Then like a tender child whose hand did just enfold
Safe in its eager grasp a bird it wept to hold
When peirced with one wild glance from the troubled hazle eye
It gushes into tears and lets its treasure fly
Thus ruth and selfish love together striving tore
The heart all newly taught to pity and adore;
If I should break the chain I felt my bird would go
Yet I must break the chain or seal the prisoner’s woe.
Wuthering Heights contains two halves concerning two generations respectively. The first half contains a dysfunctional love story between Heathcliff and Catherine which compels the reader and sets the stage for the younger generation. The second half concerns the shadows of the primary passionate characters that dominated the first half. Fascinating as their dramatic love story is, Catherine and Heathcliff are flat, unchanging characters. They are not fit for their surroundings, and they either cannot or refuse to adjust to the realities of their situations. The only characters who display the capacity for genuine change are the little Catherine and the younger Hareton. Both nature and nurture play key roles in the development of this second generation. In this little world among and between Wuthering Heights and The Grange, a small but significant evolution occurs. Cathy and Hareton make the proverbial adaptation to their surroundings to gain some of life’s slightest pleasures. In little Cathy and Hareton we see progress. If the story of Wuthering Heights and the Grange, told by Nelly, listened to by Lockwood, represents society as a whole, a small slice of society (in this case little Catherine and Hareton) represents a small amount of possible change, a brand of social Darwinism. To show this micro-evolution, Brontë gives us the roots, the heritage, the biological factors along with the social factors dictate the behavior of the characters in the first half. Then the author proves how, despite all these factors, little Cathy and Hareton could still invoke the power of forgiveness, allow for change, and acclimate to their harsh surroundings. Little Catherine and Hareton, though less compelling characters than Catherine and Heathcliff, become more fit for their surroundings than their predecessors.
The novel repeatedly refers to the importance of biology, both in the handing-down-of-traits as well as the departure from family traits.