NCERT Solutions for Class 9th Science
Chapter 7. Diversity in Living Organisms
- A eukaryotic cell has membrane-bound organelles, including a nucleus, which allow cellular processes to be carried out efficiently in isolation from each other.
- Organisms which do not have a clearly demarcated nucleus and other organelles would need to have their biochemical pathways organised in very different ways.
- Nucleated cells would have the capacity to participate in making a multicellular organism because they can take up specialised functions.
- Cells that group together to form a single organism use the principle of division of labour.
- Groups of cells will carry out specialised functions.
- Organisms that perform photosynthesis are called plants.
- Some groups of organisms which have ancient body designs that have not changed very much are called as ‘primitive’ or ‘lower’
- Some other groups of organisms that have acquired their particular body designs relatively recently are called ‘advanced’ or ‘higher’ organisms.
- There is a possibility that complexity in design will increase over evolutionary time, it may not be wrong to say that older organisms are simpler, while younger organisms are more complex.
- The warm and humid tropical regions of the earth, between the tropic of Cancer and the tropic of Capricorn, are rich in diversity of plant and animal life. This is called the region of megadiversity.
- Rough estimates state that there are about ten million species on the planet, although we actually know only one or two millions of them.
- All living organisms are categorised into broad categories, called kingdoms.
- There are five kindoms in the classification proposed by Whittaker: Monera, Protista, Fungi, Plantae and Animalia.
- Kingdoms further divides into phylum for animals and divisions for plants.