Lecture 5 & 6 - These notes are from the JMU Maymester, from the instructor Louie Wurch PDF

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These notes are from the JMU Maymester, from the instructor Louie Wurch ...

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Sex: Sex and reproduction; female gives up half of her genes in progeny  Sex involves expenditure of energy and time to find mates, combat, other males  Benefits of sex  Sex increases genetic diversity, confers resistance to disease, offspring can survive in a variety of habitats  Clones must wait to be mutations  Sexual selection for extreme forms that breed more successfully; major claw of fiddler crabs, deer, antlers Sexual selection:  The major claw of fiddler crabs is employed for display to attract females and for combat with other males  Arthropods have skeleton on the outside, so they have to shed their skeleton after multiple rounds of skeleton.  Claw to trick females into mating with them  The cost of carrying it becomes detrimental  They might also be spotted by predators  Which select for bigger claws  Different types of sexuality Gonochoristic: organisms that have 2 sexes  May involve direct mating or using water to shed gametes Hermaphroditism: individual can have male and female function  Simultaneously or sequentially. During sexual activity  Once they settle, they are stuck mating with whatever is around them  Barnacles: have very large penises, because they have to be able to stick it out without moving  Advantages:  Every individual you meet is a potential mate which provides a big advantage Simultaneous: barnacle example  Sex cells for both egg and sperm are active in an organism at the same time  Advantages: encounter between two individuals can result in mating  Ex. Acorn barnacles  Barnacles are sessile, but still need to copulate to reproduce. An extraordinarily long penis allows Sequential: Protandrous: 1st male, then female Protogynous: 1st female, then male Advantages of being male earlier in life:  It is easier to reproduce  When you're smaller it makes sense to be male because you can make a lot of sperm  Wait until you're bigger to make eggs Advantages of being male later in life:  Bigger as a male then being  To protect them  Lots of male co 

At some point it becomes advantageous to become a female over a male

Gonochoristic: Males don’t have to carry around female reproductive parts Females don’t have to carry around male reproductive parts  They don’t have to specialize The male has to be big to protect all the females from competitors and Deep sea angler fish, attach to the female Factors in fertilization success  Direct sperm transfer; problem of finding mates  Free spawners: take advantage of water environment, simply shed gametes into the water column Problems to overcome:  Timing: males and females have to time it together for when their gametes will meet up; has to be at the same time Edpidemic spawning:  The rest of the individuals pick up on that Mass spawning:  certain nights out of the year Timing of spawning  Determine their gametes  Get their sperm and egg off of the boundary layer  Density is more important Reproductive success:  Spawning  Parental care  All marine mammals exhibit a great deal of parental care  See that in grey whales  Male sea horses carry eggs in pouch Nonsexual reproduction:  Each descendant is genetically identical to clone  Ex. Bacteria they divide asexually  Ex. Phytoplankton The colonies are free individual but then form on rocks One clonal population comes into contact with another clonal population; which then breaks out into fighting  Organisms will do sexual reproduction if there is something in the environment that is not stressing them out  Is a nutrient starts to run out then they will switch to asexual reproduction because they will be able to reproduce quickly.   

Dispersal: undirected movement Migration: when the animal wants to move Between a spawning area and then they migrate to the nursery area

 Concentration gradients, Diaromous: species that can go between fresh and saltwater Anadromous: higher latitudes  Fish live as adults in salt water, spawn in fresh water, more common in higher latitudes Catadromous: lower latitudes  Fish live as adults in fresh water, spawn in salt water (eels), more common in lower latitudes Tropical regions as the dessert Food is more available in Lower latitudes in freshwater Food is more available in Higher latitudes in seawater High latitudes they are more nutrients Green turtles migrate from specific beaches then go back to the same beaches where they spawned. Geomagnetic cues for long distance Chemical imprinting for  Just beginning to understand satellite tags, tags pop off to the top of the ocean, which then sends a signal to the satellite Plankton:  Organisms in the water column, cannot overcome ocean currents  Further divide based on certain characteristics '  Some act as plants: phytoplankton  Some act as animals Zooplankton:  Mixoplanktons: display both animal and plant characteristics  Holoplankton: permanent residents  Meroplankton: temporary residents  Neuston: associated with slick (air water interface)  Underslide of the slick  Pleuston: sticking up above water surface  Stick up out of the slick  Further based upon their size  Femtoplankton: include marine viruses, they are the smallest Diatoms in falling create a whole ecosystem How are plankton collected for studying?  By using a net, specifically a plankton net  Plankton gets filtered through the cod end  Filter them, by taking them directly from the water  Also by the use of the MOCNET, going down meters  Using a CTD rosette,  Conductivity measuring salinity  Temperature:  Depth: measuring pressure Microorganisms: Viruses:  Parasitic agents  They are tiny and in the phentoplankton  50 million virus particles per milliliters of ocean drops Marine bacteria and Archea:

 Order of 1  Accurate abundances only in last 20 years  Important for organic matter decomposition  Both aerobically and anaerobically  Most of the bacteria is not cultured  Took some out and sequenced it  The most abundant is pelagibacter ubique  Didn’t culture until 2002  Found genes for rhodopsin: a photoreceptive protein  Associated with light  At first they thought it was contamination Why?  Phototrophy, still producing energy using light Cyanobacteria:  invented oxygenetic photosynthesis  Oxygen is rocket fuel for metabolism  Made multicellular life possible  The most abundant is prochlorococcus Base of the marine food web  The next abundant is crocosphaera  nitrogen fixation, fixes nitrogen only at night  Produces a paradox ; how?  Producing a molecule that destroys nitrogen fixation  Another is trichodesmium  Nutrient poor: oligotrophic waters  Can fix nitrogen during the day  Sea sawdust Toxic:  They produce toxins, they get into our drinking supplies  Microcystis: which affects portable water as well as damaging the ecosystem Eukaryotic phytoplankton: Diatoms:  Glass cell walls  Occur singly or form chains  Size range of nano to microplankton  Cell wall made of glass  Encased in silica shell consisting of two values  Radially symmetrical  Reproduce asexuallly by binary fission  The big glass spines; at first thought it was to defend themselves  But has to do with drag, so they slow their sinking rate  Outer valve; it will form a new diatom cell  Pseudo-nitzchia: bloom there are bivalves which eat the psedo, which accumalates in their tissue, mass mortality of marine birds, seal lions Dinoflagellates:  Organic cell walls  Dino:  Secrete organic test and have two flagellae

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One on the anterior end and the other around their body Size range of nano and microplankton Asexual and sexual reproduction Have complicated life histories Many species are heterotrophic A few of them are the cause of red tides

Lighting up due to physical stress because the burgular alarm hypothesis, what eat them are cocpods, small and see through  It is already dead and toast, it lights up the copods Alexandrium: is a toxic one  Found in west coast and some parts of new england Coccolithophores:  Calcium carbonate cell walls  The biological pump, through biological means  Can be seen off the coast of Newfoundland  They are white because of the calcium carbonate  Was underground but then rose up Crustacean zooplankton:  Phylum: arthopoda  Subphylum: crustacea Key features of crustaceans:  They have jointed appendeages  Some degreed of body segmentation  External skeleton made Copepods:  This is what plankton is  Largest group of Crustacean zooplankton  They swim mainly with the 5 pairs of thoracic appendages  When they eat they are feeding at low re number  They feed on phytoplankton or smaller zooplankton, depending on the size  Hairs: for chemical sensory, they are somewhat transparent, Solution:  Beat there thoracic appendages to create a current  *know which ones are bigger  Is surrounded by this pocket of water,  So they try to siff it out  They reach out and grab the particle  Females carry fertilized eggs with them Euphasids: or krill  Shrimplike, up to 5 cm long  Abundant in antartic and in upwelling regions  Main food of baleen whales in antartic  Feed on algea that grow on the underside of sea ice  Sea ice is getting less overtime, the same amount of sea ice, 85 percent reduction  Affects everything that eats krill  Pleaopods: swimming feet Phylum: Cnidaria

 Possess stinging cells  Mesoglea between two epithelial cells Plantonic cnidara:  Class scryphozoa: true jellyfish  Class hydrozoa: colonial cnidarians; some meroplanktonic; medusa stages, rare examples of holoplanktonic species  A coiled up harpoon: nematocysts  Which shoot the harpoon out  Use to paralyze their prey  The true jellyfish: scyh  The lion's mane: the largest jellyfish have tenticles over 20 feet long Box jellyfish:   64 human deaths Hyrozoan:  very small and tiny benthic stage  Reproductive pulleps  The medusa creates the gametes However, there is a Siphonophores: specialized colonial hyrods  They don’t have a benthic form  Spend time in the twilight zone  They look just like copods, to attract the things that eat them (prey)  One polyp forms the sail, one reproductive, and some form feeding tentacles  The bluebottle fish hangs around the tenticles of the portugese man of war  For:  Scraps  Protection  It may be  Rely on dodging, very dexterous Comb jellies:  Feed on larger plantonic eggs  They all have the meridional plates  And sticky cells that release adhesives Salps:  Are related to benthic sea squirts  Close to vertebrates as you can get  Gelatinous creatures, that can just shoot through the water  Form really long chains  They can grow very quickly  Don’t move swiftly through sea currents Larvaceans:  Very small gelatinous  They filter things, then they feed off of those particles  They shed the whole house and create a new one  Below the thermocline, so they gather into huge nets

 Speed up the genatilnous Mollusca: Preropods:  Feed on suspended particles  Which means winged foot Kingdom protista:  Secrete skeleton of calcium carbonate, something greates\t ornamentation Radiolarians:  Produce the sicilica test  Have glass cell wall  They string their cytoplasm  At depths of 2,000 meters there are radiolarian weird beause in the water column above they have both Why?  The acid breaks down the calcium carbonate  Deeper you get the lower the pH  Below the depth it dissolves: the foreams Sea floor mapping:  Ship sonar sends down a sound down the water column  Deep scattering layer  During the middle day it was very deep  The sound reflects closer at night  At night the scattering moves back down to depth  The migration of platonic organisms  All the organisms come up at night  Diel: happens over a 24 hour period Reasons why they do this?  To avoid predators with eyes (visual predators )  They come to the surface to eat during the night  Water temp. surface water is much warmer and col  Speeds up their metabolism, go down the thermocline to increase the scope for growth  Conserving energy  Strong light hypothesis: Phytoplankton recovery hypothesis  Feed at night to allow the phytoplankton to recover during the day Predation hypothesis: most accepted  Avoiding visual predators Energy conservation hypothesis: most accepted Surface  Brought in new food sources during the day...