Marine Biology Final Exam

What type of "rock" do true corals deposit as they grow?

calcium carbonate (limestone)

How does the presence of zooxanthellae inside the polyps affect coral growth?

zooxanthellae supplies most of the nutrients through photosynthesis for coral reef growth

How do corals eat?

they extend their tentacles to capture prey and then sweep it into their mouths, they also have stinging cells (nematocysts) that stun their prey

Since most corals are colonial, how are they connected to one another?

the colonies are connected by a thin sheet of living tissue, they share a digestive and nervous system

How do corals reproduce sexually?

broadcast spawning, where they release sperm and eggs into the water column

How do corals reproduce asexually?

budding, where new polyps grow out from existing polyps on the colony, creating genetically identical clones of the parent polyp

What are some conditions needed for coral growth?

hard substrate, sunlight (cannot live more than 50 m deep), specific temp ( 70 F - 90 F), right salinity (do not see them near large rivers), clear water

What happens when corals are exposed to very warm temperatures?

coral bleaching, when corals expel the zooxanthellae from their tissues and they turn completely white

What do corals do when they are exposed to lots of sediment?

when sediments settle directly on top of the corals, this reduces the rate of growth and productivity, and can cause bleaching

How do excess nutrients in the water affect phytoplankton, seaweed, and coral growth?

excessive nutrients can cause excessive growth of the phytoplankton and seaweed which forms algal blooms, which can then significantly hinder coral growth by blocking the sunlight

Where are most coral reefs located on earth?

in tropical waters, specifically the Indo-Pacific Region

What are fringing reefs?

reef flat and reef slope with rubble at the base, form near rocky shores

What are barrier reefs?

separated from nearby land by a lagoon of open water, have a back slope, reef flats, and spurs and grooves

What are atolls?

ring of reef with calcium carbonate growing on top, spur and groove formations on edges

How are fringing reefs and barrier reefs similar and how are they different?

they both grow parallel to a coastline and are important ecosystems, but a fringing reef is close to the shore, whereas a barrier reef is further away with a lagoon in between

How do atolls form?

fringing reef forms around a volcanic island that subsides completely below sea level while the coral continues to grow upward, an atoll forms

What are the main primary producers in the coral reef?

zooxanthellae and crustose coralline algae

Why is it so important for corals to be able to fix nitrogen?

corals typically live in nutrient-poor waters, so when they can fix nitrogen it allows them to sustain their growth and symbiotic relationship with algae

What is the depth of the mesopelagic (twilight zone)?

200 - 1000 meters

What is the depth of the deep water (dark zone)?

1000 - 4000 meters

What organisms are the beginning of the food chain in the mesopelagic and the deep?

bacteria and detritus

What adaptations do fish in the mesopelagic have to survive?

small size, large mouths with hinged and extendible jaws, broad diets, large eyes, camouflage, and photophores

What are vertical migrators?

upward migration of organisms towards the surface at night, and a downward movement to deeper waters in the daytime

How do vertical migrators and non-migrators differ?

they move up and down throughout the water column and have adaptations for large depth, temperature, and light changes

What are photophores and what are they used for?

light producing organs for communication, attracting mates and prey, and as a defense

Body characteristics of non-migrators

large eyes and mouths, may lack a swim bladder, less stream-lined body, photophores, usually black, red, or silver

Body characteristics of vertical migrators

strong swimmers, streamlined shapes, and sensitivity to light changes

How do animals camouflage themselves in the mesopelagic?

transparent bodies (could be silvery or black), counter shading, thin bodies, and counter-illumination

What is the oxygen minimum zone, why does it form, and what impact does it have on species distribution?

the zone in which oxygen saturation in seawater in the ocean is at its lowest, it forms due to high biological productivity at the surface, many species cannot survive in these areas

Why are oxygen concentrations higher at depths below the oxygen minimum zone?

colder deep ocean water can hold more dissolved oxygen than warmer surface waters

What are the physical characteristics of the deep sea?

very cold ( 1-2 degrees C), contains oxygen due to deep water formation and thermohaline circulation, uniform salinity

How are fish in the deep sea different from those in the mesopelagic?

deep sea fish grow slower but are larger, sluggish and have flabby muscles and weak bones, no scales and swim bladder, and use smell to locate food on the bottom

What organisms are at the beginning of the food chain in hydrothermal vents?

chemosynthetic bacteria and archaea

Describe a typical food chain at the hydrothermal vents

chemosynthetic bacteria and archaea - tubeworms, clams - crabs - shrimp

What is a tropic cascade?

powerful indirect interactions that can control entire ecosystems, occurring when a trophic level in a food web is suppressed

What are the layers from shallowest to deepest in the ocean?

Epipelagic, Mesopelagic (Twilight Zone), Bathypelagic, Abyssopelagic, and Hadalpelagic

What is male parasitism?

when a male permanently attaches to a female to ensure reproduction

What are some main types of shapes corals can be?

plate-like, encrusting, foliaceous, free-living, columnar, massive, and branching

Where are sandy shorelines located in the U.S.

wave-dominated, depositional settings such as the Atlantic Ocean and Gulf of Mexico coasts

Where do the epifauna or infauna live along the sandy shores: on top of the sand or burrowed in the sand?

epifauna live on top of the sand, while infauna live burrowed in the sand

What is the main problem that organisms along the sandy shorelines must deal with?

lack of stable ground to hold onto from moving sand and changes in tides

Compare sandy vs clay bottoms

sandy bottoms have high water movement, little OM, lots of oxygen, and dry out at low tide; clay bottoms are calm, sheltered areas, lots of OM, no oxygen, and HS2 is created by anoxic bacteria eating the OM

Why do waves refract or bend as they hit the coast?

when they enter shallower water near the shoreline, the part of the wave closer to the shore slows down due to friction with the seabed, causing the wavefront to change direction and bend towards the slower section, effectively aligning itself more parallel to the coastline

What is longshore drift?

the movement of sediment along the coast by wave action

How do jetties and groins affect longshore drift?

acting as barriers perpendicular to the shoreline, trapping sand on their updrift side and significantly reducing the amount of sediment available for transport further down the coast, often leading to increased erosion on the downdrift side

What is the longshore current?

a current that flows parallel to the shoreline, caused by waves that approach the beach at an angle

What is a rip current?

a rush of water that flows rapidly back to sea through a narrow opening

What are some structural approaches to reducing beach erosion?

jetties, groins, and breakwaters

What are some non-structural approaches to reducing beach erosion?

beach nourishment and land use planning

What is a living shoreline?

a protected, stabilized coastal edge made of natural materials such as plants, sand, or rock

What is an ecosystem vs community vs population?

population is a group of individuals from the same species, living in a particular area, a community is a collection of multiple species interacting within the same area, an ecosystem is a community including both the living and non-living components

How do the habitats of benthic and pelagic organisms differ?

benthic habitats are characterized by a solid substrate to live on, whereas pelagic habitats are open water with no fixed surface to attach to

How does energy flow in a food web?

producer, primary consumer, secondary consumer, tertiary consumer

How do nutrients flow in a food web?

nutrients move through the food chain as organisms eat each other, with decomposers playing a key role in recycling nutrients back into the ecosystem

Describe the carbon cycle

plants absorb carbon dioxide from the air through photosynthesis, then animals eat those plants, and when organisms die, their carbon is released back into the atmosphere through respiration

Describe the nitrogen cycle

nitrogen gas is fixed and modified by soil-dwelling bacteria and taken up by plants; moves through food chain as organisms eat plants; animal waste and dead animals/plants are broken down by soil bacteria

Why are bacteria such an important part of the nitrogen cycle?

they are primarily responsible for converting atmospheric nitrogen gas, which most organisms cannot directly use, into biologically available forms like ammonia through a process called nitrogen fixation

What is the increasing accumulation of a persistent pollutant at each higher trophic level called?

biological magnification

What is the area, 200 miles from shore, which give rights to resources within it to the nation that shoreline belongs to called?

exclusive economic zone

Transplanting key species from a healthier area is referred to as what?

habitat restoration

desalination

converting seawater into fresh water

biofouling

growth of unwanted organisms

OTEC

the use of temperature differences in ocean water to produce electricity

polymetallic nodules

lumps of minerals that are scattered in the deep-ocean

tidal energy

uses the tremendous energy from the natural ebb of flow of the tides

assymetrical

no symmetry

radial symmetry

a pattern of symmetry where similar parts are arranged around a central axis in a balanced way

bilateral symmetry

arrangement of body parts so there are distinct left and right halves that mirror each other

anterior

front of the body

posterior

back of body

dorsal

upper half of the body

ventral

belly side

gastropod

a mollusk with a single shell or no shell

bivalve

mollusk with two shells held together by powerful muscles

cephalopod

an ocean-dwelling mollusk whose foot is adapted as tentacles that surround its mouth

arthropod

an invertebrate that has an external skeleton, a segmented body, and jointed appendages

exoskeleton

hard protective structure developed outside the body

endoskeleton

internal skeleton or supporting framework in an animal

jointed appendages

arms and/or legs that have joints (arthropods)

molting

the process of shedding an outgrown exoskeleton

echnioderms

a marine invertebrate that have a number of similar body parts (as the arms of a starfish) arranged around a central axis

mollusk

invertebrate with a soft, unsegmented body

chordate

animal that has for at least one stage of its life: a dorsal hollow nerve cord, a notochord, a tail that extends beyond the anus; and pharyngeal slits

comb jellies

phylum ctenophora, oval shaped animal with cilia

water vascular system

system of fluid-filled tubes used by echinoderms in locomotion and feeding and respiration

crustacean

division of arthropods, containing lobsters, crabs, and crawfish

filter feeding

the animal traps organic material that is floating in the surrounding water

deposit feeding

take in detritus and sediment and extract usable organic matter

parasite

an organism that lives on or in a host and causes harm to the host

scavenger(detritivore)

organisms that feed on dead or dying animal

What is the difference between a medusa vs polyp body type?

polyps have a tubular shape and are fastened at their base, with the mouth facing the water at the other end of the tube; medusa has a bell-shaped body with hanging tentacles

Gastropods body structure and feeding

muscular foot for movement, a coiled shell for protection, and a unique feeding mechanism called a radula, which is a ribbon-like structure covered in tiny teeth used to rasp and scrape food from surfaces (snails and slugs)

Bivalves body structure and feeding

two hinged shells (valves) that enclose their soft body, lacking a distinct head, and primarily feeding as filter feeders using their highly developed gills (ctenidia) to strain food particles from the water column

Cephalopods body structure and feeding

large head, prominent eyes, a muscular mantle covering their internal organs, and a set of arms or tentacles modified from their "foot" which they use to capture prey; feed by capturing prey with their tentacles, drawing it into their mouth and taking bites from it

List some crustaceans that are plankton (phylum Arthropoda)

copepods, krill, amphipods

Why do arthropods need jointed appendages and why must they molt to grow?

they need jointed appendages for flexibility, during the molt they form a larger exoskeleton for expansion

List some echinoderms

sea stars, sea cucumbers, sea urchins

Do all animals have digestive systems? How did this evolve over time?

not all animals have true digestive systems; as animals evolved in complexity of form and function, their digestive systems have also evolved to accommodate their various dietary needs

Do all animals have respiratory systems? What are some ways animals obtain oxygen?

all animals have respiratory systems; most land animals obtain oxygen through lungs, aquatic animals like fish use gills to extract oxygen from the water, and some insects use a network of tubes called trachaea to access oxygen from the air

How does body structure (asymmetry, radial symmetry, bilateral symmetry) influence the type of nervous system an animal has?

bilaterally symmetrical animals have a more complex, nervous systems with a brain, while radially symmetrical animals have a simpler nerve net due to their need to respond to stimuli from all directions equally; asymmetric animals have very basic nervous systems with limited sensory capabilities