Inverts - Mode of existence Flashcards
Bilateral symmetry
Right and left side of the animal are a mirror
free moving animals are bilateral
Radial symmetry
More than one axis of symmetry
no left or right side
mostly sessile animals
Marine environment
All invertebrate families have marine representatives
Many are strictly marine
Splash Zone (marine habitats)
Only gets small amount of water
Intertital Zone (marine habitats)
Where the tide rises and falls
Spring tides - wide range
Neap tides - not such a wide range
Both affected by lunar cycles
Specialised animals living in the intertidal zones
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
Littoral zone
Where the land meets the sea
(subdivided into splash zone & intertidal zone)
Continental shelf size
50-100km length / 150-200m depth
Continental shelf
- Nutrients coming off land
- light can penetrate
- primary producers
- Productive areas
Example of ecosystem in the continental shelf
Coral reefs - 0.01% oceans area, home to 25% of marine species
Continental slope
Steep decline
Ends at abyssal plain
Abyssal plain
3000-5000m
Bottom of the deep sea
Pressure increases by 1 atmosphere every 10m
no light
inhospitable place
Marine snow
Waste/animal etc that falls down from ocean above
food for deep sea filter feeders
Harp sponge (found on abyssal plain)
Predacious sponge
live animals stick to harp structure and are digested
Vampire squid (abyssal plain)
Can remove skin to reveal spine underneath
Is a filter/suspension feeder (has filaments that unfurl and collect food)
Spines are for protection
Deep sea trenches (measurements)
5000 - 11,000 m
Mariana trench
Challenger deep is the deepest point of mariana trench
Invertebrate found in the Mariana trench
Amphipod (Hirondella gigas)
Shrimp like animal
significance of deep sea Amphipod (Hirondella gigas)
Specialised feature that digests cellulose
believed to feed on decomposing wood that falls to the ocean floor
Deep sea hydrothermal vents
Input chemicalsand nutrients into the system
have their own ecosystems
Pelagic (animals)
- Live in the pelagic zone
- Suspended or swimming in water
e.g.
Nekton (actively swim)
Plankton (Drift)
Benthic (animals)
Live at the bottom
(in / on muddy deposits)
Errant
Mobile / active
Sessile
Attached (not free moving)
Sedentary
Unattached but immobile
Advantages of the sea
Lots of space
High productivity (Total primary production = 48.7 x 109 metric c/yr)
71% of earths surface
Ocean Biomass (measure of productivity)
Decreases from the shoreline to the open ocean
Productivity decreases
Why is the sea a relatively constant environment? (thermal buffer)
retains heat well
takes a long time to heat up and cool down
Why is the sea a relatively constant environment? (Salinity)
- Salinity is relatively constant
- High density (bouyancy, ionic concentration)
- Allows large organisms
Why is the sea a relatively constant environment?
short term extremes in intertidal seas
Oxygen - highest in the top 100m
pH 7.5-8.5 (increased CO2 can lower pH)
Isosmotic sea water
- Same salinity concentrations as organisms body tissues
- Osmoconformers (don’t have to maintain body salinity)
Waste as ammonia
- Needs water to get rid of
- Organisms living in aquatic environment dont need to process ammonia
Freshwater - Temp variation
- 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
Thermocline of river waters
In summer differences between top and bottom much greater than in winter
this is know as thermocline
water lower down is much colder
Osmotic regulation
Freshwater animals require osmotic regulation
What are estuarine habitats?
Where fresh and marine water come together
Estuarine features
Salt marshes, estuaries, mangroves
Salinity <3.5%
Productive - not many species but high abundance of animals
Freshwater environments are less favourable than marine
Less constant
temp & Oxygen variation
Osmotic regulation required
freezing and drying causes issues
Terrestrial
- Hardest environment
- E.g. Earthworms - will go into hibernation/ restoration state when conditions become too extreme (aestivation)
- Arthropods are best adapted for terrestrial
Terrestrial - Oxygen intake
lots of oxygen in air but moist surface is needed for gaseous exchange
Terrestrial - waste
no water so waste needs to be excreted as uric acid or urea
