BIOL 125 Midterm 2

What characterizes the phylum Porifera?

They have no true tissues, only different cell types. They are the sponges.

What are the porifera cell types?

Pinacocytes - part of the epithelium and play a role in movement
Archaeocytes - in mesohyl, ingest and digest food
Choanocytes - flagellated cell

Know the parts of a sponge.

What is the asconoid body form?

In an asconoid porifera, the choanocytes will line the spongocoel. The water will flow into the ostia before being released into the spongocoel then get shot out of the osculum.

What is the syconoid body form?

The choanocytes will line the radial chambers in the body wall, and water will flow into the ostia, from which it is released into the radial chamber, into the spongeocoel, then the osculum.

What is the leuconoid body form?

The choanocytes are in chambers dispered throughout the body. Water flows in to the ostia, into the inhalent canal, then back to the exhalent canal and out of the osculum.

How does reproduction work in Porifera?

They have both sexual (gametocytes) and asexual (budding) reproduction. Typically monoecious

What characterizes the cnidaria?

Cnidocytes (specialized "stinging cells"), radial symmetry, they have an epidermis, mesoglea, and gastrodermis, they have a gastrovacular cavity, and have two body forms, the polyp and medusa.

What is phylum ctenophore and their characteristics?

They are the comb jellies. They are characterized by moving with cilia, having biradial symmetry, they are diploblastic (meaning having only two embryonic cell layers, no mesoderm)

What is class hydrozoa?

Cnidaria, they are solitary or cononial, like the portugese man o' war.

What is class anthozoa?

Cnidaria, they are collective ex. corals and anemones

What is class cubozoa?

Cnidaria, box jellies.

What is class scyphozoa?

Cnidaria, they are the true jellies.

What are ctenophores and what are their characteristics?

They move with cilia, or comb plates. They have biradial symmetry, are diploblastic, monoecious, and have tentacles with colloblasts. They are the comb jellies.

What does lophotrochozoa include?

Rotifera, platyhelminthes, mollusca, annelida

What is phylum rotifera?

They have a wheel organ/corona, a mastax (a pharynx), and are eutely (the entire body of the adult consists of a fixed number of cells)

What is phylum platyhelminthes? What are their characteristics?

They are the flatworms. They are free-living or parasitic, acoelomate, bilaterally symmetrical, have cells with no boundaries, and have a gastrovascular cavity.

What is class turbellaria?

Platyhelminthes, they are the free-living flatworms (planarian). They are able to regenerate

What is class trematoda?

Platyhelminthes, they are the flukes which have life cycles related to parasitism. Their intermediate host is typically a gastropod

What is the trematoda life cycle?

egg -> miracidium (larva) -> sporocyst (adult) -> redia (adult) -> cercaria (larva) -> metacercaria -> fluke (adult)

What is class monogenea?

Platyhelminthes, they are the monogenic (controlled by a single gene) flukes, have prothaptor (allows them to attach to host), and opisthaptor (keeps them attached to the host).

What is class cestoda?

Platyhelminthes, they are the tapeworms. They are monoecious.

What characterizes the Phylum mollusca?

They are eucoelomate, bilaterally symmetrical, having open or closes circulatory system, they have ctenidial gills, and are the 3rd largest phylum.

What is class gastropoda? What are the key characteristics?

In the mollusca, they are the snails and slugs. They have torsion (rotation of the visceral mass). They have a single valve.

What is class Bivalvia? What are their key characteristics?

In the mollusca, they have two halves to their shell, they are suspension feeders, they have a 3 chambered heart (open circulatory), and are very specialized for filter feeding.

What is phylum Annelida? What are the key characteristics?

They are the segmented worms which have a closed circulatory system, are eucoelomate, have gills or epithelial gas exchange, have setae (cilia like structures that keep the worm in place), and have a proteinaceous cuticle.

What is class polychaeta?

Part of the anneldia, polychaeta have lots of setae, have parapodia (muscle flaps for locomotion), and have strong cephalization (evolved sensory and feeding organisms)

What two classes have a clitellum?

The oligochates and hirudenea.

What is class oligachaeta?

In the annelids, they are earthworms and others. They are mostly terrestrial with some aquatic, they have no parapodia. they have few setae, they are deposit feeders, they do epithelial gas exchange, and they are monoecious.

What is class hirudinea?

In the annelids, they are the leeches. they have a reduced or lost septa, no setae, anterior and posterior suckers, and are mostly freshwater.

What is included in the ecdysozoa?

Phylums Nemata and arthropoda.

What characterizes the Nemata?

Some are parasitic but many are free-living, they are the second biggest phylum, they are eutely, they have a collagenous cuticle, they are pseudocoelomate, and have only longitudinal muscles.

What characterizes the phylum arthropoda?

They have a chitnous exoskeleton, they molt, they undergo metamorphosis, they have bodily segments (metamerism), and jointed limbs.

What is subphylum chelicerata? What are the key characteristics?

They have chelicerae (specialized "fangs"), two tagmata, no antennae or mandibles, six pairs of limbs.

What is class arachnida?

A part of chilicerata and arthropoda, it includes spiders, scorpions, mites, and ticks.

What is subphylum myriapoda?

Includes class chilopoda (centipedes) and diplopoda (millipedes).

What is subphylum pancrustacea? What are the key characteristics?

They are a part of the arthropods, they have 3 tagmata and 2 pairs of antennae. They have heavily calcified exoskeletons, and ancestrally biramous (forming two branches) appendages

What is class malacostraca? What are their key characteristics?

A part of the pancrustacean arthropods, it includes most of the large crustaceans including shrimp, crab, lobster, crayfish, and isopods. They have 3 tagmata, some biramous appendages, and are generally aquatic.

What is class insecta? What are their key characteristics?

They're a part of the pancrustacean arthropods, and in general have three tagmata, two or four wings, six legs, uniramous appendages, mostly terrestrial or freshwater, undergo metamorphosis, have a tracheal system, and have malphigian tubules.

What phylums are deuterostomes?

echinodermata, chordata, hemichordata

What is class asteriodea?

They are echinodermates, they are sea stars with penraradial symmetry and gastric eversion.

What are class ophiuroidea?

They are echinodermates, they include brittle stars with pentaradial symmetry, closed ambulacrum, excellent regeneration, they are highly motile, and have articulated ossicles.

What is class echinoidea?

The sea urchins, sand dollars, and sea biscuits in echinodermata.

What is class holothuroidea?

They are the sea cucumbers with reduced ossicles, soft bodies, and bilateral symmetry in the echinodermata.

What is class crinoidea?

They are somewhat sessile filter feeders with many arms and ciliated ambulacrum, they are echinodermata.

What characterizes phylum hemichordata?

They burrow or dwell in tubes, they have pharyngeal slits, a dorsal nerve cord, and are likely sister to echinoderms.

What are the characteristics of phylum chordata?

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

What is subphylum urochordata and what are the key characteristics?

They are chordates consisting of sea squirts and tunicates, they are filter feeders with sessile adult forms

What is subphylum craniata?

All chordates that aren't urochordata.

What is class myxini?

Craniata of chordata, hagfish

What is class petromyzontes?

Craniata of chordata, lampreys

What is class chonrichthyes?

Craniata of chordata, cartilage fish like sharks, rays, chimera

What is class actinopterygii?

Craniata of chordata, the ray finned fish with swim bladder and lungs

What is class sarcopterygii?

Craniata of chordata, they are the lobe-finned fish

What is class amphibia?

Craniata of chordata, no scales, frogs

What is class mammalia?

Craniata of chordata, hair, mammary glands

What is class reptilia?

Craniata of chordata, includes crocodiles and turtles

What is class aves?

Craniata of chordata, they are birds and technically belong in reptilia

Why is radial symmetry beneficial?

It is good for organisms who move slowly, or are sessile. Sensory organs can be split

Why is bilateral symmetry beneficial?

It allows for move movement, for more structures that can turn an organism around quickly. Additionally, it allows certain structures to be on different sides, like mouth and anus.

What does diploblastic refer to?

Having a body derived from only the ectoderm and endoderm, but no mesoderm.

What does triploblastic refer to?

A body derived from the endoderm, ectoderm, and mesoderm.

What do body cavities say about relatedness?

Nothing.

What is coelomate?

Body cavity with complete lining derived from the mesoderm.

What is pseudocoelomate?

A fluid filled cavity partly lined with mesoderm

What is acoelomate?

No body cavity, but still derived from all three layers.

What is the benefit of segmentation?

Also known as metamerism, segmentation allows for muscles to move independently of one another and may lessen the impact of injury. Segmentation may also include tagmatization.

What is the syncytial ciliate hypothesis?

Hypothesizes that metazoans evolved from a unicellular ciliate with multiple nuclei that went through cellularization

What is the colonial flagellate hypothesis?

Proposes that multicellular organisms evolved from a single flagellated cell within a colony.

What are the main tissue types?

epithelial, connective, nervous, muscle

What is epithelial tissue?

A sheets of tightly packed cells that line organs, glands, ducts, or bodily surfaces. They are like the barrier tissue.

What is connective tissue?

Tissue made of loosely arranged cells in a liquid to solid extracellular matrix. Includes bone, cartilage, tendons, and ligaments.

What is nervous tissue?

Tissue made of neurons and supporting cells

What is muscle tissue? What are the different types?

Tissue with protein filaments organized into repeating structures that create a band like appearance. It includes cardiac, striated, obliquely striated, and smooth.

What is cardiac tissue?

It makes up the walls of the heart, and has a branching pattern.

What is striated tissue?

Striated tissue is skeletal muscle tissue, and has long cells with a striped appearance due to the overlapping of proteins.

What is smooth muscle tissue?

Smooth muscle tissue lines organs that are under involuntary control, and are tapered at each end.

What is ectothermy?

Having a body temperature determined primarily by environmental temperature, meaning no internal control. Their control of temperature comes from their behaviour and some physiological controls such as vasodilation or colour change.

What is endothermy?

The ability to internally regulate body temperature. This can be done through an increase of the basal metabolic rate, specific dynamic action of food ration, actions of skeletal muscle, or piloerection.

What is poikilothermy?

The state in which an organism will allow their body temperature to change based on the environment.

What is homeothermy?

The state in which an organism has the ability to keep their body temperature constant regardless of the environment.

What are regulators?

Organisms that control their own body state within a set range of acceptable conditions. They have systems that involve negative feedback loops.

What are conformers?

Organisms that allow their state to be determined by external factors.

What is convection?

Moving heat, such as in water or wind.

What is radiation?

The transfer of energy by electromagnetic waves, such as a hand over a heater.

What is conduction?

The direct movement of heat to an organism, like the heat of a rock on a lizards stomach.

What is evaporation?

The transfer of heat from an organism to the air.

What is the Q10 effect?

The ratio between the rate of biological processes at two temperatures ten degrees apart.

What are the methods of metabolic heat production?

The heat of the basal metabolic rate, the specific dynamic action of food ration, NST (non-shivering thermogenesis), piloerection (goosebumps, ruffled feathers)

What is hibernation?

The state of an organism in which the metabolic rate, body temperature, and activity decreases for a prolonged period. It is voluntary.

What is torpor?

The state of an organism in which the metabolic rate, body temperature, and activity decreases for a short It is involuntary.

How does freshwater osmoregulation work?

There is uptake of water and some ions in consumption, and salt will be taken up in gills. There will be osmotic water gain through gills and other parts of body surface. They will produce large amounts of dilute urine, as the kidney must retain as much salt as possible.

What are the freshwater osmoregulation concerns?

They are hyperosmotic regulators, meaning they must be hyperosmotic relative to surroundings. Water wants to come into their body all the time, and it's going to be difficult to obtain salt as there is little in the surroundings.

What are the marine concerns of osmoregulation?

They are hypoosmotic regulators, have issues as water always wants to leave their body. Additionally, salt will always want to come in their body.

How does marine osmoregulation work?

Salt is brought in during consumption, and it is then excreted through the gills, the epithileal cells. Additionally, water is lost through the gills. The kidneys must then get rid of most of the salt, meaning super concentrated urine is produced.

What is stenohaline?

Unable to withstand a wide range of salinity.

What is euryhaline?

Good osmoregulators that may be able to move between salt and fresh water environments.

What is anadromy?

Movement between fresh and salt water once in lifetime as a part of the life cycle. Usually, they spend their adult life at sea but return to freshwater to spawn.

What is catadromy?

Born in fresh water, mature in the ocean, and return to fresh water later on.

How does nocturnal activity prevent water loss?

The daytime is too hot in places like the desert, so water loss is prevented in the nighttime.