BIO 121a Final Chapter 16-18

The lateral line system is a sensory system found in fish and some amphibians. It consists of a series of mechanoreceptors called neuromasts, which are located in canals along the sides of the body. This system allows the animal to detect water movements and vibrations, helping them navigate, avoid predators, and locate prey.

The ampullae of Lorenzini are specialized sensory organs found in cartilaginous fish, such as sharks and rays. These electroreceptors detect electric fields generated by other organisms, helping the fish locate prey, navigate, and sense their environment. The ampullae of Lorenzini are located in small pores on the fish's head and are filled with a conductive gel that transmits electrical signals to the sensory cells.

Placoid scales are small, tooth-like structures found in cartilaginous fish, such as sharks and rays. These scales are made of dentin and enamel, similar to teeth, and provide protection and reduce friction while swimming. Placoid scales are also known as dermal denticles due to their tooth-like composition and structure.

A clasper is a specialized reproductive organ found in male cartilaginous fish, such as sharks and rays. These structures are used to transfer sperm to the female during mating. Claspers are modified pelvic fins that have evolved to facilitate internal fertilization.

Oviparous animals are those that lay eggs, with embryos developing and hatching outside the mother's body. This reproductive strategy is common in many species of fish, amphibians, reptiles, birds, and some invertebrates. The eggs are often laid in a safe environment where they can develop until they are ready to hatch.

Viviparous animals give birth to live young rather than laying eggs. The embryos develop inside the mother's body, receiving nutrients directly from her. This reproductive strategy is common in mammals and some species of fish, reptiles, and amphibians.

Ovoviviparous animals produce eggs that develop and hatch inside the mother's body, resulting in the birth of live young. The embryos receive nutrients from the egg yolk rather than directly from the mother. This reproductive strategy is seen in some species of fish, reptiles, and invertebrates.

Intrauterine cannibalism is a phenomenon observed in some species of sharks and other animals where embryos consume their siblings within the mother's uterus. This behavior ensures that the strongest and most developed embryos survive, increasing their chances of survival after birth. It's a fascinating yet brutal aspect of reproductive strategy in certain species.

Histotrophy is a form of maternal nutrient provision in which the developing embryos receive nutrients from the mother's tissues, rather than from a yolk sac or placenta. This can occur in some species of fish and amphibians, where the mother secretes nutrient-rich fluids or cells that the embryos absorb for their development.

die after spawning

**1 and done**

An ammocoete is the larval stage of a lamprey, a type of jawless fish. Ammocoetes are filter feeders that live buried in sediment in freshwater environments. They have a long, eel-like body and lack the adult lamprey's distinctive mouthparts. This larval stage can last several years before the ammocoete undergoes metamorphosis into an adult lamprey.

A heterocercal tail is a type of tail fin where the upper lobe is larger than the lower lobe, providing lift and stability while swimming.

Osmoregulation is the process by which organisms maintain the balance of water and salts in their bodies to ensure proper cellular function. This is crucial for maintaining homeostasis, especially in environments with varying salinity levels. Different organisms have evolved various mechanisms to achieve osmoregulation, such as excreting excess salts or conserving water.

An osmoconformer is an organism that maintains its internal environment to be isotonic with its external environment. This means that the osmotic pressure of their body fluids is equal to that of their surroundings. Many marine invertebrates, such as jellyfish and sea anemones, are osmoconformers, allowing them to thrive in various salinity levels without expending much energy on osmoregulation.

An ionoconformer is an organism that maintains the ionic composition of its body fluids to match its environment.

An ionoregulator is an organism that actively regulates the ionic composition of its body fluids, maintaining a stable internal environment regardless of external conditions.

A spiral valve intestine is a corkscrew-shaped structure in some fish (mainly sharks) that increases surface area for nutrient absorption.

The rectal gland, also known as the salt gland, is an organ found in cartilaginous fish like sharks and rays. It helps these animals excrete excess salts from their bodies, maintaining osmotic balance in their marine environment. The gland is located near the rectum and plays a crucial role in osmoregulation.

Regional endothermy is when certain body parts maintain a higher temperature than the environment.

The vascular countercurrent heat exchanger, also known as the rete mirabile, is a network of closely aligned blood vessels that allows for efficient heat exchange. This system helps certain animals, like some fish and birds, maintain a stable body temperature by conserving or dissipating heat as needed. The countercurrent flow of blood in these vessels maximizes heat transfer, enabling these animals to thrive in varying environmental conditions.

The Tanaculum is a specialized clasping organ found in male chimaeras, also known as ghost sharks or ratfish. These organs are located on the forehead and in front of each pelvic fin. They help the male chimaera grasp the female during mating

a skin or bony structure used to cover gills

Endothermic animals are those that can regulate their body temperature internally, maintaining a stable temperature regardless of the external environment. This ability allows them to remain active in a wide range of temperatures. Mammals and birds are prime examples of endothermic animals.

Ectothermic animals rely on external sources of heat to regulate their body temperature. They often bask in the sun or seek shade to maintain an optimal temperature. Reptiles, amphibians, and many fish are examples of ectothermic animals.

Poikilothermic animals have body temperatures that vary with the external environment. They do not maintain a constant internal temperature, unlike endothermic animals. Examples include reptiles, amphibians, and many fish.

Do not use behavior to regulate body temperature

Homeothermic animals maintain a constant internal body temperature regardless of external environmental conditions. This ability allows them to remain active and function efficiently in a wide range of temperatures. Mammals and birds are prime examples of homeothermic animals.

Homeotherms always maintain a constant temperature while endothermic animals can have variable body temperatures

The term pulmo-circulatory refers to the system of blood vessels that forms a closed circuit between the heart and the lungs. This system is responsible for oxygenating blood by transporting it to the lungs, where it picks up oxygen and releases carbon dioxide, and then returning the oxygenated blood to the heart to be pumped throughout the body.

Paedomorphosis is where an organism retains juvenile or larval traits into its adult stage. This can occur through the slowing down or halting of developmental processes. It is commonly seen in some amphibians, such as the axolotl, which retains its gills and aquatic lifestyle throughout its life.

Amplexus is a mating behavior observed in amphibians, particularly frogs and toads. During amplexus, the male grasps the female with his front legs, typically around her waist or behind her forelimbs. This position allows the male to fertilize the eggs as the female lays them in water. It's a crucial part of their reproductive process, ensuring that the eggs are fertilized externally.

Anura is an order of amphibians that includes frogs and toads. These animals are characterized by their lack of tails, long hind legs adapted for jumping, and a wide variety of vocalizations.

Urodela is an order of amphibians that includes salamanders and newts. These animals are characterized by their elongated bodies, tails, and often, their ability to regenerate lost limbs.

Marsupial Frog:

Larvae develop in a pouch on the back.

Surinam Frog:

Eggs are embedded in a brooding pouch on the back.

Poison Dart Frog:

Tadpoles hatch and are carried to water-filled plants.

One tadpole per plant.

The mother lays unfertilized eggs in the plants to feed the tadpoles until they metamorphose into adult frogs.

Darwin's Frog:

Froglets develop in the vocal pouch.

Salamander Reproduction

Life Stages: Aquatic larvae & terrestrial adults (most); some fully aquatic or terrestrial with direct development.

Fertilization: Internal in most species.

Sperm Transfer: Male lays chin on tail, drops spermatophore, moves ahead, female picks it up in vent.

Aquatic Reproduction: Eggs laid in water; larvae have gills & finlike tail, lose gills if metamorphosis occurs.

Terrestrial Reproduction: Eggs laid on land in moist places; parental care; gilled larvae hatch with lungs, lose gills.

In amphibians, positive pressure breathing involves actively pushing air into their lungs. They achieve this by lowering the floor of their mouth to draw air in through their nostrils, then closing their nostrils and raising the floor of their mouth to force the air into their lungs.

Negative pressure breathing is when the diaphragm is used to create a vacuum in the chest cavity to draw air into the lungs

1. Amnion – encloses embryo in fluid2. Allantois –metabolic waste & gas exchange3. Chorion – gas exchange4. Yolk sac – food & nutrition

Morphology:

Body Shape: Snakes have elongated, cylindrical bodies with no limbs. Their bodies are highly flexible, allowing them to move in various ways.

Scales: Their skin is covered in overlapping scales, which provide protection and aid in movement.

Head: The head is often distinct from the body, with a wide range of shapes and sizes depending on the species. They have specialized jaw structures that allow them to swallow prey much larger than their head.

Eyes: Snakes have a variety of eye shapes and sizes, often with vertical slit pupils in nocturnal species and round pupils in diurnal species.

Tongue: They have a forked tongue that they use to sense their environment by picking up chemical cues.

Morphology

Shell: Turtles have a distinctive bony or cartilaginous shell that encases their body. The shell is divided into two parts: the upper carapace and the lower plastron.

Limbs: Their limbs are adapted for their environment. Aquatic turtles have webbed feet or flippers for swimming, while terrestrial turtles have sturdy, elephant-like legs for walking.

Head: Turtles have a beak-like mouth with no teeth. Their heads can retract into their shells for protection.

Eyes: They have well-developed eyes with good vision, adapted to their specific habitat.

Morphology:

Body Shape: Lizards have elongated bodies with four limbs, although some species have reduced or no limbs. Their bodies are covered in scales.

Tail: Many lizards have long tails, which can be used for balance, communication, and in some species, can be shed to escape predators.

Head: Lizards have a distinct head with movable eyelids and external ear openings. Their jaws are typically strong and equipped with teeth.

Skin: Their skin is covered in overlapping scales, which provide protection and reduce water loss.

Morphology:

Body Shape: Crocodilians have elongated bodies with a robust, muscular build. They have a long, powerful tail used for swimming and defense.

Skin: Their skin is covered in tough, scaly armor, providing protection and aiding in thermoregulation.

Head: They have a broad, flattened head with a strong jaw filled with sharp teeth. Their eyes, ears, and nostrils are positioned on top of their head, allowing them to see, hear, and breathe while mostly submerged.

Limbs: They have short, sturdy limbs with webbed feet, aiding in swimming and walking on land.

Behavior:

Movement: Crocodilians are excellent swimmers, using their tails for propulsion. On land, they can move quickly in short bursts.

Feeding: They are carnivorous and use a combination of stealth and power to catch prey. They often ambush animals at the water's edge.

Reproduction: Crocodilians lay eggs in nests made of vegetation or sand. Females often guard the nests and may assist hatchlings to the water.

Social Behavior: They exhibit complex social behaviors, including vocalizations and body postures to communicate with each other

Behavior:

Movement: Lizards are generally agile and can move quickly. They use their limbs for running, climbing, and digging.

Feeding: Most lizards are carnivorous, feeding on insects and small animals, but some are herbivorous or omnivorous.

Reproduction: Lizards exhibit a range of reproductive behaviors, including oviparity (laying eggs) and viviparity (giving birth to live young).

Defense: Lizards have various defense mechanisms, such as camouflage, tail autotomy (shedding their tail).

Behavior:

Movement: Turtles move slowly on land but can be agile swimmers in water. Their movement is influenced by their limb structure.

Feeding: They are generally omnivorous, with diets ranging from plants to small animals. Their feeding habits vary by species and habitat.

Reproduction: Turtles lay eggs on land, even if they are aquatic. Females dig nests in the sand or soil to deposit their eggs.

Behavior:

Movement: Snakes use several methods of locomotion, including lateral undulation, sidewinding, concertina, and rectilinear movement.

Feeding: They are carnivorous and use various hunting strategies, such as ambush or active hunting. Some species use venom to subdue their prey, while others constrict their prey.

Reproduction: Snakes exhibit a range of reproductive behaviors, including oviparity (laying eggs) and viviparity (giving birth to live young).

Defense: They have various defense mechanisms, such as camouflage, hissing, and striking. Some species also have venom for defense and hunting.

Amniotic Egg: Contains membranes that protect and nourish the embryo, allowing reproduction away from water.

Waterproof Skin: Less permeable to water, reducing water loss and enabling survival in dry environments.

Efficient Lungs: More efficient respiratory systems with a greater surface area for gas exchange.

Internal Fertilization: Ensures fertilization occurs within the body, protecting gametes from desiccation.

Advanced Kidneys: Better at conserving water, crucial for living in terrestrial habitats.

Stronger Limbs and Skeleton: Adapted for supporting body weight on land.