Lecture 5 & 6 - The Rocky Shore Ecosystem Flashcards
Explain a high energy rocky shore?
This is a high energy shoreline, high erosive forces such as waves, tides and wind
What is a low energy rocky shore?
Low energy shoreline, low erosional processes, small fetch and a sheltered shore probably with sandy beaches
What are the zones on the rocky shore (based on tidal coverage) from top to bottom and a brief explanation
Supralittoral - terrestial
Littoral Fringe - wave splash (saline)
Eulittoral - tidal zone
Sublittoral - Always covered in water
Explain the divisions of the the Eulittoral zone
Upper - MHWN to EHWS
Middle MLWN to MHWN
Lower ELWS to MLWN
What are the two types of Primary producers
Lichens
Macroalgea (seaweeds)
Where are the Lichens found
Middle to supra, areas where there is decent exposure time
What are the three growth forms
Crustose
foliose
fruticose
What are lichens (explanation of relationship too)
there are in fact a combination a combination of two species one algea and one fungie. They have a symbiotic relationship of which both benefits.
Explain the ecology of Lichens
The algea is embedded in the fungal hyphae, fungus takes up water and nutrients for algea and the algea povides organic carbon for fungus,
Why are Lichens important on the ecology of the rocky shore
They are the colonisers
Explain the two methods of reproduction by Lichens
Spore - The fungus grows a spore forming body, then the spores are released and they are very resilient which make for perfect colonisation. Bacteria joins the party after
Fragmentation - not sexual reproduction but growth by expansion
where are macroalgea found
Sublittoral to upperlittoral, anywhere where they are immersed at least once in the tidal cycle
Explain the three (and one extra) components of macroaglea
Holdfast (anchor)
Stipe (stem)
Frond (lamina, thallus, blade)
Bladders (for flotation when high tide)
Explain the 3 ecological adaptations of macroalgea
For Water loss
> Mucilaenous coast (oily coat) and channeled thallus
For Light loss (must be submerged for photosyn to occur
> Some spp. have bladders for bouyancy
> Photosynthetic pigments: Chlorophyll a + accessory pigments
Explain the growth of macroalgeal (2 forms)
> Simple cell division
> Meristematic cell division at the algal apex, division of specialised cells
Explain the reproduction of macroalgea
Haploid gametophytes produce gametes, combine to form a diploid zygote, grows into a diploid organism, the sporophyte. Meiosis in the spohorophyte leads to production of haploid spores which grown into a gametophyte
What is a haploid gametophyte
a organism with a single set of chromosomes
What is a diploid zygote
An organism with two sets of chromosomes (just like us!)
Give the sexual reproduction story of Porphyra a red macroalgea
the spores germinate when they reach the shell of a mollusc, grows into a filament, the sporophyte, which releases spores into water. These spores attach to rocks and grow into a gamephyte
Give the sexual reproduction story of Laminaria, a brown macroalgea
Dominant form is the sporophyte, releases flagellate spores from a sporangium, spores settle on rocks and grown into small filamentous gametophytes. Male gametophytes release microgametes, female gametophytes grow an oogonium containing a macrogamete which is fertilised by the male microgamete. This fertilised egg grows into a zygote. The sporophyte then grows out of the zygote, i.e. out of the gametophyte.
Name the 2 main consumer spp. found on the rocky shore in latin (english names in brackets)
Crustacea (crabs)
Mollusca (Limpits/snails)
What are the main form of Mollusca spp. and the three types therein
Mainly the gastropoda spp. (snails) the three types are:
Trochidae - Topshells
Patellidea - Limpits
Littorinidae - Winkles
Location of Mollusca spp.
Sublittoral to upper littoral and sometimes into the littoral fringe, range depends on the species, either stress tolerant or competitors resistant to predation
Describe the growth form and the five specific bits of mollusca spp.
these are shelled organisms to reduce dessication and soft bodies insides with a strong muscular foot to hold on to rock or algea, compontents include:
Tentacle
Syphon
Eye
Foot
Operculum (shell like structure to ‘close the door’
What are adaptations of Mollusca spp to minimize water loss
Thick shell, operculum
What are adaptations of mollusca spp. to temperature fluctuations
> large surface area of shells
ridges on shells
Tolerance of enzymes to high temp (dont denature) and low temp (due to their slow metabolism)
What are the adaptations of mullusca spp.
> Thick shell and operculum
Camouflage
Position on the shore (hard to reach places)
Strong muscular foot of limpits (hard to prise off)
Explain the reproduction of mollusca spp.
Marine molluscs on the whole are Gonochoristic (male and female, producing two types of gametes) although some are one or the other, alteration of sex occours a small male grows into a larger female. Larvae are planktonic called veliger larvae
What are the two types of Crustacea
Cirripedia - barnacles non moving
Decapoda - shrimps and prawns and crabs (benthic crawlers)
Draw a anatomy of a barnacle (cirripedia spp.)
Cant do it on here but should include the Mouth Stomach muscle Cement gland eggs testis mantle cavity intestine muscle penis feeding legs
What are adaptations of cirripedia spp. to minimise water loss?
Cacerous plates which close over aperture during emersion (exposure, no water covering)
What are adaptations of cirripedia spp. to temp fluxs
well adapted to variations in temp, enzymes can tolerate high temps, in a pale colour to minimise heat absorption
Adaptations of cirripedia spp. to predation
Cement glad to facilitate fastening to rocky substratum, calcerious plates
Explain reproduction of the cirripedia
The male barnicle has the largest penis in the world (based on size) female broods fertilised eggs which hatch into a cypris larvae and swim as zooplankton until settlement on a new substratum, settlement possibly caused by chemical stimuli including pheromones from other barnacles! how mad is that!
Explain the ecology of Reptania spp (crabs)
Have gills, exoskeleton,
What are the adaptations of reptania spp. to water loss
Not really anything, exoskeleton isnt great at preventing water loss although not really needed as aquatic lifestyle
Adaptations to temperature variation of reptania spp.
Not very tolerant to temperature change, relies on stability of the water column
Adaptations to predation of reptania spp.
> Carapace
exoskeleton
camouflage
location on the rocky shore
Adaptations to predator lifestyle of reptania spp.
> Compound eyes (move differently)
Chemical receptors (to aid food selection)
Touch receptors (to feel movement)
Sexual reproduction of reptania spp.
Gonochoristic -> Sexual reproduction
Mating involves courtship and courtship sounds produced. Transfer of sperm from male to female
Female in “berry form” broods fertilised eggs
Eggs hatch into zoea larvae which is planktonic.
Larvae develops and settles to seafloor
and develops into adult crab
what stresses increase as you move up the rocky shore
Temperature
Salinity
Desiccation
Food Supply
What stresses increase as you move down the rocky shore
Wave action
Competition
Predation
