2 Marine Biology Main elements are functional biology and ecology Functional biology is the study of organismal function, such as reproduction, locomotion, feeding, and cellular and biochemical processes relating to digestion, respiration, and other aspects of metabolism
3 Marine Biology 2Ecology - the study of the interaction of organism with their physical and biological environments, and how these interactions determine the distribution and abundance of the organisms
4 Historical Background Early biologists were “natural philosophers” who made wide-ranging observations of the marine world as well as fishing folk who often ranged widely on the oceanAristotle ( B.C.) and his contemporaries made many observations of behavior and form of shore organisms
5 Historical Background 2 Linnaeus ( ) who developed means of naming species (e.g. Homo sapiens), described many marine species
6 Historical Background 3 Georges Cuvier ( ) developed a larger-scale scheme to classify the animals into four major body plans: Articulata, Radiata, Vertebrata, and Mollusca. Others at this time in the late 18th century also developed beginning theories of evolution (Lamark) and major divisions to classify organisms.
7 Historical Background 4 Late 18th century - many trans-oceanic voyages resulted in important marine biological discoveries (e.g., British voyage of captain Cook across Pacific, voyage of French captain Nicolas Thomas Baudin, which brought back many specimens.)
8 Historical Background 5 19th Century - beginning of modernization of scientific approach to marine biology. Previously all work was descriptive, now hypotheses emerged
9 Historical Background 6 Edward Forbes ( ) - English biologist sampled Mediterranean and proposed the Azoic Hypothesis, that there was no marine life in depths deeper than 300 fathoms (1800 feet). First testable hypothesisAzoic hypothesis falsified by work of Norwegian Michael Sars who described 19 species living deeper than 300 fathoms.
10 Historical Background 7 Charles Darwin ( ), more famous for theory of evolution, also proposed other major marine hypothesis at this time - hypothesis of coral reef growth as a balance between upward coral reef growth and sinking of the sea floor
11 Historical Background 8 Darwin’s Coral Reef Hypothesis:Test of hypothesis: you should be able to drill through coral down to a great depth before hitting the non-coral rock below.Hypothesis tested in 1950s - hole drilled in Enewetak Atoll in Pacific and went through hundreds of meters of coral before encountering volcanic rock. Sinking not true on all reefs, however.
12 Historical Background 9 Late 19th century - beginnings of fisheries research in EuropeW. B. Carpenter and C. Wyville Thomson led the steam-powered Lightning that explored waters of northern British Isles
13 Historical Background 10 Thomson and J. Murray led the 5-year voyage of the Challenger, circumnavigated the globe, major contributions to oceanic exploration, collection of new species, most important voyage of 19th century for marine science
14 The H. M. S. Challenger anchored at a remote equatorial Atlantic island.
15 Historical Background 11 Late 19th century - early 20th century: Founding of a number of important marine laboratories, including coastal labs and open-ocean labs, such as the Scripps Inst of Oceanography and Woods Hole Oceanographic Inst.
16 Historical Background 12 20th century involved more sophisticated ship expeditions, use of new technology including submarines, SCUBA diving, satellite navigation systems, sophisticated ship-deployed samples, underwater video, etc.
17 New technology from the 20th century. Left: The Alvin, a deep diving submersible, capable of exploring the deep sea bottom.Right:The Jason, a remote operating vehicle, which was used to findthe Titanic in the open deep Atlantic.
18 Observations, Hypotheses, Experiments Marine biology, like all science depends upon a scheme of observation and inference of the natural world known as the scientific methodInduction - accumulation of a number of observations, leading to a general conclusionDeduction - more powerful method of scientific inference, involving some premises, whose logical connection leads to a testable prediction, or hypothesis
19 Observations, Hypotheses, Experiments 2 Hypothesis is testable - e.g., Increasing temperature increases the rate of oxygen consumption of crabs.An untestable statement - Mermaids can never be observed, but they exist.An inappropriate hypothesis, because the premise is wrong - Predators cannot eat prey, and they therefore have no effect on marine populations.
20 Observations, Hypotheses, Experiments 3 Observations can be connected by means of correlation, the association of some phenomena with others - e.g., Larger body sized animals are found in colder waterCorrelation is not causality. Body size might not be due to cold. Perhaps colder water is also deeper, and it is pressure that is the important factor
21 Observations, Hypotheses, Experiments 4 Experimentation is more effective than establishment of correlationsInstead of looking for correlations, design an experiment that varies a hypothetically important factor; experiments can also be done in the field to manipulate factors such as predation.
22 Hypotheses Need to pose a null hypothesis, which can be tested If null hypothesis is falsified, then you can proceed with further testingExample: null hypothesis might be: Temperature has no effect on crab metabolic rate. Experiment could vary temperature, and result might be that metabolic rate increases with increasing temperature. Result: Null hypothesis is falsified.
23 Null Hypothesis and Field Experiment Null hypothesis: There is no effect on barnacle prey of placing a cage on the lower shore, which excludes predatorsThis is an experiment aimed at understanding if predation is more intense on the lower shore, where we believe predators are more common (than on the upper shore)
24 HIGHUncaged Fully caged Top-only cage Side-only cageLOWUncaged Fully caged Top-only cage Side-only cageCaging experiment, showing fully caged experimental conditionwith three types of controlsPlace on upper shore and lower shore
28 Habitats Intertidal Subtidal Continental shelf or Neritic - waters and bottoms on the continental shelfOceanic or Pelagic - waters and bottoms seaward of the shelfEpipelagic zone - upper 150 m of water depthMesopelagic zone m m depthBathypelagic zone m m depthAbyssopelagic zone m m depthHadal - trench environments
29 High tideIntertidalLow tideNeriticOceanic(pelagic)150mMesopelagicBenthic2000mBathy-pelagic4000mAbysso-pelagicHadal