The ultimate source of energy (for most ecosystems) is the sun<span>. The ultimate fate of energy in ecosystems is for it to be lost as heat. Energy and nutrients are passed from organism to organism through the food chain as one organism eats another.</span>
Natural springs hope this helps :D
The pollen grain is actually the male gametophyte generation of seed plants. Inside the anther, pollen mother cells divide by meiosis to form pollen grains whose nuclei contain half the number of chromosomes characteristic of the parent plant.
(hope that helped answer the question)
