Use subordination (dependent clauses) to enhance rather than cripple your main story.
Thoughtful subordination can add useful information (by qualifying ideas, stating causation, and connecting ideas) and can improve rhythm and emphasis; we will discuss effective use of subordination when we discuss paragraphs. But thoughtless subordination will cripple the sentence.
In the next two examples, I have placed brackets around dependent clauses and have colored adjective clauses red and noun clauses blue. Note how each clause, whether independent or dependent, tells a story. Note also that these sentences are needlessly difficult to understand because they are trying to simultaneously tell too many stories. Finally, recognize that these sentences are inflated.
The interaction [that drives any coevolutionary system] occurs at a phenotypic interface [that comprises the characters] [that determine the outcome of any confrontation between individuals].
A very important aspect of this is [that invertebrates at higher trophic levels create feedback mechanisms] [that modify the spatio-temporal framework] [in which the micro-food web affects soil organic matter stability].
Although stories are usually expressed as clauses, they are also expressed as phrases. In the following example, there is one independent clause (we use ...), one dependent clause (that contribute), one gerund phrase (to understanding selection), and one infinitive phrase (to dissect). The sentence is comprehensible but clumsy, especially because the gerund phrase and infinitive phrase are close together.
In this article, we use a covariance approach to understanding selection to dissect those components of an interaction that contribute to the strength of selection by one species on another.
You should by now recognize that ineffective sentences, like those above, often make many mistakes. You can often improve sentences by simplifying ineffective dependent clauses (see Mightier Than the Sword by C. Edward Good).
We discussed the fact that the data were reliable. (simplify the noun clause to a noun).
We discussed the data's reliability.
We added a treatment that was essential. (simplify the adjective clause to an adjective).
We added an essential treatment.
There are instances when full replication is impossible. (simplify the independent clause to an adverb).
Full replication is sometimes impossible.
The researchers, who were led Professor J. Snoball, collected lots of data. (simplify the adjective clause to a past participle).
The researchers, led by Professor J. Snoball, collected lots of data.
If scientists are going to succeed, they must learn to write effectively. (simplify the adverb clause to an infinitive).
To succeed, scientists must learn to write effectively.