Tag: vertebrates

When dissociated cells from different tissues are mixed, they exhibit selective affinity and re-aggregate based on their tissue type rather than their species origin. This is a classic demonstration of cell-cell recognition and adhesion.

• The heart pumps only impure blood in sharks. Sharks have a two-chambered heart which is an S-shaped tube. It has an atrium and ventricle. The blood is pumped by the heart through the afferent branchial arteries to capillaries in the gills, where the blood is oxygenated). 
• The blood then flows through efferent branchial arteries, through the tissues of the body, and back to the heart in veins. Sharks have low blood pressures; the walls of the pericardium are rigid, creating suction within the pericardium to maintain the flow of blood. To circulate blood throughout their bodies, many sharks must swim continuously. 
• The blood flow is similar to humans because blood is pumped by the heart to the rest of the body by arteries and returned to the heart by veins. 
• A difference is that humans have 4-chambered hearts while sharks only have two chambers.

Viviparous sharks give birth to live young. The number of pups in a litter ranges from 2-20 or more. For example, the Bull sharks, Whitetip reef shark, Lemon shark, Blue shark, Mako, Porbeagle, Salmon shark, the Silvertip shark, and Hammerheads.

Herdmania is an ascidian urochordate.

Statement A is correct, but the question asks for the incorrect statement. Statement B is incorrect because while most vertebrates have a heart, the number of chambers varies significantly (e.g., fish have two, amphibians three, birds/mammals four), and the term single heart is misleading in the context of evolutionary complexity.

Fishes are ectothermic, commonly referred to as cold-blooded animals, meaning their internal body temperature varies with the ambient environment. They cannot regulate their body temperature internally like birds and mammals.

The axis vertebra, which is the second cervical vertebra, is uniquely identified by the presence of the odontoid process, also known as the dens. This bony projection acts as a pivot around which the atlas vertebra and skull rotate.

Arctic terns, salmon, and Siberian cranes are well-known for their long-distance annual migrations. Salamanders generally do not perform long-distance annual migrations.

In anurans (frogs and toads), the caudal vertebrae are fused into a single rod-like bone called the urostyle.

Because they are supposed to be associated with the function of excretion just like liver.