The Brain

The corpus callosum allows information to be transferred from one hemisphere to the other

Cerebrum

The cerebrum is convoluted to increase the surface area, allowing a larger surface for the location of nerve cells.

Specific areas of the cerebrum control specific functions.

The bigger the area of the cerebrum involved, the greater the degree of control or sensitivity.

Memory

Short term memory

Long term memory

Incoming information

Transfer

Displaced

Rehearsal

STM can hold 7+ 2 items for 30 seconds

Capacity of STM can be improved by ‘chunking’ e.g. phone number = 0141 629 3801 = 11 items But divided into chunks = 0141 (national code = 1 chunk)

629 (area code = 1 chunk)

3801 (4 chunks)

This gives 6 items instead of 11.

Rehearsal extends the time that information is held in the STM and facilitates its transfer to the LTM

Alzheimer's disease involves memory loss due to the loss of the neurotransmitter Acetylcholine.

Development

Maturation = progression through a sequence of inherited developmental stages. e.g. walking, speech.

Maturation provides periods of optimum potential for learning.

The rate at which learning occurs is determined by genetic and environmental factors.

Motor control in early development is affected by myelination of nerve fibres.

As myelination increases, so does the improvement in motor control.

Inherited conditions can affect development / behaviour.

e.g.

Muscular dystrophy – may lengthen the time it takes for a child to learn to walk on its own.

Huntington’s chorea – premature death of neurones and decreased neurotransmitter affects behaviour.

Behaviour / LearningPractice of a motor skill improves performance – the time taken to carry out a task reduces.

A maximum level pf performance will be reached as there is a limit to how quickly the nervous system and muscles can function.

Common ways of learning are;

Trial and Error

Imitation

Imitation = copying a demonstration.

You learn even faster if you receive motivation (e.g. a reward).

Social Facilitation = increased performance in a competitive situation.

PopulationsToday's population is different from 100 years ago.

Today we have;

More older people

The average age is higher

Reasons;

Improved medical care

Improved sanitation

More food

Demography = the study of trends in human populations.

Food ProductionFood production has increased because;

Pesticides – have significantly reduced crop loss by killing organisms which would otherwise eat or damage crops.

Selective plant breeding – has developed plants which produce higher yields and are disease resistant.

Pesticides

May be retained in the body and build up to high levels.

High levels = Death

Lower levels = Reduced reproduction

The animals most affected by pesticides are at the end of the food chain – they have accumulated most pesticide.

e.g.

algae fleas small fish big fish fish eagle

Least pesticide Most pesticide

Reason – pesticides are persistent, therefore build up each time food is eaten. As each organism will eat a large number of prey, it becomes more concentrated as we go along the food chain.

Algal blooms

High levels of nitrate (from sewage / fertiliser) cause algal blooms.

Algal blooms reduce oxygen in rivers because when the algae die they are decomposed by bacteria, which increase in number and use up the oxygen.

Graphs;

•Always label axes + remember units

•Always mark origin with starting value

•Draw correct graph (line or bar)

•Always use a ruler

•Don’t extend line above or below values

•Scale should be sufficient for graph to cover more than half of graph paper given.

•If more than one line to be drawn then label each one.

Problem solving

Make sure you can do ratios and percentages.

Use correct terms; i.e. mass, volume etc – not amount.

Reliability -- this is increased by repeating experiment a number of times / setting up duplicates.

Choice of controls – The test and the control should be identical except for the variable being tested.