A beautiful, natural enquiry 4grownups and 4kids.
An ecosystem is an identifiable universe of life / organisms, their inter-dependence, and relationship with the environment, on earth or in space. The biological diversity is infinite in the realm of light, air, temperature, moisture and nutrients from soil, etc. which are so highly variable geographically. An ecosystem boundary is defined by man's own continually improving, yet incomplete, understanding of the many variants - it is an immense finite continuum otherwise. Earth is the only home for us and our children.
A Google search brings out a treasure of information and images. Certainly, a great topic for undertaking local and regional ecological nurturing and human sustenance in harmony with nature; Let us refrain from the word 'resource management' which often implies unmindful exploitation and modifications that are detrimental to life over time.