Wednesday, November 28, 2012
Monday, November 26, 2012
Follow this link for a cool interactive about how shark jaws stick out when they attack their prey! The interactive is down at the bottom.
If you are doing a final project on a shark... check out this new link! www.shark.ch
And once again... one try only... how much do you know about sharks? MsJ scored a 1467. Try Shark Weeks Ultimate Shark Challenge to see how much you know. Please limit yourself to 15 minutes.
Wednesday, November 21, 2012
Monday, November 19, 2012
Next up is SHARKS! Great whites in the waters off the coast of South Africa leap out of the water to chase the fur seals they want to eat that also leap out of the water.
Try Shark Weeks Ultimate Shark Challenge to see how much you know. (Play only once) MsJ scored 1370.
Wednesday, November 14, 2012
Netting is the most popular method of commercial fishing because a lot of fish can be caught in short amount of time without a lot of effort.
One the major problems with most commercial fisheries is the amount of bycatch. Bycatch is anything caught in the net that you do not want. This could include edible fish that your company is just not equipped to process.
Most organisms brought up in nets as bycatch do not survive because they are crushed or drowned. Sea turtles and dolphins sometimes get swept into nets and drown because they cannot make it to the surface to breathe.
Most scientists and fisherman agree that the oceans have been and are being overharvested. People may not like regulations, but without regulations, many fish species that we used to commonly consume would be extinct.
Monday, November 12, 2012
We started discussing marine harvesting and fishing today by talking about who harvests the most seafood (China), who eats the most seafood (China), and which people eat the most seafood pounds per person (the Maldives). Americans are about sixth on the list as far as consumption, but we are the number one consumer and importer of shrimp. Importing shrimp is damaging to the environment for two reasons.
1. Shrimp that are farmed in other countries are not as regulated as here in the states, so shrimp farm pollution is not as regulated and it damages coral reefs. Also many mangroves are cleared to build these farms.
2. US boats are required to have turtle excluder devices (TED) on trawl nets so that turtles do not get caught in shrimp nets and drown. Other countries do not regulate this and as a result catch and drown sea turtles.
I went prawn fishing while in NZ!
Friday, November 2, 2012
Fish reproduce in a variety of ways. Most are broadcast spawners, meaning that when the time is right, the females release their eggs, the males release their sperm and they both meet and mix producing fertilized eggs that develop into fish fry (meroplankton) and eventually into adult fish. These snapper are spawning and you can tell by the large cloud of gametes in the water.
By producing a lot of eggs, the snapper hope to overwhelm any predators trying to make a meal so that there is no way all the fry are eaten and some will have a chance of surviving. Course there are predators that time their arrival with this spawning to eat all those nutritious eggs and gametes.... Yum!
Monday, October 29, 2012
Body shape also tells you a bit about a fish. Com- pressed fish have flash and look skinny and can only be found in slow moving waters like coral reefs. Fusi-form fish are tapered like footballs and are very streamlined for constant fast swimming. Depressed fish are benthic and squashed looking. Eel shaped fish are poor swimmers and live on the benthos or in cracks and crevices.
Here is a website you can use to identify shapes - realize they are named a bit differently than how I do in class.
Crescent caudal fins indicate a very fast fish that is constantly swimming - not time for resting, it is time to go go go! Forked caudal fins are the second fastest, and very maneuverable. Square fins are for your every day swimming fish - they have ok acceleration ad maneuvering. Round fins and Funky fins are slooooooow swimmers that don't spend a lot of time swimming. They can be quick for very short bursts.
Thursday, October 25, 2012
Pictured to the right, you can see five lamprey mouths and one lamprey head with blue eyes and seven gill holes.
Jawless fish include lampreys which are parasites and hagfish which are detritavores. Neither one will ever win a beauty contest.
Monday, October 22, 2012
We have covered molluscs, crustaceans, and echinoderms in larger units, but there are lots of other invertebrate phyla including three types of worms, sponges, and cnidarians.
There are three types of worms - Flatworms (Platyhelminthes), R0undworms (Nematodes), and Segmented Worms (Annelids).
Flatworms (Platy-hel- minthes) are flat and ribbon like, have bilateral symmetry and include things like tapeworms, planarians, flukes, and brightly colored marine flatworms. Marine flatworms have similar adaptations to nudibranchs (molluscs), but are flat and have no tufts. They are simple animals and are often parasites.
Roundworms (Nematodes) are ubiquitous and found commonly worldwide in every biome... but they are poorly understood because they are very very small. Less than 5cm. They have radial symmetry and often are parasites. Roundworms have scary looking mouths with teeth for attaching - often used in scary movies.
For those of you studying invertebrates, you can use these matching cards to help!
Echinoderm means spiny skin. Echinoderms include sea urchins, sea stars, sand dollars, sea cucumbers and some other odd organisms like feather stars and basket stars. All echinoderms have radial symmetry, spiny skin, and an endoskeleton called a test.
Most people are familiar with an orange sea star because on the east coast, that's all we've got. On the west coast and in other places around the world, it is easier to find a variety of sea stars in other colors and with different amounts of legs.
Sea stars have powerful tube feet that use water suction to open molluscs. When they eat molluscs, they actually stick their stomach into the shells of the mollusc, digest it, and then put their stomach.
Feather stars and basket stars both have crazy looking legs that they wave around to filter feed. Sea urchins and sand dollars are both covered with protective spines and eat with a scraping mouth called Aristotle's Lantern.
Sea cucumbers have lost most of their exoskeleton and are a bit squishier than other echinoderms. Sea cucumbers are important detritus eaters on the sea floor. When attacked by predators they will expel their guts as a meal for the predator as they make a get away. Sea cucumbers are able to regenerate these guts over time.
Friday, October 19, 2012
Thursday, October 18, 2012
- Gulf shrimp are the ones people most people are familiar with because these are the ones we eat!
- Shore shrimp live in sea grasses, are fairly small and clear, and are not commercially harvested because no one would make any money.
- Snapping shrimp (or pistol shrimp) have slightly larger claws and can use them to make sonic waves to stun their prey with sound.
- Mantis shrimp whack their prey with arms that can unfold and strike lightning quick.
- Cleaner shrimp make their living eating parasites off of fish and other sea creatures.
Wednesday, October 17, 2012
- Blue Crabs are found in the Chesapeake Bay. They are very agressive, like to pinch, but are good to eat. They have a pointy-ended shell and swim fins. (you can kind of see the swim fins on the last leg of the crabs on the right)
- Spider Crabs have a rounder body shape, often a bumpy shell that will grow algae for camouflage, and longer more spindly legs. Spider Crabs include snow crabs and king crabs like the ones seen on Deadliest Catch. A decorator crab is a kind of spider crab that attaches stuff to its bumpy shell to blend in.
- Fiddler Crab males have one claw that is a lot bigger than the other. This is for impressing the ladies, and used to show dominance over other males.
- Hermit Crabs have a weak exoskeleton and thus protect it with a stolen mollusc shell. They have adapted to this lifestyle and have modified back legs that hook on the inside to hold the shell on and one claw that is slightly larger to use as an operculum.
Tuesday, October 16, 2012
Monday, October 1, 2012
Cephalopods are characterized by their large well developed eyes, numerous tentacles, a parrot like beak in the center of the tentacles, and well developed chromatophores in their skin that allow them to change color.
We watched numerous videos today to see and understand how and why cephalopods make ink clouds, to see how an octopus can swim with jet propulsion or use its tentacles to crawl around, and we also saw how a octopus can eat a shark!
more information about cephalopods, check out CephBase and the Australian Cephalopod Research page.
Friday, September 28, 2012
Some shells are spiral and have an operculum to act as a door for when they hide inside. The snail lives in the entire shell (all the way up into the top and retreats inside to hide when it feels threatened or exposed. The operculum blocks any would-be attackers and is made of a material similar to fingernails. These types of molluscs include whelks and moon snails.
Other shells are not spiral and the snail has good suction power so that predators have a difficult time pulling the snail off the rocks. These types of molluscs include slipper snails, abalones, and limpets.
Even though they don't have a shell, they do however have some interesting adaptations to keep from getting eaten. Most nudibranch exhibit warning coloration because they are poisonous or have stingers - none that they make - they acquire them from the prey that they eat!
National Geographic did a great article a few years ago full of lovely photos. Both are linked here. Watch the video for a full-range spectrum of photos.
Wednesday, September 26, 2012
Today classes got a close up look at the Limax maximus and their slimy mollusc bodies. Thank you Cassie for bringing in Professor Paulie Slops! Students looked at the two sets of tentacles (eyespots and sensory tentacles) and the hole the land slug breathes through. Some touched it to see what the slug felt like and quite a few third period students let the slug slime all over them. Way to be brave!
Slugs can be considered gross because of the copious amounts of mucus they leave behind. The mucus helps them get a better grip on surfaces and helps prevent dessication, drying out. It can also make the slug more difficult to pick up by predators. More information about slugs can be found here.
Tuesday, September 25, 2012
A mollusc makes a pearl to cover an irritating spot like a piece of sand that gets inside the shell. Pearls can be "glued" to the side of the shell or free to move inside the mollsucs shell. We prefer the "free" kind.
Here is a great short video that explains the process!
Any mollusk that produces a shell can produce a pearl. Nevertheless, naturally occurring pearls are rare, found in perhaps one of every 10,000 animals. The cultured pearl industry, which has flourished since the early 20th century, has developed techniques to greatly improve these odds. Indeed, more pearls are produced now than at any time in human history.( SOURCE This is a good website for lots of information on pearls)
Monday, September 24, 2012
- The shells found on the beach are from dead organisms.
- Any mollusc that has a shell, makes it shell.
- Sea shells are made of calcium carbonate.
- Shells are smooth on the inside because slimy molluscs don't want to rub their soft bodies on something rough. If they are smooth on the outside, then the mollusc also wears its body on the outside of its shell.
Today's cool mollusc was the chiton, an odd mollusc that has 8 overlapping plates held together by its soft squishy mantle, and the plates come apart when the animal dies. Chitons are built like armored cars and have great suction to stay on the rocky coast in waves and storms. They spend their days sliming around scraping algae. When pulled off a rock, it can roll into a ball to protect its squishy parts. More info can be found here.
Mussels make byssal threads for attaching (so do ark shells and jingle shells) and scallops have eyespots to see predators. Oysters make cement to stick together and clams have a powerful foot for digging down and hiding.
Tuesday, September 18, 2012
One of the weirdest, but also most interesting is Whalefall. Whalefall is when a dead whale settles to the bottom of the ocean and organisms move in to feed on the carcass until even the bones are decomposed. Hagfish are a dominant scavenger as well as bacteria. It may not seem like a big deal, but this biome boasts over 160 species that are not found on the surrounding benthos. More info can be found at the link above, or here. Listen to a podcast here.
Deep sea benthos is another biome and it is pretty boring. Its a gooey squishy substrate populated by some dd scavengers, but there is not a high biodiversity and not a lot of food to eat.
Photic vs Aphotic is an odd one involving the light and dark zones of the ocean. Some organisms hide in the dark aphotic zone during the day and migrate up to the surface (the photic zone) at night to eat the phytoplankton. Predators also migrate to eat the things that are eating the phytoplankton.
Not all biomes are found at the bottom of the sea or in the dark. Along coasts you can find rocky coasts, sandy beaches, salt marshes, mangroves, sea grass beds, kelp forests, and fouling communities.
I think fouling communities are really interesting... because all these organisms need is a hard substrate (surface) to stick on. This could be a dock, a pier, a boat, or anything that's in the water long enough. Most people have seen all the 'stuff' growing on the pole legs of piers and docks, but don't really think of the variety of organisms that grow there - or their importance. Most of these organisms are filter feeders and do a lot for water quality. They also break down the surfaces like scavengers... not something we want for our boats and docks we use, but important nonetheless.
There is a lot of information to learn this unit. Students will be given two review sheets one general, one biome specific. The Unit 3 Test is one of the hardest of the year, and it is coming soon!
Monday, September 17, 2012
We also discussed sea grass beds. Sea grass is super-important for stabilizing the substrate and holding the sand down. This promotes water clarity and decreases turbidity. Nothing eats sea grass when it is alive except for manatees. Everything else eats it after the bacteria have decomposed it a bit.
Salt Marshes are one of the most productive ecosystems, but nothing eats the salt marsh grass when its alive... once the anaerobic bacteria break it down into black mush, then other organisms eat it.
There is a lot of information to learn this unit. The Unit 3 Test is one of the hardest of the year.
Friday, September 14, 2012
Students identified zones on rocky coast pictures and took notes on the material. Here is an example of a photo where the zones can clearly be seen by changes in dominant seaweeds. The yellow layer is the upper zone and the white pink is the middle zone. It is easy to see the high water mark or where the high tide will reach. You can also see the lichens in the spray zone.
The spray zone is one of the hardest areas to live in because of the huge changes in salinity and temperature.
We also talked about tide pools. Tide pools are depressions that trap water when the tide recedes. You can find all kinds of things in tide pools, but tide pools in the lower zone have a higher biodiversity than tidepools found in the upper zone. This is because they are more often "refreshed" with water that keeps salinity, dissolved oxygen, and the temperature stable, as well as add nutrients and more food! Here is a neat article from National Geographic about tidepools (and where this photo is from).
Wednesday, September 12, 2012
There is also cyanobacteria - or the blue green algae which we discussed during the plankton part of the unit.
Some algae is calcareous - meaning it stores calcium carbonate in its tissues. This makes it crunchy and deters herbivores. The most common is a calcareous red algae that makes a pink crust on just about everything left in the ocean.
A lot of seaweed has air bladders to help it float towards the surface. Air bladders ensure adequate sunlight for photosynthesis. Other important adaptations include flexibility and gels to stay hydrated when the tide goes out. Students observed samples of dried seaweed.
Computer Lab Etiquette
You are in the computer lab to do work for this class. If you are not doing work, then we will have problems.
Do not pack up early. Work until the bell or until MsJ says.
SAVE OFTEN. And if you save to a key, also save it to your number. If you lose it, you will have to do it again.
If MsJ asks for your attention, stop what you are doing and listen to what she has to say.
You may watch videos about your organism through reliable websites.
You may listen to music through the computer if you have your own headphones. Rule1 MsJ cannot hear it. You get one warning. Rule2 Turn it on and listen – no million clicks and constant changing. Take both ear phones out when MsJ is talking.