Question

Which of these does not correctly match the skull morphology with the correct taxon? Tuatara: contains upper and lower temporal arches Lizards: lost lower arch and has flexible articulations Snakes: lost lower and upper arch with pairs of flexible joints Amphisbaenids: contains no arches, but has a loose kinetic skull

Answer 1

1. Answer:- Snakes: lost lower and upper arch with pairs of flexible joints.

Explanation:- The snake skull is a remarkable structure. Snake skulls are highly kinetic, with a lot more moving parts than our skulls. Human skulls have just one movable part: the temporomandibular joint, which opens and closes your mouth. Snake skulls have many joints and moving parts; they can move the left and right sides of their jaws independently, as well as the outer (maxilla) and inner (palatine+pterygoid) parts of their upper jaws. Many bones that are tightly knit together in the skulls of most animals are loosely connected by stretchy ligaments in snakes, allowing them to stretch their jaws over huge prey.

2. Answer:- Selection acts on organism as a whole

Ambush predators or sit-and-wait predators are carnivorous animals that capture or trap prey by stealth or by strategy (typically not conscious), rather than by speed or by strength. Ambush predators sit and wait for prey, often from a concealed position, and then launch a rapid surprise attack.

The ambush may be set by hiding in a burrow, by camouflage, by aggressive mimicry, or by the use of a trap. The predator then uses a combination of senses to assess the prey and to time the strike. Nocturnal ambush predators such as cats and snakes have vertical slit pupils, helping them to judge the distance to prey in dim light. Different ambush predators use a variety of means to capture their prey, from the long sticky tongues of chameleons to the expanding mouths of frogfishes.

3. Answer:- a) shunt allows for oxygen from left to right lung

All ectothermic reptiles have the ability to shunt blood. In chelonians (turtles and tortoises) and lepidosaurs (tuatara, lizards and snakes) the cardiac ventricle is partially divided by two septa, forming three chambers within the heart. The lack of complete septation enables intracardiac shunting. Because these animals have a great deal of neurological control over patterns of blood flow, it is plausible that shunting has conferred selective advantages, although the benefits of shunting remain poorly understood. The mechanism of shunting depends on the resistance in the pulmonary artery and the left and right aortas, and depends on the state of the heart at the after ejection. A left-to-right intracardiac shunt occurs when oxygen-rich blood, which has entered the left atrium and moved into the cavum arteriosum in the left side of the ventricle, is pumped into the pulmonary artery, to be recirculated to the lung. This shunt may function to provide the heart with oxygen