Cardiac Cycle and its Phases
The cardiac cycle refers to the sequence of events that results in the continuous and rhythmic contraction and relaxation of the heart chambers. All the events in a cardiac cycle…
Read MoreCardiac Cycle and its Phases
Sub-phylum Cephalochordata: Definition, Characteristics, Classification, Examples
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…
Sub-phylum Urochordata: Definition, Characteristics, Classification, Examples
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…
Phylum Hemichordata: Definition, Characteristics, Classification, Examples
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,…
Xanthophyta (Yellow Green Algae): An Overview
The members of the Xanthophyta or Heterokontae (class Xanthophyceae) are characterized by their yellow-green pigments, including xanthophylls, which distinguish them from other algae. They are commonly known as yellow-green algae.…
Bacillariophyta (Diatoms): An Overview
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…
Phaeophyta (Brown Algae): An Overview
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…
Rhodophyta (Red Algae): An Overview
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…
Evolution of Female Gametophyte in Gymnosperms
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…
Spirogyra: Salient Features, Occurrence, Thallus Structure, Reproduction
Spirogyra is a free-floating, freshwater, filamentous green alga of the class Chlorophyceae. Salient Features of Spirogyra The salient features of Spirogyra are as follows: Occurrence of Spirogyra Thallus Structure of…