invertebrate diversity Flashcards
Protosome
deuterostome
characteristics of sponges
do not have tissues but have specialized cells
free-swimming larval stage and a sessile adult stage
no nerves or muscles but individual cells can sense and react to changes in the environment
both marine and freshwater species
sessile
anchored in one place, cannot escape predators
sponge life cycle
free swimming larva, young sponge, adult female or male sperm or female
fertilization occurs in the mesophyl
specialized cells on sponges
osculum
water goes in through the pores
amoeboid cells digest nutrients
collar cell(choanocyte) have flagella which generate current
spicule
epidermal cell
sponge wall
central cavity
Cnidarian general characteristics
radial symmetry
arise from two layers of tissue
no internal organs or coelom
Marine and freshwater species
contain stinging cells on tentacles called cynidocytes
which have structures called nematocytes
cnidarian life cycle
sexual or asexual
sessile in adult form (hydra)
2 life structures
Platyhelminthes (flat worms)
bilateral symmetry
some level of cephalization, anterior eye spots(detect light), chemoreceptors, simple brain
follows protostome development but lacks coelom (acoelomate)
many are non-self fertilizing
marine, freshwater and terrestrial species
hermaphrodites
non-self fertilizing
playhelminthes life cycle
some are parasitic (tapeworms)
general characteristics nematodes
roundworms
lack segmentation
most are very small
freshwater, marine, terrestrial many are parasitic
protostome development, but have a pseudocoelom filled with acellular fluid
some are hermaphroditic, some can self fertilize, some are dioecious
external layer is cuticle with collagen
can self-fertilize
dioecious
male and female
mollusks general characteristics
contain muscular foot, visceral mass with internal organs, and mantle- some have shell formation that can be internal or external
general classes
- bivalves clams
- Gastropoda snail
- Cephalopoda squids
marine, freshwater, terrestrial
protostome development, but are coelomates(have coelom)
some are hermaphroditic (most are non-self fertilizing), but most are dioecious
snail anatomy
annelids general characteristics
segmented worms- metamerisms
found in marine, freshwater and terrestrial
protostomic development with coelom
thin external cuticle, projecting hairlike extension called setae/chaetae
developed/ complete digestive system
some can asexually reproduce through budding, but most are either non-self fertilizing hermaphrodites or dioecious
metamerisms
true segmentation
setae/chaetae
thin external cuticle, projecting hairlike extensions
Arthropoda general characteristics
body segment
jointed appendages
respiration can vary some have spiracles gas exchange occurs directly between the cells and air in tracheae, gills(crusteans), book lungs, book gills
some are hermaphrodites, but most are dioecious
freshwater, marine, terrestrial
arthropoda subphylum
hexipoda- six pairs of legs, 3 body segments, can be winged or not, usually have antenna attached to the head, abdomen contains reproductive structures
myripoda- many legs, usually found in dead decaying matter in soil
crustacea- most are aquatic, but some terrestrial, have two body segments(head/thorax fused to produce a cephalothrorax), breathe by use of gills
chelicerata- also have two body parts , have specialized, claw-life or fang appendages known as pedipalps, can have either gills or book lungs
Echinodermata characteristics
spiny skin, pentaradial symmetry in adult form, bilateral symmetry in larval stages
marine
endoskeleton made of ossicles
many have tube feet for mobility;water vascular system
water vascular system
use water to create hydraulic pressure to move feet
