The mass extinction refers to a catastrophic event, which wiped out most of the species living on the earth at that time. There have been five... View Article
The main driving force for adaptive radiation is the new adaptive zone or ecological opportunity. Organisms get adapted to the new ecological... View Article
Analogous structures are an example of a convergent trait. Here different structures evolve to perform the same function and hence share... View Article
Divergent evolution refers to the process by which different organisms having common ancestors develop different traits to adapt to varying... View Article
Positive selection refers to an increase in the frequency of the beneficial trait in a population and it leads to adaptive evolution. A trait... View Article
Adaptive traits evolve through natural selection. An adaptive trait is heritable, functional, maximises its reproductive capacity and makes an... View Article
An adaptive heritable trait is a genetic trait, which has evolved through natural selection and plays a functional role. It helps an organism to... View Article
The first mammals were like shrews. Morganucodontids were thought to be one of the first mammals to evolve. They evolved around 250 million years... View Article
Central nervous system or CNS is the main command and control centre of the body. It is responsible for all the information processing. Central... View Article
The most important function of the cell membrane is to maintain cellular integrity and transport of molecules inside and outside the cell. It is... View Article
Ribosomes are present on the surface of rough endoplasmic reticulum. They are involved in the process of translation, i.e. protein synthesis.... View Article
The cell theory was proposed by Schleiden and Schwann. The first part states that all living organisms are composed of one or more cells. The... View Article
Xylem is the main water conducting tissue. Primary xylem is derived from the primary meristem, i.e. procambium. It is of two types, namely... View Article
The circulatory system of mammals is closed type. The blood from the heart passes through a closed network of blood vessels to different parts of... View Article
Bacteria are the best known prokaryotes. They are unicellular and lack membrane-bound organelles and nuclei. They are beneficial as well as... View Article
Fungi are separately categorised in a kingdom. They have a cell wall, like plants but are heterotrophic, like animals. The cell wall of fungi is... View Article
It is a type of monochasial cyme, where only one lateral branch arises from the base of the terminal flower. Here the secondary bud develops on... View Article
Lysosomes are polymorphic as they are present in more than one form inside the cell. Lysosomes are derived from vesicles released from the Golgi... View Article
Each living cell is enclosed by a cell membrane. The cell membrane mainly consists of lipids and proteins. Lipid molecules form the bilayer with... View Article
The nervous system is composed of specialised cells called neurons. It is responsible for receiving and responding to various stimuli. The main... View Article
