intro to marine invertebrates

Question 1

Ecological importance of marine invertebrates

Answer 1

• Near bottom of food webs
• important in structuring ecosystem function
• Indicate aquatic system wellbeing

Question 2

Economic importance of marine invertebrates

Answer 2

• Food
• Biofouling
• More specialised uses, e.g. medical studies

Question 3

2 ways we classify marine invertebrates

Answer 3

1. where they live (intertidal or subtidal)
2. how they get energy (herbivore, carnivore, deposit feeder, filter feeder)

Question 4

what are deposit feeders and filter feeders

Answer 4

Deposit feeder - sive through sediment + take out organic material (depositing cleaner sediment)
Filter feeder – filter organic matter through the water collum

Question 5

what are the challenges intertidal animals face

Answer 5

air = much more O2 than water (proportional to temp + salinity)

Question 6

what are the factors intertidal animals need to maintain to breath air

Answer 6

• moisture
• surface area of gas exchange

Question 7

what are the [O2] and [CO2] in rock pools driven by

Answer 7

• respiration
• photosynthesis

Question 8

when can hypoxic (less O2) / hypercapnic (too much CO2) conditions develop in rock pools

Answer 8

• hypoxic/hypercapnic - at night (no photosynthesis)
• Hypoxic - in the summer (warmer water - less O2)

Question 9

traits intertidal animals need to have to survive

Answer 9

• Tough (resistant to dessication, wave action, able to avoid predation)
• Eurythermal
• Euryhaline
• Able to tolerate hypoxic/hypercapnic conditions

Question 10

which part of a species’ distribution does temp |+| salinity (abiotic) affect most

Answer 10

upper limit

Question 11

what temperature traits do invertebrates have

Answer 11

Ectothermic: rely on external heat source
Poikilothermic: variable body temp

Question 12

why does Salinity fluctuate in rock pools more than in the open ocean

Answer 12

• Heat from the sun will cause evaporation > increase salinity
• Strong rainfall dilutes rockpools > decrease salinity

Question 13

why are physical disturbances more of a problem for intertidal organisms

Answer 13

• have second set of predators e.g. sea birds
• Competition (both inter- and intra- specific) is extremely high > mostly determined by lower limit of a species’ distribution

Question 14

why do animals live intertidally

Answer 14

Lots of food – energy-filled environment

Question 15

what are spring and neap tides

Answer 15

-Spring tide: high tides are higher and low tides are lower than average -> sun, moon, and Earth lined up
- Neap tide: lower high tides and higher low tides -> sun, moon, and Earth form a right angle