Can you help me answer these?

Question

1.) What characters were used in the classification of Kindom Monera?Kingdom Protoctista?

2.) What are some of the most significant changes that occured in Kingdom Monera that may have paved the way for the evolution of more advanced forms of life? How about in kingdom Protoctista?

3.) What is meant by "alteration of generations" in the life cycle of plants?

4.) Why are plants important to man and to all ecosystems of the earth?

Answer 1

Plants are important because they change carbon dioxide to oxygen , which benefits animals and humans and all organisms that live off of oxygen. Also, they feed many animals and human and are important to are food chain. (they are producers and feed consumers)

Answer 2

1) Whittaker classified on basis of many features like cell structure, phylogenetic relation, mode of nutrition ....

     Kingdom Monera includes only the unicellular prokaryotes.

     Kingdom Protista includes only unicellular eukaryotes except for yeast which is included in Kingdom Fungi.

2) As far as i know there weren't major significant changes in Kingdom Monera that could pave way for more advanced forms. The Protistan Kingdom evolved from progenotes (also the ancestor of eubacteria & archaebacteria) but not from monerans.

The Protistans grew from unicellular to few celled(spirogyra, volvox) to multicelluar. Slowly their primitive sense organs were developed & basicly almost all observable features in higher kingdoms developed from them

3) Alternation of generation in plants mean the alternating life cycle between the haplontic gametophyte & diplontic sporophyte or vice-versa as in case of Bryophytes & Pteridophytes

4)Plants are the only living organisms that can produce O2 by biological means which is essential for the survival of 99.9%  of organisms