Vertebrate Phylogeny and Key Features of Chordates

What are the three main groups of Chordates?

Urochordates, Cephalocordates, and Vertebrates.

What are Agnathans and provide examples?

Agnathans are jawless vertebrates, including lampreys and hagfish.

What are the two main groups of Gnathostomes?

Chondrichthyes (sharks, rays, chimaeras) and Osteichthyes (bony fish).

What are the two subclasses of Osteichthyes?

Actinopterygii (ray-finned fishes) and Sarcopterygii (lobe-finned fishes).

What distinguishes Actinopterygii from Sarcopterygii?

Actinopterygii have ray-finned structures, while Sarcopterygii have fleshy, lobed fins.

What are the characteristics of Palaeonisciformes?

Living members include paddlefish, sturgeon, and bichirs; they have ganoid scales.

What are the characteristics of Neopterygii?

They have smaller scales for increased flexibility and include species like bass, perch, and trout.

What is the function of the swim bladder in fish?

It helps with buoyancy control.

What are the two types of swim bladders?

Physoclistous (derived, more prone to barotrauma) and Physotomous (primitive, allows gulping air).

What adaptations do lungfish have?

Lobed fins, a prominent notochord, paired lungs, and alternating fin movement.

What is Tiktaalik roseae and why is it significant?

A transitional fossil showing features between fish and tetrapods, such as robust pectoral fins.

What are the main characteristics of Lissamphibia?

Includes salamanders, frogs, toads, and caecilians; they often have paired lungs and lack scales.

What distinguishes Anurans from Urodela?

Anurans (frogs and toads) have no tail in adults, while Urodela (salamanders) retain a long tail.

What are the two main lines of Amniotes?

Sauropsida (birds and reptiles) and Synapsida (mammals).

What are the four primary skull types in amniotes?

Based on temporal fenestra and arches: Synapsid (mammals) and Diapsid (birds and reptiles), with turtles being Anapsid.

What are the key characteristics of mammals?

Hair, mammary glands, non-nucleated red blood cells, and a single jawbone (dentary).

What are the three groups of mammals?

Monotremes (egg-laying), Metatherians (marsupials), and Eutherians (placental mammals).

What are some examples of mammal diversity?

Cetaceans (whales), Sirenia (manatees), Chiroptera (bats), and Primates.

What is the significance of surface area in biological functions?

Surface area affects heat loss, fluid absorption, respiration, and metabolism.

What are the three primary germ layers in organogenesis?

Ectoderm, Endoderm, and Mesoderm.

What are the four tissue types found in adults?

Epithelial, connective, muscle, and nervous tissue.

What is the role of the ectoderm in development?

It forms the epidermis and nervous tissue.

What is the role of the endoderm in development?

It forms the digestive and respiratory linings, including organs like the liver and pancreas.

What is the role of the mesoderm in development?

It forms skeletal muscles, circulatory components, kidneys, and connective tissue.