invertebrates
animals without a backbone (95% of all animal species)
spongocoel
central cavity of a sponge
choanocytes
collar cells that beat to move water through pores and sponge; trap and eat small particulates and plankton
mesohyl
gelatinous, protein-rich matrix between choanocytes and epithelial cells
amoebocytes
mobile cells within the mesohyl that absorb food from choanocytes, digest, and carry the nutrients to other cells
sponges
unique in their use of intracellular digestion (uptake of food particles by cells)
spicules
tough, sharp skeletal fibers that support the body forming skeleton; formed of protein, calcium carbonate, or silica
spongin
fibers of tough protein that lend skeletal support (skeleton sold as bath sponges)
hermaphrodites
produce both sperm and eggs
mesoglea
gelatinous substance connecting endoderm and ectoderm
gastrovascular cavity
body cavity with a single opening to the external environment where extracellular digestion takes place
nerve net
true nerve cells in Radiata consisting of interconnected neurons with no central control organ; nerve impulses pass in either direction along a neuron
polyp
sessile form of cnidarians; tubular body with an opening at the oral end that is surrounded by tentacles and functions as both mouth and anus, bottom end is attached to substrate
medusa
motile form of cnidarians; has an umbrella-shaped body with an opening that serves as both mouth and anus on the concave underside that is surrounded by tentacles, often possess simple sense organs
ocelli
photosensitive organs; allow medusa to position themselves in particular light levels
cnidocytes
stinging cells, function in defense or capture of prey
nematocysts
powerful capsules with an inverted coiled and barbed thread within a cnidocyte
cnidocil
hairlike trigger of cnidocyte on surface
bioluminescence
results from chemical reactions that give off light rather than heat
protonephridia
two lateral canals with branches, making up distance excretory system in flatworms; dead end tubules lacking internal openings
flame cells
caps on branches of protonephridia
cerebral ganglia
clusters of nerve cell bodies that receive input from photoreceptors in eyespots and sensory cells
corona
ciliated crown that looks similar to a rotating wheel when beating
mastax
circular, muscular pharynx in mouth of rotifers
pedal glands
in foot, secrete a sticky substance that aids in attachment to a substrate
parthenogenesis
unfertilized diploid eggs that have not undergone meiotic division develop into females
foot
used for mollusk movement
visceral mass
contains internal organs and rests on top of the foot
mantle
fold of skin draped over the visceral mass, secretes a shel in those species that form shells
mantle cavity
houses delicate gills in a chamber
gills
filamentous organs that are specialized for gas exchange
open circulatory system
heart that pumps body fluid called hemolymph through vessels and into sinuses
metanephridia
excretory organs that remove nitrogen and other wastes
radula
unique protrusible tonguelike organ that has many teeth and is used to eat plants, scrape food particles off of rocks, or if mollusk is predatory, bore into shells of other species and tear flesh
veliger
free swimming larvae that has a rudimentary foot, shell, and mantle
closed circulatory system
blood flows throughout an animal entirely within a series of vessels (oxygen more readily available, quick pumping)
septum
seals off old chamber and secretes a new one
setae
chitinous bristles
parapodia
fleshy foot-like objects that are pushed into the substrate to provide traction during movement
giant axons
very large nerve cells that facilitate high-speed nerve conduction and rapid responses to stimuli
ecdysis
periodic molting of the exoskeleton
cuticle
nonliving cover that serves to both support and protect the animal
collagen
structural protein that makes up the majority of cuticle
stylets
sharp, piercing organs present in the mouth of nematode
exoskeleton
body covering of hard cuticle made of layers of chitin and protein
tagmata
body segment that have become fused into functional units
ommatidia
independent visual units that make up compound eyes of arthropods
tracheal system
organs that permit gas exchange
spiracles
pores on the body surface that provide openings to a series of finally branched air tubes within the body called trachea
Malpighian tubes
extensive tubes that extend from the digestive tract to the body cavity, where they are surrounded by hemolymph
cephalothorax
fused head and thorax
pedipalps
sensory, predatory, or reproductive functions
pedicel
narrow, waistline point of attachment joining cephalothorax and abdomen
entomology
study of insects
proboscis
coiled tongue of butterflies and moths
complete metamorphosis
change in body form during development
incomplete metamorphosis
gradual change of body form during development
carapace
hard protective fold covering the head that extends over most of the cephalothorax
nauplius
first larval stage
endoskeleton
internal hard skeletons composed of calcareous plates overlaid by thin skin
water vascular system
network of canals derived from coelom; uses hydraulic power which enables tube feet to extend and contract, allowing echinoderms to move very slowly
tube feet
function in movement, gas exchange, feeding, and excretion
madreporite
sievelike plate on the animals surface where water enters the water vascular system
ampulla
muscular sac at base of each tube that stores water
autonomy
ability to intentionally ditch a body part, such as a limb, that will eventually regenerate
notochord
single flexible rod that lies between the digestive tract and the nerve cord
pharyngeal slits
function as filter-feeding device, later developing into gills
incurrent siphon
used to draw water through the mouths of tunicates (filter feeders) using a ciliated pharynx
tunic
encloses whole animal, made of a protein and a cellulose-like material called tunicin