Cephalochordata (Gr., kephale, head; chorde, cord) is a sub-phylum within the phylum Chordata. The animals in this group are small, marine invertebrates. They are commonly called lancelets or amphioxi. Cephalochordates show many typical chordate features, including a notochord, a dorsal…
The sub-phylum Urochordata (Gr., uro, tail; chorde, cord) is a part of the phylum Chordata. The animals in this group are called sea squirts,or tunicates. These animals are very unique and show a high degree of diversity in their form,…
Phylum Hemichordata is generally considered the sister group of the phylum Echinodermata. The animals are marine deuterostomes. They are more or less worm-like, having the ancestral tripartite body of proboscis, collar, and trunk. The name Hemichordata is derived from the…
The members of the Xanthophyta or Heterokontae (class Xanthophyceae) are commonly known as yellow-green algae. Characteristics of Xanthophyta: Xanthophyta show the following general characteristics: Distribution of Xanthophyta: There are about 100 genera and 600 species in the division Xanthophyta. Most…
Algae present in the group Bacillariophyta (class Bacillariophyceae) are known as diatoms. They constitute a very large assemblage of unicellular algae. Diatoms differ from other algae due to their symmetrical structure and delicately designed cell walls. Thus, diatoms are considered…
The members of the Phaeophyta (class Phaeophyceae) are known as brown algae due to their characteristic brown colour. They exhibit a brown colour because of the presence of the golden brown pigment fucoxanthin. The plant body of brown algae is…
Algae found in the group Rhodophyta (class Rhodophyceae) are red in colour. So these are also known as red algae. The algae show red colour due to the presence of the red pigments r-phycocyanin and r-phycoerythrin. Characteristics of Rhodophyta Distribution…
The female gametophyte of gymnosperms is a multicellular structure serving the functions of bearing the archegonia and nourishing the developing embryo. It exhibits a progressive series of significant changes leading towards angiosperm conditions. Due to the absence of fossil records,…
Spirogyra is a free-floating, freshwater, filamentous green alga of the class Chlorophyceae. It is usually found in stagnant water bodies such as ponds, pools, ditches, etc. Spirogyra is also known as water silk or blanket weed, as its filament is…
Ulothrix is an unbranched filamentous green alga of the class Chlorophyceae. It is commonly found in freshwater ponds, pools, lakes, etc. The word Ulothrix means shaggy or curly hair (in Greek, oulos = shaggy or curly and thrix = hair).…