Midterm 2 Flashcards

Question

levels of disturbance or predation

Answer 1

- Low levels of disturbance or predation: Competitive dominant species takes over - Intermediate levels: Promotes coexistence, more species present - High levels: most individuals removed, reduces total number of species

Answer 2

- Parasites can result in the reduction of growth and reproduction in the host. Recall the complex life histories of parasites - marine parasites often have several possible hosts - Population declines have been attributed to disease that results in massive mortality (E.g. Pacific sea star wasting, Toxoplasma gondii & sea otters) - Diseases are not well understood in the marine environment. - All of these can affect the dynamics in a community

Answer 3

- Positive interaction between species where some species facilitate the other’s presence - E.g. seaweeds retaining moisture or providing substratum - Foundation species

Answer 4

- Predictable order of appearance and dominance of species, usually following a disturbance. - Examples of disturbance and colonization: - volcanism--> coral colonization; deep-sea invertebrate colonization - Deposition of sand --> colonization by burrowers

Answer 5

1. Initial colonists - properties: not specialized, high reproductive rate, dispersal-oriented 2. Later colonists - better competitors that displace earlier species? 3. Prevention of invasion - good competitor? Good at resisting predation? Environment altered, which prevents further colonists from invading? 4. Is there a climax community? Assemblage of competitively superior species? Resistant to predators? Evidence for such communities? Dominance?

Answer 6

- Direct effects: Predator consumes prey, prey population decreases - Indirect effects: Sea otter consumes urchins; as a consequence, seaweed prey of urchins increases in population size - Density mediated indirect effect: Density at one feeding level increases, which reduces prey of another species, and, in turn results in an increase of the prey of the second species - Trait-mediated indirect effect: Presence of a predator, causes prey to be active less and feed less on their own prey, so prey of second species increase in abundance, even though the second species did not decline (their feeding activity declined).

Answer 7

- Ecosystem: group of interdependent biological communities and abiotic factors in a single geographic area that are strongly interactive. - Nearly all ecosystems have primary producers (mainly photosynthetic), secondary producers (herbivores), and carnivores. Material escaping this cycle is material to be decomposed in the saprophytic cycle. - Food webs may be controlled by top-down processes where top predators have strong effects or bottom-up processes where changes in primary production drive changes in food web. - Strong top-down linkages or bottom-up linkages generate a tropic cascade through the food web

Answer 8

- Biomass (standing crop) – mass of organisms in a defined area or volume - Primary productivity – amount of living material produced in photosynthesis per unit area per unit time - Secondary productivity – primary consumers per unit area per unit time - Tertiary productivity – consumers of herbivores. - Example: energy transfer to an adult herring - However, marine communities do not exist as simple food chains

Answer 9

- Some organisms have strong effects on competitive interactions and on entire ecosystems - Examples, otters & killer whales on urchins, seastars and mussels. - These are top-down effects - Bottom-up effects, e.g. phytoplankton can affect the number of apex preditors (e.g. algae, sea ice, krill, fish, whales)

Answer 10

- No marine species occurs worldwide - Two factors limit distribution: – habitat-physiology limitations – barriers to dispersal - The marine assemblages are known as provinces - Currents and temperature changes affect differences - Present distribution due to evolutionary history - vicariance and dispersal

Answer 11

- Seasonal and daily changes - cyclic - Rapid environmental changes (flooding, rain) - Organisms must have receptors to sense the change in order to respond – Receptors-antennae, tentacles, protein systems – Transfer systems - nervous connections to muscle systems, endocrine systems - Responses can be adaptive (e.g. organisms in a tide pool) and maximize fitness

Answer 12

- Behavioural - Physiological (cellular changes at large systemic level) - Biochemical (changes of concentrations of enzymes, ions within specific cell types) - Gene regulation - Metabolic rate (total rate of energy used by an organism, usually oxygen consumption) is typically used to get an overall impression of a response to a change in the environment

Answer 13

response followed by new equilibrium

Answer 14

maintenance of constancy despite environmental change

Answer 15

internal state changes to match external environmental change

Answer 16

- The difference between energy assimilated and the cost of metabolism - Measure of energy reserves: Scope for growth minus excess energy beyond that needed for maintenance - Surplus energy may be divided between somatic growth & reproduction - More food, scope of growth will increase

Answer 17

- Can be measured by scope that the organism has for activities e.g. swimming - Organisms need to have reserves and oxygen systems for quick muscular responses - Mortality rate can also measure effect of changes in the environment (e.g. temperature) - LD50 - where 50% of the population dies (24h)

Answer 18

- Temperature variation is common in marine environment: – Latitudinal temperature gradient, regional differences – Seasonal temperature change – Short term changes (e.g., weather changes, tidal changes) - Temperature regulation: - Homeotherms - regulate body temperature, usually higher than ambient - Poikilotherms - do not regulate body temperature - Species evolve differences in temperature tolerance - Populations living along a latitudinal gradient might evolve local physiological races, with different temperature responses - Freezing - winter & high latitudes - Some fish have glycoproteins and glycopeptides, which function as antifreeze and bind to incipient ice crystals to prevent further growth

Answer 19

- Have the advantage of no cost of keeping temperature constant and high, but at the price of metabolic efficiency - Heat gain - problem for poikilotherms in intertidal zone at low tide or tidal pools on a hot day – Circulation of body fluids - brings heat to surface of body so it can be dissipated – Evaporation - also allows heat loss to avoid overheating - can compensate for temperatures by means of acclimation; can stabilize metabolic rate over a wide range of intermediate temperature

Answer 20

- Homeotherms - advantage of constancy of cellular chemical reactions, disadvantage of heat loss - Heat loss - problem for homeotherms who maintain high body temperatures - Insulation - used by many vertebrates (blubber in whales, feathers in birds) - Countercurrent heat exchange - circulating venous and arterial blood in opposite directions while vessels are in contact to reduce heat loss - Marine mammals typically have a higher metabolic rate compared to terrestrial mammals of similar size

Answer 21

- Heat Shock - has effects on physiological integration of biochemical reactions in cells, can denature proteins that cannot function at high temperature – heat shock proteins - are formed during heat stress, which forestall unfolding of protein 3D structure – ubiquitin - low molecular weight protein

Answer 22

- Seasonal extremes of temperature affect both activity and reproduction - Effects are different at northern and southern limits of geographic range - Seasonal changes in timing and amount of egg and sperm production and release are highly correlated to temperature

Answer 23

- Variation of salinity: estuaries, tide pools, intertidal zone - Many marine groups intolerant of salinity change (low salinity) - Populations in open ocean often less tolerant of salinity change: e.g., pelagic planktonic organisms - Regulation of vertebrates of ionic concentrations to very narrow variation, other groups show more variation and response to external change

Answer 24

- Diffusion - problem of regulation of ion concentration - Osmosis - problem of regulation of cell volume - Osmosis - movement of pure water across a membrane permeable to water, owing to difference in total dissolved material on either side of membrane - Example of osmosis problem -animal with a certain cellular salt content is placed in water with lower salinity: water will enter animal if it is permeable - cell volume will increase, creating stress - Diffusion - random movement of dissolved substances across a permeable membrane; tends to equalize concentrations - Problem - diffusion makes it difficult to regulate concentration of physiologically important ions such as calcium, sodium, potassium - Most marine organisms have ionic concentrations of cell constituents similar to seawater

Answer 25

- Done by many species, but best by crustacea (e.g., crabs), vertebrates - Accomplished when isolation of body possible (e.g., crab carapace) so exchange and regulation localized - Poorly accomplished by species with poor isolation (e.g., echinoderms, sea anemones)

Answer 26

- Osmolytes: organic substitute for inorganic ions - allows regulation of cell volume and maintenance of inorganic ion concentrations - Free amino acids used by many invertebrates, bacteria, hagfishes. Use uncharged amino acids that have little effect on protein function (e.g., glycine, alanine, taurine) - Urea used by sharks, coelocanths - Glycerol, mannitol, sucrose used by seaweeds, unicellular algae

Answer 27

- Oxygen - synthesis of ATP; energy source in cells - Some habitats are low on oxygen - Low tide for many intertidal animals - Within sediment: often anoxic water - Oxygen minimum layers in water column: where organic matter accumulates at some depths - Seasonal oxygen changes: hypoxic zones, “dead zones” - Oxygen consumption increases with increasing body mass, but weight specific oxygen consumption rate declines with increasing total body mass - Oxygen consumption increases with activity - Nearly all animals are obligate aerobes, but many animals have a mix of metabolic pathways with and without use of oxygen - Anaerobic pathways: - Vertebrates and some invertebrates use glycolysis - breakdown product is lactic acid, which accumulates in muscle tissue - Many invertebrates have alanine and succinic acid as anaerobic breakdown products - Oxygen uptake mechanisms: - diffusion - feathery gills - Larger animals have circulatory systems and oxygen-carrying blood pigments

Answer 28

- Blood pigments: substances that greatly increase blood capacity for transporting oxygen - Haemocyanin - copper-containing protein, found in molluscs, arthropods - Haemoerythrin - iron-containing protein, always in cells, found in sipunculids, some polychaetes, priapulids, brachiopods - Chlorocruorin - iron-containing protein, found in some polychaetes - Haemoglobin - protein unit (globin) and iron-bearing unit (heme), found in many phyla (Myoglobin is part of this family of proteins) - Blood pigments can serve as reservoirs for animals living in low oxygen environments

Answer 29

- Bohr effect: Hb ability to hold oxygen decreases with decreasing pH - pH is less near capillaries that are starved for oxygen, owing to presence of CO2 released from cells (respiring); Hb releases oxygen, which diffuses into cells

Answer 30

- Low tide (not immersed in seawater) - Oxygen minimum layer - Climate change: –Thermal stratification –Loss of movement of layers of water to depth –Hypoxic zones –Decrease in O2 over 50 years (solubility decreases as temperature increases)

Answer 31

- Many animals detect light with aid of a simple layer of sensory cells, but many species have complex eyes with focusing mechanisms (and can see colour) - Allows detection of prey, predators - Aids in navigation - Behaviour (including mating) - Photosynthetic organisms can also sense light and have phototropic responses - some have eye spots that sense light as well as the direction of light

Answer 32

- Relies on pigments that absorb light - Rhodopsins - Vertebrates have rods & cones - Retina focuses the light - Colour vision is widespread among vertebrates and invertebrates in the marine environment

Answer 33

- Bioluminescence - light manufactured by organisms, using specialized light organs, sometimes with the aid of symbiotic bioluminescent bacteria - Functions to confuse predators - Perhaps other as yet undiscovered functions

Answer 34

- Life in seawater is a selective force on marine organisms - Primary effects - direct results of properties of seawater - Secondary effects - secondary impacts of properties of seawater

Answer 35

- The properties of water are different from air - Density (greek letter rho - ρ) –seawater is more dense than freshwater - Dynamic viscosity (greek letter mu - μ) –molecular “stickiness” between layers of a fluid –the more “sticky” the more energy that is required to move within - Kinematic viscosity (greek letter nu - ν) –“gooeyness” under gravity (how it falls) - Two forces compete in fluids: viscous forces and inertial forces - Reynolds number (Re) is an estimate of the relative importance of each of these

Answer 36

- When Re is less than 1000 then viscous forces are dominant - If Re is much greater than 1000 then inertial forces predominate - Objects exist under very different conditions in the same seawater, depending on their size and velocity - Re=Vlρ/μ - Low temperature: viscosity dominates - High temperature: inertia dominates – Temperature range of 5-15°C - kinematic viscosity decreases 45%! - Energetically less costly to swim at higher temperature

Answer 37

- If Re is high = flow is turbulent - If Re is low = flow is laminar - Shear can result in microturbulence

Answer 38

- Assume fluid is incompressible and moving through a pipe - What comes in must go out! - Velocity of fluid through pipe is inversely proportional to cross section of pipe - Allows organisms to regulate water flow

Answer 39

- Sponges consist of networks of chambers, lined with cells called choanocytes - Velocity of exit current can be 1-2 cm/s (10,000- 20,000 μm per sec) - But, velocity generated by choanocytes is 50 μm per sec. How do they generate such a high exit velocity? - Cross-section of flagellated chambers adds up to several thousands of times the cross sectional area of the exit canal

Answer 40

- Bernoulli’s principle: pressure varies inversely with fluid velocity (if total energy is constant) - If diameter of a pipe decreases then velocity will increase but pressure will decrease - Can provide lift or create a current

Answer 41

Water moving past an object creates drag - At high Reynolds number, the pressure difference up- and downstream explains the pressure drag. Streamlining and placing the long axis of a structure parallel to the flow will both reduce pressure drag - At low Reynolds number, the interaction of the surface with the flow creates skin friction - Fast and continually swimming fish (e.g. sharks) are very streamlined to reduce drag, many also have adaptations such as arrangement of scales to reduce minor irregularities as well as having slime on their skin

Answer 42

- Problem: You are attached to the bottom and sticking into the current - Drag tends to push you down stream - you might snap! - Examples : Seaweeds, corals - Solutions: –Flexibility - bend over in current –Grow into current –Strengthen body

Answer 43

the replication of individuals

Answer 44

the spread of offspring from one area to another

Answer 45

directed movement between areas and populations

Answer 46

- Sex is complex - Sex is inefficient - Sex is costly - Is sex necessary? –Sex means genetic recombination - Crossing over & segregation - Matings between non-related individuals - Genetic recombination is believed to be why sexual reproduction is so successful - Sex produces genetically diverse offspring

Answer 47

- Many organisms can reproduce asexually & sexually - Rarely is sex wholly absent - Exclusively sexual reproduction is also rare (mammals) - Asexual predominates in small organisms - Sexual predominates in large organisms - Sexual selection can result in traits that are useful in attracting a mate or competing for a mate

Answer 48

- Selection for extreme forms that breed more successfully - major claw of fiddler crabs, - Can involve selection for display coloration, enhanced combat structures - Female choice often involved; selection for fit males (good genes hypothesis) - Intrasexual selection: within a sex - Intersexual selection: between males & females

Answer 49

- Separate sexes: gonochoristic - Hermaphroditism: individual can have male or female function, simultaneously or sequentially, during sexual maturity

Answer 50

- first male then female - Eggs costly in terms of resources, so more offspring produced when individual functions as female when large - Male function does not produce great increases in offspring when it gets larger - Therefore, there is a threshold size when female function begets more offspring; smaller individuals do better as males - larger females with smaller males produce more offspring

Answer 51

- first female, then male - Male function must result in more offspring when male is older and larger - Important when aggression is important in mating success, e.g., some fishes where males fight to maintain group of female mates

Answer 52

- Males may occur as aggressive fighting morphs, or less aggressive morphs - Observed in a number of groups, e.g., some fishes and some amphipod or isopod crustaceans - Determination of morphs can be environmental, genetic - Less aggressive morphs can obtain mates by “sneaky” tactics, which are often successful

Answer 53

- Percent investment in reproduction - reproductive effort - Age of first reproduction (generation time) - Predictability of reproductive success - Juvenile versus adult mortality rate

Answer 54

- Planktonic sperm (and eggs in many cases): problem of timing, specificity - Direct sperm transfer (spermatophores, copulation): problem of finding mates (e.g., barnacles, timing of reproductive cycle) - Planktonic sperm: – Specialized binding/fertilization proteins in sperm and receptors in eggs (bindin in sea urchin sperm, lysin in abalone sperm) – Sperm attractors in eggs – Binding proteins are species specific, proteins with high rates of evolution

Answer 55

- known in mussels, stimulus of one spawner causes other individuals to shed gametes

Answer 56

- known in coral species, many species spawn on single nights

Answer 57

- (also production of spores by seaweeds) at times of quiet water (slack high or low tide) to maximize fertilization rates

Answer 58

- Tactics that maximize population growth - Evolutionary “tactics”: variation in reproductive effort, age of reproduction, whether to reproduce more than once - Presume that earlier investment in reproduction reduces resources available to invest in later growth and survival - Examples: – Strong variability in success of reproduction: reproduce more than once – High adult mortality: earlier age of first reproduction, perhaps reproduce only once – Low adult mortality: later age of first reproduction, reproduce more than once

Answer 59

- Parental care is non- existant in many marine animal species - but there are instance where females or males provide care. * Courtship can be related to parental care

Answer 60

- Clone - descendants are genetically identical - Colonial - individuals are genetically identical, comprise a module; each module may have arisen from a sexually formed zygote - Fragmentation is also a form of asexual reproduction seen in many seaweeds and some corals

Answer 61

- Dispersal is undirected whereas migration is directed and return specific - Fish, crustaceans, turtles and marine mammals migrate between mating/spawning and feeding grounds

Answer 62

- Anadromous - fish live as adults in salt water, spawn in fresh water (shad, striped bass, salmon), more common in higher latitudes - Catadromous - fish live as adults in fresh water, spawn in salt water (eel), more common in lower latitudes - Diadromous - divide their lives between freshwater and marine - Fully oceanic - herring, green turtle, cod

Answer 63

Three spatial scales to understand dispersal and recruitment –microscale (cm) –mesoscale (m-km) –macroscale or biogeographic scale - Marine invertebrates may be: –brooded - direct release –dispersed a small degree - lecithotrophic –dispersed a great degree - planktotrophic

Answer 64

- female produces many (103 to 106) small eggs, larvae feed on plankton, long dispersal time (weeks), some are very long distance (teleplanic) larvae - cross oceans

Answer 65

- female produces fewer eggs (102 to 103), larger, larvae live on yolk, short dispersal time (hrs to days usually)

Answer 66

- female lays eggs (oviparous) or broods young, juveniles released and crawl away (viviparous)

Answer 67

- Larger scale (mesoscale) - 10 - 10 3 km. Small scale movements to take advantage of currents, seasonal release and settlement - Smaller scale (microscale) - Positive, neg phototaxis, timing, near cues (< 10 -1 m)

Answer 68

Presettling problems: –Starvation –Predation in plankton –Loss to inappropriate habitats - Larval recruitment is the result of habitat selection & mortality

Answer 69

- Species with a planktonic larval dispersal form have a greater biogeographic range than species without planktonic larvae

Answer 70

- Local extinction - to export young - Hedging bets - spread over habitats - Not for dispersal! Feeding in plankton

Answer 71

- Planktonic organisms are dependent on the movement of masses of water - Phytoplankton require light and zooplankton rely on phytoplankton as food - Hence both need to remain in surface waters (or migrate into surface waters) - In order to remain in the surface waters plankton must: – be less dense than seawater – increase surface area and hence drag – swim

Answer 72

- Plankton: organisms living in the water column, too small to be able to swim counter to typical ocean currents - Phytoplankton or Zooplankton: – Mixoplankton (or mixotrophic) – Holoplankton - permanent residents – Meroplankton - temporary residents – Neuston - associated with slick – Pleuston - sticking up above water surface

Answer 73

- Phylum Mollusca - Carnivores (squid feed on smaller fish, larger zooplankton) - Mouth - powerful beak - Mantle + siphon = rapid movement - Squids and octopus have an ink gland; ink expulsion confuses predators - Squid, cuttlefish (demersal), octopods (benthic) - photophores that allow rapid colour change, camouflage, deception of predatory cuttlefish

Answer 74

Nekton: organisms living in the water column that can swim strongly enough to move counter to modest water currents - Nekton: live under high Reynolds number, meaning that inertial forces dominate over viscous forces - Boundary layer on fast moving forms is thin - Minimizing pressure drag is important for fast and continual motion

Answer 75

- Locomotion of squid - rhythmic muscular movement of fins, rapid expulsion of water through siphon hypnome) from mantle cavity. - Nautilus - gas-water balance keeps animal stationary, also can expel water through siphon for rapid attack over short distances - Cuttlefish - cuttlebone + osmotic pump

Answer 76

–cartilaginous fishes including sharks, skates, rays - cartilaginous skeleton, replaceable tooth rows

Answer 77

–bony fishes, true bony skeleton - much more diverse than Chondrichthyes, teeth fixed in jaws - Form of fishes strongly related to their locomotion type and feeding ecology

Answer 78

- Water over gills - Water flows over gill lamellae and oxygen diffuses into gills - Blood flow is in opposite direction of water flow - countercurrent exchange - same principle as for heat conservation in dolphins

Answer 79

- Fish can regulate bulk chemistry - Sharks - high lipid content - reduces bulk density - Bony fish - lower salt content than sea water - reduces bulk density - Swim Bladder - most bony fish - Most bony fish - swim bladder; fish can acquire air at surface and esophagus is connected to swim bladder - Gas gland - gas uptake and release - Rete mirabile - intertwined capillaries and veins - countercurrent exchange to retain oxygen near the gas gland

Answer 80

- Two mechanisms in water column: suction and ram feeding - Many fish chew prey by means of teeth; some have specialized crushing teeth (puffer fish, some sculpins) - Some species suspension feed, trap zooplankton, phytoplankton, or particulate organic matter on gill rakers

Answer 81

- Bony fish and sharks have a lateral- line system - This consists of mechanoreceptors that respond to disturbances in the water - All elasmobranchs and some fish can sense prey via electroreceptors - Lateral line system - Eyes - fish often have excellent vision - Otoliths in contact with hairlike fibers - Sounds can be produced during mating seasons

Answer 82

- Behaviourally based aggregation of fish - Most tightly schooling species have silvery sides, which would confuse predators - Schools sometimes in the form of “fish balls” - Behaviour related to predation; fish leaving school are attacked successfully - Schooling may also reduce drag, save on energetic cost of swimming

Answer 83

- Most fishes - temperature conformers - Tunas and relatives, some sharks, use countercurrent heat exchange to reduce heat loss - have elevated body temperature - Elevated body temperature allows higher metabolic rate, localized heating of nervous system in some species (e.g., swordfish)

Answer 84

- Fish living 150-2000 m - Fish have well developed eyes, often large mouths for feeding on large prey - Many have ventral photophores, serves purpose of counterillumination - camouflage to blend in with low light from above

Answer 85

Cetaceans: whales and porpoises Pinnipeds: seals, sea lions, walruses Mustelids: sea otters Sirenians: sea cows, dugong

Answer 86

All belong to the Cetacea * Odontoceti-toothed whales * Mysticeti-baleen whales * All homeothermic * Reproduce much the same as terrestrial mammals * Posterior strongly muscular- propulsion by means of flukes

Answer 87

Whales and dolphins: – Very different from other marine mammals – Adapted to a completely oceanic existence * No hair * Breath through blowholes * Very streamlined body plans * Have broad horizontal tail flukes (similar to dugong) * No pelvic appendages * Two major groups of Cetaceans—toothed and baleen whales – Toothed whales are carnivores and relatively small. * Dolphins, pilot whale, orca – Baleen whales are filter feeders and relatively large. * Humpback whale, blue whale

Answer 88

- Toothed, usually good hunters, feed on squid, fish, small mammals * Good divers * Oral communication common * Many species have bulbous melon, filled with oil - function could be sound reception * Usually social, killer whales live in pods, maternally dominated

Answer 89

- Most widely distributed marine mammal species * Males have distinctly larger body parts than females (sexual dimorphism). * Up to 22,000 lb * 22 ft long * Resident, transient, and offshore forms that vary. – Food choice depends on location. * North Pacific populations (Puget Sound) eat salmon. * Transients feed on larger prey (seals, porpoises, other cetaceans). * In New Zealand, eat sharks and stingrays

Answer 90

- Lack teeth * Have rows of comb-like baleen * Use baleen to filter the water * Filter huge volumes of water to capture enough plankton to meet energetic needs * The largest whales, in fact, the largest creature on earth (blue whale) * Adults have horny baleen plates, which strain zooplankton * Right whales are continuous ram feeders * Rorqual whales (e.g. Blue) are intermittent ram feeders, periodically squeeze water out of large mouth chamber

Answer 91

- continuous - intermittent

Answer 92

- Includes manatee, dugong, extinct Stellar Sea Cow - Sluggish, herbivorous * Live in inshore waters, estuaries

Answer 93

- Sea otters are weasels that evolved to live their entire lives in the water. * Care for young out in the water, so do not use haulout sites. * Actually use tools to open shelled prey items

Answer 94

- Must breathe at surface - no “bends” * Problem oxygen for long dives * Most have increased volume of arteries and veins * Have increased blood cell concentration * Can decrease heart beat rate and O2 consumption * Can restrict peripheral circulation and circulation to abdominal organs

Answer 95

- Often colonial breeders * Believed to be monogamous * Courtship involves elaborate displays * Crowded breeding sites, often with several species, protected from predators such as mammals * Feeding involves either diving or underwater swimming * Long-distance migration between nesting and feeding areas is common

Answer 96

- Penguins - flightless, southern hemisphere, high latitude, divers, insulated by blubber and feathers, countercurrent heat exchange in circulation to wings and feet, colonial breeders * Petrels - great gliders, colonial breeders, often divers from air * Pelicans - generally tropical, heavy, diverse hunting from diving to underwater swimming * Gulls, auks, puffins - feed on fish, often very abundant

Answer 97

- Include sandpipers, plovers, other groups * Great dependence upon terrestrial sites, especially for feeding * Often migrate great distances between feeding and nesting areas * Variety of feeding mechanisms, ranging from probing beaks into sediment to catching crustacea and other organisms in the surf to clipping bivalve adductors and scooping out bivalve flesh

Answer 98

- Flightless birds - wings have evolved into flippers. – Can dive at speeds up to 17 mph! * 17 to 20 species * Adaptations for life in cold environments – Very thick layer of insulating feathers. – Control blood flow to extremities—reduces amount of blood that is cold at any one time * Reproduce with only one partner each season – Both parents care for young once eggs hatch. – Caring for young is very stressful and strains parents

Answer 99

- Sea snakes - common through the Indo- Pacfic region - are venomous. Some lay eggs on land or breed at sea with live young * Marine Iguanas - Galapagos Islands (studied by Darwin), not fully adapted to marine life * Saltwater crocodiles – not fully adapted but do have a salt gland to excrete excess salt * Extinct marine reptiles – Mosasaur – Icthyosaurs – And others

Answer 100

- Eight species, thought to be tropical or subtropical, but also found in temperate seas (e.g., California) * All species either threatened or endangered status – Easily disturbed by humans because they have a land component to their habitat for nesting – Have flippers for swimming * Excellent eyesight * Some of the longest breath-holders of all air breathing marine vertebrates—up to 8 hours! – Specialized nasal glands * Located below each eye * Salts concentrated by salt- excreting glands, then leave the body by dripping down or being blown out the nose - All nest on sandy beaches and migrate to feeding grounds; females return to beach where they hatched, usually repeatedly; several species shown to use earth magnetic field to navigate in migrations * Feeding of adults varies (e.g., green turtle consumes seagrasses and seaweeds, Kemp’s Ridley eat bottom invertebrates, leatherbacks eat jellyfish * Leatherbacks distinct from other species, have temperature conservation mechanisms, including a countercurrent exchange heat retention

Answer 101

- Nekton: – Most nekton are vertebrates, and most are teleost fishes. – Squids are a molluscan exception. – Small squids live in high densities. – Giant squids reach 18 m in length and live at great depths. * Zooplankton: – Holoplankton spend their whole lives as plankton. – Meroplankton are planktonic only as larvae

Answer 102

- Most pelagic animals reside in this zone * Bright colouration is not common in epipelagic organisms - countershading is much more common * occurs within the photic zone - (~200 m) * A few major habitats are apparent: * Tropical, subtropical, temperate, polar

Answer 103

- How do pelagic organisms orient without a solid reference point? * Environmental and seasonal factors * Changes in time are indicated by: – Night/day – Water temperature – Changes in food source * Changes in space are indicated by: – Position of the sun – Olfaction – Ocean currents – Earth’s magnetic field - magnetoreception

Answer 104

- Planktonic organisms are dependent on the movement of masses of water * Phytoplankton require light and zooplankton rely on phytoplankton as food * Hence both need to remain in surface waters (or migrate into surface waters) * In order to remain in the surface waters Plankton must – be less dense than seawater – increase surface area and hence drag – swim

Answer 105

- Spatial changes in physical- chemical conditions * Depth gradients in salinity, temperature, oxygen * Water turbulence and current transport * Zooplankton grazing balanced against phytoplankton growth * Localized reproductive behavior * Localized feeding behavior

Answer 106

- Planktonic organisms often migrate on a diurnal basis (response to light) –towards the surface during the day –descend during the night –or vice versa * Largest migration on earth * Copepods can migrate ~400 m (upwards 15 m/h, downwards 100m/h) * Some migrations can be ~1000 m * Highly variable

Answer 107

- Some zooplankton and some fish are poor long- distance swimmers. * Small changes to vertical position can change their environment drastically. * Life in the mesopelagic is always dark with little food. * Life in the epipelagic is light during the day and has a lot of food. * Diel vertical migration * Allows organisms to remain in the dark mesopelagic during the day * Organisms move into the dark epipelagic at night to feed

Answer 108

- Rhythm is set by day - night cycles * But then after it is set, animals can be placed in a constant environment (lab, dark) and day-night vertical migration will continue. * After a few days- weeks the cycle will dampen

Answer 109

- Strong light hypothesis –zooplankton are affected by strong light and UV * Phytoplankton recovery hypothesis –zooplankton migrate to let phytoplankton recover * Predation hypothesis - avoid predators * Energy conservation hypothesis –less cost to spend energy in cold waters * Surface mixing hypothesis –hope for better surface waters upon return

Answer 110

- Small spatial scale - Schooling - usually single species of fish * Larger spatial scale - Migrations between reproduction and feeding sites

Answer 111

- Behaviourally based aggregation of fish * Most tightly schooling species have silvery sides, which would confuse predators * Schools sometimes in the form of “fish balls” * Behaviour related to predation; fish leaving school are attacked successfully * Schooling may also reduce drag, save on energetic cost of swimming

Answer 112

- Movement over large distances detected with tracking devices. * GPS tag implanted, and detaches and floats to surface - sends signal to satellite * Other tags are permanent in fish - can produce acoustic signal, give evidence of where tag was implanted

Answer 113

- Most production is in the surface waters - phytoplankton - photosynthesis * Not all phytoplankton is consumed by zooplankton * Plankton sink to deeper waters - supplies organic matter to many consumers in deeper water * Sinking and vertical position of dead plankton is related to bulk density of the organism, structures that create * Drag (bell of jellyfish), water motion, and swimming ability. * Meals scarcer at depth - organisms adapted to low input of food from above

Answer 114

- Bone and muscle tissues are needed for locomotion of many pelagic organisms. * Maintaining position in the water column is a struggle with a body that is more dense than seawater. * A variety of factors that offset dense body parts are used by pelagic organisms. * Adaptations to increase buoyancy – Stored fats and oils – Blubber – Gas-filled floats – Lungs full of air – Swim bladders

Answer 115

- Many animals detect light with aid of a simple layer of sensory cells, but many species have complex eyes with focusing mechanisms (and can see colour) - Allows detection of prey, predators - Aids in navigation - Retinas in twilight zone fish have fewer cones (high intensity & colour) than rods (low light) and cones are often completely absent in deep sea fish

Answer 116

- Bioluminescence - light manufactured by organisms, using specialized light organs, sometimes with the aid of symbiotic bioluminescent bacteria * Functions to confuse predators * Perhaps other as yet undiscovered functions

Answer 117

- Below the photic zone, also called the twilight zone * 200 m to 700 or 1000m * organisms rely on food that rains down from above, marine snow, or predation * Fishes of the mesopelagic have a variety of unique adaptations. * Small size (usually <10 cm) * Large teeth and mouths * Large eyes * Photophores

Answer 118

Defensive: - Startle (flash to confuse predators): squid - Counterillumination: fish, crustaceans, squids - lit smoke screen (release of luminescent slime): fish, crustaceans, squid, ctenophores Offensive: - lure prey or attract host: angler fish, cookie cutter shark - illuminate prey: dragonfish, flashlight fish

Answer 119

- Fish living 150-2000 m * Fish have well developed eyes, often large mouths for feeding on large prey * Many have ventral photophores, serves purpose of counterillumination - camouflage to blend in with low light from above

Answer 120

- Below 700 to 100 m - Bathylpelagic and Abyssalpelagic * Fish tend to be black and have fewer photophores (except angler fish) * Eyes are reduced as is central nervous system * Weakly ossified skeleton * long jaws * unique adaptations for mating

Answer 121

- Predictability of tides induces tidal rhythms in organisms * Affects life history and ecological characteristics of various species * E.g. spawning, laying eggs, feeding etc

Answer 122

- Universal feature of rocky shores, also true of soft sediments but not as distinct * Zonation claimed to be universal in mid- and high- latitude rocky shores, but there often are exceptions * Generally – a lichen zone – a periwinkle (littorine gastropod) zone with sparse barnacles – a barnacle-dominated zone either overlapping with mussel-dominated zone or with mussels below – a zone dominated variously, but usually by seaweeds * Two Gradients: – Vertical – tide levels, time of exposure to air/water – Horizontal - changing wave exposure

Answer 123

- Conditions –Heat stress, desiccation –Gas exchange - dissolved oxygen –Reduced feeding time –Wave shock –Biological interactions - competition, predation * Higher intertidal organisms - more resistant to heat and desiccation stress than lower intertidal organisms, less time to feed, sessile forms grow more slowly. * Mobile carnivores can feed only at high tide, usually feed more effectively at lower tide levels, which are immersed a greater proportion of the day

Answer 124

- Varies on small spatial scales * Body size, shape are both important - reduction of surface area/volume reduces heat gain and water loss * Evaporative cooling and circulation of body fluids aids in reduction of heat loss * Well-sealed exoskeletons aid in retarding water loss (acorn barnacles, bivalves) * Heat Shock proteins

Answer 125

- Intertidal animals usually cannot respire at time of low tide * Respiratory organs (gills of polychaetes, bivalves) must be moist to acquire oxygen, and therefore are usually withdrawn at low tide * Some animals reduce metabolic rate at time of low tide * Some high intertidal animals can respire from air (e.g., some mussels) even at low tide, as long as air is not too dry Pacific sand bubbler crab, Scopimera inflata, has membrane on each leg (shaded green), which exchanges gas from air into arterial blood

Answer 126

- Abrasion - particles in suspension scrape delicate structures * Pressure - hydrostatic pressure of breaking waves can crush compressible structures * Drag - impact of water can exert drag, which can pull organisms from their attachments to surfaces, erode particles from beaches, and carry organisms from their burrows or living positions - Swash riders: move up and down to maintain burrowing position in moist sand, as tide rises and falls; includes some bivalves, burrowing mole crab Emerita

Answer 127

- Physiological tolerance of different species at different levels of the shore * Larval and adult preference - larvae may settle at time of high tide at high levels, mobile juveniles/adults have a series of behavioural responses that keep them at certain levels of shore * Competition - species may be capable of excluding others from certain levels of the shore * Predation - mobile predators more effective usually on the lower shore: affects distributions of vulnerable prey species * Behaviour - selective movement

Answer 128

- Why are there vertical zones, with dominance often of single sessile species within a zone? * Possible explanations: –(1) differences in tolerance of species at different tidal heights –(2) competitive interactions –(3) predation changes with tidal level –(4) larval and adult preference

Answer 129

- Studied factors controlling vertical zonation by selective inclusion and exclusion of hypothesized interacting species * Species –Chthamalus stellatus - acorn barnacle, ranging from subtropical latitudes to northern British isles –Semibalanus balanoides - acorn barnacle, ranging from Arctic to southern British isles, overlapping in range with C. stellatus –Nucella lapillus - carnivorous gastropod, drills and preys on barnacles - Experiment: –Transplanted newly settled Chthamalus to all tidal levels –Caged some transplants, excluded Nucella –Allowed Semibalanus to settle and cleaned newly settled Semibalanus off some rocks * Results: –Chthamalus survival poorer in presence of Semibalanus –Chthamalus survival decreased where Semibalanus grew the fastest –Chthamalus survival increased in high intertidal due to its resistance to desiccation Conclusion: - Predation important in lower intertidal * Biological factors control lower limit of species occurrence * Physical factors control upper limit * Community structure a function of very local processes (larval recruitment not taken into account as a factor) * Predators reduce prey density * Prey species compete * Conclude: predation may promote coexistence of competing prey species

Answer 130

- Rocky shores of outer coast of Washington State - 1966 American Naturalist. * Principle predator - starfish Pisaster ochraceus * Pisaster preys on a wide variety of sessile prey species, including barnacles, mussels, brachiopods, gastropods - Removal of Pisaster ochraceus * Successful settlement of recruits of mussel Mytilus californianus * Other species greatly reduced in abundance, Mytilus californianus became dominant * Conclude: Pisaster ochraceus is a keystone species, a species whose presence has strong effects on community organization mediated by factors such as competition and predation

Answer 131

- Disturbances are physical events that influence the distribution and abundance of organisms (biological disturbance can occur as well) * Disturbances may also reduce abundance of competing species * Disturbances may therefore allow coexistence of competitively inferior species or may allow colonization of species adapted to disturbance - A very small scale disturbance in a mussel bed might just result in the mussels moving and sealing off the opened patch * Larger patches might be colonized by other species, and the patch might last many months or even indefinitely * Therefore, spatial scale of disturbance might affect the spatial pattern of dominance of species, creating a mosaic of long-lived patches

Answer 132

- Cannot extrapolate all interactions at small scales to large scales * Alternative stable states at some large spatial scale * Thus large patches created by disturbance may be qualitatively different than small scale interactions - outcomes may be different

Answer 133

- Results from manipulative experiments usually depend upon steady recruitment of larvae of competing species * What if recruitment is variable? * Competitively superior species might not take over, owing to low rates of recruitment * Recruitment might be reduced if currents are not favourable, high water flow results in flushing of larvae from inshore habitats, poor year for phytoplankton results in poor year for success of plankton-feeding larvae

Answer 134

- Higher intertidal species burrow more deeply * Zonation not as distinct as on rocky shores * Water retention reduces vertical desiccation and temperature stress gradients

Answer 135

- Dominant species found at different levels below sediment-water interface * Experimentally reduce density of deep-dwelling clams, remaining individuals grow faster; demonstrates effect of density * Removal of shallow dwelling species of bivalves has no effect on growth of deeper- dwelling species

Answer 136

- Suspended phytoplankton for suspension feeders (e.g., bivalves, polychaetes) * Microalgae and bacteria for deposit feeders * Decomposing organic matter (phytodetritus and decomposing seaweeds) * Input can be spatially variable

Answer 137

- Exposed beaches - strong erosion and sediment transport * Difficult environment for macrobenthos to survive and maintain living position * Swash riding - means of moving up and down with rising and falling tide - maintain position in wet but relatively noneroded tidal levelm

Answer 138

- Dominated by species of mangroves, common in subtropical and tropical protected shores * Mangroves broadly rooted but only to shallow depth in quite anoxic soils * Underground roots have projections into air that allow gathering of oxygen - Highly salt tolerant * High primary productivity * High supply of particulate organic matter, especially falling leaves, which subsidize animal growth * Zonation of mangrove species * Roots support a rich assemblage of sessile marine invertebrates

Answer 139

- Sea grasses are marine angiosperms, or flowering plants, that are confined to very shallow water * Extend mainly by subsurface rhizome systems within soft sediment * Found throughout tropical and temperate oceans * Grow best in very shallow water, high light and modest current flow

Answer 140

- High primary production, support a diverse group of animal species * Sea grass beds reduce current flow * Deter the entry of crab and fish predators from side * May enhance growth and abundance of infaunal suspension feeders near edge, although phytoplankton may not penetrate far into bed

Answer 141

- Grazing on sea grasses variable: in temperate zone, grazing on Zostera marina (eel grass) is minimal * In tropics, sea grass beds comprised of several species that are grazed differentially because of different toughness, cellulose content * Green turtles nip leaf tips,which encourages growth of more soft and digestible new grass * Even tough grasses grazed by turtles, urchins, dugongs. Green turtles have extended hindguts with intestinal microflora, digesting cellulose

Answer 142

- Sea grasses very vulnerable to eutrophication - phytoplankton shade sea grasses, strong reductions of eel grass beds in North America * Possible that overfishing results in reduced grazing and overgrowth of epiphytes, which smothers sea grasses * Dredging, boat traffic, also causes decline of sea grasses * Disease important, fungus caused eelgrass epidemic in 1930s, recovery, but other fungi are now cause of sporadic diseases in tropical sea grasses

Answer 143

- Kelp forest - rocky reef complex found in cooler coastal waters with high nutrients * Kelp forest–rocky reefs are often dominated in shallow waters by kelps and seaweeds and by epifaunal animals in deeper waters animal- dominated rocky reefs * Switch from cover dominance by rapidly growing seaweeds in shallow water to epifaunal animal dominance in deeper water - Dominated by brown seaweeds in the Laminariales * Found in clear, shallow water, nutrient rich and usually < 20°C, exposed to open sea * Generally laminarian seaweeds have high growth rates, often of the order of centimeters/day (Macrocystis -60 cm/day) * “Forests” can be 10-20 m (Macrocystis - 50 m) high or only a meter in height

Answer 144

- Abundant communities of algae and invertebrates, often dominated by colonial invertebrates. * Often are very patchy, with alternations of rocks dominated by rich invertebrate assemblages and turf-forming calcareous red algae * Subtidal rock wall patches of animals often are short on space, suggesting the importance of competition

Answer 145

- Herbivory - herbivorous sea urchins * Carnivory - sea otter Enhydra lutris can regulate urchin populations * Result: trophic cascade; add otters, have reduction of urchins and increase of kelp abundance; reduce otters: kelp grazed down by abundant urchins * Recent history: otters hunted to near extinction, their recovery has strong impacts on urchin/kelp balance * In lower-latitude California kelp forests, a larger diversity of predators beyond sea otters exerts top-down effects

Answer 146

- Effect of storms: remove kelp * El niño: storms + warm water = kelp mortality * California kelp forests: storms remove kelp, urchins roam, and inhibit kelp colonization and growth: barrens * California kelp forests: if kelp growth is rich, urchins stay in crevices and capture drift algae * This leads to two alternating states: barrens and kelp forest

Answer 147

- Geological importance: often massive physical structures * Biological importance: biological structure, High diversity, * Economic importance: shoreline protection, harbours, fishing, tourism - Compacted and cemented assemblages of skeletons and sediment of sedentary organisms * Constructional, wave-resistant features * Built up principally by corals, coralline algae, sponges, and other organisms, but also cemented together * Reef-building corals belong to the Scleractinia, have endosymbiotic algae known as zooxanthellae; high calcification rate * Topographically complex

Answer 148

- Belong to the phylum Cnidaria, Class Anthozoa, Order Scleractinia * Secrete skeletons of calcium carbonate * Are colonies of many similar polyps * Can be divided into branching and massive forms * Have abundant endosymbiotic zooxanthellae

Answer 149

- Dinoflagellate: – Once considered as one species: Symbiodinium microadriaticum – at least 10 distinct taxa with large genetic distance among species * Observed in species of anemones, hermatypic corals, octocorals, bivalve Tridacna, ciliophora (Euplotes) * Found in corals within tissues (endodermal), concentrated in tentacles

Answer 150

- Hermatypic: Reef framework building, have many zooxanthellae, hi calcification * Ahermatypic: not framework builders, low calcification

Answer 151

- Branching: grow in linear dimension fairly rapidly 10 cm per year * Massive: Produce lots of calcium carbonate but grow more slowly in linear dimensions, about 1 cm per year Costa Rica, Acropora palmata (elkhorn coral) Costa Rica, Colophyllia natans (brain coral) K. Müller K. Müller

Answer 152

- Coral species usually first identified on basis of morphology * Problem: coral species have a large degree of morphological plasticity - variable growth response to variation in water energy, light, competitive interactions with other species * Problem: nearly morphologically identical species * Species now identified more with DNA sequencing

Answer 153

- Bleaching - expulsion of zooxanthellae * Causes - stress (temperature, disease) * Mechanisms - poorly understood - zooxanthellae cells appear to die and are expelled * Test among mechanisms with fluorochromes; support for cell death under temperature stress (Strychar et al. 2004 J. Exp. Mar. Biol. Ecol.)

Answer 154

- Warm sea temperature (current problem of global sea surface temperature rise) * High light (symbiosis with algae) * Open marine salinities * Low turbidity - coral reefs do poorly in near- continent areas with suspended sediment * Strong sea water currents, wave action * Reef growth a balance between growth and bioerosion * Reef growth must respond to rises and falls of sea level * pH? Increasing ocean acidity a problem?

Answer 155

- Coastal reefs - wide variety of reefs from massive structures ( Great Barrier Reef), to small patches such (Eilat, Israel) * Atolls - horseshoe or ring-shaped island chain of islands atop a sea mount

Answer 156

- Absence of Light –Hence, absence of Photosynthesis –Adaptations of organisms reflect this absence of light * to find food * to find a mate * Pressure –considerable range –has significant effect - Salinity –tends to be quite constant * Temperature –Thermocline - isothermal - no changes (unusual) –Some exceptions (e.g. hydrothermal events) * Oxygen –due to thermohaline circulation and O2 rich waters from arctic and antarctic

Answer 157

- Effects of pressure are not well understood, but there are some apparent trends. –Lower metabolic rates –Lowered growth rates –Lowered reproductive rates –Longer life spans –Gigantism

Answer 158

- Sedimentary materials from planktonic organisms - Siliceous ooze - Radiolarians, Diatoms - Calcareous ooze - Foraminiferans (foraminiferan ooze) or coccolithophores * Accumulate very slowly (1cm/1000 years)

Answer 159

- Types of bottom samplers: –Dredges –Sleds –Grabs –Corers

Midterm 2 Flashcards

(183 cards)