Inverts - Mode of existence

Question 1

Bilateral symmetry

Answer 1

Right and left side of the animal are a mirror

free moving animals are bilateral

Question 2

Radial symmetry

Answer 2

More than one axis of symmetry

no left or right side

mostly sessile animals

Question 3

Marine environment

Answer 3

All invertebrate families have marine representatives

Many are strictly marine

Question 4

Splash Zone (marine habitats)

Answer 4

Only gets small amount of water

Question 5

Intertital Zone (marine habitats)

Answer 5

Where the tide rises and falls

Spring tides - wide range

Neap tides - not such a wide range

Both affected by lunar cycles

Question 6

Specialised animals living in the intertidal zones

Answer 6

Barnacles - have a cover (carapace) during low tide - stops them drying out (Arthropods)

Sea anemone - Hydrostatic skeleton. retracts tentacles when the sea is out to protect from drying

Question 7

Littoral zone

Answer 7

Where the land meets the sea

(subdivided into splash zone & intertidal zone)

Question 8

Continental shelf size

Answer 8

50-100km length / 150-200m depth

Question 9

Continental shelf

Answer 9

• Nutrients coming off land
• light can penetrate
• primary producers
• Productive areas

Question 10

Example of ecosystem in the continental shelf

Answer 10

Coral reefs - 0.01% oceans area, home to 25% of marine species

Question 11

Continental slope

Answer 11

Steep decline

Ends at abyssal plain

Question 12

Abyssal plain

Answer 12

3000-5000m

Bottom of the deep sea

Pressure increases by 1 atmosphere every 10m

no light

inhospitable place

Question 13

Marine snow

Answer 13

Waste/animal etc that falls down from ocean above

food for deep sea filter feeders

Question 14

Harp sponge (found on abyssal plain)

Answer 14

Predacious sponge

live animals stick to harp structure and are digested

Question 15

Vampire squid (abyssal plain)

Answer 15

Can remove skin to reveal spine underneath

Is a filter/suspension feeder (has filaments that unfurl and collect food)

Spines are for protection

Question 16

Deep sea trenches (measurements)

Answer 16

5000 - 11,000 m

Mariana trench

Challenger deep is the deepest point of mariana trench

Question 17

Invertebrate found in the Mariana trench

Answer 17

Amphipod (Hirondella gigas)

Shrimp like animal

Question 18

significance of deep sea Amphipod (Hirondella gigas)

Answer 18

Specialised feature that digests cellulose

believed to feed on decomposing wood that falls to the ocean floor

Question 19

Deep sea hydrothermal vents

Answer 19

Input chemicalsand nutrients into the system

have their own ecosystems

Question 20

Pelagic (animals)

Answer 20

• Live in the pelagic zone
• Suspended or swimming in water

e.g.
Nekton (actively swim)
Plankton (Drift)

Question 21

Benthic (animals)

Answer 21

Live at the bottom
(in / on muddy deposits)

Question 22

Errant

Answer 22

Mobile / active

Question 23

Sessile

Answer 23

Attached (not free moving)

Question 24

Sedentary

Answer 24

Unattached but immobile

Question 25

Advantages of the sea

Answer 25

Lots of space

High productivity (Total primary production = 48.7 x 109 metric c/yr)

71% of earths surface

Question 26

Ocean Biomass (measure of productivity)

Answer 26

Decreases from the shoreline to the open ocean

Productivity decreases

Question 27

Why is the sea a relatively constant environment? (thermal buffer)

Answer 27

retains heat well

takes a long time to heat up and cool down

Question 28

Why is the sea a relatively constant environment? (Salinity)

Answer 28

• Salinity is relatively constant
• High density (bouyancy, ionic concentration)
• Allows large organisms

Question 29

Why is the sea a relatively constant environment?

Answer 29

short term extremes in intertidal seas

Oxygen - highest in the top 100m

pH 7.5-8.5 (increased CO2 can lower pH)

Question 30

Isosmotic sea water

Answer 30

• Same salinity concentrations as organisms body tissues
• Osmoconformers (don’t have to maintain body salinity)

Question 31

Waste as ammonia

Answer 31

• Needs water to get rid of
• Organisms living in aquatic environment dont need to process ammonia

Question 32

Freshwater - Temp variation

Answer 32

• Summer and winter temperatures vary
• Movement of waters in spring and autumn
• In summer differences between top and bottom much greater than in winter
• Thermocline

Question 33

Thermocline of river waters

Answer 33

In summer differences between top and bottom much greater than in winter

this is know as thermocline

water lower down is much colder

Question 34

Osmotic regulation

Answer 34

Freshwater animals require osmotic regulation

Question 35

What are estuarine habitats?

Answer 35

Where fresh and marine water come together

Question 36

Estuarine features

Answer 36

Salt marshes, estuaries, mangroves

Salinity <3.5%

Productive - not many species but high abundance of animals

Question 37

Freshwater environments are less favourable than marine

Answer 37

Less constant

temp & Oxygen variation

Osmotic regulation required

freezing and drying causes issues

Question 38

Terrestrial

Answer 38

• Hardest environment
• E.g. Earthworms - will go into hibernation/ restoration state when conditions become too extreme (aestivation)
• Arthropods are best adapted for terrestrial

Question 39

Terrestrial - Oxygen intake

Answer 39

lots of oxygen in air but moist surface is needed for gaseous exchange

Question 40

Terrestrial - waste

Answer 40

no water so waste needs to be excreted as uric acid or urea