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Buettners Bio 1407 Test IV

Cleavage

A succession of mitotic cell divisions without cell growth between the divisions.

Blastula

Cleavage leads to this multicellular stage, which in many animals takes the form of a hollow ball.

Gastrulation

Process during which the layers of embryonic tissues that will develop into adult body parts are produced.

Gastrula

Resulting developmental stage of gastrulation.

Larva

Sexually immature form of an animal that is morphologically distinct from the adult, usually eating different food and even living in a different habitat than the adult.

Metamorphosis

A developmental transformation that turns the animal into a juvenile that resembles an adult, but is not yet sexually mature.

Ediacaran biota

Fossils of soft-bodied Eukaryotes, named for the Ediacara Hills of Australia.

Cambrian Explosion

A wave of animal diversification that occurred 535-525 million years ago, during the Cambrian period of the Paleozoic era.

Body Plan

Particular set of morphological and developmental traits, integrated into a functional whole- the living animal.

Radial Symmetry

Type of symmetry found in a flowerpot.
Ex: Sea Anemone

Bilateral Symmetry

Two-sided symmetry
Ex: Lobsters

Dorsal Side

Top side

Ventral Side

Bottom Side

Anterior End

Front end

Posterior End

Back end

Cephalization

Evolutionary trend in whih sensory equipment is concentrated at the anterior end, including a central nervous system ("brain") in the head.

Ectoderm

The germ layer covering the surface of the embryo, gives rise to the outer covering of the animal and, in some phyla, to the central nervous system.

Endoderm

The innermost germ layer, lines the pouch that forms during gastrulation (the archenteron) and gives rise to the lining of the digestive tract (or cavity) and organs such as the liver and lungs of vertebrates.

diploblastic

Animals that have only two germ layers.

Mesoderm

Layer present in all bilaterally symmetrical animals, which fills much of the space between the ectoderm and the endoderm.

Triploblastic

Having three germ layers.

Body Cavity

A fluid or air-filled pace between the digestive tract and the outer body wall found in most triploblastic animals.

Coelom

Body cavity

Coelomates

Animals having "true" coeloms, formed from tissue derived from mesoderm. The inner and outer layers of tissue that surround the cavity connect and form structures that suspend internal organs.

Pseudocoelomates

Some triploblastic animals have a body cavity that is formed from mesoderm and endoderm.

Acoelomates

Triploblastic animals lacking a body cavity altogether.

Protostone Development

Molluscs, Annelids
Spiral and determinate
Mouth develops first

Deuterostome development

echinoderms, Chordates
Radial and indeterminate
Anus develops first

Spiral cleavage

Planes of division are diagonal to the vertical axis of the embryo; smaller cells are centered over the grooves between larger, underlying cells.

Determinate Cleavage

Rigidly casts ("determines") the developmental fate of each embryonic cell very clearly.

Radial Cleavage

Cleavage planes are lateral to the vertical axis of the embryo; the tiers of the cells are aligned one direction above the other.

Indeterminate Cleavage

Each cell produced by the early cleavage divisions retain the capacity to develop into a complete embryo.

Archenteron

An Embryo;s developing digestive tube which becomes the gut.

Blastopore

The indentation that during gastrulation leads to the formation of the archenteron.

Lophophore

A crown od ciliated tentacles that funtion in feeding.

Trocotphore Larva

Distinctive stage fo development for molluscs and annelids.

Invertebrates

Animals lacking a backbone.

Suspension Feeders

Animals that capture food particles suspended in the water that passes through their body, which in some species resembles s sac perforated with pores.

Spongocoel

Pores in the central cavity of a suspension feeder.

Osculum

Larger opening through which water flows out of the sponge.

Choanocytes

Collar cells lining the interior of the spongocoel, they are flagellated and engulf bacteria and other food particles by phagocytosis.

Mesohyl

Gelatinous region that separates two layers of sponge.

Amoebocytes

Cells that move through the moshyl and have many functions.

Hermaphrodites

Each individual functions as both male and female in sexual reproduction.

Gastrovascular cavity

The sac of a cnidarian that is the digestive compartment.

Polyps

Cylindrical forms that adhere to the substrate by the aboral end of their body (the end opposite the mouth) and extend their tentacles, waiting for prey.

Medusa

Resembles a flattened, mouth-down version of the polyp that moves freely in the water by a combination of passive drifting and contractions of its bell-shaped body.

Cnidocytes

Cell unique cnidarians that function in defense and prey capture.

Nematocysts

Specialized cnidae that contain a stinging thread that can penetrate the body wall of the cnidarain's prey.

Protonephridia

Networks of tubules with ciliated structures called flame bulbs that pull fluid through branched ducts opening to the outside.

Planarians

rhabditophoran; Genus Dugesia; Free-living, fresh-water species

Alimentary Canal

A digestive tube with two openings, a mouth and an anus present on rotifers.

Parthenogenesis

A type of asexual reproduction in which females produce only female eggs.

Ectopracts

Greek meaning outside anus. Colonial animals that superficially resemble clumps of moss.

Exoskeleton

External skeleton

Brachiopods

Lamp Shell, superficially resemble clams and other hinged-shelled molluscs, but the two halves of the brachiopod shell are dorsal and ventral, rather than lateral, as in clams.

Foot

A muscular foot used for movement in Coelomates like molluscs.

Mantle

A fold of tissue that drapes over the visceral mass and secretes a shell (if one is present).

Mantle cavity

Water-filled chamber found in many molluscs, which houses the gills, anus, and excretory pores.

Radula

A straplike organ used by molluscs to scrape food.

Torsion

In gastropods, a developmental process in which the visceral mass rotates up to 180°, causing the animal's anus and mantle cavity to be positioned above its head.

Ammonites

Shelled cephalopods

Cuticle

Tough external coat that is shed by some animals.

Molting

Process of shedding cuticle.

Arthropods

Segmented body, hard exoskleleton, and jointed appendages.

Open Circulatory system

Fluid called hemolymph is propelled by a heart through short arteries snd then into spaces called sinuses surrounding the tissues and organs.

Chelicerates

One of the four major lineages of arthropods consisting of sea spiders, horseshoe crabs, scorpions, ticks, mites, and spiders
Named for the claw-like feeding appendages claaed chelicerae, which serve as pincers or fangs. Anterior Cephalothorax and a posterior abdomen. lacking antennae, with simple eyes.

Myriopods

One of the four major lineages of arthropods; centipedes and millipedes

Hexapods

One of the four major lineages of arthropods including insects and their wingless, six-legged relatives

Crustaceans

One of the four major lineages of arthropods including crabs, lobsters, shrimps, barnacles, and many others

Eurypterids

Water Scorpions; earliest chelicerates. extinct.

Arachnids

Bulf of modern chelicerates; Cephalothorax has six appendages, the chelicerae; a pair of appendages called pediapalps that function in sensing, feeding, or reproduction, and four pairs of walking legs. Spiders, ticks, mites.

Book Lungs

In most spiders, gas exchange is carried out by stacked platelike structures contained in an internal chamber.

Mandibles

Jaw-like part of myriapods.

Incomplete Metamorphosis

The young (nymphs) resemble adults but are maller, have different body proportion, and lack wings. nymph undergoes a series of molts, each time looking more like an adult, reaching sexually maturity with the final molt.

Isopods

One of the largest groups of crustaceans, which includes terrestrial, fresh-water, and marine species, including pill bugs or wood lice.

Decapods

Crustaceans that includes lobsters, crayfishes, crabs, and shrimps.

Copepods

Planktonic crustaceans, which are the most numerous of all animals.

Echnoderms

Slow-moving or sessile marine animals like sea stars.

Water Vascular system

A network of hydraulic canals branching into extensions called tube feet that function in locomotion and feeding.

Vertebrates

Animals containing a back bone.

Chordates

Phylum Chordata that contains the vertebrates; Bilateral animals, within bilateria, they belong to the clade of animals known as Deuterostomia

Notochord

Longitudinal, flexible rod located between the digestive tube and the nerve cord.

Pharyngeal Clefts

In chordate embryos, one fo the grooves that separate a series of pouches along the sides of of the pharynx and may develop into a pharyngeal slit.

Pharyngeal Slits

In chordates embryos, one of the slits that form from the pharyngeal clefts and communicate to the outside, later developing into gill slits in many vertebrates.

Lancelets

The most basal group of living chordates, which get their name from their bladelike shape.

Tunicates

Member of the clade Urochordata, sessile marine chordates that lack a backbone.

Cranates

Chordates with a head.

Neural Crest

Feature unique to cranates, collection of cells that appears near the dorsal margins of the closing neural tube in an embryo.

Conodonts

Were slender, soft-bodied vertebrate with prominent eyes controlled by numerous muscles.

Gnasthostomes

Jawed vertebrates

Lateral Line System

Characteristic of aquatic gnasthostomes in which organs form a row along each side of the body and are sensitive to vibrations in the surrounding water.

Placoderms

Plate-skinned; earliest gnasthostomes

Acanthodians

Group of jawed vertebrates that emerged at roughly the same time as placoderms.

Chondrichthyans

Cartilage fish; have a skeleton composed predominately of cartilage, though often impregnated with calcium.
Sharks, Rays and their relatives.

Oviparous

Lay eggs that hatch outside the mother's body.

Oviviviparous

Retain the fertilized eggs in the oviduct; born after hatching in the uterus.

Viviparous

Young develop within the uterus and obtain nourishment from the mother's blood through a yolk sac placenta, by absorbing a nutritious fluid produced by the uterus, or by eating other eggs.

Cloaca

A common chamber that ha a single opening to the outside.

Osteichthyan

Vertebrates; clade gnasthostomes; have an ossified (bony) endoskeleton with a matrix of calcium phosphate.

Operculum

Protective bony flap that covers the gills of most fish.

Swim Bladder

An air sac that helps fish control their buoyancy.

Amphibians

Salamanders, frogs, and caecilians; tetrapods

Amniotes

Group of tetrapods whose extant members are the reptiles (including birds) and mammals.

Amniotic Egg

Contains four specialized membranes; the amnion, the chorion, the yolk sac, and the allantois.

Reptile

Clade includes tuataras, lizards, snakes, turtles, crocodillians, and birds, along with a number of extinct froups, such as plesiosaurs and icthyosaurs.

Ectothermic

Animals that absorb external heat as their main source of body heat.

Endothermic

Capable of maintaining body temperature through metabolic activity.

Parareptiles

Mostly large, stocky, quadrupedal herbivores.

Diapsids

Ancient reptile clade; derived characters pair of holes on each side of the skull, behind the eye socket; muscles pass through these holes and attach to the jaw, controlling jaw movement.

Lepidosaurs

A lineage of the diapsids which include tuataras, lizards, and snakes

Archosaurs

A lineage of diaspids that produced the crocodilians, pterosaurs, and dinosaurs.

Pterosaurs

Originated in the alte Triassic, were the first to exhibit flapping flight.

Dinosaurs

Diversified into a vast range of shapes and sizes.

Theropods

Bipedal carnovores.

Ratites

Consists of ostrich, rhea, kiwi, cassowary, and emu- all flightless birds.

Synapsids

Member of an amniote clade distinguished by a single hole on each side of the skull. Synapsids include mammals.

Montremes

Found only in Australia and New Guinea and are represented by one species of platypus and four species of echnidnas (spiny anteaters). Lay eggs, have hair, produce milk, but they lack nipples. Milk is secreted byl glands on the belly of the mother. After hatching, the baby sucks the milk from the mother's fur.

Marsupials

Opossums, kangaroos, and Mole, Sugar glider, Wombat, Tasmanian devil

Placenta

The lining of the uterus and the extraembryonic structure in which nutrients diffuse into the embryo from the mother' blood.

Eutherians

Placental mammals; Placentas are more complex than those of marsupials.

Opposable Thumb

Can touch the ventral surface (fingerprint side) of the tip of all four fingers with the ventral surface of the thumb of the same hand.`

Anthropoids

Includes monkey and apes

Paleoanthropology

Study of human origins.

Hominins

20 extinct species that are more closely related to humans than to chimpanzees.

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