Growth and Development

Syllabus tag: KCSE | Biology | Form 3 | Topic 4 Growth and Development

Lesson objectives

By the end of this topic, you should be able to:

• Define growth and development and describe how growth is measured.
• Describe seed structure, germination and its conditions.
• Explain apical and secondary growth in plants.
• Describe growth in insects and the role of plant and animal growth hormones.

Summary

Growth is a permanent irreversible increase in size and dry mass; development is the accompanying change in form and complexity. In plants growth occurs at meristems, chiefly at root and shoot tips. Germination requires water, oxygen and a suitable temperature. Insects grow in steps by moulting, since the exoskeleton cannot stretch.