EBIO 3850 Spring 2025 Exam 3 Key Concepts Flashcards

Vocabulary flashcards covering key concepts from EBIO 3850 lecture notes, focusing on Deuterostomia, Hemichordata, Echinodermata, Chordata, Phylogenetics, Symbiosis, Invertebrate-inspired Design, and Conservation/Invasive Species.

Deuterostomia

Development characterized by enterocoely (mesoderm buds off from archenteron) for coelom formation, blastopore becomes the anus, and regulative development (cell fate depends on neighbor interactions).

Protostomia

Development characterized by schizocoely (mesoderm splits) for coelom formation, blastopore becomes the mouth, and mosaic development (cell fate predetermined by cytoplasm).

Hemichordata

Sister group to echinoderms, exhibits radial symmetry and has calcified internal plates; acorn worms with trunk, collar, and proboscis.

Echinodermata

Synapomorphic traits include bilaterally symmetrical larvae evolving into pentalateral radial symmetry as adults, endoskeleton, and a water-vascular system; possesses mutable collagenous tissue.

Water-vascular system

Echinoderm feature consisting of madreporite, stone canal, ring canal, radial canal, and rows of tube feet; functions in locomotion, feeding, and respiration.

Class Crinoidea

Sea lilies; attached to substrate, oral surface faces up for filter feeding, lack madreporite and spines.

Class Asteroidea

Sea stars; mostly unselective carnivores with everted stomach, capable of remarkable regeneration.

Class Ophiuroidea

Brittle stars; largest group with slender long arms, madreporite on oral surface, tube feet without suckers aid in feeding, locomotion primarily via arm movement; includes basket stars.

Class Echinoidea

Sea urchins; possess endoskeletal test, lack arms but exhibit radial symmetry, water vascular system, Aristotle's lantern, tube feet extending to aboral side, mostly grazers on algae, spines controlled by muscles and 'catch' collagen, pedicellariae.

Class Holothuroidea

Sea cucumbers; reduced water vascular system, respiratory tree for gas exchange, oral tentacles (modified tube feet), suspension/deposit feeders, employ evisceration and Cuvierian tubules as defense mechanisms.

Chordata

Phylum including Vertebrata, Cephalochordata (lancelets), and Urochordata (tunicates); characterized by synapomorphies such as notochord, dorsal hollow nerve cord, post-anal tail.

Notochord

Stiff cartilage-like rod in chordates that secretes factors for surrounding tissues and provides structural support.

Urochordata

Tunicates/sea squirts; all marine, possess a double encasing, can be colonial/social or solitary, have pelagic larvae with tail and notochord; includes appendicularians and salps.

Cephalochordata

Lancelets; small marine group with cilia in pharynx for water beating, myomeres (muscle segments); share regulative development with vertebrates; retain more ancestral traits than tunicates.

Vertebrata

Chordate subphylum characterized by skull made of bones, vertebral column, relatively well-developed brain, and neural crest cells responsible for diverse cell lineages.

Synapomorphy

A shared derived character or trait that distinguishes a clade from other organisms. It is an evolutionary novelty unique to a particular group.

Homoplasy

A character shared by a set of species but not present in their common ancestor. Can arise from convergent evolution where species independently evolve similar traits due to similar environmental pressures.

Parsimony

A principle used in phylogenetic analysis that favors the simplest explanation. In tree building, it typically selects the tree that requires the fewest evolutionary changes.

Mutualism

A type of symbiosis where both species involved benefit from the interaction.

Commensalism

A type of symbiosis where one species benefits and the other is neither harmed nor helped.

Parasitism

A type of symbiosis where one species (the parasite) benefits at the expense of the other (the host).

Invasive Species

Organisms introduced to non-native environments that cause ecological or economic harm. The definition is not rigid and can be interpreted differently.