Animal Kingdom: General Zoology and Comparative Physiology

Comprehensive vocabulary flashcards covering general animal characteristics, phyla, embryonic development, tissue layers, coelom types, symmetry, and comparative physiology systems (digestive, circulatory, respiratory, and excretory).

Zoology

The branch of science dedicated to the study of animals.

Eukaryotes

Organisms characterized by having cells with an organized cell nucleus.

Multicellular

Organisms that are composed of more than one cell.

Heterotrophs

Organisms that cannot synthesize their own food and must consume organic material from other sources.

Arthropoda

The animal phylum containing the largest number of described species (~1 million), including insects, arachnids, and crustaceans.

Mollusca

The animal phylum with the second largest number of described species (~150 thousand), including slugs, snails, and octopuses.

Diploblastic (Diblásticos)

Animals possessing only two embryonic germ layers: ectoderm and endoderm. Found exclusively in Cnidarians.

Triploblastic (Triblásticos)

Animals possessing three embryonic germ layers: ectoderm, mesoderm, and endoderm. Includes flatworms (Platyhelminthes) and all higher animal groups.

Ectoderm

The outermost germ layer in triploblastic animals that gives rise to the epidermis and associated structures such as hair and glands.

Mesoderm

The middle germ layer in triploblastic animals that gives rise to the dermis, muscles, and the circulatory, skeletal, excretory, and reproductive systems.

Endoderm

The innermost germ layer in triploblastic animals that gives rise to the epithelium and glands of the digestive tract, as well as respiratory and lining epithelium.

Acoelomate (Acelomado)

An animal lacking a body cavity other than the digestive tract, such as flatworms (Platyhelminthes).

Pseudocoelomate (Pseudocelomado)

An animal with a body cavity lined only by mesoderm and endoderm, such as roundworms (Nematoda).

Coelomate (Celomado)

An animal possessing a true body cavity completely lined by mesoderm tissue, characteristic of the majority of animal phyla.

Radial Symmetry

A body organization where multiple longitudinal planes of symmetry divide the body into identical halves, as seen in jellyfish.

Bilateral Symmetry

A body organization where only a single plane of cut divides the body into two symmetrical halves, found in most animals.

Incomplete Digestive System

A digestive system with a single opening that serves as both mouth and anus, found in jellyfish, planarians, and tapeworms.

Complete Digestive System

A digestive system with separate mouth and anus openings, found in mollusks, arthropods, humans, and other higher animals.

Glycogen

The storage carbohydrate reserve molecule utilized by animals.

Protostomes (Protostômios)

Animals in which the blastopore (gastrula opening) develops into the mouth, comprising phyla from Cnidaria through Arthropoda.

Deuterostomes (Deuterostômios)

Animals in which the blastopore develops into the anus while the mouth forms as a second opening, comprising Echinoderms and Chordates.

Ectotherms

Animals that rely on external energy sources (such as sunlight) to regulate body temperature without internal thermoregulation, including invertebrates, fish, amphibians, and reptiles.

Endotherms

Animals that generate and rely on internal metabolic heat to maintain a constant body temperature, including birds and mammals.

Amniotic Egg

An egg adaptation found in reptiles that protects the developing embryo from dehydration and environmental temperature variations.

Open Circulatory System

A circulatory system where hemolymph exits vessels to directly bathe internal tissues in spaces or lacunae, present in arthropods and most mollusks.

Closed Circulatory System

A circulatory system where blood remains entirely within vessels, exchanging materials by diffusion, present in annelids, chordates, and cephalopod mollusks.

Arteries

Thick-walled, elastic blood vessels that lead blood away from the heart under high pressure, branching into arterioles.

Veins

Blood vessels with a thinner middle layer and internal valves to prevent backflow, responsible for carrying blood back toward the heart.

Capillaries

Microscopic blood vessels consisting of a single layer of cells where actual exchange of gases and substances occurs.

Cutaneous Respiration

Respiration performed across a thin, moist, and highly vascularized skin layer, utilized by annelids and most adult amphibians.

Tracheal Respiration

A respiration system in insects where a network of tracheae opens through spiracles to transport air directly to tissue cells independently of the circulatory system.

Air Sacs

Structures connected to bird lungs that allow continuous, highly efficient unidirectional airflow.

Ammonia

A highly toxic nitrogenous waste requiring large amounts of water for excretion, excreted primarily by fish and aquatic animals.

Urea

A moderately toxic, liver-synthesized nitrogenous waste requiring moderate water expenditure, excreted by cartilaginous fish, adult amphibians, and mammals.

Uric Acid

An insoluble, low-toxicity nitrogenous waste that enables high water conservation, excreted by birds and reptiles.

Protonephridia

Excretory tubules equipped with flame cells that empty waste through excretory pores, found in Platyhelminthes.

Metanephridia

Excretory structures consisting of an internal funnel (nephrostome) and an external exit pore (nephridiopore), found in annelids and mollusks.

Malpighian Tubules

Excretory organs in insects and myriapods that discharge uric acid directly into the digestive system to be eliminated with feces.

Antennal Glands (Green Glands)

Excretory organs located near the base of the antennae in crustaceans that excrete ammonia.

Metanephros

The advanced vertebrate kidney located in the abdominal region that directly filters blood, present in reptiles, birds, and mammals.