Some of the things to take into account are:
A category can include very many people.
A group can be any size.
A team is usually of a limited and sometimes (in sport, for example) pre-determined size.
Usually individuals are selected for team membership based on their skills or attributes in relation to other members of the team
By definition a category includes many people with the same attribute.
Membership of a group is often by self-selection.
PERMANENCE AND PURPOSE
While membership of a category may persist, there is unlikely to be anything like ‘category spirit’ to bind its members together.
A crowd may be united in purpose for a short time, but the same members are unlikely to come together again.
A team will have both a purpose to bind it together and will also work together for more than a transitory period.
TEAM DEVELOPMENT AND TEAM ROLES
Read the CIPD factsheet on Teamworking. This is available from their website at www.cipd.org.uk (not restricted to CIPD members).
You may well have come across the work of Belbin on team roles, and have completed a questionnaire to discover which role or roles you prefer.
Refresh your memory by looking at the summary table [Belbin_Team_Role_Descriptions.pdf].
Now read the article from the Sunday Times which discusses a typology proposed by Honey Langcaster-James and the summary table. [Langcaster-James Summary.docx].
Do you find these typologies helpful? Can you identify with any of these team-roles yourself, or identify any of your colleagues? Do you think that you undertake different roles in different teams and/or at different times?
Discuss your ideas with fellow students and your tutor using the online discussion board.
There is a lot more reading about teams in “Management and Organisational Behaviour” or any other similar book which you are using.