM]see crassulacean acid metabolism
[carbohydrate]member of organic substances that include sugars, starch and cellulose. General formula Cx(H2O)x
[Cestrum]night jasmin, nightshade family Solanaceae, Cestroideae. Shrub with few seeded berries
[chitin]white horny substance which forms the outer skeleton of insects, crustaceans, and the cell wall of fungi. Formula (C8H13NO5)n , a complex carbohydrate with molecular weight of 400 000 that is derived from N-acetyl-D-glucosamine. Similar to the cellulose molecule.
[Chlorella]genus Chlorococcales of green algae, in fresh or salty water or soil. Spherical cubshaped chloroplast.
[chloroplast]cell organell for photosynthesis
[chronobiology]describes and studies the time structure of organisms
[circadian]cycles of about 24 hours in organisms
[circumnutation]climbing, circular or pendulum like movements of plants or plant organs. Based on unequal growth of different flanks
[Clunio]marine midge (chironomid), insect
[cockroach]or roach. Primitive, often large sized winged insect of the order Blattaria. Blattoidea. Usually found in tropical or other mild climates.
[coleoptile]protective sheet which covers embryonic leaves of grasses during germination
[colloquium]scientific talk, meeting of scientists and students
[complex demodulation]time series analysis method to determine the period length and phase position of data. Also usable for data sets with non-stationary periods.
[correlation]measure of association between two or more variables and its mathematical description. Correlation coefficient between -1 and +1 (0: no correlation)
[cotyledon]first leaves to appear after germination
[Crassulaceae]stonecrop or orpine family of perennial herbs or low shrubs. Native to warm and dry regions of the earth. Thick leaves. Order Rosales
[Crassulacean acid metabolism]or diurnal acid metabolism. Special mechanism in many succulent plants to fixate carbon dioxide (`CAM'-plants)
[cuticula]membrane lamella covering the outer walls of epidermis cells
[cuvette]small container out of glass or plastic material
[cyanobacteria]bacteria with bluegreen pigment which photosynthesize
[daylength ,critical]length of the light period in a 24 hour day at which 50% of a photoperiodic reaction has occurred. Example: at a critical daylength of 11.5 hours of a particular shortday plant half of the experimental plants would flower, at shorter light periods more, at longer less. At the critical daylength of a particular longday plant half of the experimental plants would flower, at shorter light periods less, at longer more.
[daily periodicity]Periodic process with period length of 24 hours. See also circadian.
[daily rhythm]rhythm found in organisms the period length of which is synchronized to 24 hours by 24 hour time cues (Zeitgeber)
[Desmodium]tick trefoil, Fabaceae, Indian telegraph plant
[diapause]spontaneous interruption of development of certain animals (especially insects) for a certain time span. Marked by reduction of metabolic activity. Serves to survive unfavorable conditions of the environment. May occur during any life stage
[dielectricum]Non-conductor with high specific resistance. Isolator in condensors
[dielectricity constant]indicates how much the capacity of a condensor is increased if a material with dielectric properties is brought betwee the condensor plates
[digitizer]see frame grabber
[digitizing]transformation of analog data in binary information needed as input for the computer
[Discette, disk]magnetic data storage for disk drive of computer
[Drosophila]vinegar fly or fruitfly, genus Drosophilidae, Diptera, Insect
[Dunaliella]Dunaliellaceae, Volvocales, unicellular flagellated green alga
[endogenous]caused by internal reasons
[endoplasmatic reticulum]`ER', intracellular, heavily branched membrane system of all eukaryotes
[enthalpy]sum of the internal energy and product of pressure and volume of a thermodynamic system. There is free and bound enthalpy
[epidermis]outermost layer of cells covering the different plant parts. With its waxy cuticle it provides a protective barrier against mechanical injury, water loss and infection.
[erythrocyte]red blood cell, component of blood which give it the characteristic colour. Circulates in the blood and its hemoglobin transports oxygen from lung to tissue. Without nucleus in humans
[Euglena]alga, single-cell protozoa, one or two flagella, spindle shaped, usually green, commonly found in stagnant water
[eukaryote]cell or organisms that possesses a clearly defined nucleus. Eukaryotes have nuclear membrane, well defined chromosomes and other organelles. All other organisms belong to prokaryotes
[evolution], theory of, postulates that the various types of organisms have their origin in other preexisting types and that the differences are due to modifications in successive generations
[Exaccum affine]xxblaues Lieschen, Gentianaceae
[exhaustor]gadget used here to suck up Drosophila flies made of a glass tube, net and rubber tube. Facilitates transfer of single flies
[fairy ring]circular appearance of fruiting bodies of fungi, caused by radial growth of the mycelium
[feedback]in biology: a response within a system that influences the continued activity or productivity of that system. Control of a biological reaction by the end product of that reaction
[ferroin]1,10 phenanthrolin-ferrisulfate-complex, redox indicator
[filter, digital]mathematical procedure to filter time series
[flow meter]for recording and controlling the flow of fluids and gasses
[forcept]elastic plier to grabb small objects
[Fourrier analysis]determination of the harmonic components of a time series
[frame grabber]printed circuit of a computer for digitizing analog recorded values
[freerun]course of biological rhythms without synchronising Zeitgeber.
[frequency folding]partitioning of a time series in parts which correspond to the period length of the recorded event. In this way sequential cycles are positioned underneath each other. Simple and sensitive procedure for determining the period length
[frq-mutants]mutants of Neurospora with changed circadian period length
[fructification]fruit formation. Here: formation of fruiting bodies in club fungi. See also fairy ring
[fruitfly]see Drosophila
[gravitropic pendulum](same as geotropic pendulum), unequal growth of flanks of plant tips and tendrills which is induced by gravity and leads to pendulum like movements
[grunion]Leuresthes tenuis, Atherinidae, fish. Eggs are fertilized and deposited on the beach at certain times of the lunar and tidal phases
[guard cell]special, often beanlike epidermis cell. Two guard cells surround a stoma
[hamster, Sibirian]Podopus sungorosus, dsungarian hamster. Order Rodentia of Family Critecidae. Short tailed with cheek pouches for carrying food.
[hamster, Syrian]Mesocricetus auratus, golden hamster. Order Rodentia of Family Critecidae. Short tailed with cheek pouches for carrying food.
[hamster pellet]hamster food pressed into small pieces
[Hellrung-system]infrared-lightbeam system for recording the locomotoric behaviour of animals
[humidity sensor]electric sensor to record humidity
[hyperpolarisation]increase of the negative membrane potential of cells
[hypocotyl]part between cotyledons and root of plants
[hypothesis]statement without contradiction, which could be true
[indolyl acetic acid](IAA), plant hormone for e.g. elongation
[infrared-lightbeam]infrared emitter (infrared light emitting diode) and -receiver (phototransistor). An interruption by e. g.  an animal leads to an electrical signal
[inhibitor]substance which inhibits a chemical reaction or a physiological process
[interface]printed circuit used to convert signals
[inverted light-dark-cycle]in an inverted 12:12 hour light-dark-cycle the normal light period is replaced by darkness, the dark period replaced by light
[isabgol]cheap agar substitue from the seedpods of an indian plantain
[jetlag]disturbance of the circadian system after jet plane travelling through time zones (to the west or east). It takes several days until the human circadian system is adapted to the new conditions
[Kalanchoe]panda plant, genus of succulent plants of the stone crop family Crassulaceae
[larva]juvenile stage of certain animals that undergoes changes in form and size to mature into the adult
[larval molding]shedding of the old cuticula when changing from one larval stage to the next
[latency time]time from the stimulus until the reaction is first seen
[lateral leaflet]lateral leaflets of pinnate leaves
[legumes]see Leguminosae
[Leguminosae]plant family Fabales, subfamily Fabaceae (Papilionaceae), largest group of legumes
[lens]piece of glass or other transparent substance to form an image of an object by focusing on it. Compound lenses are used in cameras, microscopes, telescopes. Lense system of an optical apparatus facing the object
[light beam]see infrared-lightbeam
[light, polarising]the waves of this light vibrate in a specific direction rather than randomly in all directions as in ordinary light
[longday]day with long light period and short dark period (e. g. 13 hours light, 11 hours darkness)
[longday plant]flowers in longdays only. See also daylength, critical
[Lotka-Volterra model]mathematical desciption of a predator-prey system by Lotka (1925) and Volterra (1926)
[lunar rhythm]Rhythms with periods in the range of a lunar cycle (28 days). See semilunar rhythm
[mammals]member of the Mammalia, class of vertebrates. Young are nourished with milk of the mother. Hairy, warm blooded, four limbed.
[manuscript]document submitted for publication
[Marantaceae]prayer plant, family of monocotyledonous plants of the order of ginger (Zingiberales) native to moist or swampy tropical forrests particularly in the Americas
[matrix]rectangular scheme of elements, here: division in horizontal and vertical fields
[maximum entropy spectral analysis]time series analysis method for determining the period length of data sets which can be rather short
[mean value]designation of a value overlinex , to which n given values are appointed to according to certain rules. It lies between the largest and the smalles value. Arithmetic, geometric, harmonic and quadratic mean value
[mean value, gliding]formation of average values of a series of values which are shifted by one value after each averaging
[menstruation]periodic discharge from vagine of blood, secretion, and disintegrated tissue that had lined the uterus of women
[mesophyll]parenchymatous tissue of leaves (pallisade- and spongeous parenchyme)
[Mimosa]sensitive plant, member of a genus in the Mimosaceae family, native to tropical and subtropical areas at the northern and southern hemisphere.
[Modus-program]special program for model simulation
[mold]mass of mycelium (masses of vegetative filaments) produced by various fungi
[molecular genetics]Subarea of genetics, in which the structure and fuction of genetic information is studied on the level of molecules (nucleic acids, proteins).
[monograph]a written account to a single subject
[morning glory]Pharbitis nil, twining plant in genus Ipomoea, Convolvulaceae
[motor cells]cells of the motor tissue of the pulvinus
[motor tissue]conglomerate of special motor cells which allow the pulvinus of plant leaves and -stalks to move
[multimedia presentation]Presentation which uses different technical media
[multiplexer]way of signal transduction in which each channel is used several times (there are time- and frequency-multiplexer)
[Musca domestica]common housefly (Diptera, Muscidae family)
[mutant]an individual strain or trait resulting from mutation of the wild type
[mutation]a relatively permanent change in hereditary material
[mycelium]mass of branched, tubular filaments (hyphae) of fungi
[Neurospora]red bread mold. Fungus of the Ascomycetes class, Xylariales order. Often found on wet bread
[nipagin]4-hydoxibenzoic acid-methylester, fungicid (kills fungi)
[nitrogen fixation]process of binding nitrogen of the athmosphere and converting it into protein
[OCR]optical character recognition: Program for the recognition of characters and its conversion into computer readable signs
[Oenothera]evening prime rose, Onagraceae family, Myrtales order
[organ]a group of tissues in an organism wich performs a specific function. Consists of certain kinds of tissue and is arranged in a certain way
[ovary]germ gland of females. Harbours, nurtures, and guides the development of the egg. Furthermore important endocrine functions.
[Oxalis]wood sorrel, Oxalidaceae
[palolo worm]Eunice viridis, annelide in corall reefs of polynesia
[paramecium]Pantoffeltierchen, free living protozoon of Holotricha (order) of Hymenostomatida. Covered with fine hairlike filaments (cilia) that beat rhythmically to propell them
[parameter]a variable for which the range of possible values identifies a collection of distinct cases in a problem
[per-mutants of Drosophila melanogaster]without circadian rhythm of locomotor activity or eclosion (per 0 ) or with changed period length per l (shorter), per s (longer)
[period]period length, time after which a certain phase of an oscillation occurs again
[periodicity]in regular distances reoccuring events
[periodogram analysis]mathematical procedure to determine the period length of an oscillation
[Petri dish]dish with nutrient medium for cultures of microorganisms after R.J. Pétri (1852-1921), bacteriologist
[Pharbitis]morning glory, twining plant in genus Ipomoea, Convolvulaceae
[phase]see phase position
[phase diagram]or phase plot: graphic display of two variables plotted on x- and y- axis respectively
[phase position]particular state in a cycle of changes. See also Period
[pheromone]substance for the chemical communication between organisms of a species. It is effective in extremely low concentrations
[phosphoinositol cycle]special cycle in cells for calcium release
[photoelectric method]recording method with electric light beam. See Infrared-lightbeam
[photoperiod](1) length of the light period of a day (2) ratio between the duration of the light and the dark period of a day
[photoperiodic induction]induction of a physiological reaction by the day length
[photoperiodic reaction]physiological answer of an organism to a photoperiodic treatment
[photoperiodism]Behaviour of an organism in respect to daylength. See shortday, longday
[photosynthesis]synthesis of organic compounds with the aid of light, especially formation of carbohydrates from CO2 and H sources (as water) under the catalysis of chlorophyll in chloroplast containing tissue of plants
[pH value]potentia hydrogenium (latin), hydrogen ion content of a solution, characterizes the acid, neutral oder basic character. pH 7 means 10-7 g H-Ions in a solution
[physiological darkness]light which has in the particular physiological process no effect. In this way the process can be observed without influencing it. see also safety light
[pigment]colouring matter in organisms
[pipette]calibrated thin glass tube for measuring volums
[pixel]any of the small discrete elements that together constitute an image (as on a monitor screen)
[plasticin]moulding made out of caolin, zinc, chalk, pigments, waxesand oils
[point of inflection]point of a curve in which the bending changes its sign
[polarisation of light]see light, polarizing
[polynome curve]mathematical expression in which the single memers are connected with each other by + or - only
[polyurethan]light polymeric material consisting of alcohols and isocyanates
[population]sum of individuals of a species in a certain area, They are genetically connected with each other over several generations
[potential]measure for the energy at a certain point in a field (e. g. an electric field)
[practical course]teaching unit for providing practical skills
[predator-prey-modell]describes the mutual interaction between the populations of predators and prey
[primary leaf]the first leaf following the cotyledons
[procaryote]all organisms (bacteria, bluegreen algae) with nucleus equivalent or nucleoide instead of a true nucleus as found in eukaryotes
[processor]the part of a computer that operates on data (central processing unit)
[propionic acid]stinging fluid with antimicrobial effect
[protocol]detailed description of a scientific experiment, treatment or procedure
[pulvinus]cushion, a mass of large thin walled cells surrounding a vascular strand at the base of a petiole or petiolule and fuctioning in turgor movements of leaves or leaflets. Found especially in Fabaceae, Oxalidaceae, Maranthaceae.
[puparium]a rigid outer shell formed during metamorphosis of insects from the larval skin that covers and protects a pupa
[pupation]to become a pupa. In the pupal stage the larva metamorphoses (changes) into the adult insect
[ Q10 -value]measure of the temperature dependence of a process. Calculated from
Q10 = (t1/t2)10/(t2-t1)
where t1 period length at temperature t1 and t2 period length at temperature t2
[reaction, radical]reaction involving radicals i.e. group of atoms bonded together to an entity
[recording]continuous measurement of physical entities
[rectal temperature]temperatur in the anus
[repolarisation]to restore the hyperpolarised condition
[rhizome bulb]more or less thickened rhizome, which are clearly different from roots
[rhythm]a regularly recurrent quantitative change in a variable biological process. See also oscillation
[Robinia pseudacacia,]locusts. Fabales, Leguminosae family
[ROM-port]input into a computer for read only memory (`ROM') storage containing special purpose programs which can not be altered.
[run-test]mathematical procedure to test whether the values of a time series are randomly distributed or not
[safety light]physiological darkness, light without effect in a special physiological process. It allows to observe a process without interfering with it
[sample]a representative part of a larger whole or population especially when presented for inspection
[scanner]device to scan point- or linewise objects such as images or text and store it in binary form. These informations can be transferred and worked at with a computer
[seed]propagative plant structure: fertilized ripened ovule of a flowering plant containing embryo, seed shell and usually also nurishing tissue. Capable of germinating to produce a new plant
[semilunar rhythm]rhythm with periods of 14 days, corresponding to half the lunar cycle. Lunar rhythm
[seminar]Teaching method at universities. Introduces in autonomous (independent) scientific work
[shift work]working hours are divided in two or three shifts (early, late and night shift)
[shortday]day with short light period and long dark period (e. g. 11 hours light, 13 hours darkness). See also photoperiodism
[shortday plant]plant which flowers under short day conditions only. See also daylength, critical
[signal-average]method for time series analysis, see in chapter `display and analysis of time series', `display of actograms'.
[simulation]technique that reproduces systems, actual events and processes by using models, often involving highly complex mathematical procedures.
[singlet]certain ground state of a molecule
[sleep movement]periodic vertical movement of leaves. See also pulvinus
[smoothing]mathematical procedure to reduce the deviations of recorded data. The smoothing window determines the kind of smoothing. See gliding average
[snowhare]Lepus timidus, mammal in forests of the northern hemisphere and the alps
[Solanaceae]night shade or potato family. Order Solanales, 95 genera with at least 2400 species, many of considerable economic impact such as the tomato, potato, tobacco
[spacelab]ESA (European Space Agency) build space station providing room and facilities for research in space.
[spectral analysis]method to measure the spectrum of a substance with spectral photometer
[spectral photometer]see spectral analysis
[spore]asexual germination- and propagation cell, often of considerable resistance against unfavourable conditions
[standard deviation]statistical measure of variability (dispersion or spread) of any set of numerical values about their arithmetic mean
[standard error]standard deviation devided by the the root of n of the single cases
[stoma]plural stomata, microscopic openings or pores in the epidermis of plant leaves and young stem. They provide for the exchange of gases between the outside air and the branched system of interconnecting air canals within the leaves. Surrounded by two guard cells
[structur diagram]Presentation of the structure of a dynamical process in form of a modell
[subsidiary cell]cell neighbouring the guard cell of stomata, which are different from the normal epidermal cells
[suction force]positiv value of the negative water potential ( S = -Y).
[sulfuric acid] H2SO4 , strongly hygroscopic and agressive fluid
[suncompass orientation]ability of organisms to navigate by using the sun direction (directly or by the polarization pattern of the sky). The daily and annual change of the sun is thereby taken into account.
[synchronisation]condition of two or more rhythms which have the same period length due to interactions
[synchronous culture]cell culture which divides at the same time
[Syrian hamster]see hamster Syrian, Mesocricetus auratus
[system-dynamics]complex network with one or more feedback loops in which the effects of a process return to cause changes in the source of the process
[Tamarindus]Tamarind, Caesalpiniaceae, tropical tree in Asia
[telegraph plant]see Desmodium gyrans
[temperature compensation]the period length of circadian rhythms is not or only slightly dependent on the temperature of the environment
[testis]or testicle. Male gonads. Contain germ cells that differentiate into mature spermatozoa, supporting cells (Sertoli cells) and testosterone producing cells (Leydig cells)
[tetraethylammoniumchloride] [(C2H5)4N]+Cl- , inhibitor of potassium channels
[Thalassomyxa]marine naked amoeba
[theophyllin]purin-alcaloidal (methylxanthine) from leaves of tea plant and other plants. Chemically related to caffeine and theobromine
[thermodynamics]fundamental science of energy and its transfer from one place to another
[tibia]part of insect leg. This consists of coxa (proximal to body), the small trochanter, femur, tibia and tarsus (with several segments and claws)
[tidal rhythm]periodic biological fluctuation in an organism that corresponds to and is in response to tidal environmental changes (regular ebb and flow of oceans). Two high tides and two low tides occur each day 24.8 hours apart. Thus the period of the tidal rhythm is around 12.4 hours.
[time-diagram]graphic display of a variable (y-axis) as a function of time (x-axis)
[Timesdia]program for the analysis of timeseries, written by W. Martin
[time series]serie of data (usually equidistant) of a variable during a certain time span
[time series-analysis]statistical analysis of time series, in order to determine for instance trend, influences of random events and periodicities
[transpiration]loss of water mainly through the stomates of plant leaves
[trend]here: tendency of a time series in a certain section
[trend removal]mathematical removal of a trend. In this way a periodicity can be better recognized if originally superimposed by a trend
[Trifolium repens,]clover, Fabaceae
[turgor]hydrostatic pressure caused by water in the vacuole of plant cells. Turgor is the cause of rigitity in living plant tissue
[ultradian rhythm]oscillation with period shorter than circadian oscillations, i.e. in the range of minutes to about 8 hours
[vacuole]cytoplasmic organelle performing functions such as storage, ingestion, digestion, excretion and expulsion of excess water. In plant cells large central space that is empty of cytoplasm, lined with membrane and filled with fluid
[variability]fluctuation, deviation from the norm
[variable]factor which can take different values during the course of observation. The independent variable is plotted on the x-axis, the dependent variable on the y-axis
[vegetative]asexual reproduction. No union of sperm and egg occurs
[vertical migration]up and down movement of small organisms in rivers, lakes and seas
[Vicia faba]broad bean, Fabales, Fabaceae
[voltage recorder]device to continuously record voltages or other values which can be converted into a voltage
[World Wide Web]part of the internet, an electronic information system
[tilting cage]cage which is balanced in such a way as to change its position if the animal is moveing. Contacts at the floor of the cage sens the movements
[time-lapse]recording with movie- or videocameras in a lower frequency as normal. The film runs therefore faster as in reality
[Zeitgeber](german) time giver, time cue. It synchronizes a biological rhythm


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1 Thanks to D. Engelmann (help with computer work), J. Dittami and P. Reinhard (proofreading), Schneider-Uhle (figures) and students (feedback). This book was typeset by LYX (http://www.lyx.org), a powerful document processor using the LATEX typesetting system.

2All our education is not worth a penny if courage and joy are lost.

3how oscillations are characterized is described on page pageref and illustrated in figure 3.1

4if you do not understand terms, check in the glossary at the end of the book

5words teach, examples bring you forward

6sometimes available in drug stores and gas stations

7The Q 10 value is a measure of the temperature dependency of a process

8if necessary cut out a page of the book to compensate for thickness

9Medline (http://www.biomednet.com), Biological Abstracts, Swets and Zeitlinger with the contents of more then 14000 journals (http://www.swetsnet.nl/direct)

10address: Buchenweg 27, D72820 Sonnenbühl(Germany)

11For this purpose the oscillation is normalized to an evident measure, e.g. to 3600 or 2p circumference of the unit circle or to 24 hours circadiane time. 1800 , p or 12 CT as phase references would all mean, that half of the oscillation has passed.

12there are further procedures for smoothing, in which the values of a smoothing window are weighted; the center value could for instance obtain a high weight, the neighbouring values a smaller weight, and the peripheral values a small weight. Digital filters weight with functions (page pageref)

13supplied by the `CoMet Verlag für Unterrichtssoftware, Duisburg'

14Dr. Diez-Noguera, Group de Cronobiologia, Laboratori de Fisiologia, Facultad de Farmacia, Av. Diagonal 643, SP 08028 BARCELONA (SPANIEN)

15available from the Marutane Trading Co. in Kyoto, Japan

16green fluorescence tubes Philips TL40W/17 covered with green foil nr. 39 Cinemoid

17e.g. plasticine

18If the offset of the recorder is not sufficient, use counter-voltage, to reduce the signal from the amplifier. This allows to switch to a smaller voltage range

19Fa. Stereo Optik, Mainstr. 13, D63128 DIETZENBACH, Tel. 06074 27222

20see study 4.

21substitute of agar from indian plantain-seed pots

22red fluorescence tube with red Cinemoid foil nr. 6, primary red

23e. g.  Altromin company

24soot with a candle. Cheap candles make more soot and are in this case to be preferred.

25Philips TL20W/15 with three layers of red Cinemoid foil nr. 6 and one layer of yellow foil nr. 5a.

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On 25 Mar 2000, 22:03.