Ecology Answers

How does 1st law of thermodynamics apply to an ecosystem, an open system?
I have been reading Odum, it states that it with 2nd law of thermodynamics applies to any ecological system at any level, when Energy is conserved (neither created nor destroyed) only in an isolated system!

What are biodiversity indices? What are the broad categories of biodiversity indices and what falls under them?

Point diversity is biodiversity in a microhabitat or a sample taken from a homogeneous habitat.

What is meant by homogeneous habitat?

Are the following correct?

1. Biodiversity
It is the variation and variability of organisms within species, between species and between ecosystems.
OR
Biodiversity is the variation and variability of organisms within species and between species in a given area and also the variations(i.e. diversity) in ecosystems.

2. Ecosystem diversity
Is it the diversity of organisms in a particular type of ecosystem over different regions of the world, or, as defined by wikipedia it is the diversity of ecosystems in a given geographical region?

Which organisms are considered the secondary producers of an ecosystem?

Are organisms of the second trophic level e.g herbivores called the secondary producers or any consumer (belonging to any trophic level) termed secondary producers in the sense that they make energy available to the following trophic levels?