Marine Biology Exam 2

colonial/modular organisms

individuals are genetically identical

if colonial organisms are connected, they compose a module

Modular organisms are brain coral, soft coral, byrozoan

gonochoristic

have separate sexes

different than sexually dimorphic

sequential hermaphrodites

an organism is one sex for a time and then another sex

protandrous - male then female

protogynous - female then male

simultaneous hermaphrodites

organs to produce male and female gametes present simultaneously (not necessarily active simultaneously)

size advantage model

for protandry

eggs are costly, so more offspring produced when individual functions as female when large

male reproductive function does increase with size, therefore there is a threshold size when female improves

smaller individuals do better as males

male polymorphism

males may occur as aggressive fighting morph or less aggressive morphs

morph determination can be environmental or genetic

less aggressive morphs can obtain mates by “sneaky” tactics, which are often successful

diadromous

move between estuaries and the open sea for migratoin

andadromous

fish live as adults in salt water, spawn in freshwater (shad, striped bass), more common in higher latitudes

catadromous

fish live as adults in freshwater, spawn in salt water (eel), more common in lower latitudes

oceanodromic

fully oceanic (herring, green turtle, humpback whale)

planktotrophic dispersal

female produces many (10³-10^6) small eggs

larvae feed on plankton

long dispersal time (weeks)

some are very long distance (teleplanic) larvae that cross oceans

lecithotrophic dispersal

female produces fewer eggs (10²-10³)

larger, larvae live on yolk

short dispersal time (hours-days usually)

what is the benefit of sexual reproduction?

crossing over and mixing of genes produces more genetic diversity and increases survival of individuals

what is a parasitic male and where would you find one? what is the benefit of this?

parasitic male latches onto female and atrophies until he dies and sperm would be available for female

you find these in the deep sea

the benefit is that you don’t have to search for a mate in the deep sea where organisms are few and far between

how do dispersal and migration differ?

dispersal is undirected

migration is directed, movement between specific sites, why specific areas? why the route and length?

compare and contrast planktotrophic and lecitotrophic dispersal mechanisms?

planktotrophic has long dispersal time and distance, larvae feed on plankton

lecithotrophic larvae live on yolk and have a short dispersal time

what can larvae control when it comes to dispersal?

larvae can control time of larval life (competency, overall development), timing of upward and downward movement, final micro-movements to “good” adult habitat

why might an organism want/need to disperse?

avoidance of crowding, local extinction, hedging bets (spread over habitats)

Compare and contrast protandrous and protogynous hermaphrodites. Give examples. Why might an organism adapt this reproductive strategy?

protandrous are male then female (clownfish) - large females can make a lot of eggs, small males compete less

protogynous are female then male (grouper) - large males can defend territory and make a lot of eggs

pick an organism that migrates and be able to describe why it migrates, where it migrates, and what benefits migration provides

sockeye salmon migrate from the ocean to specific rivers and pools where they were born to spawn, this benefit allows them to return to safe breeding locations year after year and be sure that other salmon are in the area

plankton

organisms living in the water column, too small to be able to swim counter to typical ocean currents

holoplankton

spends entire life as plankton

meroplankton

part of life spent as plankton

cyanobacteria

blue green algae

most abundant photosynthetic organism

picoplankton (1 micrometer)

nitrogen fixation

nematocysts

stinging or sticky grabbing cells - on tentacles

trait of Cnidaria

phytoplankton

diatoms, dinoflagellates, cyanobacteria, coccolithophores

photosynthetic, live in water column but too small to swim countercurrent to typical ocean currents

zooplankton

plankton that eat other animals - can’t swim against ocean currents

briefly describe diatom reproduction

they reproduce asexually by binary fission (also use sexual reproduction)

there is a small and large side of their frustule (silica skeleton) so they will split and each form a new diatom

get smaller and smaller until they are too small, then they have to sexually reproduce

briefly describe nitrogen fixation

cyanobacteria do this

converts gaseous nitrogen into NH4+

available for synthesis of amino acids and proteins

compare and contrast diatoms and dinoflagellates

compare - they both asexually and sexually reproduce, they have some sort of outer casing

contrast - diatoms occur singly or form chains, do not swim, usually radially symmetrical, reproduce very fase

dinoflagellates - have two flagellae and can swim, have several life history stages such as benthic cysts, heterotrophic, abundant in tropics, mid-latitudes in summer, can cause red tides

briefly explain how algal blooms occur and why do we care?

algal blooms occur when there is an influx of nutrients, mainly nitrogen and phosphorus, that increase the carrying capacity of algae which reproduce out of control

we care because it disrupts ecosystems, creates hypoxic zones, and creates harmful neurotoxins in the water

compare and contrast cnidarians and ctenophores

cnidarians are scyphozoans and siphonophores, they are mainly carnivores, and use nematocysts to hunt, siphonophores can be colonial

ctenophores have combs which refract and flash light (Newton rings), micro carnivores with two long sticky tentacles and feed on smaller zooplankton, planktonic eggs, invertebrate larvae, and bioluminesce with luciferin-luciferase system

briefly describe the importance of crustacean zooplankton

main food of many megafauna such as baleen whales

nekton

organisms that can swim against current

otolith

calcium carbonate ear stones that sense vibrations which travel to auditory brain region for processing

lateral line

excellent mechanoreception, line down body which can sense movement in water

pinniped

seals, sea lions, walruses

mustelidae

sea otters

sirenian

sea cows, dugongs

Describe the functional-morphology plane for locomotion in fishes (distinguish between acceleration, cruising, and maneuvering specialists

acceleration specialists have minimum resistance (barracuda)

maneuvering specialists have paired fins around center of mass for steering and stabilization (buttterfly fish)

cruising specialists minimize drag and have a high aspect ratio tail with stiff streamlined body (tuna)

what is the difference in swim bladder rete mirable lengths between shallow and deep sea fish?

deep water fish have longer rete mirable than shallow water fish because they can increase the maximum air concentrations in their swim bladder to cope with high pressure in deep water

what are the three different feeding mechanisms fish use?

ram feeding (overtake prey by ramming water through mouth (filter feeding))

suction feeding (create suction by rapid expansion of buccal cavity)

manipulation (biting, scraping, grasping, usually with use of teeth)

why do fish need to hear?

to avoid predators, communicate, and water is effective at transmitting sound

what is the biggest difference between Odontoceti and Mysteceti?

Odontoceti are toothed whales

mysticeti are baleen whales

describe some key features of seabirds

often colonial breeders, monogamous, courtship involves elaborate displays, crowded breeding sites with several species, protected from predators, feeding involves either diving or underwater swimming, long distance migration between nesting and feeding areas is common

what are the two problems with diving in marine mammals? how do marine mammals achieve such long dives (name at least 2-3 reasons why)

problems - must breathe at surface and have oxygen for long dives

they do this by increased volume of arteries and veins, increased blood cell concentration, decrease heart beat rate and O2 concentration, can restrict peripheral circulation and circulation to abdominal organs

describe some key features of the sea turtle life cycle

females return to same beach, eggs hatch a few weeks after being laid, hatchlings crawl toward shoreline using cues of light and magnetic field of the earth

predation on hatchlings is very high

adults use magnetic field of earth

sex determination is temperature dependent, females are born in colder temperatures and males are born in warmer temperatures

diurnal vertical migration

zooplankton rise to shallow water at night and sink to deeper water during the day

start to sink before dawn, rise before dusk

internal biological clock that is reinforced by day-night light changes

predation hypothesis

cause of vertical migration is based on visual prey detection

counterillumination

fish have ventral bioluminescent organs, camoflages them from below (deep sea organisms)

bioluminescence

either luciferin-luciferase or photoprotein-calcium system to avoid predation or help hunt

what are some of the defenses plankton utilize?

large elaborate spines, transparent bodies, toxic substances, bioluminescence

what are the benefits of schooling?

protect against predators (spherical aggregation, have trouble attacking individual fish, many eyes theory), reduction of drag (slipstreaming fish in front, fish in front exchange places periodically)

describe what happens during the diurnal vertical migration. describe one of the hypotheses used to describe the process

strong light hypothesis (zooplankton are adversely affected by UV radiation)

phytoplankton recovery hypothesis (zooplankton exploit phytoplankton but allow them to recover)

surface mixing hypothesis (surface waters bring more food when zooplankton return)

energy conservation hypothesis (lower metabolic cost in cooler water)

limiting nutrients

nitrogen, phosphorus, silicon, iron, trace elements

briefly describe the nitrogen cycle

gaseous N2 from atmosphere to nitrogen fixation (NH3) to organic/inorganic nitrogen then denitrification (back to N2) back to atmosphere

be able to describe what is happening in Figure 11.1

over the winter there are high phosphates and nitrates at the surface of the water and available sunlight increases

in the spring as sunlight availability increases there is a large spring diatom bloom with a zooplankton bloom lagging behind

as they consume all the nutrients there is a bust, and then as nutrients accumulate there is a second smaller diatom bloom

which nutrient is generally thought to be most limiting and what are some sources of it?

nitrogen is believed to be the main limiting element for phytoplankton growth - sources include nitrogen cycle and runoff from human development

what would happen if more of the limiting nutrient were added to the ecosystem? what type of ecological regulation would this be an example of?

the phytoplankton population would increase

bottom up regulation

biomass

mass of living material present at any time

g/unit area or volume

productivity (primary and secondary)

rate of production of living material per unit time per unit area/volume

primary is due to photosynthesis, secondary is due to consumers of primary producers

food chain

linear sequence showing which organisms consume which other organisms, making a series of trophic levels

food web

more complex diagram showing feeding relationships among organisms, not restricted to a linear hierarchy

gross primary productivity (GPP)

total carbon fixed during photosynthesis

Net Primary Productivity (NPP)

total carbon fixed during photosynthesis minus the part which is respired

Why is energy lost from one trophic level to the next (three reasons)

some material not eaten, not all food eaten is converted with 100% efficiency, metabolic costs are a loss

describe three reasons for the differences in geographic variation of productivity

continental shelf and open-ocean upwelling areas are most productive

convergences and fronts often are sites of rise of nutrient rich deep waters

central ocean, gyre centers are nutrient poor, low primary production