2.11 An Explanation
Social purpose: To explain how and why phenomena occur in scientific and technical fields
The Life Cycle of Barramundi
| Text structure | Language features | |
| Identification; statement of phenomenon | 1Barramundi are tropical fish and are found in the waters of the 3northern half of Australia. | 1. General non-human nouns
2. Technical terms |
| Explanation sequence (showing how the process occurs; the main phases of the process) | Barramundi 1eggs and 2larvae require salt water for successful 2fertilisation. Therefore 2spawning usually takes place in 2estuaries at night at the full and new moons during the summer wet season. Females can lay up to three to six million eggs in a season.
The juvenile fish 5then 4swim upstream and spend the first three to four years of their life in 3fresh 1water 6because there is a wide variety of food as well as protection for them. As the 3wet season finishes and the 3flood plains dry up, the barramundi 4move even further inland to freshwater billabongs. Some may become trapped there and never return to the ocean. However most 4migrate back to the coast to spawn when they are 3mature. Like many other 1fish barramundi change sex during their life history. 2Juveniles mature 5first as males and 4change to females 5when they are six to eight years old. |
3. Factual and classifying adjectives to describe phenomena
4. Action verbs in the simple present tense to show the occurrence of events in the process 5. Time connectives, conjunctions and adverbials to show the sequence of events 6. Causal connectives, conjunctions, adverbials and verbs to show cause and effect sequence of events |
A series events may be related according to time or cause, or according to both relationships.
The text above is a sequential explanation concerned with how a process occurs. The use of time connectives and adverbials is typical of these texts to show the order in which the events occur.
In causal explanations which are concerned with why phenomena occur, causal connectives and adverbials such as 'because' are used to show the cause and effect relationship of the events.
Other typical language features of this type of text are: nominalisation to summarise events and name abstract phenomena; the use of the passive to make the phenomenon or object undergoing the process the focus of the sentence or clause; abstract nouns to name abstract phenomena such as pollution.