Animal Diversity, Form, and Function

Review vocabulary flashcards covering animal diversity, phylogeny, anatomy, and physiological principles.

Multicellularity

A defining characteristic common to all known animals.

Bilateral symmetry

A body symmetry typically exhibited by organisms that possess a head with sensory structures.

Animal body plans

Morphological designs present today that have been evolutionarily advantageous compared to others in the past.

Nematode classification

Distinguished from annelids by the shedding of an external skeleton to grow.

Porifera

Sponges that are phylogenetically more closely related to Ctenophora than to Acoela.

Choanoflagellates

Flagellated protists similar to the ancestral organisms from which animals are thought to have evolved.

Bilateria

The major clade to which the majority of animal species belong.

Nematocysts

Stinging structures found on the tentacles of sea anemones that can adhere to surfaces upon contact.

Radula

A specialized feeding organ used by sea slugs to feed on prey.

Lophotrochozoa

A clade whose evolutionary placement was revised following the integration of molecular data alongside morphological data.

Ecdysis (Nematodes and Arthropods)

A shared characteristic between nematodes and arthropods where growth occurs in conjunction with the shedding of an exoskeleton.

Nematoda

The animal phylum that includes heartworms, characterized by a hemocoel, an alimentary canal, and an outer covering that is occasionally shed.

Water vascular system

A specialized fluid-filled system in echinoderms that functions in both locomotion and feeding.

Echinodermata

An animal phylum characterized by bilateral symmetry in the larval stage and a water vascular system.

Post-anal tail

A morphological feature present in all chordates at some stage during their life cycle.

Lancelets

Extant chordates that most closely resemble the earliest chordates in physical appearance.

Oviparous reproduction

A mammalian reproductive strategy in which the mother lays eggs that develop and hatch outside of her body.

Lateral line

A sensory structure sensitive to vibrations that is shared by both sharks and ray-finned fishes.

Amniotic egg

An evolutionary adaptation whose most significant result was that tetrapods were no longer tied to water for reproduction.

Endothermy

A physiological characteristic that evolved independently in both mammals and birds.

Depth perception

A primate evolutionary adaptation made possible by the anatomical placement of the eyes at the front of the head.

Marsupials

Mammals whose extant native geographic distribution is limited to Australia and the Americas.

Bipedal posture

The primary structural and postural trait that distinguishes hominins from all other anthropoids.

Convergent evolution (swimming adaptations)

The evolutionary process that produced similar streamlined body forms in penguins, seals, and tuna to reduce drag while swimming.

Epithelial tissue

The primary animal tissue type that lines most exchange surfaces of multicellular animals.

Connective tissue

A primary tissue type characterized by having relatively few cells dispersed within a large amount of extracellular matrix.

Muscle tissue

Tissue whose various types universally function through interactions between actin and myosin filaments.

Homeostasis

The body's automatic tendency to maintain a constant and optimal internal environment.

Ectotherm

An animal that invests little energy in temperature regulation, allowing it to survive longer periods of food deprivation in cool environments compared to an endotherm.

Mouse (mass-specific metabolic rate)

An example of a small mammal that exhibits a very high total annual energy expenditure per unit mass.