Unit 4: Annelida, Arthropoda, and Deuterostomes Overview

These flashcards cover key vocabulary and concepts related to the biology of annelids, arthropods, and deuterostomes, aiding in the understanding of their traits, classification, and evolutionary significance.

Phylum Annelida

A phylum of segmented worms.

Vermiform

Worm-shaped form.

Metamerism

Segmentation, the division of an organism into repetitive segments.

Homonomous

Segments that are similar in structure and function.

Setae

Hair-like structures in annelids used for locomotion.

Parapodia

Fleshy lateral outgrowths in polychaetes used for movement.

Closed circulation

A circulatory system where blood is contained within vessels.

Metanephridia

Excretory organs in annelids that help in osmoregulation.

Coelom

A body cavity surrounded by mesoderm.

Trochophore larva

A larval stage found in some annelids and mollusks.

Class Polychaeta

A class of annelids known as 'Many Setae' with well-developed heads and parapodia.

Class Oligochaeta

A class of annelids known as 'Few Setae' including earthworms.

Clitellum

A thickened band of segments in oligochaetes for reproduction.

Respiration: Diffusion

Gas exchange in oligochaetes through moist skin.

Class Hirudinea

A class of annelids that are blood-sucking parasites, known as leeches.

Phylum Arthropoda

The largest animal phylum, including insects, arachnids, and crustaceans.

Heteronomous Metamerism

Specialized segmentation found in arthropods.

Tagma

Specialized segments in arthropods, including head, thorax, and abdomen.

Exoskeleton

A hard outer structure that provides support and protection in arthropods.

Cuticle

The outer covering of arthropods, part of the exoskeleton.

Musculature: Flexors/Extensors

Muscle types that allow movement in arthropods.

Malpighian tubules

Excretory structures in arthropods that remove waste from the hemolymph.

Open circulation

A circulatory system where blood is not always contained within vessels.

Ecdysis

The process of molting in arthropods.

Ecdysone

Hormone that triggers molting in arthropods.

Subphylum Trilobitomorpha

An extinct group of arthropods with biramous appendages.

Subphylum Chelicerata

Includes mostly terrestrial arthropods like spiders and scorpions.

Class Arachnida

A class of chelicerates including spiders, scorpions, and ticks.

Class Merostomata

Class including horseshoe crabs.

Class Pycnogonida

Class known as sea spiders.

Subphylum Crustacea

Includes crabs, lobsters, and shrimp with biramous appendages.

Class Crustacea

A class including marine and freshwater crustaceans.

Order Copepoda

Planktonic crustaceans, often abundant in aquatic environments.

Order Cirripedia

Includes barnacles, some of which are symbiotic.

Order Isopoda

Includes pill bugs and isopods.

Subphylum Uniramia

Includes insects and myriapods like centipedes and millipedes.

Class Insecta

The largest and most diverse class of animals on Earth.

Metamorphosis

The developmental process insects undergo during their life cycle.

Instars

The multiple stages of development in insects between molts.

Ametabolous

Insects without metamorphosis.

Metabolous

Insects undergoing metamorphosis.

Hemimetabolous

Insects with incomplete metamorphosis.

Holometabolous

Insects with complete metamorphosis.

Class Chilopoda

Class including centipedes.

Class Diplopoda

Class including millipedes.

Phylum Onychophora

Terrestrial worms that resemble both annelids and arthropods.

Phylum Echinodermata

Marine animals with spiny skin and radial symmetry.

Water vascular system

A hydraulic system used by echinoderms for movement and feeding.

Class Crinoidea

Includes sea lilies and feather stars.

Class Asteroidea

Class including sea stars.

Class Ophiuroidea

Includes brittle stars and basket stars.

Class Echinoidea

Includes sea urchins and sand dollars.

Class Holothuroidea

Includes sea cucumbers.

Phylum Chaetognatha

Contains marine, planktonic predators known as arrow worms.

Phylum Hemichordata

Burrowing marine worms with features resembling chordates.

Phylum Chordata

Animals with a notochord, dorsal hollow nerve cord, and pharyngeal slits.

Subphylum Urochordata

Includes tunicates and sea squirts.

Tadpole Larva

The larval stage of urochordates before metamorphosis.

Subphylum Cephalochordata

Includes lancelets, which have a prominent notochord.

Vertebrate Origins

The evolutionary link between urochordates, cephalochordates, and vertebrates.

Agnatha

Jawless fishes like lampreys and hagfish.

Gnathostomes

Jawed vertebrates that evolved from Agnatha.

Class Chondrichthyes

Includes sharks and rays with cartilaginous skeletons.

Class Osteichthyes

Bony fishes including many diverse species.

Subclass Sarcopterygii

Lobe-finned fishes, potentially the ancestors of tetrapods.

Subclass Actinopterygii

Ray-finned fishes with high species diversity.

Ichthyostega

An extinct genus representing an evolutionary link between fish and amphibians.

Class Amphibia

Amphibians, which transition from water to land.

Amplexus

The mating posture of frogs where males and females embrace.

Tetrapods

Four-limbed vertebrates including amphibians, reptiles, and mammals.

Class Reptilia

Reptiles with adaptations for life on land.

Order Crocodilia

Order including crocodiles and alligators.

Order Squamata

Order including snakes and lizards.

Class Aves

Birds, believed to be modified reptiles.

Class Mammalia

Mammals characterized by hair and mammary glands.

Hair

A defining characteristic of mammals, providing insulation.

Homeothermy

The ability to maintain a constant body temperature.

Subclass Prototheria

Monotremes, such as the platypus and echidna.

Subclass Theria

Includes marsupials and placentals.

Primates

A group including lemurs, monkeys, apes, and humans.

Anthropoids

Higher primates, including humans.

Australopithecus afarensis

An early hominin species known as 'Lucy'.

Out of Africa

The hypothesis regarding the migration of early humans from Africa.