Question

4.1 are turtles dioecious? how do you know?
4.2 how is the turtles reproductive system modified for increasing the survival of the eggs on land?
4.3 how does the turtles urinary system help it survive in dry environments?
exercise 21 - 2 snakes and lizards (order squamata)
materials needed
mounted snake skeleton
preserved snake
dissecting tools
dissecting pan
latex gloves
approximately 3,550 species of lizards and 3,680 species of snakes constitute the order squamata, the largest and most diverse order of reptiles. both groups have been highly successful and have worldwide distribution, with the exception of the arctic and antarctic regions. lizards probably are the most familiar of the reptiles and certainly the most typical in their body plan. in comparison, snakes have a “strangeness” that has made them an often - feared and misunderstood group of creatures. further evidence of their mystique lies in the fact that in many cultures for thousands of years, snakes have been revered as magical creatures with special medicinal and sometimes spiritual powers, and often are important religious symbols. in reality, snakes are a simple and fascinating assemblage of creatures that exemplify the extent to which selective pressures can drive evolution. the serpentine body plan has been extensively shaped by natural selection, becoming extremely elongated with organ reduction and rearrangement and the ability to swallow and digest incredibly large prey. to say that snakes are simply lizards without legs is to grossly underestimate their true uniqueness.
external anatomy
procedure
1 obtain a preserved snake specimen.
2 examine it carefully, using figure 21.12 to assist you in identifying the external features of the head.
some may see the lack of legs in snakes as a handicap, but the fact that snakes have lost their legs over the course of evolution actually has improved their ability to move. some snakes, such as racers and coachwhips, can easily outpace humans over difficult terrain. eyelids in snakes are also absent; instead, a transparent scale called the spectacle protects each eye. external ear openings are absent as well, and though they are unable to hear higher - frequency sounds, most snakes respond to low - frequency ground vibrations.

Explanation:

4.1 Turtles are dioecious as they have separate male and female individuals. This can be known from their distinct reproductive organs and mating - behavior where male and female turtles come together for reproduction.
4.2 The turtle's reproductive system has several modifications for egg - survival on land. Female turtles have a cloaca that allows for the deposition of eggs. They also dig nests in the ground to protect the eggs from predators and environmental extremes. The eggs have a tough, leathery shell that helps prevent desiccation.
4.3 The turtle's urinary system helps it survive in dry environments. Turtles can concentrate their urine, reducing water loss. They also have specialized kidneys that can reabsorb water efficiently, allowing them to conserve water in arid conditions.

Answer:

4.1 Turtles are dioecious. This is known from their distinct male and female reproductive organs and mating behavior.
4.2 Female turtles have a cloaca for egg - deposition, dig nests for protection, and eggs have a tough shell to prevent desiccation.
4.3 Turtles can concentrate urine and have efficient water - reabsorbing kidneys to conserve water.