Likely Questions Flashcards
(31 cards)
What was the Paleocene/Eocene Thermal Maximum? Why was it important? What is the significance for calcifying organisms?
A period around 55 million years ago when rates of CO2 change were comparable to now, and temperatures got to around 8 degrees warmer.
It’s important because its the best analogy for current climate change.
There was a total absence of calcareous deposits during this time, indicating the loss of calcifying organisms.
What were some of the major bleaching events in the last 30 years and what were the approximate distributions?
1998 : Global - ENSO 2001 : Global - ENSO 2006 : Caribbean and Pacific 2010 : Mostly Pacific 2016: Mostly Pacific
What is the current status of temperatures and its relationship to coral bleaching?
Temperatures have exceeded bleaching thresholds in 3 of the last 3 years, all over the planet, with mass mortality.
What were the earliest reefs made of and when?
Stromatolites, which are structures that are a mix of microorganisms, biofilms, and cyanobacteria. Earliest known from the precambrian but may have been important during the cambrian.
When did the first coral reef system appear?
240 million years ago
Approximately how old are modern reefs?
10,000 years
What are nephridia?
An invertebrate version of a kidney, removes metabolic waste, surplus ions, hormones and toxins. Its a ciliated funnel into the body cavity
How does solubility of calcium carbonate organisms change with water temperature?
Solubility goes up when temperature goes down
What kind of skeletons would you expect to see given climate change? Why?
Calcitic, bicarbonate ions go up, carbonates go down, aragonite saturation goes down.
What are the key features of Cnidarian movement?
Siphonoglyph - a ciliated groove at one or both ends of the mouth of sea anemones and some corals. The siphonoglyph extends into a pharynx and is used to create currents of water into the pharynx. These water currents are important for respiration and maintenance of internal pressure.
Cilia - help create water currents
Muscles - use jet propulsion by expanding and contracting muscles and pushing water out.
What is Halimeda and why is it important?
A calcareous algae, major contributor to calcification.
What are some other reef builders?
Microbilites thought to be important - they deposit calcium carbonate in spaces deeper in the structure in areas that are generally anoxic.
What is the calcification significance of the Bahamas Banks?
Seagrasses cause spontaneous precipitation of calcium carbonate by dropping carbon dioxide down.
What are some limitations associated with not having a circulatory system?
You can’t get very big because transporting nutrients and oxygen becomes more difficult, likely would make metabolic activity less efficient
When were sponges important reef builders?
In the Paleozoic
How do zooxanthellae help corals calcify?
By providing energy, and also because they provide the conditions for bicarbonate to disassociate into carbonates so the corals don’t need to pull carbonates straight from the water column.
What are organisms besides corals that have zooxanthellae?
Forams, anemones, Tridacna clams, some sponges.
What are some of the groups and representatives of bioeroders?
Microborers: algae, fungi or bacteria
Epilithic and Endolithic, mostly depending on light requirements
Macro (surface): grazing molluscs and fishes, excavating parrotfish and urchins
Macro (deep): boring bivalves, sponges, urchins, polychaetes, etc.
How does bioerosion happen?
Mechanical methods like rasping, chemicals that dissolve the calcium carbonate.
Describe forams.
A protist cell is divided into granular endoplasm and transparent ectoplasm from which a pseudopodial net may emerge through a single opening or through many perforations in the test. Individual pseudopods characteristically have small granules streaming in both directions. The pseudopods are used for locomotion, anchoring, and in capturing food, which consists of small organisms such as diatoms or bacteria.
The foraminiferal life-cycle involves an alternation between haploid and diploid generations, although they are mostly similar in form. The haploid or gamont initially has a single nucleus, and divides to produce numerous gametes, which typically have two flagella. The diploid or schizont is multinucleate, and after meiosis divides to produce new gamonts. Multiple rounds of asexual reproduction between sexual generations are not uncommon in benthic forms.
Describe alternation of generations.
A multicellular gametophyte, which is haploid with n chromosomes, alternates with a multicellular sporophyte, which is diploid with 2n chromosomes, made up of n pairs. A mature sporophyte produces spores by meiosis, a process which reduces the number of chromosomes to half, from 2n to n.
What is the difference between mitosis and meiosis?
Mitosis: cell division with 2 daughter cells, same number of chromosomes as parent nucleus, normal tissue growth
Meiosis: cell division with four daughter cells, each with half the number of chromosomes of the parent cell. e.g. the production of gametes and plant spores
What is Crustose Coralline Algae and why is it important?
Algae that has a calcareous skeleton. Important reef builder, binder, lures babies to settle on it, can grow into algal ridges. Has a broader distribution than corals.
Why does having closed systems facilitate the transition to land?
Conservation of water, rapid flow rates accelerate transport of O2 to particular tissues and removal of CO2 (especially in larger organisms)
