BIOL 321 LAB Flashcards
a diagram of a hierarchical system of nested sister groups of taxa
cladogram
meaning of ‘dissection’
exposing to view
what are dissecting microscopes used for
viewing are, relatively opaque objects
dissecting microscope lens system is designed to
maximize working distance between object lenses and the subject
illumination in a dissecting microscope
above
side
below
side illumination
reflected light
illumination from below
transmitted light
compound microscope is used for
observing fine details in small specimens that have been rendered transparent
compound microscope illumination
generally transmitted light
built-in illuminator concentrates light beams through condenser
compound microscope objecties
scanning (4x)
low power (10x)
high power (40x)
oil immersion lens (100x)
most frequent objective used for studying invertebrates
low power 10x
primary magnification power
objective lens
Parfocal
objects remain in focus when a different objective is rotated into position
what does the ocular lens do
convert the magnified real image from objective lens into a magnified virtual image
objects remain in the centre of the field when a different objective is rotated into position
parcentral
how to obtain maximum resolution
Koehler illumination
center and focus illumination system
10x objective field diameter
1.6mm
40x objective field diameter
0.4mm
calculate magnification of a drawing
size of drawing / size of object
calculating scale bar
(drawing length)/(specimen length) = (scale bar length)/x
Phylum Porifera Classes
Class Calcarea
Class Hexactinellida
Class Demospongiae
Sponges lack
mouth
digestive cavity
nerves
muscles
how sponges eat
most capture bacteria/phyto. and digest in intracellular food vacuoles
‘carnivorous’ sponges
Cladorhizidae
eat small zooplankton - break into small pieces, phagocytize, digest with intracellular vacuoles
sponge symmetry
some radially symmetric, most asymmetrical
sponge body plan
two photo-epithelial layers sandwiching a layer of connective tissue
outer surface of sponge body
pinacoderm
internal surfaces (canals and chambers) of sponge body
choanoderm
connective tissue layer of sponge body
mesohyl
cells in outer layer of sponge body
pinacocytes
inside of the mesohyl
collagen fibres, ameboid cells, skeletal elements
cells in inner layer of sponge body
choanocytes
sponge skeletal elements
biomineralized spicules and/or organic cord mesh
organic mesh skeletal element of some sponges
spongin
choanocyte function
use flagella to propel water through sponge body
capture and digest food particles suspended in water
grades of complexity in sponges
Asconoid
Syconoid
Leuconoid
Asconoid
minute
vase-shaped
choanocytes line a central spongocoel
central spongocoel
atrium
Syconoid
larger
vase-shaped
choanocyte-lined chambers each open directly into central spongocoel
Leuconoid
massive form
spongocoel replaced with extensive system of choanocyte-lined chambers interconnected by canals
advantage to sponges increasing surface area
increased efficiency in filter water and capturing food
Class Calcarea features
exclusively marine
CaCO3 spicules
all 3 architecture types
individuals can cluster, but live independently
buds occasionally appear at base of mature specimens
asconoid Calcarea observed in lab
Leucosolenia
syconoid Calcarea observed in lab
Grantia
Scypha
Class Demospongiae
All freshwater sponges
Most marine sponges
Leuconoid
most local intertidal sponges have encrusting growth
Demosponge skeleton
anastomosing ropes of proteinaceous spongin and/or siliceous spicules
NO CaCO3
Class Hexactinellida
glass sponges
pinacoderm and choanoderm are syncytial
Hexactinellida skeleton
chitin
6-pointed silica dioxide spicules
syncytium
a multinucleate animal tissue without internal cell boundaries
Hexactinellid observed in lab
Aphrocallistes
Gemmules
a dormant structure entered in to mostly by freshwater sponges, during times of unfavourable conditions
significance of gemmules
more resistant to desiccation/freezing/anoxia
protect sponge
secondary metabolites
organic molecules not part of biochemical pathways involved in metabolism of nutrient molecules
Poriferans manufacture secondary metabolites to
deter predators
deter competitors for living space
inhibit pathogens
Halichondria secondary metabolites
unpleasant odour when rubbed
local species
why sponges are rarely overgrown by other sessile organisms
defensive chemicals (secondary metabolites)
importance of sponge spicules
support- body would collapse without
taxonomy - shape and mineral composition distinguish species
easy way to tell if sponge is Calcarea
acid test (dissolves CaCO3)
spicule shapes, axes
suffix -axon
# of axes
monoaxons
triaxons
spicule shapes, number of points
suffix -actine
# of points
triactine
hexactine
demosponge spicules
most are monoaxons
Grantia spicules
triaxon and triactine
glass sponge spicules
triaxon and hexactine
Carnivorous sponges tend to inhabit
the deep sea
shallow-water Cladorhizidae in Salish Sea
Asbestopluma occidentalis
18m
co-occur w/ hexactinellid sponges
Asbestopluma occidentalis reproduction
adult disassociates tissues facilitating larval release and dispersal
larvae have actively beating cilia (no swimming observed)
parent reaggregates into spherical balls of undifferentiated tissue that can disperse and settle
Asbestopluma occidentalis feeding
observed capturing Artemia nauplii using anisochelae spicules
nauplii
first larval stage of many crustaceans, having an unsegmented body and a single eye
Subphylum’s in Phylum Cnidaria
Medusozoa
Anthozoa
Class’s in Subphylum Medusozoa
Staurozoa s.g. to
Hydrozoa s.g. to
Scyphozoa s.g. w
Cubozoa
Class’s with free-floating Medusae
Hydrozoa
Scyphozoa
Cubozoa
Example of Class Hydrozoa from lab
Obelia
Siphonophores
Example of Class Scyphozoa from lab
Aurelia
Class’s in Subphylum Anthozoa
Octocorallia
Hexacorallia
Class Octocorallia includes the
soft corals
sea pens
Example of Class Hexacorallia from lab
Anthopluera
Class Hexacorallia includes the
sea anemones
stony corals
Cnidarian size
1mm - 2m in diameter
Cnidaria germ layers
epidermis covers body surface
gastrodermis lines body cavity (GVC)
Mesoglea between
Mesoglea
collagen fibres
extracellular matrix
ameboid cells (in most clades)
What do Cnidarians have that Poriferans do not
true gut
nerve cells
cnidocysts (unique to them)
Cnidarian GVC
digests ingested food
circulate nutrients and gases throughout body
Cnidarian symmetry
most radial
sea anemones, corals = biradial
biradial symmetry
similar parts are located to either side of a central axis and each of the four sides of the body is identical to the opposite side but different from the adjacent side
Alternation of generations
in most Medusazoans
asexual polyp stage
sexual medusa stage
polyp, medusa both diploid, only egg is haploid
Polymorphism
colonial individuals develop differently morphologically
preform different specialized jobs (feeding, reproduction, defense)
genetically identical - express diff. parts of the genome
Cnidarian lifestyle
All carnivorous
prey capture facilitated by cnidocytes (in high density on tentacles)
Nematocyst function
prey capture
defense
aid in digestion
Hydra
freshwater
class Hydrozoa
no medusa stage
2 germ layers, cnidocytes only in epidermis
Hydra morphology
mouth at apex of hypostome ring of tentacles at base of hypostome body column, gastric region, stalk basal disk (adhesive) budding zone
hypostome
the oral tip surrounded by tentacles in hydrozoan cnidarians (cone-shaped)
Hydra budding zone
junction of gastric region and stalk
where new polyps arise as asexual buds
Hydra reproduction
bud forms on stalk as simple evagination - distal end of bud forms mouth + tentacles - bud drops off
acontia
thread-like pieces of the body found near the pedal disc, attached to septal filaments inside the body, at times flow in/out of GVC
Medusazoans that stray from typical alternation of generations homology
Staurozoans - free-living medusa completely absent
Hydrozoa - some members exhibit secondary loss of medusa stage (e.g. Hydra)
Morphological character in common with all Medusazoans
linear mitochondrial chromosome
other Cnidarians, most eukaryotes have circular
Scyphozoa
scyphomedusa larger, more conspicuous life stage some freshwater cnidocytes in epidermis + gastrodermis gametes originate from gastrodermis ameboid cells in mesoglea frilly oral arms thick mesoglea
cnidarian medusa swimming
rhythmic contraction of epitheliomuscle cells (circular muscle sheet on underside of bell)
manubrium
a tubular structure that contains the mouth
Scyphozoa digestion
prey captured with cnidocytes on tentacles/oral arms, transferred to mouth at end of manubrium, ingested, conveyed to stomach, distributed to 4 gastric pouches, partially digested enzymatically - digestion completed intracellularly w/i gastrodermal cells – then circulated via ciliated gastrovascular canals
Scyphozoa gastric pouces
contain short gastric filaments (tentacles) that secrete digestive enzymes
Scyphozoa gastrovascular canals
adradial (unbranched)
interradial, perradial (branched)
GV canals connect gastric pouces to ring canal (around periphery of bell)
common moon jellyfish
Aurelia floats close to surface local short tentacles and manubrium feeds on small plankton 0.2-2mm
Aurelia feeding
slow contraction of bell – draws prey toward medusa – recovery stroke – sucks prey into subumbrellar cavity – captured, subdued by nematocysts in oral arms
feed on smaller organisms than other scyphomedusae b/c of short oral arms
sensory cells around bell of Scyphomedusae
rhopalia
8 small ‘knobs’
statocyst, pigment spot, cluster of photoreceptor cells, chemoreceptor cell
Statocyst
gravity receptor