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Chapter 13 - Life in the Ocean

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Chapter 13 - Life in the Ocean

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  1. Chapter 13 - Life in the Ocean

  2. characteristics of life • require energy • can capture, store, and transmit • ultimately from sun, earth heat or chemical reactions • highly ordered • reproduce • change through time • adapt to environment

  3. capture and flow of energy • cell • energy capture • from sunlight • from food

  4. capture and flow of energy • trophic relationships • autotrophs • primary producers • convert energy to food • heterotrophs • consumers & decomposers • consume food produced by others

  5. capture and flow of energy • depicting trophic relationships • trophic levels • food chain - simple • food web - complex • trophic pyramid

  6. physical (abiotic) factors • transparency • dissolved nutrients • temperature • exothermic/poiklilothermic/cold-blooded • endothermic/homeothermic/warm-blooded • salinity • extremes - 6 to 30 ppt

  7. dissolved gases cold water holds more oxygen not easily dissolved avg - 6 ml/l plants use at night large blooms can result in low oxygen levels esp. in closed basins CO2 easily dissolved avg - 50 ml/l 60x that of the atmo. deep water has the most consumers downwelling cold water dissolving organisms physical (abiotic) factors

  8. pH avg seawater is about 8 below CCD about 7.6 lowered by CO2 hydrostatic pressure animals equalize inside and outside pressure effects of high pressure gasses more soluble enzymes don’t work metabolic rates higher physical (abiotic) factors

  9. physical (abiotic) factors • factor interplay • factors are interlinked • also influenced by life

  10. biotic factors • diffusion • tendancy of a concentration of a substance to even out • from high concentration to low concentration • faster in warm water • across membranes

  11. biotic factors • osmosis • diffusion of water through a semi-permeable membrane • diffusion from high concentration of water to low concentration of water

  12. isotonic concentration inside = concentration outside Some animals in ocean hypotonic concentration of salts inside > concentration of salts outside concentration of water inside < concentration of water outside marine animal in fresh water animal gains water hypertonic concentration of salts inside < concentration of salts outside concentration of water inside > concentration of water outside animal in Great Salt Lake freshwater and some marine animal in ocean animal loses water biotic factors - osmosis

  13. biotic factors - osmosis • examples and exceptions • animal with salt concentration less than seawater drinks seawater • cells lose water to even concentration in the blood • animal dehydrates • fish (?evolved in fresh water?) • internal salinity 1/3 that of the ocean • lose water through gills • solution: drink seawater and excrete salts • seabirds - excrete salt through glands in skull • salmon - large kidneys remove excess water during freshwater phase of life, able to recover salts from food and urine

  14. biotic factors • active transport • movement of dissolved substances from low concentration to high concentration • requires energy

  15. biotic factors • surface-to-volume ratio • smaller cells are more efficient at transport and diffusion • spherical cell • surface area increases with the square of its diameter • volume increases with the cube of its diameter • cells divide to maintain proper ratio

  16. gravity and bouyancy density differences water = 1 g/cm3 seawater = 1.025 g/cm3 marine fish = 1.07 g/cm3 adaptations gas bladders strong muscles less dense solutions in body ie.NH3Cl food stored in waxes and oils biotic factors

  17. biotic factors • viscosity and movement • reduce drag to swim • increase drag to stop sinking • large surface area to volume ratio • ornamentation • warm water less viscous than cold • water movement • use of currents to move

  18. classification of environment • light • photic • aphotic

  19. location pelagic - open water neritic - shallow oceanic - deep water epipelagic mesopelagic bathypelagic abyssopelagic benthic supralittoral - above the tidal range littoral sublittoral inner - near shore outer - to the edge of the shelf bathyal abyssal Hadal classification of environment

  20. Marine Communities • organization • organism • population • community • ecosystem • ecosphere

  21. Marine Communities • organism’s place • habitat - organisms physical location within a community • niche - organisms place (duties) within a habitat

  22. Marine Communities • physical and biological factors • examples • temp, pressure, salinity • crowding, predation, grazing, parasitism, shading from light, waste substances, competition for resources (food, oxygen, nutrients) • limiting factors • limits chances for success • different for different animals • steno-: tolerant of a narrow range • eury-: tolerant of a wide range

  23. Marine Communities: competition • within a species • between species • overlapping niches • results • survival and reproduction of the most successful • less successful moves or dies off • growth rate and carrying capacity

  24. distribution of organisms • population density • species diversity • distribution patterns • random • rare • same conditions must exist throughout the community • clustered • most common • individuals of a spies cluster near optimal conditions • uniform - vary rare • motile vs sessile

  25. species interaction • trophic • symbiotic • often species specific • types • mutualism • commensalism - symbiont benefits, host is not harmed • parasitism - host is harmed • dependencies • one species depends on another (for food) but they do not live in extended contact

  26. change in marine communities • usually slow • marine conditions rarely change rapidly • some rapid processes - volcanoes, earthquakes, landslides • climax community • stable • long established • reestablished through succession • may be slightly different

  27. evolution • development of complex life forms • through mutation and selection • natural selection - survival of the • fittest (for a niche) • luckiest • combination • species • reproductively isolated group of living organisms • speciation & extinction • divergent & convergent evolution • phyletic gradualism & punctuated equilibrium

  28. Organic evolution: observations • sedimentary rocks • deposited in layers • oldest layers are on the bottom • layers may be correlated with other sedimentary layers • fossil record • oldest rocks have only simple fossils • younger rocks have more organisms similar to those living today (at levels from species to kingdom) • fossils record includes appearances and extinctions of many species

  29. Organic evolution: observations • geographic distribution of organisms • many organisms are similar but unique • they are confined to specific areas (islands, continents, water bodies) • includes modern and fossil organisms • distribution has changed through time

  30. Organic evolution: observations • anatomy • cell structure is similar in all living organisms • embryology - embryos of mammals, birds, and reptiles are very similar • homologus organs - similar organs, different functions • vestigal organs - no purpose in one, purpose in another

  31. Organic evolution: observations • genetics • structure of DNA and RNA is the same in all living organisms • similarity in genetic code varies between organisms (some organisms are more similar than others)

  32. Organic evolution: conclusions • the characteristics of populations of living organisms have changed through time • life has become more complex • life has become more diverse • this is excepted as a factual observation • all life is related

  33. Natural selection: observations • populations of organisms display a variety of characteristics • characteristics may be useful, not useful, or detrimental • the variety is reflected in an organisms genes • mutations • produced by random alteration of genes and passed to offspring during reproduction • provides variety

  34. Natural selection: observations • artificial selection • domesticated plants and animals can be bred to favor certain characteristics • populations of wild and domestic plants and animals develop characteristics that favor their survival

  35. Natural selection: observations • the natural environment • organisms with favorable characteristics for their niche are more likely to thrive and reproduce • organisms with unfavorable characteristics are less likely to thrive and reproduce • a new niche or stress on an existing niche will enhance selection

  36. Natural selection: conclusion • the natural environment provides conditions that result in evolution through the process of natural selection

  37. Evolutionary trends • speciation & extinction • divergent & convergent evolution • phyletic gradualism & punctuated equilibrium

  38. Natural selection: speciation • a population has a gene pool • members of the population interbreed • the population may become isolated from others of a species • development of niches & resource partitioning • migration • development of physical barriers • populations may be selected • by stress • by opportunity • isolation may result in genetic divergence

  39. Natural selection: extinction • stress on limiting factors reduce or destroy a population • evolution into subsequent species (pseudo-extinction)

  40. Phylogeny • relationships between organisms can be determined using • genetics • anatomy & physiology • Fossils

  41. Evolutionary trends • speciation & extinction • divergent & convergent evolution • phyletic gradualism & punctuated equilibrium

  42. primary productivity • photo- and chemo-synthesis

  43. measurement grams of carbon bound (appx 10% of producers mass) per square meter of ocean surface per year sampling measure oxygen produced in a suspended set of bottles follow carbon through the process (in the lab) breakdown phytoplankton - 90-98% seaweeds - 2-10% chemosynthesis - 1% production avg - 75 to 150 g(C)/m2/yr primary productivity

  44. primary productivity - limiting factors • water - plenty • CO2 - plenty • nutrients • non-conservative - change with bio activity • nitrates, phosphates, silicates • lost to organisms then to the depths • replaced by runoff, upwelling, atmosphere

  45. primary productivity - limiting factors • light • quantity - can have too much or too little • quality - color • red and violet are best absorbed by green • quantity and quality vary with • depth • red is absorbed near the surface • concentration of organisms • concentration of sediment • adaptations: accessory pigments - absorb light for chlorophyll

  46. Plankton • floaters and weak swimmers • producers and consumers • collection and study • plankton nets • microscopic

  47. phytoplankton • autotrophs • depth of greatest productivity • 20 m at noon • 5-10 m daily • compensation depth • energy consumed = energy produced • go below - die

  48. near cont. shelves upwelling & runoff 1 g(C)/m2/day tropics much sunlight & CO2 low nutrients 30 g(C)/m2/yr reefs - tightly cycle nutrient through the reef - more productive polar low sun angle dark winter, long days in summer upwelling seasonal blooms temperate and subpolar good mix of light and nutrients seasonal global distribution of productivity

  49. phytoplankton - dinoflagellates • swim with whirling flagella • reproduce through fission • nutrients can causes blooms • red tides • some are bioluminescent

  50. phytoplankton - diatoms • SiO2 shell (frustule) • two perforated valves • highly energy efficient • store energy as oils - for floating • some are benthic • reproduction • fission - generate new shell inside the parent • smaller with each generation • size gets too small • sexually reproduce new offspring with no shell