Biology exam

Heterotrophic

Organisms that obtain their energy by consuming organic matter, not by producing it themselves.

Choanoflagellates

Single-celled or colonial flagellates closely related to animals but not considered animals themselves.

Choanocytes

Specialized cells in sponges with a collar and flagellum that capture food particles from the water.

Porocytes

Tube-like cells in sponges that create openings (pores) for water to flow into the sponge body.

Amoebocytes

Mobile cells within a sponge that distribute nutrients and can differentiate into other cell types.

Sclerocytes

Cells in sponges responsible for secreting spicules (skeletal elements).

Spicules

Structural elements in sponges that form part of the sponge’s skeleton, providing rigidity and defense.

Spongocytes

Cells in sponges that secrete spongin, a flexible protein component of the sponge skeleton.

Secondary metabolites

Compounds not essential for basic metabolic processes but may serve defensive or ecological roles.

Trade-Offs

Evolutionary compromises where organisms allocate resources to optimize specific functions, often sacrificing others.

Sessile

Organisms that are fixed in place and do not move, such as adult sponges.

Benthic

Refers to organisms living on the seafloor or in its sediments.

Pelagic

Refers to organisms that live in the open ocean, away from the seafloor.

Polyp vs. Medusa

Two life stages in cnidarians; polyps are sessile, while medusae are free-swimming.

Gastrovascular Cavity

The central digestive compartment in cnidarians and flatworms.

Nematocyst

A specialized stinging structure within cnidocytes used for capturing prey or defense.

Cnidocyte

A cell in cnidarians that contains nematocysts and plays a role in prey capture and defense.

Zooxanthellae

Symbiotic algae living within coral tissues, providing energy through photosynthesis.

Coral Bleaching

The loss of zooxanthellae from coral tissues, often due to stress, resulting in coral losing color and energy source.

Complex Life Cycle

A life cycle involving multiple developmental stages, often with more than one host species.

Scolex

The head-like structure of a tapeworm with hooks or suckers for attachment.

Proglottid

A segment in tapeworms containing reproductive organs, which detaches when mature.

Metazoa

A major division of the animal kingdom encompassing all multicellular animals.

Eumetazoa

Animals with true tissues, including all animals except sponges and a few other simple forms.

Radial vs. Bilateral Symmetry

Radial symmetry allows body parts to radiate from a central point; bilateral symmetry divides the body into two mirror-image halves.

Ectoderm, Mesoderm, Endoderm

Primary germ layers that give rise to tissues and organs in triploblastic animals.

Diploblastic vs. Triploblastic

Diploblastic organisms have two germ layers (ectoderm and endoderm), while triploblastic organisms have three, adding the mesoderm.

Coelom

A fluid-filled body cavity entirely lined by mesodermal tissue.

Body Cavities

Coelomate have a true coelom lined entirely by mesoderm; acoelomate lack a coelom.

Lophophore

A crown of ciliated tentacles around the mouth used for feeding.

Zooid

An individual animal in a colonial organism.

Alimentary Canal

A complete digestive tract with a mouth and an anus.

Trochophore

A free-swimming larval stage in some annelids and mollusks characterized by bands of cilia.

Proboscis

An extensible tubular organ used for feeding or defense.

Chaetae (Setae)

Bristle-like structures made of chitin in annelids, aiding in locomotion and anchoring.

Septum

Internal wall separating segments in segmented worms.

Soil Cycling

The process by which soil organisms decompose organic material, recycling nutrients.

Detritivore

An organism that feeds on decomposing organic matter.

Parapodia

Paired appendages in polychaete worms that assist in locomotion and gas exchange.

Biomass

The total mass of living organisms in a particular area or ecosystem.

Whale Fall Communities

Ecosystems that develop around whale carcasses on the ocean floor.

Haemophagic (Hematophagic)

Organisms that feed on blood.

Hirudin

An anticoagulant protein secreted by leeches.

Infaunal

Organisms that live buried in sediment.

Radula

A toothed, chitinous ribbon in mollusks used for scraping or cutting food.

Mantle

A layer of tissue in mollusks that secretes the shell.

Incurrent Siphon

A structure that brings water into the body of a mollusk.

Gills

Respiratory structures in aquatic animals that extract oxygen from water.

Ink Sac

An organ in cephalopods that releases ink.

Nacre Layer (Aragonite Crystals)

The iridescent inner layer of mollusk shells, often referred to as mother-of-pearl.

Ecdysis

The process of molting the exoskeleton in arthropods.

Metamorphosis

The developmental transformation into a new stage.

Chelicera

A pair of appendages in arachnids used for feeding.

Spinnerets

Silk-spinning organs in spiders.

Pollination

The process of transferring pollen from male to female plant structures.

Zygote

A fertilized egg cell formed by the union of sperm and egg.

Blastula

An early stage in embryonic development where cells form a hollow ball.

Gastrulation

The process where cells begin to form distinct tissue layers.

Radial Cleavage

A type of embryonic cell division in deuterostomes.

Spiral Cleavage

A characteristic of protostomes where cells divide at an angle.

Madreporite

A sievelike structure on the surface of echinoderms.

Water Vascular System

A unique hydraulic system in echinoderms used for locomotion and feeding.

Keystone Species

A species that plays a crucial role in maintaining the structure of an ecosystem.

Notochord

A flexible, rod-shaped structure that provides support in all chordates.

Dorsal Hollow Nerve Cord

A tube of nervous tissue that runs along the back, characteristic of chordates.

Amniotic Egg

An egg with a protective shell and specialized membranes that support embryonic development.

Mammary Glands

Milk-producing glands in mammals.

Laurasia and Gondwana

Two supercontinents that existed during the late Paleozoic and early Mesozoic eras.