phylum porifera

Question 1

what type of feeders are sponges ?

Answer 1

almost all suspension feeders (filter feeders)

Question 2

exception to suspension feeding sponges

Answer 2

cold water deep carnivorous sponges - Chondrocladia grandis
prey on planktonic crustaceans

Question 3

what is multicellularity ?

Answer 3

a condition or state of having or being composed of many cells — with more than one cell type performing different functions

Question 4

possible evolutionary progression of multicellularity characteristics

Answer 4

1. cell adhesion (cells become selective)
2. cell specialization and interdependence
3. embryonic differentiation

Question 5

what are the advantages of multicellularity? why did it develop ?

Answer 5

1. cells can perform all life functions more efficiently due to specialization
2. larger body sizes and more complex body types can be achieved w this, positive competitive advantage
3. the diversity of body sizes and types opened up much larger range of habitat niches (not avail to unicellular) - in relation to temp, pH, chemical availability etc)

Question 6

metazoan tissue types

Answer 6

1. epithelial tissue
2. connective tissue
3. nervous tissue
4. muscle tissue
5. gametogenic tissue

Question 7

defining characteristics of epithelial tissue

Answer 7

1. forms tight and regular cell sheets (cellularity)
2. have a dictated direction (polarity)
3. is surficial layer for other cells (attachment)
4. have no blood cells (avascular)
5. show rapid growth (regeneration)

Question 8

functional importance of epithelial tissue

Answer 8

1. transitional covering on all internal and external surfaces on body
2. lines body cavities and hollow organs - is the major tissue in glands
3. performs protection (skin), secretion (glands), absorption, excretion, filtration, diffusion, and sensory reception

Question 9

connective tissue defining characteristics:

Answer 9

1. formed by an abundant intercellular matrix with relatively few connecting cells
2. contains collagen (the main structural protein - most abundant protein in mammals) — whats being released when making bone broth

Question 10

functional importance of connective tissue

Answer 10

1. binding and holding other tissues together
2. supporting and protecting individuals organs
3. provides elasticity for movement (ex// cartilage)

Question 11

defining characteristics of nervous tissue

Answer 11

1. ropelike linear or branching bundles in structure
2. fibers are excitable - capable of sending and receiving electrochemical signals
3. comprised of neurons and neuroglial cells - glial cells supporting the neural structures

Question 12

functional importance of nervous tissue

Answer 12

1. generate and conduct sensory or motor impulses between the brain or spinal cord
2. provides all parts of the body w information, and controls both voluntary (movement) and autonomous body functions (digestion)

Question 13

defining characteristics of muscular tissue

Answer 13

1. ability to shorten and lengthen
2. highly cellular and highly vascular (supplied well w blood vessels)
3. often have elongated nuclei

Question 14

functional importance of muscular tissue

Answer 14

1. contractions produce movement of body parts
2. must work w nervous tissue for stimulus
3. used for heat generation and fluid distribution functions (ex// blood)

Question 15

defining characteristics of gametogenic tissue

Answer 15

1. haploid (n) or one set of chromosomes. ONLY tissues that are haploid
2. produced by dedicated diploid (2n) germ cells which undergoes meiosis that forms haploid cells
3. typically sexually dimorphic — male gamete smaller in size and motile — female gamete several times bigger and non-motile

Question 16

functional importance of gametogenic tissue

Answer 16

1. for reproduction only
2. combines w another haploid cell at fertilization
3. can generate genetic variation among progeny - may allow for faster adaptation of the population to novel and/or stressful environments
   — evolution stems from this - genetic variation

Question 17

how many sponge classes are there ? what are they ?

Answer 17

3

1. class calcerea (grantia)
   — have hard spicules composed of calcium carbonate (concrete) - can still be flexible
2. class hexactinella (glass sponges)
   — have hard spicules composed of silica dioxide - like glass (not flexible)
3. class demospongiae (haliclona, halichondria)
   — NO spicules - dominant structure of spongin (bath sponges)

Question 18

habitat and lifestyle of a sponge

Answer 18

• both marine and freshwater
• larval as juveniles, sessile as adults
• hydraulic suspension feeders
• circulating TONS of water all the time

Question 19

sponge feeding

Answer 19

• small pores lead to complex system of channels lined w specialized feeding cells — called choanocytes or collar cells (pump water in)

Question 20

sponge morphology and tissue type

Answer 20

• no “true tissues” — like nervous tissue or muscle tissue
  — sponges are the only metazoans without these
• although they do have different inner and outer tissues
• no specialized digestive system, no nerve tissue, no muscle tissue, no ovaries or testes
• gametes produced by choanocytes
  — most are hermaphroditic, and can ALSO reproduce sexually

Question 21

what are choanocytes and what do they do ?

Answer 21

choanocytes are specialized feeding cells within protoepithelial tissue.

they pump water in, produce gametes, capture and absorb nutrients (collar)

Question 22

components of a choanocyte

Answer 22

flagellum - moves water thru sponge

collar - not really moving, just at base — filter water w microvilli
— capture and absorb nutrients

cell body - adhering to sponge

Question 23

external sponge morphology component

Answer 23

pinacocytes

— external cells forming solid sheets (like an epithelium)
— directs water into channels thru negative pressure
— can expand or contract slightly to alter size shape of sponge

Question 24

2 differences between choanocytes and pinacocytes

Answer 24

choanocytes have flagellum that line interior of sponges — pinacocytes are flat cells in the outer most layer of sponges

choanocytes help to accumulate oxygen and nutrients — pinacocytes provide a shape to body of sponge

Question 25

sponge morphology: cell type arrangements across body plans (3 body types and matrix)

Answer 25

asconoid - synconoid - leuconoid increasing complexity from left to right 1. asconoid - shaped like a simple tube 2. synconoid - now w choanocyte lined radial canals 3. leuconoid - now w a complex system of branching inhalant and exhalant canals leading to and from choanocyte chambers mesohyl : the gelatinous matrix within a sponge

Question 26

demospongiae: where are they found, structure, what are they used for ?

Answer 26

only class found in freshwater contain siliceous spicules and/or spongin structure most abundant ~ 80% of all sponge species used for bath sponges - huge industry

Question 27

what happened to sponges ? - downfall and action to try and make them come back

Answer 27

collected by wading and boats in shallow water collected w poles eventually were only left in deep water — greek divers going after these take action: 1. legislation 2. aquaculture 3. violence and intimidation 4. fished harder the last remaining sponges hit by disease — the sponges have no recovered** this effected sponges, turtles, sharks, shrimp, lobster as well

Question 28

how did the sponge extraction manifest in biology ?

Answer 28

have evolved chemical and structural defence mechanisms to avoid predation and compete w other benthic organisms like coral

Question 29

what specifically feeds on sponges?

Answer 29

hawksbill turtle can ingest the “glass” contents— even tho they prefer to feed on non toxic sponges the historical observation demonstrates the internal biological impacts of extreme reduction in hawksbill turtle populations

Question 30

overfishing and sponge/coral dynamics

Answer 30

overfished sites had way more overgrowth of corals by sponges — where lacked parr

Question 31

conclusions : ecological dimensions of sponges

Answer 31

- sponges and all organisms exist in dynamic ecological and human systems - changes to populations alter ecology which can further impact individual or population biology - historical ecology opens up a lot of questions