Zoology Test 1c Flashcards
Porifera reproduction
- sexual reproduction
- broadcast fertilization
- species take in sperm from exterior and fertilize internally, larva hatched internally
- some species broadcast both sperm and oocytes
broadcast fertilization
throw it out there, need a phase to be synchronized
blastula
stage after fertilization that contains flagella on the inside which turns itself inside out
what is the motile stage of porifera reproduction?
parenchymula larva
How do sponges differ from protozoa?
- cell specialization in form and function
- coordination of different cell types
- begin to hint at tissues
How are sponges similar to protozoa?
- sexual and asexual reproduction
- intracellular digestion
- no organs or true tissues
common characteristics of Cnidaria
- radial symmetry
- invented movement
- germ-layers
- do have tissues
- have mouth
- have digestive cavity - extracellular digestion
- mostly marine
significance of Cnidarians
- contains most primitiver members on main line of eumetazoan evolution
- fossils up to 700 million years old
cnidarian symmetry
- have two ends
- oral end which is the mouth
- aboral end which is the opposite side of mouth
nematocysts
- mechanism used in cnidarians
- located in the cnidocytes
- sting and paralyze prey
- entangle prey
- triggered by contact
cnidocytes
specialized cell
nervous tissue of cnidarians
- true tissues include nerve net
- bidirectional nerve cells
- radial symmetry means no CNS
- nerve cells connect to muscular cells forming coordinated neuromuscular system
cnidarian body plan
- basic structure: digestive sac with one opening, two-way digestive system
- diploblastic
- two distinct layers: epidermis and gastrodermis
- gastrovascular cavity
- two forms: polyp and medusa
diploblastic
when blastula, has two layers of tissue
epidermis
outer tissue layer
gastrodermis
inner tissue layer
mesoglea
jelly-like layer inbetween the epidermis and gastrodermis
gastrovascular cavity
for digestion and circulation of nutrients, waste and gases
alternation of generations
type of pattern where the two forms of cnidarians perform different kinds of reproduction
polyp has what kind of reproduction
asexual
medusa has what kind of reproduction
sexual
what are the tissue layers of the embryonic cell?
- endoderm: inside
- ectoderm: outside
- mesoglea in the middle
What are the four classes of cnidarians?
- hydrozoa
- scyphozoa
- cubozoa
- anthozoa
hydrozoa
- hydra
- obelia
- physalia
scyphozoa
aurelia
cubozoa
box jellyfish
anthozoa
- sea anemone
- coral
characteristics of hydra
- freshwater
- polyp form
- both sexual and asexual budding
- dioecious
cell types in the hydra
- interstitial cells
- epitheliomuscular cells
- cindocytes
- sensory cells
interstitial cells
the stem cells of hydra
epitheliomuscular cells
shorten body, longitudinal muscles for body movement
cindocytes
capture prey and defend
sensory cells
sense chemical and tactile stimuli
What are the gastrodermis cell types?
- nutritive-muscular cells
- gland cells
nutritive-muscular cells
extend body and phagocytize food for intracellular digestion
gland cells
secrete enzymes to digest food in gastrovascular cavity for extracellular digestion
characteristics of physalia
- Portuguese man-o-war
- marine
- floating
- colonial
- prime example of polymorphism, contain both medusae and polyp in same colony
characteristics of obelia
- marine sessile
- colonial
- hydranths
- gonangia
hydranths
used for feeding in obelia
gonangia
produce medusa buds via asexual reproduction in obelia
planula larvae
stage that comes after the blastula in a obelia, fertilization to zygote to blastula to planula larvae
characteristics of scyphozoa
- true jellyfish
- example: aurelia
polyp stage is solitary, not colonial
sexual reproduction in scyphozoa
- male/female medusa produce gamete
- male releases sperm, female takes sperm in gastrovascular cavity to ovaries
- after fertilization, zygote develops into planula
- planula settles on substrate to become scyphistoma polyp
asexual reproduction in scyphozoa
- scyphistoma goes through strobilation to produce strobila stage of life cycle
- strobila buds to release multiple clones which called ephyra
- ephyra develop into male and female medusae
