Animal Diversity and Biology Review

This set of vocabulary flashcards covers the anatomical features, developmental patterns, and physiological characteristics of major animal phyla including Arthropoda, Echinodermata, Chordata, and others.

Tagmatization

The evolutionary process in arthropods where segments become fused or functionally united into specialized body regions, such as the head, thorax, and abdomen.

Ecdysis

The process of molting or shedding a rigid external cuticle or exoskeleton to allow for growth, which is energetically expensive and leaves the animal vulnerable.

Water Vascular System

A unique network of hydraulic canals in echinoderms that branches into tube feet and is used for locomotion, feeding, and gas exchange.

Madreporite

The opening of the water vascular system in echinoderms through which water enters the hydraulic canal network.

Deuterostomia

A clade of animals, including echinoderms and chordates, characterized by radial and indeterminate cleavage and the development of the anus from the blastopore.

Notochord

A flexible rod found in all chordates that provides skeletal support and a base against which muscles can work.

Dorsal, Hollow Nerve Cord

A chordate characteristic that develops into the central nervous system, consisting of the brain and spinal cord.

Pharyngeal Slits

Structures in chordates used for suspension feeding in invertebrates, gas exchange in aquatic vertebrates, and developing into parts of the ear and neck in tetrapods.

Cyclostomes

A group of jawless vertebrates that includes hagfishes and lampreys.

Chondrichthyans

A group of fish, such as sharks and rays, characterized by a skeleton composed primarily of cartilage.

Osteichthyans

A group of fish possessing an ossified (bony) skeleton.

Oviparous

A mode of reproduction where eggs hatch outside the mother's body.

Ovoviviparous

A mode of reproduction where eggs hatch within the uterus and the young are nourished by the egg yolk.

Viviparous

A mode of reproduction where the young are nourished by a placenta or uterine fluid before birth.

Tiktaalik

A transitional fossil, often called a "fishapod," that possessed a neck, ribs, and wrist bones, representing a link between fish and tetrapods.

Amniotic Egg

An evolutionary adaptation in amniotes (reptiles and mammals) that functions as a "private pond," allowing embryo development to occur on land.

Monotremes

A group of mammals that lay eggs and lack nipples, secreting milk directly onto their belly fur.

Marsupials

Mammals whose young are born very early and complete their development while nursing in a maternal pouch called a marsupium.

Eutherians

Placental mammals characterized by complex placentas and longer pregnancies where the young are more developed at birth.

Endothermy

A thermoregulation strategy where body heat is generated internally by metabolism, requiring high energy and food intake.

Ectothermy

A thermoregulation strategy where heat is gained from external environmental sources, resulting in lower food requirements.

Open Circulatory System

A system found in arthropods and most molluscs where the circulatory fluid (hemolymph) is also the interstitial fluid and bathes organs directly in sinuses.

Closed Circulatory System

A system found in annelids, cephalopods, and vertebrates where blood is confined to vessels and is distinct from the interstitial fluid.

Hox Genes

A unique family of regulatory genes containing homeoboxes that control the expression of other genes influencing animal morphology and embryo development.

Diploblastic

Animals that possess only two germ layers: the ectoderm and the endoderm.

Triploblastic

Bilateral animals that possess three germ layers: the ectoderm, endoderm, and mesoderm.

Coelomate

An animal possessing a true coelom, which is a body cavity completely lined by tissue derived from the mesoderm.

Hemocoel

A body cavity formed between the mesoderm and endoderm (previously referred to as pseudocoelomate).

Protostome Development

A developmental mode characterized by spiral and determinate cleavage and a blastopore that becomes the mouth.

Deuterostome Development

A developmental mode characterized by radial and indeterminate cleavage and a blastopore that typically becomes the anus.

Choanocytes

Flagellated collar cells in sponges that create water currents and trap food particles through phagocytosis.

Amoebocytes

Totipotent cells in sponges that transport nutrients, produce skeletal fibers called spicules, and can transform into other cell types.

Cnidocytes

Specialized stinging cells in cnidarians that contain stinging capsules called nematocysts used for defense and capturing prey.

Parthenogenesis

A form of asexual reproduction, common in rotifers, where females produce more females from unfertilized eggs.

Lophophore

A crown of ciliated tentacles used for suspension feeding, found in phyla like Ectoprocta and Brachiopoda.

Radula

A specialized scraping organ used for feeding found in many molluscs, such as snails and chitons.