pinacocyte definition

thin, flat cells that line the outer surface of a sponge; may be mildly contractile, which changes shape of sponge

porocyte definition

specialized pinacocytes that regulate water circulation; make pathways for water moving through the body wall

mesenchyme (ameboid) cells definition

move in the mesohyl, aid in reproduction, secreting skeletal elements, transporting and storing food, forming contractile rings around openings in sponge wall

choanocytes definition

collar cells that lie below the mesohyl and line the inner chamber; create water currents and filter food particles

monoecious definition

one organism producing both egg and sperm

dioecious definition

having the male and female reproductive organs in separate individuals

gemmules definition

asexual reproduction in porifera; internal capsules of ameboid cells that resist freezing and drying

cnidocytes definition

specialized cells for defense, feeding, and attachment

nematocysts definition

in cnidocytes; discharge tubes armed with spines and toxin

statocysts definition

small sac surrounding a calcium carbonate statolith to detect tilting in cnidarians

colloblasts definition

adhesive cells in cnetophorans

parenchyma definition

spongy mass of mesoderm cells; skeletal support, nutrient and oxygen storage and transport, motility, reserve of regenerative cells

parthenogenesis definition

female species that can lay unfertilized eggs

dimorphic definition

two distinct forms; males smaller than females in phylum nematoda

molting definition

possessing and shedding of an external cuticle

what is the difference between poisonous and venomous?

if it bites you and you die: venomous if you bite it and you die: poisonous

monoecious vs. dioecious

monoecious: sperm and egg in one indiv. dioecious: sperm and egg in separate indiv.

mesohyl

jelly-like layer below pinacocytes

porifera- characteristics

asymmetrical, no true tissues or organs

porifera- 3 types of cells

pinacocytes, mesenchyme, choanocytes

porifera- skeletal structures

spicules made of calcium carbonate or silica, and/OR spongin: fibrous protein made of collagen

porifera- body form

ascon, sycon, leucon

ascon body form

simplest, least common; vase-like, in ostia and out single, terminal osculum

sycon body form

folded walls, water enters through dermal pores, into radial canals where choanocytes push water into the spongocoel

leucon body form

most common; branched canals, no true spongocoel, multiple osculua

porifera- maintenance functions

filter feeders, choanocytes trap food and mesenchyme cells transport it to other cells, nitrogenous wastes diffuse from cells, no nervous system , cells may communicate

porifera- reproduction

sexual: monoecious, some choanocytes lose collars and undergo meiosis to form sperm and eggs, external fertilization, free-swimming larvae

what are examples of cnidarians?

jellyfish, sea anemones, corals, hydra

what classes are within cnidaria?

hydrozoa, scyphozoa, staurozoa, cubozoa, anthozoa

cnidaria- charatceristics

biradial, diploblastic, gastrovascular cavity (blind cavity with a single opening - mouth)

cnidaria- specialized cells

cnidocytes and nematocysts

cnidaria- body forms

polyp and medusa

polyp

mostly asexual, sessile, cylindrical with mouth surrounded by tentacles

medusa

dioecious, free-swimming, bell-shaped with mouth and tentacles facing downward

cnidaria- alternation of generations

swapping between polyp and medusa stages

cnidaria- maintenance functions

gastrovascular cavity used for feeding and discharge of gametes, digestion partially extracellular and intracellular, water-filled gastrovascular cavity serves as a hydrostatic skeleton

cnidaria- movement

polyps move slowly by somersaulting, gliding, or walking on tentacles; medusae swim and float, using water currents or surface winds

cnidaria- nervous system

most primitive; two-dimensional nerve net, some have statocyst to detect tilting

cnidaria- reproduction

dioecious, external fertilization, planula ( ciliated, free-swimming larva that attaches to a substrate and develops into a polyp), medusae form by budding from a polyp

what is an example of a hydrozoan?

obelia and hydra

hydrozoa characteristics

only class with freshwater members

what is an example of a scyphozoan?

"true jellyfish"

scyphozoa characteristics

dominant medusa stage, several display negative photo-taxis

what is an example of a cubozoan?

sea wasp

cubozoa characteristics

cube-shaped medusa

staurozoa characteristics

stalked jellyfish, polyps with oral ends that look like medusa, no true medusa stage

what is an example of an anthozoan?

anemones and coral

anemones reproduction

some dioecious, some monoecious; monoecious species are protandrous (male gametes mature earlier)

what are ctenophores?

sea walnuts and comb jellies

ctenophora characteristics

swim using 8 comb rows (bands of cilia), diploblastic, biradial symmetry, complete digestive tract, some have colloblasts,

ctenophora reproduction

monoecious with external fertilization

what are the most primitive animals?

sponges

primitive ____ (i.e. polyps) may have been ancestors to other groups

anthozoans

what are the 2 groups of protostomes?

ecdysozoans and lophotrochozoans

triploblastic animals can be divided in two ways:

protostomes and deuterostomes

what is the more recognized way to classify triploblastic animals?

molting patterns

plylum acoelomorpha: characteristics

small, flattened marine worms, very primitive digestive and other organs, mostly free-living, asexual reproduction or monoecious

what are some examples of platyhelminthes?

panarians, monogenetic and digenetic flukes, and tapeworms

what classes are within platyhelminthes?

turbellaria, monogenea, trematoda, cestoidea

platyhelminthes- characterstics

flattened dorsoventrally, blind-sac body, distinct head with centralization of nervous system

platyhelminthes- class turbellaria

planarians

class turbellaria- characteristics

free-living, ciliated epidermis for locomotion

class turbellaria- digestion

most carnivorous, incomplete digestive tract, tube-like pharynx

class turbellaria- gas exchange

no circulatory system or respiratory organs, gases exchanged through body wall

class turbellaria- osmoregulation

marine: near osmotic equilibrium freshwater: hypertonic, must osmoregulate protonephridia: tubules along parenchyma tissue (first kidney) flame cells: tiny, hollow enlargements at the tips of branches tubules with beating cilia that create negative pressure

class turbellaria- nervous system & sense organs

primitive nerve nets to nervous systems with lateral branches, nervous tissue concentrated anteriorly in pair of cerebral ganglia (primitive brain) auricles:sensory lobes with chemoreceptors and ocelli with photoreceptors

class turbellaria- reproduction

asexual: transverse fission, monoecious sexual: reciprocal sperm exchange, eggs deposited into cocoons

example of class monogenea

monogenetic flukes

class monogenea characteristics

monoecious, ectoparasites of fish, opisthaptor (posterior attachment organ)

example of class trematoda

digenetic flukes

class trematoda- digestive system

oral sucker and acetabulum, anterior mouth, digestic system divides into two blind pouches called cecae

class trematoda- life cycle

most complex; larvae hatch in water, live in snail, free swimming in water, ingested by definitive host via vegetation

example of class cestoidea

tapeworms

class cestoidea- characteristics

endoparasites, lack mouth and digestive system

class cestoidea- body regions

scolex: structure with suckers and sometimes hooks neck: immature proglottids strobila: series of proglottids, which produce eggs when mature

class cestoidea- structural adaptations

tegument: only means of absorbing nutrients reduced nervous system: nerve mass in scolex and a pair of lateral nerve cords

class cestoidea- reproduction

monoecious, fertilized eggs accumulate in gravid proglottids and other organs degenerate

class cestoidea- common tapeworms

beef, pork, fish

phylum nemertea characteristics

extendable proboscis, carnivorous, among longest invertebrates, complete digestive tract, dioecious

phylum gastrotricha characteristics

complete digestive system, acoelomate, monoecious, reproduce sexually, freshwater: parthenogenetic

phylum cycliophora characteristics

live on mouthparts of lobsters, dioecious

pseudocoelomate (aschelminthes) members

rotifera, acanthocelphala, nematoda, nematomorpha

aschelminthes characteristics

pseudocoelom (often fluid-filled), lacks mesenteries, serves in circulation, digestion, and locomotion (hydrostatic skeleton)

aschelminthes body plan

non-cellular cuticle, muscular pharynx for feeding, adhesive glands, complete digestive tract, dioecious, bilaterally symmetrical, protonephridia, some cephalization

utely definition

body is made up of constant number of cells, fixed number of cells at maturity, constant across species, further growth by cell enlargement

phylum rotifera example

rotifers

rotifera characteristics

cuticle (lorica), ciliated organs (corona) around the head, cilia beat in cycle, foot with two toes for attachment, mastax for grinding food

rotifera- facultative parthenogenesis

in monogononta: mitosis (amictic) or haploid (mitic): unfertilized (males) fertilized (females)

phylum acanthocephala example

spiny-headed worms

acanthocephala characteristics

two hosts, retractable proboscis with recurved spines for attachment in host's intestine. absorb food through tegument, dioecious

phylum nematoda example

roundworms

nematoda- general characteristics

abundant, many parasitic, outer cuticle molted 4 times, chemoreceptors (amphids and phasmids), paired ocelli in aquatic members

nematoda- internal characteristics

longitudinal muscles result in thrashing, complete digestive system, anterior nerve ring

nematoda- external characteristics

nematoda- osmoregulation

glandular system: free-living nematodes have ventral gland cells (renettes) that empty wastes via a pore tubular system: parasitic nematodes, renettes unite to form a large, long canal w/ an excretory pore

nematoda- reproduction

usually dioecious, dimorphic, internal copulation, come oviparous, some ovoviviparous

nematoda- human parasites

single host, some annoying (pinworms), some cause severe problems (filarial)

phylum annelida examples

tube worms, clam worms, fan worms earthworms and leeches

annelida- general characteristics

complete digestive system, coelomates, no lungs or gills, paired, large ganglia in head region, receptors to light, chemical, and mechanical stimulation on body surface

annelida- internal characteristics

excrete ammonia (aquatic) and urea (terrestrial), metanephridia