Invertebrates

Porifera

Phylum that includes sponges, the least complex animals with no true tissues.

Ctenophora

Phylum that includes comb jellies, characterized by fused rows of cilia called ctenes.

Cnidaria

Phylum that includes jellyfish, sea anemones, and coral; radially symmetrical with stinging cells.

Bilateria

Clade of animals with bilateral body symmetry and three tissue layers.

Choanocytes

Flagellated collar cells that line the spongocoel of sponges and generate water currents.

Spongocoel

The large internal cavity within sponges through which water flows.

Nematocyst

A specialized stinging organelle found in the cnidocytes of cnidarians.

Medusa

The mouth-down swimming, sexual stage of certain cnidarians like jellyfish.

Polyp

The mouth-up sedentary stage of certain cnidarians, such as sea anemones and corals.

Lophotrochozoa

A major clade of bilaterians characterized by a lophophore or trochophore larvae.

Ecdysozoa

A grouping of animals that molt their outer covering, including arthropods and nematodes.

Exoskeleton

A hard, waterproof outer covering found in arthropods that provides support.

Cephalization

The concentration of sensory organs and nervous tissue at the anterior end of bilateral animals.

Annelida

Phylum that includes segmented worms, characterized by a coelom and a segmented body.

Mollusca

Phylum that includes diverse taxa such as clams, snails, and octopuses.

Arthropoda

Phylum characterized by jointed appendages and a segmented body, includes insects and crustaceans.

Deuterostomia

Clade of animals that includes echinoderms and chordates, characterized by 'mouth second' development.

Echinodermata

Phylum that includes starfish and sea urchins, known for their unique water vascular system.

Chordata

Phylum that includes vertebrates and some invertebrates, characterized by a notochord at some stage.

Water vascular system

Unique system in echinoderms used for locomotion and feeding, facilitated by tube feet.

Hermaphroditic

An organism that has reproductive organs of both sexes, like many sponges and flatworms.

Amoebocytes

Cells in sponges that move food around and carry nutrients.

Diploblasts

Animals with two tissue layers: ectoderm and endoderm, characteristic of cnidarians.

Parapodia

Lateral extensions found in some annelids, used for locomotion.

Mantle

The tissue layer in mollusks that secretes the shell and covers the visceral mass.

Radula

A toothed, tongue-like organ used for feeding in mollusks, except in bivalves.

Fate of blastopore

Determines whether an organism develops into a protostome (mouth first) or deuterostome (anus first).

Flame bulbs

Cells in flatworms' protonephridia that help maintain osmotic balance.

Regeneration

The ability of certain organisms like echinoderms to regrow lost parts.

Lancelets (Cephalochordata)

Invertebrate chordates that resemble small fishes and are capable of swimming.

Tunicates (Urochordata)

Invertebrate chordates that are sedentary suspension feeders in their adult form.

Porifera reproduction

Sponges primarily reproduce sexually and asexually, with some species being hermaphroditic.

Hydra

A genus of small, simple, freshwater organisms in the phylum Cnidaria, notable for their regenerative abilities.

Coral reefs

Complex ecosystems formed by colonies of living corals, which are critical for marine biodiversity.

Planarians

Flatworms known for their regenerative capabilities and found in freshwater, marine, and terrestrial environments.

Nematodes

Also known as roundworms, these are unsegmented worms that play significant roles in decomposition and nutrient cycling.

Trematodes

Flatworms, also known as flukes, that are mostly parasitic and have complex life cycles.

Segmentation

The division of an organism's body into repetitive segments, providing flexibility and efficiency in movement.

Mollusks locomotion

Mollusks move using a muscular foot, and many use cilia or jet propulsion.

Bivalve feeding

Bivalves like clams filter feed by siphoning water through their gills.

Cephalopod intelligence

Cephalopods, like octopuses, are known for their high intelligence and problem-solving abilities.

Echinoderm regeneration

Echinoderms can regenerate lost arms or even entire bodies, demonstrating remarkable healing capabilities.

Lophophore

A specialized feeding structure found in some aquatic invertebrates, including bryozoans.

Trochophore larvae

A free-swimming larval stage common in mollusks and annelids featuring a band of cilia.

Setae

Bristle-like structures on the segments of annelids used for locomotion and anchoring.

Tissue layers

The three primary tissue layers in bilaterians are ectoderm, mesoderm, and endoderm.

Gastrovascular cavity

A central cavity in cnidarians that functions in digestion and circulation.

Cnidocyte function

Specialized cells in cnidarians that contain nematocysts for prey capture and defense.

Ecosystem roles of sponges

Sponges filter water and provide habitat for a variety of small marine organisms.

Parasites that infect mollusks

Some parasites, such as certain trematodes, require mollusks as an intermediate host.

Ecdysozoan characteristics

Animals in this group grow by molting their exoskeletons, including arthropods and nematodes.

Mesoderm function

The middle tissue layer in bilaterians that develops into muscles, circulatory systems, and internal organs.

Annelid diversity

Annelida includes various classes such as Oligochaeta (earthworms) and Polychaeta (marine worms).

Coelom definition

A body cavity lined by mesoderm, found in many bilaterian animals, aiding in organ development.

Deuterostome characteristic

Deuterostomes develop the anus from the blastopore during embryonic development.

Five chordate characteristics

Chordates possess a notochord, dorsal hollow nerve cord, pharyngeal slits, a post-anal tail, and endostyle.

Cnidarian life cycle

Cnidarians typically have both medusa (free-swimming) and polyp (sessile) stages.

Giant squid

A large cephalopod recognized for its size and elusive nature, exemplifying mollusk diversity.

Flatworm habitat

Flatworms can be found in diverse environments ranging from marine to freshwater and on land.

Aquatic adaptations

Many marine animals have adaptations such as gills for breathing underwater.

Sea star feeding

Sea stars evert their stomachs to digest prey externally, primarily bivalves.

Coral bleaching causes

Coral bleaching occurs due to environmental stressors like temperature changes and pollution.

Nemertea

Phylum of ribbon worms characterized by a long, flat body and a unique proboscis for capturing prey.

Antennas in arthropods

Arthropods possess antennae that serve as sensory organs to detect chemicals and movement.

Gills in arthropods

Aquatic arthropods typically have gills for respiration, while terrestrial species may have modified structures.

Hexapoda classification

Hexapoda consists of insects and their relatives, characterized by three body segments and six legs.

Ecto and endoparasites

Ectoparasites live on the host's exterior, while endoparasites reside within the host's body.

Bilateral symmetry evolution

Bilateral symmetry is thought to have evolved to enhance movement and coordination.

Crustaceans habitat

Crustaceans primarily inhabit aquatic environments, including freshwater and marine ecosystems.

Lobster climbing abilities

Lobsters use their muscular legs and claws to navigate rocky seafloors effectively.

Aplysia

The sea hare, a marine gastropod known for its distinct colors and capability for learning and memory.

Barnacles feeding

Barnacles filter feed by extending their feathery antennae to capture plankton from the water.

Poriferan body plan

Porifera lack true tissues and organs, consisting of a porous body structure that allows water flow.

Cnidaria economic importance

Coral reefs support fisheries and tourism, contributing significantly to many coastal economies.

Trochophore transition

The trochophore larvae stage is key in the life cycles of some mollusks and annelids.

Germ layers

Embryonic development involves the formation of ectoderm, mesoderm, and endoderm.

Ray-finned fishes

A group of fishes characterized by bony rays supporting their fins, diverse in form and habitat.

Octopus camouflage

Octopuses can change color and texture for camouflage using specialized skin cells called chromatophores.

Coral polyps anatomy

Coral polyps have tentacles around their mouths, equipped with cnidocytes for capturing prey.

Echinoderm symmetry

Echinoderms exhibit radial symmetry in adults but are bilaterally symmetrical in their larval stages.

Pharyngeal arches

In chordates, these structures develop into gills in fish and lead to different structures in tetrapods.

Simple nervous systems

Many early animals, such as sponges, lack a nervous system, while cnidarians have a simple nerve net.

Molluscan respiration

Mollusks respire using gills or lungs, depending on their habitat.

Crayfish circulatory system

Crayfish have an open circulatory system where hemolymph circulates through sinuses.

Medusa movement

Medusa stage of jellyfish moves by contracting and relaxing their bell-shaped body.

Starfish anatomy

Starfish have a central disc and arms radiating out, typically five, covered in spines.

Zoological classification

Animal species are classified based on shared characteristics into hierarchical groups.

Unique echinoderm features

Echinoderms possess a water vascular system, tube feet, and a calcareous endoskeleton.

Bivalve shell structure

Bivalves have two hinged shells which are often symmetrical, protecting their soft bodies.

Ctenophora bioluminescence

Many ctenophores exhibit bioluminescence, producing light through chemical reactions.

Polychaete diversity

Polychaetes are characterized by their numerous setae and diverse habitats in marine environments.

Ostracods

Small crustaceans with a bivalve-like shell, often found in marine and freshwater environments.

Clade definition

A clade represents a group of organisms that includes an ancestor and all its descendants.

Gas exchange in aquatic animals

Aquatic animals typically obtain oxygen through gills, facilitating gas exchange in water.

Locomotion in sponges

Sponges rely on water currents for feeding and waste removal, as they do not move actively.

Phylum characteristics

Different phyla of animals are defined by unique structural, developmental, and genetic characteristics.

Animal evolutionary history

Animal evolution is marked by key milestones like the emergence of multicellularity and bilateral symmetry.

Cilia functions

Cilia can aid in locomotion or feeding, commonly seen in many protozoans and some animal larvae.