Diversity in Living Organisms Test - 6

The organism which is single celled; eukaryotic and photosynthetic are placed in kingdom protista.Protists are eukaryotic organisms that cannot be classified as a plant, animal, or fungus. They are mostly unicellular, but some, like algae, are multicellular. Kelp, or 'seaweed,' is a large multicellular protist that provides food, shelter, and oxygen for numerous underwater ecosystems. Even though kelp resembles a plant, it is not classified into Kingdom Plantae because it lacks the cellular complexity of plant cells.Protists can be heterotrophic, which means they obtain the energy they need to live by consuming other organisms. Or, they can be autotrophic, which means they obtain energy from the environment through photosynthesis, the process of capturing light energy and storing it in carbohydrates.

Leech belongs to Phylum Annelida, Octopus belongs to phylum Mollusca and liver fluke belongs to phylum Chordate but Starfish belongs to Phylum Echinodermata.Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea. Starfish are marine invertebrates. They typically have a central disc and five arms, though some species have a larger number of arms. The aboral or upper surface may be smooth, granular or spiny, and is covered with overlapping plates. 

Class Reptilia have organisms having dry and non-glandular skin with scales. Mammals have glandular skin with hairs. Aves have dry and non-glandular skin with feathers. Amphibians have glandular skin without feathers. Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. They inhabit a wide variety of habitats, with most species living within terrestrial

Bryophytes do not have well defined stem, root and leaves. Bryophytes get attached with substratum with the help of rhizoid, which is a fibrous structure. Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi Rhizoids may be unicellular or multicellular.Rhizoids are multicellular organs composed of multiple tissues that collectively carry out a common function.

The angiosperm plants in which seeds contain two dicotyledons are called as dicot plant. Brassica Campestris (mustard) is dicot plant out of the given plants. Brassica  is a genus of plants in the mustard family . The members of the genus are informally known as cruciferous vegetables, cabbages or mustard plants. The genus Brassica is known for its important agricultural and horticultural crops and includes a number of weeds,  both of wild taxa and escapees from cultivation. Brassica species and varieties commonly used for food nutritional values

The lower plants that do not form flower are called cryptogams plant or non-flowering plants. Vascular bundle is absent in these plants but Pteridophytes contain xylem and phloem. Vascular Cryptogam is an old botanical phrase, and it refers to those vascular plants that do not make seeds.  Thus, cryptogam (literally hidden gametophyte) refers to the production of a separate, usually very small, archegoniate gametophyte. Pteridophytes are free-sporing vascular plants that share a unique life cycle with independent gametophyte and sporophyte phases that are frequently discussed together due to common characteristics, including vascular plant 

There are two kinds of venation in leaves of angiospermic plant, parallel venation and reticulate venation. Monocot plants show parallel venation. If the veins show a more or less parallel disposition, the condition is described as parallel venation. The parallely running veins are often connected at intervals by short links which are placed at right angles to the prominent parallel veins. Parallel venation is characteristic of leaves of monocotyledons.

Gymnosperms are those plants that have naked seeds. The seeds are not enclosed inside the ovary. Gymnosperms were the first plants to have seeds. They are often referred to as having naked seeds because they do not have flowers, and their seeds develop on the surface of the reproductive structures of the plants rather than being contained in a specialized ovary. These seeds are often found on the surfaces of cones and short stalks.

Algae are most primitive plants found exclusively in water. The sex organs of algae are unicellular and non-jacketed. The most primitive algae, i.e., the members of Cyanophyceae e), e.g., Gloeocapsa, Chroococcus, etc., reproduce by means of fusion, whereas  Nostoc, Anabaena, etc., reproduce vegetatively, by means of a group of few cells called hormogonia, which later on give rise to new plants by further division. Some members of Cyanophyceae reproduce by means of arthrospores. This shows that all the blue-green algae reproduce asexually and the sexual reproduction is altogether absent. In rest of algae, whether unicellular or filamentous, both asexual and sexual methods of reproduction prevail.It is thought that probably the gametes have been originated from the motile asexual spores or zoospores. Except few cases, the sexual reproduction has not replaced the asexual method but has been added as a supplementary method. The zoospores usually resemble the gametes except for their size.

Bryophytes are called as amphibian of plant kingdom because they can survive on both land and water but water is necessary for completion of life cycle.Amphibians are those organisms which live on both land and in water. Bryophytes are called amphibians of the plant kingdom because these plants though live in soil but they need water for sexual reproduction. The sperm of bryophyte (antherozoids) are flagellate and need water to swim to the eggs. In other words, as these plants need water for reproduction unlike other plants, they are called as amphibians.