Biol 111 Lab Final

Front 1

phylum Cnidaria

Back 1

simplest of animals other than sponges
possess specialized stinging cells (cnidocytes) that assist in capture of prey and defense
radially symmetrical
two forms: polyp and medusa - if show both and dimorphic

Front 2

cnidocytes

Back 2

specialized stinging cells on Cnidarians that assist in capture of prey and defense

Front 3

radial symmetry

Back 3

The arrangement of the body of an animal in which parts are arranged symmetrically around a central axis

Front 4

polyp

Back 4

a fairly sessile form of Cnidarian in which the oral surface (mouth) is upward and the aboral surface (other end) is attached to a substrate

Front 5

medusa

Back 5

a free swimming form of the Cnidarian in which the mouth is usually downward

Front 6

Cnidarian lifecycle

Back 6

usually alternate between a motile sexual medusa stage and a sessile asexual polyp stage
are dimorphic if they have both stages

Front 7

Hydra

Back 7

a small freshwater polyp with no medusa stage
commonly found in ponds and streams attached to plants and rocks
carnivore

Front 8

basal disk (hydra)

Back 8

[Hydra]
foot

Front 9

Hydra feeding/digestion

Back 9

[Hydra]
capture prey using their tentacles and subdue them with toxic stings of their nematocytes
food is transferred to their mouth, partially digested in the gastrovascular cavity and then absorbed by gastrodermal cells
there intracellular digestion occurs
undigested material is voided thru mouth

Front 10

Does the Hydra actively move to capture its prey or does it sit and wait for the prey to bump into its tentacles?

Back 10

For the most part, they remain attached to their substrate and let their tentacles drift with the water currents. If a prey item (e.g., a zooplankton species) brushes into one of the tentacles, the hydra quickly grabs onto it with the other tentacles subduing it with poisonous threads/filaments from its nematocysts.

Front 11

How does the radial symmetry of your hydra (and cnidarians, in general) assist them in this feeding strategy?

Back 11

Most cnidarians are opportunistic feeders and capture prey as they bump into their tentacles, rather than stalking or chasing after its prey. Having sensory and feeding structures (tentacles) radiating from their body increases their abilities to sense and capture prey that may be coming at them from any direction. This differs from animals that go after their prey. In this case, being bilaterally symmetrical is more beneficial because the sensory structures are concentrated in one area, which is moving in one direction.

Front 12

➢ How many tentacles does your hydra have?

Back 12

around 6, and they can regenerate lost tentacles

Front 13

➢ Describe the environmental conditions that would favor sexual reproduction over asexual reproduction in Hydra. What is the probable evolutionary reason for having two different reproductive strategies?

Back 13

Hydra and other aquatic invertebrates often reproduce asexually in the summer months. At this time, food resources are high (lots of light leads to lots of phytoplankton which leads to lots of zooplankton) and water temperatures are stable.
In contrast, in the spring and fall of temperate climates, the environmental conditions are more variable, thus genetic variation in the offspring is necessary for survival of some members of the population

Front 14

➢ Technically, Gonionemus is not a jellyfish. Why?

Back 14

The term “jellyfish” is reserved for members of Class Scyphozoa. Gonionemus is a hydrozoan. Both Gonionemus and jellyfish have a dominant medusa form. Jellyfish lack a velum which you saw in Gonionemus.

Front 15

nematocytes

Back 15

[hydra]
harpoon-like structures
released from cnidocytes

Front 16

[hydra]
gastrovascular cavity

Back 16

[hydra]
location where digestion and absorption of food occurs
some gas exchage (respiration) occurs in cells lining the cavity (gastrodermis)

Front 17

[hydra]
gastrodermis

Back 17

[hydra]
inner layer of epithial cells
cells lining the gastrovascular cavity
some respiration occurs here

Front 18

mesoglea [hydra]

Back 18

[hydra]
a thin, gelatinous layer between the epidermis and gastrodermis

Front 19

[hydra]
epithelio muscular cells

Back 19

act as both epithelial cells by covering and lining both surfaces and as muscle cells by having contractile muscle fibers
one type of these cells had longitudinal muscle fibers and is located in the epidermis
the other has circular fibers and is located in the gastrodermis
work antagonistically to enable movement

Front 20

[hydra]
gland cells

Back 20

located in the epidermis of the basal disc
secrete a sticky substances used for anchoring the basal disc

Front 21

[hydra]
sexual reproduction

Back 21

sperm + egg cell (gametes) -> zygote
sperm and eggs produced in gonads (small mounds in epidermis)
sperm made in testes on upper half , ovary in lower half
occurs during fall
zygote remains dormant until spring

Front 22

[hydra]
asexual reproduction

Back 22

budding of a new individual from the body of an adult by the process of mitosis
the bud detaches itself from the parent hydra when it is large enough to capture its own food and live intependently

Front 23

[Gonionemus]
bell

Back 23

the dome-shaped structure compised of epidermis, gastrodermis, and a thick layer of mesoglea

Front 24

[Gonionemus]
tentacular bulbs

Back 24

dark swellings located at the base of each tentacle
contain interstitial cells which will develop into cnidocytes to replaced discharged ones on the tentacles

Front 25

[Gonionemus]
adhesive pads

Back 25

located near the tips of the tentacles. These are cused in the attachement to seagrass and macroalgae

Front 26

[Gonionemus]
velum

Back 26

a shelf under the edge of the bell
when epitheliomuscular cells in the velum and bell contrace, a jet of water is projected downward, pushing the animal upward
to go down they sink

Front 27

[Gonionemus]
cnidocytes (cnidoblasts)

Back 27

stinging cells occur in spiral swellings (batteries) along the length of the tentacles
each cell contains a nematocyst the explosively projects a tube capable of penetrating the tissue of its prey and injecting a paralyzing poison

Front 28

[Gonionemus]
Manubrium

Back 28

a tube that hangs in the space inside the bell terminating with the mouth
homologous with the hyposome in the Hydra
the stomach (gastrovascular cavity) is located below the base

Front 29

[Gonionemus]
oral lobes

Back 29

fleshy projections that ring the edge of the mouth
assist with ingestion

Front 30

[Gonionemus]
radial canals

Back 30

four canals radiating out from the manubrium - extensions of the stomach

Front 31

[Gonionemus]
ring canal

Back 31

connecting with the ends of the radial canals and running around the edge of the bell
the stomach and canals form a continuous gastrovascular system where food is partially digested and circulated throughout the system

Front 32

[Gonionemus]
statocysts

Back 32

small swellings between the bases of the tentacles. they contain a stone suspended on a flexible stalk
pressur of the stone agains the cells lining the cavity provides the basis for orientation with respect to gravity

Front 33

[Gonionemus]
gonads

Back 33

have four ruffled gonads

Front 34

[Gonionemus]
planula

Back 34

the fertilized egg develops rapidly into a small ciliated larva
soon attaches to some solid object and becomes a polyp

Front 35

[Gonionemus]
polyp stage

Back 35

after planula attaches to a solid and becomes a poly, it reproduces asexually by budding, creating more polyps
the polyps produce medusa buds that detach and grow directly into adult medusae

Front 36

anterior end

Back 36

front

Front 37

posterior end

Back 37

end of organism/butt

Front 38

dorsal surface

Back 38

upper side or back

Front 39

ventral surface

Back 39

underside (belly)

Front 40

bilateral symmetry

Back 40

he arrangement of the body components of an animal such that one plane divides the animal into two halves which are approximate mirror images of each other.

Front 41

[earthworm]
female genital pores

Back 41

two pores on segment 14
where eggs are released

Front 42

[earthworm]
male genital pores

Back 42

two pores on segment 15
where sperm is released
sperm travels down two seminal grooves running from segment 15 to the clitellum

Front 43

[earthworm]
clitellum

Back 43

a thickened glandular section of the body wall in earthworms and some other annelids, that secretes a viscid sac in which the eggs are deposited

Front 44

[earthworm]
genital setae

Back 44

segment 26
help hold the ventral surfaces of the worms together, in opposing directions, during copulation

Front 45

[earthworm]
hydrostatic skeleton

Back 45

a fluid-filled cavity, the coelom, surrounded by muscles. The pressure of the fluid and action of the surrounding muscles are used to change an organism's shape and produce movement

Front 46

[earthworm]
septa

Back 46

(singular = septum)
semi-transparent walls that mark the boundaries of each segment

Front 47

[earthworm]
coelom

Back 47

fluid filled body cavity, enclosed within the body wall

Front 48

[earthworm]
pharynx

Back 48

first digestive organ after the mouth
muscular organ that pulls the soil and detritus into the digestive tract
radial muscles dilate the pharynx to assist with ingestion

Front 49

[earthworm]
crop

Back 49

after esophagus in digestive tract
dark coloured, thin-walled storage pouch

Front 50

[earthworm]
gizzard

Back 50

after crop in digestive tract
muscular and hard, grinds up food

Front 51

[earthworm]
typhlosole

Back 51

a dorsal infolding of the intestine
increases SA and this absorption

Front 52

[earthworm]
seminal vesicles

Back 52

white structures part of the male reproductive system
store sperm

Front 53

[earthworm]
testes

Back 53

contained within the seminal vesicles in segments 10 and 11

Front 54

[earthworm]
"brain"

Back 54

a pair of ganglia (cluster of neurons) called the cerebral or suprapharyngeal ganglia

Front 55

[earthworm]
sensory receptor cells

Back 55

within epidermis
these specialized neurons receive sensory information such as light, chemicals and pressure from the external environment and transmit them to the suprapharyngeal ganglia

Front 56

[earthworm]
nepheridium

Back 56

an organ part of the excretory system
comes in pairs (with nephridiopore) repeated in almost every segment
picks up chemicals from the coelomic fluid and from blood capilllaries surrounding it
excretes thru the nephridiopore in body wall