Biol 121a Final Exam Chapter 14-15

Same as Pentaradial symmetry - Body can be arranged into 5 equal parts around a central axis

Pentaradial symmetry, or five-part symmetry, is found in echinoderms like sea stars and sea urchins. Their bodies are arranged in five equal parts around a central axis, allowing them to interact with their environment from all directions.

Ossicles are small, calcareous elements in the endoskeleton of echinoderms, like sea stars and sea urchins. They provide structural support and protection, allowing for movement and flexibility.

An endoskeleton is an internal support structure found in many animals, including vertebrates like humans and echinoderms like sea stars. It provides structural support, protection for internal organs, and a framework for muscle attachment, enabling movement and flexibility.

Mutable collagen is a type of connective tissue in echinoderms, like sea stars, that can quickly change its stiffness or flexibility in response to nervous control. This allows them to adapt their body structure for various functions, such as defense and movement.

In echinoderms, the term "oral" refers to the side of the body where the mouth is located. This is typically the underside of the animal, such as in sea stars and sea urchins. The opposite side, where the anus is located, is called the "aboral" side.

In echinoderms, the term "aboral" refers to the side of the body opposite the mouth. This is typically the upper side of the animal, such as in sea stars and sea urchins. The aboral side often contains the anus and other structures like the madreporite, which is involved in the water vascular system.

The water vascular system in echinoderms, like sea stars and sea urchins, is a network of fluid-filled canals and tube feet used for movement, feeding, and respiration.

The madreporite is a porous structure in echinoderms, like sea stars, that allows seawater into the water vascular system.

The stone canal is a tube in the water vascular system of echinoderms, like sea stars. It connects the madreporite to the ring canal, helping to transport seawater into the system.

The ring canal is a circular tube in the water vascular system of echinoderms, like sea stars. It connects the stone canal to the radial canals, distributing water to the tube feet for movement and other functions.

The radial canal is part of the water vascular system in echinoderms, like sea stars. It extends from the ring canal along each arm, distributing water to the tube feet for movement and other functions.

Ampullae are small, bulb-like structures in the water vascular system of echinoderms, like sea stars. They help control the movement of the tube feet by regulating water pressure.

Tube feet, or podia, are small, flexible, and hollow appendages found in echinoderms, like sea stars and sea urchins. They are part of the water vascular system and are used for movement, feeding, and respiration. Tube feet can extend and contract by regulating water pressure, allowing the animal to grip surfaces and manipulate objects.

Oral tentacles are flexible, sensory appendages found around the mouth of some echinoderms, like sea cucumbers. They help in feeding by capturing food particles and bringing them to the mouth.

Pedicellaria are small, pincer-like structures found on the surface of echinoderms, such as sea stars and sea urchins. They help keep the surface of the animal clean by removing debris and small organisms, and can also assist in capturing prey and providing defense against predators.

Aristotle's lantern is a complex, jaw-like structure found in sea urchins. It consists of five calcareous plates, or teeth, that are used for feeding. This structure allows sea urchins to scrape algae and other food from surfaces.

The cardiac stomach is a part of the digestive system in echinoderms, like sea stars. It can be everted, or turned inside out, through the mouth to engulf and digest food externally before pulling it back in for further digestion.

The pyloric stomach in echinoderms, like sea stars, is responsible for further digestion and nutrient absorption. It connects to the pyloric caeca, which are digestive glands that secrete enzymes to aid in the digestive process.

Asteroidea is the class of echinoderms that includes sea stars (starfish). These marine animals are known for their star-shaped bodies, typically with five arms, although some species can have more. They exhibit pentaradial symmetry and have a water vascular system that aids in movement and feeding. Sea stars are also known for their ability to regenerate lost arms.

Echinoidea is the class of echinoderms that includes sea urchins and sand dollars. These marine animals have a globular or flattened shape and are covered with spines. They possess a hard, calcareous endoskeleton called a test, which is made up of fused ossicles. Echinoids use their spines and tube feet for movement, and many species have a specialized feeding structure called Aristotle's lantern for grazing on algae and other food sources.

Holothuroidea, or sea cucumbers, are a class of echinoderms. They have elongated, soft bodies and are found on the sea floor worldwide. Sea cucumbers play a crucial role in marine ecosystems by recycling nutrients and breaking down organic matter. They have a unique defense mechanism where some species can expel their internal organs to distract predators.

Crinoidea, or sea lilies and feather stars, are a class of echinoderms. They have long, feathery arms that they use for filter feeding, capturing plankton and other small particles from the water. Crinoids can be found in both shallow and deep-sea environments, and some species are capable of swimming by undulating their arms.

Ophiuroidea, or brittle stars, are a class of echinoderms. They have long, slender arms that are distinct from their central disc. Brittle stars use their flexible arms for movement, often in a snake-like fashion, and can regenerate lost limbs. They are found in various marine environments and are known for their ability to quickly escape predators.

Informal group of chordates that includes Urochordata and Cephalochordate they possess all of the 5 chordate traits at some point during their life cycle

Craniata, also known as Craniota, is a clade of chordate animals that possess a skull made of hard bone or cartilage. This group includes all vertebrates, such as fish, amphibians, reptiles, birds, and mammals, as well as some jawless fish like hagfish and lampreys. Craniates are characterized by having a well-defined head with a brain encased in a cranium, a dorsal nerve cord, and other complex structures.

Homologous structures are anatomical features in different species that share a common ancestry. These structures may have different functions in each species but have similar underlying anatomy. For example, the forelimbs of humans, bats, and whales are homologous structures. They have different functions—grasping, flying, and swimming—but share a similar bone structure, indicating a common evolutionary origin.

A flexible, rod-like structure that provides support and is present during some stage of development in all chordates.

A tube-like structure located dorsally (along the back) that develops into the central nervous system, including the brain and spinal cord.

Openings in the pharynx (throat area) that are used for filter-feeding in some chordates and develop into gills or other structures in others.

An extension of the body past the anus, which provides propulsion in aquatic species and may be reduced or absent in others.

A groove in the pharynx that produces mucus to trap food particles in filter-feeding species; in vertebrates, it develops into the thyroid gland, which regulates metabolism.

The pharynx is a muscular tube that connects the mouth and nasal passages to the esophagus and larynx, playing a key role in swallowing and breathing.

Neural crest cells are embryonic cells that migrate and differentiate into various cell types, including pigment cells, cartilage, and neurons.

Ectodermal placodes are thickened regions of the ectoderm that develop into sensory organs and structures in vertebrates.

Conodonts are an extinct group of jawless vertebrates known for their tooth-like microfossils, called conodont elements. These elements were part of the feeding apparatus in the mouth of the conodont animal, which had an eel-like body with large eyes. Conodonts lived from the Cambrian period (over 500 million years ago) to the beginning of the Jurassic period (around 200 million years ago).

Pikaia is an extinct, primitive chordate known from the Middle Cambrian Burgess Shale of British Columbia. It lived around 505 million years ago and is considered one of the earliest known chordates. Pikaia had an elongated, eel-like body with a notochord and myomeres (segmented muscle blocks)

Myllokunmingia is an extinct genus of early chordates from the Lower Cambrian period, around 518 million years ago. These ancient creatures are among the earliest known vertebrates, although this classification is not conclusively proven. Myllokunmingia had an elongated body, with a distinct head and trunk, and it likely had a notochord, a pharynx, and segmented muscles (myomeres). Fossils of Myllokunmingia have been found in the Maotianshan shales of China.

Extinct group of armored, jawless fish that lived during the Paleozoic Era, particularly from the Cambrian to the Devonian periods. These early vertebrates had bony plates covering their bodies, providing protection against predators. Ostracoderms lacked jaws and paired fins, and they used their muscular pharynx to create suction for feeding. They are significant in the study of vertebrate evolution as they represent some of the earliest known vertebrates.

Placoderms are an extinct class of armored prehistoric fish that lived during the Devonian period, around 419 to 359 million years ago. They are among the earliest jawed vertebrates and are characterized by their bony armor plates covering the head and thorax

Acanthodians, or spiny sharks, are an extinct group of jawed fish from the Silurian to Early Permian periods, characterized by their spiny fins and features of both bony and cartilaginous fish.