Discuss how learning to juggle fits the criteria for learning.
First some definitions of Kinesis and Taxis behaviour.
Designing an Experiment:
The design of an experiment for this syllabus statement is no different to any other Biology or science experiment that you have designed.so use your PSOW skills to help you meet this syllabus requirement.
A scaffold for good experimental design is provided for reference and is applied to the design of an investigation into woodlouse kinesis.
Kinesis and Taxis Experiments:
Example: Woodlouse Class: Crustacea
Applying the design criteria:
Design: Aspect 1
The focus of this research is the behaviour of the Woodlouse.
The question to be answered is what effect does humidity have on the behaviour of the Woodlouse.
Specifically where do the woodlice go when given a choice of humid or dry conditions.
At this point you could include some background biology about the woodlouse as a terrestrial crustacean and how that may lead to a prediction about your experiment.
E.g. Woodlice tend to choose moist humid conditions as they are terrestrial crustaceans without a water proof exoskeleton.
You may formulate a hypothesis to be tested:
'Woodlice will choose humid condition in preference to dry conditions.'
The independent variable is the choice of dry or humid environment
The dependent variable will be the number of woodlice found in either dry or humid chambers .
Time in chamber
Size of chambers
Establishing conditions in the chambers
Variation in the crustaceans (phenotypic/ genetic)
Design: Aspect 2
The method need to set up the independent variable, measure the dependent variable and control the other variables which may affect this experiment.
The classic method used in such behaviour experiments involves choice chambers. Often constructed from modified petri dishes these can be quickly set up and provide a reasonable method. The two most common design include two chambers connected by a passage way or the 2, 4 split to a single chamber. Each method has its own merits and short falls which can be reviewed in the evaluation.
A round plastic dish has a platform constructed on which the woodlice can move about. This platform allows movement but is made of a gauze which allows the lower chamber to manipulate the conditions in the upper chamber. If we have two such chambers one might have a dry environment by placing Calcium chloride in the basement so that the humidity within the chamber might be absorbed.
The second chamber is to have a humid environment so water probably a soaked fabric can be placed in the basement of this chamber. Circular chambers do not provide corners to hide in!
(In actual trials of this experiment the breadth of the platform becomes an issue and when too small the animals fail to locate it in their random movement.)
The chambers conditions could be monitored with data loggers and a humidity probe, a temperature probe and a light probe.
The size of the chamber is controlled in the choice of equipment.
The chambers are connected by a connecting pathway.
Alternative choice chambers:
An alternative set up is choice chamber with four regions. This allows more combinations of conditions to be trailed but requires more complex analysis of data.
Long thinner chambers in which it is attempted to set up a humidity gradient provide very interesting results but need data logging to monitor the conditions at a specific location.
The animals need to be kept in the same conditions prior to the treatment in the experiment.
The chambers need time to adjust the controlled conditions perhaps 10 minutes
The animals need sufficient time to move around the chamber.
It would be good practice to record the distribution of animals overtime allowing for a fuller description of the behaviour.
A control experiment is required to show that it is the treatment (humid and dry) that is causing the distribution of animals not the chamber themselves.
Control chamber in which there are identical conditions in both chambers. It is possible the animals could be moving for reasons other than the tow different 'climates' provided. These control conditions will help eliminate that possibility.
Design: Aspect 2 Sufficient data:
We might anticipate at this point if you are going to use a statistical test. There will be two counts so we would be looking for a significant difference between the distribution of animals in the two chambers.. The data however is not measured on a scale so we cannot perform the T-test, instead we would use the chi square test.
Alternative choice chambers produce data which may require a different type of analysis.
Long thin chamber provide number of woodlice against % humidity.
The reliability of the data: which means repeating the choice process on a number of occasion and trying to keep those occasions as similar as possible. Also the number in each trial should be large enough to be representative, so perhaps 10-20 on each side, but the number must be equal.
The accuracy of the data: The unit of counting is the whole woodlouse so there’s not much of an issue. The woodlouse will either be ‘count’ statistic in the dry or humid area. However this will change if you use a different type of choice chamber.
Data Analysis (data processing): should be made consistent with the standards for IA. Again this syllabus statement is nothing new, just apply the same standards that you used in your PSOW. Once more a criteria grid is provided for some guidance:
The hypothesis for the experiment is either looking for a difference or a relationship between the two sets of data:
Two sets of data can be compare for a differences using tests of significant difference
Distribution of numbers along a gradient with a correlation analysis.
Conclusions when made must be consistent with the data analysis.
In practice the woodlouse show behaviour called kinesis. They move around in a non-orientated manner until they arrive in an area which the animal seems to reduce its behaviour and remain in that location. Generally woodlice will be seen to move away from dry conditions in an apparently ‘random’ manner.
The behaviour of the animals whether in a taxis or kinesis moves the animal away from negative stimuli or towards positive stimuli. In either case the condition of the animals will improve and in so doing their survival chances improve.
Having survived to reproduce because of these behaviours the animals reproduce and pass on the genes for these behaviours to the next generation.
Conversely animals whose behaviour does not remove them from undesirable stimuli risk a reduction in their fitness, gene frequency for such behaviour will decline due to poorer reproduction.
Taxic or kinetic behaviour and where genetically based will have become common in the population.
Any interpretation of laboratory behaviour must be carefully handled as animals often change their behaviour when captured or restrained. Invertebrates may be less so but these factors must still be considered.
In behaviour experiments there is a temptation to attribute human characteristics to the behaviour of animals, this should be avoided.
Innate behaviour is unchanging and unresponsive to environmental change. An organism relying on innate behaviour requires many generations of selection to change, which has little consequence for the immediate generation of animals.
If an animal has a nervous system that can allow it to change or modify behaviour it will have a survival advantage over less flexible animals.
This type of behaviour is called learning, in which behaviours can be acquired or modified during the course of a life cycle and provides the animal with an immediate increased chance of survival.
To become more frequent in the population ‘learning’ behaviour must have a genetic component
e.g. In Herring gulls the young show innate behaviour when they peck at the yellow/orange bills spot of the mother. This causes the mother bird to regurgitate food for the young. It clearly is not in the birds interest to ‘learn’ this behaviour.
In comparison however the adult Herring gulls need to learn the flight direction from their roosting areas to the location of food supplies. If the food supply runs out they need to have the behaviour to seek out new sources, remember locations and modify flight plans.
The same type of discussion can be related to recognition of predators, prey and hunting techniques.
Learning permits the immediate satisfaction of needs without recourse to the tedious process of selection over several generations (modified from Lemon & Hertzog 1969).
Pavlov was a Russian Physiologist carrying out experiments on digestion.
When Pavlov presented food (UCS) to the dogs they salivated (UCR) in anticipation of being fed.
Pavlov rang a bell (NS) each time he fed the dogs with food. Early in the experiment the dogs did not salivate when the bells was rung.
After many repetitions of ringing the bell and presenting food, the dogs began to salivate (CR)when they heard the bell only.
Pavlov described this as a conditioned reflex, in other words the stimuli that produces the response has been changed.
In this example the reflex of salivation has had the stimuli changed from the smell of food to the ringing of a bell.
This provides the animal with a flexible behaviour which will allows the modification of the behaviour which can improve survival chances
Breaking down the experiment
In practice the conditioning stimuli (CS) cannot always be arbitrary and there may be restrictions on the possible types of conditioning stimuli. The range of possible conditioning stimuli may well be reflected or be limited by those to be found in the animals natural environment.
Laboratory experiments on behaviour must be treated with some care as they may not represent changes that are possible within the natural environment of the animal.
Quote: Learning permits the immediate satisfaction of communicative needs without recourse to the tedious process of selection over several generations (Lemon & Hertzog 1969, The vocal behaviour of the cardinals and pyrrhuloxias in Texas, Condor, 71 (1): 1-15
Male birds use song as a means of communication whether singing to attract the attention of females or signaling their territorial boundaries. Bird song has been studied to determine the role of genetics (inheritance) and the environment (learning) in the development of this important communication method by birds.
The study of bird song has a long history but was greatly advanced with the introduction of the sound spectrograph. The sonograms produced allow analysis of song such that the following conclusions might be drawn:
Bird song is species specific.
For a few birds the ability to sign the right song is completely inherited.
Most birds however are born with a ‘template song’ which is a crude version of the adult song
The immature bird hatches with a template song.
There are sensitive periods in which exposure to the adult song is required
There are silent ‘listening’ phases in the immature bird
Immature bird develops song through practice
Example: White crown sparrow ( Zonotrichia leucophrys)
Distribution: North America
Adult song begins around 200-250 days after hatching
Song is a plaintive whistle followed by some trills in the range of 3-4 Kilo hertz
Dialect: The song is subject to local (geographic) variations
Song begins with an innate species specific template song which is then modified to the adult song through experiences.
The White crown sparrow song has an innate component and a learned component the advantage of which is:
Innate component; the innate template song prevents hatchlings learning the wrong species song.
Learned component; allows the bird to modify the song to the correct local dialect.
More detailed analysis:
(a)The newly hatched bird is capable of a crude version of the adult song called the ‘template’.If another species of bird sings at this stage the hatchling rejects this song being so different to the ‘template’ inherited song. Here is the influence of the innate behaviour which reject modification of 'other species' songs.
(b) There is critical period in which exposure to the white sparrow adult song initiates a ‘listening period’ in which the young does not sing but listens to the adult song. This demonstrates the learned behaviour as this period allows the fledgling to modify its song to the local dialect. This provides the bird with a level of flexibility in its behaviour.
(c) The young bird starts with the template song and listens to the adults singing. This listening period is a learning period in which the bird modifies the template to the sub song.
d) The young bird now begins to sing the sub song which is now fine tuned to match that of adult birds in the same location.
These birds are born with a genetic component to their song which is modified by experience.
The possession of the template prevents the young bird learning the wrong species song.
The learning phase allows for adaptability to the local dialect.