Marine Senior Exam 2009 Review
Phylum Mollusca – snails, sea slugs, soft bodied animals. They all have a mantle, foot, radula
Mollusks in Gastropoda are single shelled mollusks, snails, and whelks
Mollusks in Bivalvia have 2 shells, lack a “head”, and have no radula.
Mollusks in Cephalopoda include octopus and squid.
The octopus is thought to be the most intelligent invertebrate.
Phylum Athropoda: chitonous exoskeleton, segmented bodies.
Crustacea: pair of appendages on every body segment, teardrop-shaped larvae, molting exoskeleton.
Copepods link smaller plankton and larger animals and are important to the ocean food web.
Crustaceans in order Decapoda have 8 legs, exposed gills, no claws.
Krill are important because they link plankton to larger animals.
Phylum Echinodermata – radial symmetry, bilateral larva, and 5 segment bodies.
Crinoidea – sea lilies and feather stars and have upward facing mouth and long feather-like arms.
Asteroidea – 5 arms with equal share of organs, downward facing mouth.
Echinoidea – sand dollars and sea urchins with no arms, ball or disk shaped.
Holothuroidea – sea cucumbers, elongated body, tentacles around mouth.
Phylum Chordata – notochord and dorsal nerve cord.
Scientists think organisms in class Agnatha may represent the ancestor of sharks and bony fish.
Chondrichthyes – sharks, skates, and rays; have skeleton of cartilage and no swim bladder.
Sharks and rays are successful predators because light cartilage skeleton, backward pointing denticles, ampullae of Lorenzini, and lateral lines.
Most sharks and rays fertilize eggs internally.
Osteichthyes – bony skeleton, scales, and swim bladders.
In most bony fish, eggs are fertilized externally.
Reptilia – breathe with lungs at all stages of their life, have scales, and lay internally fertilized eggs.
Marine reptiles include sea snakes, marine lizards, saltwater crocodile, and 7 species of marine turtles.
Aves – feathers and lay internally fertilized eggs and forelimbs that are wings. The role birds play in the environment is to be predator and prey and to provide nitrogen compounds to the ocean.
Some adaptations that birds have is they have webbed feet, bill adaptations like a pelican pouch, and the ability to “fly” underwater and over wide expanses of water.
Mammalia – almost all give birth to live young, nourish the young with milk from mammary glands, and are homeothermic.
Marine mammal adaptations to life in the sea include diving reflex, myoglobin for storing oxygen, and breathing air to meet oxygen demands.
Pinnipedia – seals and sea lions.
Seals lack ear flaps and sea lions have ear flaps.
Cetacea – whales, porpoises, and dolphins.
Human activities like whaling, overfishing, and fur hunting have endangered or may endanger marine mammals.
Biological resource – fish, fisheries, kelp, etc.
Physical resource – oil, minerals, etc.
Salinity is all the inorganic dissolved solids in seawater.
A thermocline is the boundary between layers of water with different temperatures.
Oil and natural gas come from the remains of marine organisms under high pressure and temperature over long periods of time.
Tuna is a renewable resource but whales are nonrenewable at this time.
Some potentially renewable resources are nonrenewable because species are taken faster than they can reproduce.
Ocean provides renewable energy with waves, tide, and energy fro the upper layers of seawater.
Whale populations were sustainable until 1868 because the modern whale harpoon didn’t exist.
Since 1900, whale populations fell from 4.4 million to 1 million.
After the IWC moratorium on whaling in 1986, the populations have improved for some and declined for others.
Sea lions and seals are marine mammals taken for their fur. About 400,000 – 500,000 seals and sea lions are taken for fur each year.
Common use of algae – algin
The trend for aquaculture is steeply upward. 25-30% of the world’s seafood comes from aquaculture.
Maximum sustainable yield is taking no more fish than would affect future populations, exceeding it is called overfishing.
According to the FAO, the National Marine Fisheries Services, ½ to 70 % of the world’s fisheries are overfished or depleted.
The government subsidizes the fishing industry as the annual fish catch sells for less than it costs to catch.
The US claims an EEZ of all ocean territory within 200 nautical miles of its coasts.
It is estimated that 25% of the world’s coral reefs have been destroyed.
Biodiversity is the concept that every organism is a biological resource because every organism is part of maintaining a healthy ecosystem.
Estuaries are at risk because they are very sensitive environments, but there is great demand to use them for harbors or as real estate.
Water is a polar molecule. It is a liquid at room temperature, it has surface tension, and it floats as a solid (ice). It becomes less dense as it freezes. This is different from most substances.
Greenhouse gases include water vapor, methane, and carbon dioxide.
Earth’s average surface temperature is rising. Supporting data include sea level rise, temperature evidence in tree growth rings, and an increase in carbon dioxide levels.
One possible solution to global warming is to find and develop cost-effective alternatives to fossil fuels.
In the marine environment, pollution is energy or substances that change the water quality or affect the chemical, physical, or biological environment.
Pollution comes from agricultural and industrial runoff; ships dumping garbage, bilge or ballast water; and propellants, hydrocarbons, and biocides in the atmosphere.
Plastics enter the oceans mainly by being dumped or lost there.
Plastics are a hazard because they can trap and entangle animals, and some animals mistake them for food.