Bio1331 Animals - Evolution - Jawed Fishes (Lecture Eight)

Mammals have a double-circuit circulatory system.

The lateral line in aquatic gnathostomes contains sense organs that are used to detect movement and vibrations in the surrounding water. This sensory system helps the organism to navigate its environment, detect prey or predators, and maintain balance and coordination. By detecting changes in water pressure and flow, the lateral line allows the organism to respond to its surroundings and survive in its aquatic habitat.

Chondrichthyans are a clade of gnathostomes that contains sharks, rays, and chimaeras. This means that within the group of gnathostomes, which are jawed vertebrates, chondrichthyans specifically include sharks, rays, and chimaeras.

Ray-Finned Fishes have gills contained in a single chamber with one flap, known as the operculum. The operculum is a bony flap that covers and protects the gills, allowing the fish to breathe efficiently. It opens and closes to facilitate the exchange of oxygen and carbon dioxide. This adaptation is essential for the survival of ray-finned fishes in aquatic environments, as it enables them to extract oxygen from the water and release waste gases.

Fish have a single-circuit circulatory system. This means that blood flows through their heart and gills in a single loop. The blood is pumped from the heart to the gills, where it picks up oxygen and releases carbon dioxide. It then flows to the rest of the body, delivering oxygen and nutrients, before returning to the heart. This single-circuit system is less efficient than the double-circuit system found in mammals and birds, but it is sufficient for the needs of fish.

In Chondrichthyans, the skeleton is composed primarily of cartilage. Cartilage is a flexible and durable connective tissue that provides structure and support to the body. It is lighter and more flexible than bone, which is advantageous for Chondrichthyans, as it allows for greater maneuverability in the water. Additionally, cartilage is less prone to damage and injury compared to bone, making it well-suited for the unique lifestyle and habitat of Chondrichthyans, which includes swimming and hunting in the ocean.

Osteichthyes, which are bony fish, have a buoyancy mechanism called a swim bladder. This air sac helps them control their buoyancy and maintain their position in the water column. By adjusting the amount of gas in the swim bladder, fish can either become more buoyant and rise in the water or become less buoyant and sink. This allows them to conserve energy and easily maneuver in their aquatic environment.

Gnathostomes refers to a group of animals that are vertebrates and have jaws. This term is used to classify various species including fish, reptiles, birds, and mammals, as they all possess jaws. Jaws are an important evolutionary adaptation that allows these animals to efficiently capture and consume their prey. Therefore, the correct answer is Gnathostomes.

The correct answer is Dipnoi. The term "Dipnoi" is the scientific name for lungfishes. It is the plural form of the word "dipnoan" which refers to any member of the lungfish family. Therefore, all the options provided in the question are correct as they represent the scientific name for lungfishes.

Dipnoi, also known as Lungfishes, go into aestivation, a state of dormancy or torpor during the summer. Aestivation is a survival strategy used by some animals to cope with extreme heat or drought conditions. During aestivation, lungfishes reduce their metabolic rate and become inactive, conserving energy and water until more favorable conditions return. This allows them to withstand the harsh environmental conditions and ensure their survival during the summer months.

The given correct answer is true.

Gnathostomes have jaws that are thought to have evolved from 2 pairs of skeletal supports of the pharyngeal slits. Pharyngeal slits are found in the pharynx of chordates and are used for filter feeding or respiration. These slits are supported by skeletal structures called pharyngeal arches. Over time, these arches became modified and eventually gave rise to the jaws of gnathostomes. This evolutionary adaptation allowed for more efficient feeding and expanded the range of food sources available to these organisms.

The scientific name for the Gnathostome clade that includes Ray-Finned Fishes is Osteichthyes. This term refers to a group of bony fishes that have skeletons composed of bone rather than cartilage. Osteichthyes is a well-established taxonomic classification for this group of fish, and it distinguishes them from other groups such as Chondrichthyes (cartilaginous fishes) and Agnatha (jawless fishes).