one last hurrah Flashcards
- Given a map of the Atlantic or Pacific Oceans
a) draw and label the prevailing ocean gyres,
b) draw the expected temperature/salinity/density profiles in the open ocean, and
c) describe the expected distribution of ocean plastics that accumulate as wastes in each of the world’s main oceans
draw bitch
a) N hemisphere go clockwise, S hemisphere go counterclockwise
b) thermocline has temp decr as depth incr; halocline has salinity decr as depth incr; pyncocline has water density incr as depth decr
c) most plastic and waste gathers in the centre of gyres because once caught in the current, the centre is relatively calm
- For animals in the pelagic zone buoyancy is always a consideration. Explain what each of the following groups use to control buoyancy:
a) jellyfish,
b) siphonophore,
c) deep sea cod, and
d) sharks.
Cephalopods have their own ways of doing this. Explain how and when Nautilus controls its buoyancy.
a) mesoglea + oil droplet
b) pneumatophore + oil droplet
c) swim bladder
d) lighter tissue due to collagenous skeleton, fatty liver
e) fill empty chambers with gas products of respiration
- The ctenophore Mnemiopsis is a voracious predator and is invasive in the black sea where it depleted the entire copepod supply causing a crash of the fish stocks which had previously eaten copepods. Explain how copepods usually detect and avoid predators and find prey and find mates, and explain why Mnemiopsis was able to avoid being detected by copepods.
copepods use a lateral feeding system, which is operated using their thoracic limbs and second antennae, with signals interpreted by setae on their first antennae.
in the black sea, their main predator Pleurobrachia were cnidaria with long tentacles that copepods could detect easily. however, the newly introduced mnemiopsis were ctenophores, with rows of short cilitated tentacles. copepods are not adapted to these predators, and only discover their predation when it is too late.
- Light penetrates to what depth in the open ocean? Where sunlight does not reach animals have wonderful ways of producing their own light. What is the generic way in which bioluminescence is produced in these animals? Describe an experiment that demonstrates the effectiveness of bioluminescence as a burglar alarm.
light penetrates to about 1000m down, where the disphotic zone tapers off.
bioluminescence is mainly produced by the substrate luciferin, which when oxidized by the luciferase enzyme, becomes an excited intermediate that releases energy in the form of light.
the burglar alarm is a usage of bioluminescence whereby prey create light to draw attention to themselves. their predator, not risking becoming prey themselves, often leave. exemplifying this is an experiment conducted by fleisher and case, which plotted the number of predatory mysids eaten by cuttlefish as a function of luminescent dinoflagellate.
- Compare and contrast the mechanism of feeding in corals via photosynthesis with the mechanism of feeding in hydrothermal vent worms, via chemosynthesis. Use labelled drawings of each animal (coral polyp and hydrothermal vent worm) to describe
a) what is taken from the water,
b) where that material is captured,
c) where food is digested, and
d) the chemical equations that describe the processes in coral and worm.
draw draw draw
a) coral take calcium ions from the water, as well as light for photosynthesis; vent worms take hydrogen sulfide, oxygen, and carbon dioxide from the water
b) calcium ions are taken from the water, and energy for photosynthesis is gathered through sunlight; vent worms draw hydrogen sulfide, oxygen, and carbon dioxide from nearby hydrothermal vents through their obteractulum.
c) in corals, food is captured at night by cnidocytes and digested in the stomach; vent worms do not have formal stomachs, but do cultivate bacteria in their trophosomes, located in the trunk
d) H20 + CO2 –> C6H1202 + O2; 4 H2S + CO2 + O2 –> [CH2O]n + 4 S + 3 H2O
- The keystone species concept was conceived by Bob Paine to explain the role of seastars in enhancing diversity of the rocky sea shore. Keystone species are in other ecosystems too. Describe what a keystone species is and describe data we studied that showed the importance of key stone species in the interaction of Killer whales, Otters, and Urchins in maintaining the Kelp forest ecosystem of the Pacific Northwest.
a keystone species is a species that is integral to the ecosystem through competition or predation.
otters demonstrate this trait in their predation of urchins; when left undeterred, urchins raze kelp forests to the ground, leaving behind urchin barrens. kelp forests bolster communities by providing food, a place for larvae to settle, etc.. as such, the removal of urchins by otters helps to protect kelp forests; otters are keystone species.
killer whales then pose a threat to these keystone species. when killer whales prey upon otters, kelp forests decline by virtue of allowing urchins to flourish. the top-down influence of killer whales does not make them a keystone species, since the community does not flourish with their presence - it does however demonstrate the delicate balance of the ecosystem.
- Sea stars like the purple sea star use two features to open a mussel shell – the hydraulic skeleton and mutable collagenous tissue. Describe how both work. Assuming normal calcification in the sea star occurs as it does in corals, describe how the endoskeleton of sea stars is calcified and explain what might happen if there is increased CO2 in the ocean?
hydraulic skeleton works by taking in water through the madreporite and filling the arms with water. to incite movement, ampullae are squeezed, causing the tube feet to extend. movement is coordinated to find food.
once a mussel is found, the sea star will place its arms upon its prey, sticking to it with chemical adhesives found on the tube feet. calcium ions, which cause glycoamino glycans in the extracellular matrix of the mutable collagenous tissue to crosslink, flood the extracellular matrix. the mussel is pried open, and externally digested.
assuming the endoskeleton of sea stars is calcified in similar manner to corals, calcification would occur through the uptake of free calcium ions in seawater combining with bicarbonate (HCO3) to form calcium bicarbonate Ca(HCO3)2, crystallizing to form the CaCO3 skeleton of the sea star, with carbonic acid produced in the process.
carbonic acid naturally breaks down into CO2 and H2O. however, increased CO2 in the ocean may cause the reaction to reverse, creating more carbonic acid. this carbonic acid forms CO3 2- that takes up Ca2- ions, as well as acidifying the ocean. the result is that the growth of sea stars is inhibited, as calcium becomes limiting.
