Diversity in Living Organism
Hierarchy of Classification
We study about the classification done by the scientist Robert Whittaker. He divided the whole organisms into five kingdoms
The order of classification is
- Phylum (Animals) / Division (Plants)
We will study about all the kingdoms in detail.
- Some have cell walls while some don’t have
- Can be autotrophic as well as heterotrophic
- Example – Blue-green algae or cyanobacteria, Mycoplasm etc.
- Some of them have locomotory organs like cilia or flagella.
- Can be autotrophic or heterotrophic.
- Example- Algae, diatoms, protozoans, etc.
- Saprophytes (feed on decaying matter)
- Many of them can become multi-cellular organisms.
- Have cell walls
- Cell walls are made up of tough and complex sugar called chitin.
- Examples – Yeast, Mushrooms, etc.
Some fungal species live in a relationship with blue green algae (cyanobacteria). Such relations are called symbiotic. These symbiotic life forms are known as lichens.
- Have chlorophyll, so they are able to do photosynthesis.
Kingdom Plantae and Kingdom Animalia are divided further. We have to study them. So first I will write down the sub groups of kingdom plantae.
- Do not have well differentiated body design.
- The plants falls in this group are commonly algae.
- Predominantly aquatic.
- Examples – Spirogyra, Ulothrix, Cladophora and Chara.
- Amphibians of the plant kingdom.
- Differentiated in stem and leaves.
- No specialized tissue for the conduction of water and other substances.
- Example – Moss (Funaria) Marchantia.
- Differentiated in roots, stem and leaves.
- Have specialised tissue for the conduction of water and other substances.
- Examples – Marselia, ferns and horse-tails.
Cryptogame- Plants coming under the Thallophyta, Bryophyta and Pteridophyta have naked embryos known as “spores”. Their reproductive organs are hidden therefore they are called ‘cryptogame’ or those with the hidden reproductive organs.
Phanerogams- The plants which have well differentiated embryos as well as reproductive organs are known as Phanerogams. Seeds are involved in it. This is further classified into two groups on the basis of their seeds:-
- Have naked seeds.
- Usually perennial, evergreen and woody.
- Example – Pines and Deodar.
- Also called flowering plants.
- Covered seeds.
- Seeds have structures known as cotyledons.
Angiosperms are further divided into two groups on the basis of cotyledons:-
Monocots – Plants whose seeds have single cotyledon.
Dicots- Plants whose seeds have double cotyledons.