Marine Invertebrates Ebook
Grantham, B.A., Eckert, G.L. and Shanks, A.L. (2003) Dispersal potential of marine invertebrates in diverse habitats. Ecol. Appl. 13 S108-S116. Lohnhart, S.A. and Tupen, J.W. (2001) New range records of 12 marine invertebrates the role of El Nino and other mechanisms in southern and central California. Bull. Southern Calif. Acad. Sci. 100 238-248. Pechenik, J.A. (1989) Environmental influences on larval survival and development, In A.C. Giese, J.S. Pearse and V.B. Pearse (eds.) Reproduction of Marine Invertebrates. Blackwell Scientific Publications, Palo Alto, CA, pp. 551-608.
How can one, unequivocally, distinguish the ad hoc kinds of migration , spurious or genuine, in the fossil record To be honest, I do not know. All I can hope to suggest is that each case must be approached with an open mind. Some years ago I had a certain success in applying quantitative statistical procedures to paleobiogeography (summary in Reyment 1991) and such methods form an integral part of my arsenal of techniques. I have not taken up this aspect in this short overview because of the far-reaching range of the subject. Examples of what I believe can open new fields for the study of migration in the fossil record are given in Reyment (1983c, 1993, 1995) for applications of multivariate quantitative genetics to paleontological problems in a broad sense. Useful paleobiogeographical information can be extracted from appropriately constructed statistical analyses of the shell-chemistry of marine invertebrates (Reyment 1996, 2000). The
The Phanerozoic record of marine invertebrates is punctuated by numerous, geologically short-term intervals (generally 3 Ma) during which biotic diversity and abundance declined significantly ( 40 at the familial level and 63 at the generic level Raup & Sepkoski 1986). The evolutionary and ecological patterns of extinction during these crises may be significantly different from normal background patterns (Jablonski 1986a), and they are followed abruptly by major evolutionary radiations (or revolutions sensu Wiedmann 1973) which change the character of the global biota. These intervals are termed mass extinctions and have been recognized by palaeontologists for over a century (Cuvier 1812 Newell 1967).
Several times during the voyage of the Beagle Darwin sent his notes and samples back to Cambridge, along with letters to his family. These materials focused on his areas of expertise in geology, beetle collecting, and marine invertebrates, but also increasingly on zoology and related biological subjects in which he was a novice. In the seacliffs of Patagonia he discovered extinct fossil species including skeletons of giant mammals, which he named Megatherium (now known to be a type of giant ground sloth that lived from 2 million to 8,000 years ago) and shipped back to England. Also in Patagonia Darwin
Sometime the concentration of nitrogen may also be high in seafood-processing wastewaters. One study shows that high nitrogen levels are likely due to the high protein content (15-20 of wet weight) of fish and marine invertebrates 8 . Phosphorus also partly originates from the seafood, but can also be introduced with processing and cleaning agents.
With age, while the sampling density decreases with age. Types of paleoclimate proxies include lithologic indicators (such as tillites, evaporites, and coals), geochemical indicators (such as foraminiferal and ice 518O, foraminiferal Mg Ca ratios), and paleo-floral indicators (such as tree-ring dendrochronology, distribution of plant types, and leaf-margin analysis). The comparison of paleoclimate models and proxies is often not direct because climate models are not usually capable of simulating geologic processes, for example, the deposition of evaporites or the incorporation of O18 in the tests of marine invertebrates. Rather, climate models produce output, such as surface temperature, rates of precipitation and evaporation, winds and currents, snow and sea ice, which are indirectly compared with climate proxies.
Reductions in Arctic sea-ice cover have well-documented effects on polar bear populations and on marine mammals such as ring seals and bowhead whales, which are concentrated near the sea-ice edge. Shifting sea-ice geography and seasonality affects migration, feeding, and breeding patterns for these species. This also impacts circum-Arctic native populations, as the changing ice season affects travel conditions and traditional hunting practices. Changes in the seasonality and extent of open water have unclear implications for marine invertebrates and algal populations. Arctic Ocean ecology is expected to become more akin to that of the adjacent subpolar seas in future decades, although changes will likely be confined to the summer and fall winter ice cover is still extensive over the Arctic.
Gutless oligochaetes require oxygen, not only for their own respiration, but also for their sulfur-oxidizing symbionts, that use oxygen or other oxidized compounds such as nitrate as an electron acceptor. While the worms can survive short periods in the absence of oxygen, presumably by switching to an anaerobic metabolism as observed in many other marine invertebrates (Grieshaber et al. 1992 Dubilier et al. 1995b), longer periods of anoxia for several days lead to massive mortalities (Dubilier, unpubl. obs.). As all tubificids, the worms contain well developed blood vessels with a red respiratory pigment (presumably hemoglobin), enabling them to store oxygen for limited time periods.
Extinction selectivity appears to change significantly at the most severe mass extinctions, however. The rules of survivorship changed during the K-T extinction, such that species-richness and species-level range failed to predict genus survivorship, singly or in concert Jablonski (1986a, 2005) and see Kiessling and Baron-Szabo (2004) for comparable results for K-T corals . In fact, survivorship of marine invertebrates in the K-T mass extinction is unrelated to a number of factors that have been shown or hypothesized to be important during more normal times. Besides the two already mentioned, these factors include local abundance, mode of larval development (which is in turn related to fecundity and species-level dispersal capability), estimated generation time, living position relative to the sediment-water interface, and trophic strategy (Jablonski, 2005).
The geologic record of life on Earth shows that there have been several sudden events that led to the extinction of large numbers of land and marine species within a short interval of time, and many of these are thought to have been caused by the impact of meteorites with Earth. Many of the boundaries between geologic time periods have been selected based on these mass extinction events. Some of the major mass extinctions include that between the Cretaceous and Tertiary Periods, marking the boundary between the Mesozoic and Cenozoic Eras. At this boundary occurring 66 million years ago dinosaurs, ammonites, many marine reptile species, and a large number of marine invertebrates suddenly died off, and the planet lost about 26 percent of all biological families and numerous species. At the boundary between the Permian and Triassic Periods (which is also the boundary between the Paleozoic and Meso-zoic eras), 245 million years ago, 96 percent of all species became extinct. Many of the...
Ordovician The Ordovician is the second period of the Paleozoic Era and refers to the corresponding rock series, falling between the Cambrian and the Silurian. Commonly referred to as the age of marine invertebrates, the base of the Ordovician is defined on the Geological Society of America time scale (1999) as 490 million years ago, and the top or end of the Ordovician is defined at 444 million years ago. Charles Lapworth named the period, in 1879, after the Ordovices, a Celtic tribe that inhabited the Arenig-Bala area of northern Wales, where rocks of this series are well exposed.
The full diversity of marine organisms is largely unknown. Current species estimates imply that only 20 of species are of marine origin however, this may reflect a bias towards terrestial research in systematics. Grassle (personal communication in Ray, 1988) suggests that deep sea fauna may rival tropical forests in species diversity. Rinehart (1992) reports that marine macroorganisms and microorganisms produce a 'dizzying array' of secondary metabolites. The hunt for drugs at sea is, however, constrained by the relatively large cost of obtaining specimens, the lack of techniques for ex situ reproduction of marine invertebrates and the difficulty of locating the source of activity. Many of the compounds isolated from macrospecies actually are produced by microorganisms.
Reef ecosystems, comprising rugose and tabulate corals and stromatoporoid sclerosponges, underwent a major crisis. Among the rest, both marine invertebrates (ammon-oids, brachiopods, trilobites) and vertebrates (conodonts, agnathan and armoured placoderm fish) suffered severe extinctions. The land record is much less clear, but there could have been an important extinction among plants.
The Ordovician period was an era of extensive diversification and expansion of numerous marine clades. Although organisms also present in the Cambrian were numerous in the Ordovician, a variety of new types including cephalopods, corals (including rugose and tabulate forms), bryozoans, crinoids, graptolites, gastropods, and bivalves flourished. Ordovican communities typically displayed a higher ecological complexity than Cambrian communities due to the greater diversity of organisms. However, as in the Cambrian, life in the Ordovician continued to be restricted to the seas. The Ordovician extinction occurred at the end of the Ordovician period, about 440-450 million years ago. This extinction, cited as the second most devastating extinction to marine communities in earth history, caused the disappearance of one third of all brachiopod and bryozoan families, as well as numerous groups of conodonts, trilobites, and graptolites. Much of the reef-building fauna was also decimated. In...
Acid-Base Regulation and Internal Physiology Much is known about the short-term effects of very high concentrations of CO2 (higher than we will see due to ocean acidification) on respiration and acid base balance in marine invertebrates and fish 9 . These early experiments were important in the discovery that CO2 in seawater readily diffuses across animal surfaces, lowering the pH of internal fluids and that many animals have developed compensation mechanisms to regulate their internal pH. We now know that for normal function of an organism, internal pH must be kept within relatively narrow ranges because processes such as enzyme function, protein phosphorylation, chemical reactions and the carrying capacity of haemoglobin for O2 are all influenced by pH and that these can be regulated for short periods of exposure to high CO2. Evidence so far indicates that fish are tolerant to these short-term high CO2 exposures but organisms such as squid, may be more vulnerable (reviewed in...
The first major mass extinction event started in the Late Ordovician time. Despite the rigorous crisis affected this extinction, for no reason it has so far received little attention from scientists. Sepkoski (1989) affirmed that 57 of the marine genera disappeared in this crisis (some authors stated that it is the second biggest extinction of marine life, ranking only below the Late Permian extinction). Scientists assigned this extinction to global cooling that triggered glaciation and significant lowering of the sea level. As a result, one hundred families of marine invertebrates died, including two-thirds of all brachiopod and bryozoan families, and once-flourishing trilobites as well as archaic groups of echinoderms also died out (for more information see Sepkoski 1984, 1989 Hallam and Wignall
One of the most pervasive spatial patterns of invasions, seemingly independent of mass extinction events, underlies the marine latitudinal diversity gradient, wherein morphologies, species, and higher taxa are richest in the tropics and decline toward the poles. Although the gradient has been known for a long time and is documented for many groups and regions, the processes underlying this pervasive biodiversity pattern remain poorly understood (Hillebrand, 2004 Mittelbach et al., 2007). The ''out of the tropics'' model for the marine gradient has taxa preferentially originating in the tropics, and then expanding their latitudinal ranges over time without actually abandoning their tropical cradle (Jablonski et al., 2006). The tropics are thus a diversity source, containing both young and old taxa, which accumulate to high richness. The poles are a diversity sink, mainly containing older taxa that have moved in from lower latitudes, and the temperate zones have intermediate richness...
Biology had its first stirrings among the ancient Greeks Aristotle was the pioneer. The founder of anatomical studies, Aristotle likely performed the first dissections. His study of anatomy presaged the work of French comparative anatomist Georges Cuvier. Aristotle also appears to have been the first taxonomist. His classification of marine invertebrates anticipated the work of Swedish taxonomist Carl Linneaus.
Winter ecology is little studied in the Arctic. Certainly, the environment is harsh, cold, and dark, hardly conducive to activity. There are three strategies to outlast the Arctic winter leave (migration), freeze (most plants and terrestrial invertebrates) or hibernate, or stay active (most vertebrates, deep aquatic, and marine invertebrates) (see Adaptation). Most so-called Arctic birds are fair-weather visitors they leave as autumn and winter approach. Some birds, such as ptarmigan, are resident in the Arctic all winter. They seek shelter under the snow from time to time and in stormy weather, but otherwise forage for food all winter. During the summer, they accumulate body fat, which assists with overwintering survival. Small mammals may build winter nests of grass or find other protection and
After the Ediacarian and Vendoza fauna died off, other marine invertebrates saw a remarkable explosion through the Cambrian. These organisms in the Cambrian included shelly fossils, trilobites, brachiopods, mollusks, archeocyathids, and echino-derms, and eventually in the Ordovician were joined by crinoids and bryozoans. Modern Metazoa include a variety of organisms including corals, gastropods, bivalves, and echinoids.
Put together, the two functions paint a grim picture (Fig. 11.4). A mass extinction on the scale of the Permo-Triassic event would probably leave diversity still 20 below its equilibrium level after 40 Myr, which is nearly as long as a typical geological period. Indeed, a comparable recovery from even the weakest modeled extinction is expected to take 10 Myr, and a 90 recovery would take 20 Myr. The worst-case scenario is not unthinkable for marine invertebrates any increase in global atmospheric CO2 by 500 ppm would cause coral reef ecosystems to collapse (Hoegh-Guldberg et al., 2007), and, putting everything else aside, biotic
Life history patterns of stomatopods are consistent with those found in other living and fossil groups for reproductive and life history traits, patterns of abundance, and frequency distributions of body size and geographic range. Body size is positively correlated with fecundity and colonizing ability in most marine invertebrates (Reaka, 1979, 1980 Strathmann and Strathmann, 1982 Jablonski and Lutz, 1983 Strathmann, 1985, 1990 Jablonski, 1986b, 1996 Reaka-Kudla, 1991 Roy et al., 2001, 2002 Jablonski
Antarctic birds live in an environment of low temperatures, unpredictable winds, and ice-strewn seas. Zink (1981), in his study of oceanic birds during a high-latitude voyage from Ross Island to Anvers Island between 16 January and 7 February 1976, sighted Snow Petrels over pack ice on all but two days and suggested an ice cover of 3-5 oktas (ice concentration) was their habitat preference. In recognition of their limited distribution, Shuntov (1974) classified the Snow and Antarctic Petrels as neritic-ice species rather than pelagic ones. Zink (1981) emphasized the need for future studies to determine the type of ice as well as its concentration. Older ice is thinner and has a more irregular surface that not only provides wind shelter for resting or moulting birds but also develops numerous small holes and crannies in which marine invertebrates are to be found (Watson, 1975 Zink, 1981).
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