Exploring Sydney and Cairns: Part 1

My trimester break was amazing! Vacations are all about making memories with family, and this will definitely be one I’ll never forget. Australia provides the unique opportunity to do things you’ll never be able to do anywhere else, and we took full advantage!

My trip started when I met up with my mom at the Sydney airport. I’m not usually a teary person, but I gotta admit, I got a little choked up for a minute when I saw her. When I landed it was later in the afternoon. We caught a shuttle to our hotel, the Holiday Inn in Potts Point and made a trip to Coles across the street for groceries. We saved a ton of money by making our own food! The only downside was that we didn’t have a microwave, so when we did make our own stuff we were pretty much restricted to a raw diet (and I am so excited for my cooked soup tonight!). It’s just hard to justify $15 for a veggie burger sometimes!

For our first full day in Sydney, we walked down to Cockle Bay Marina in Darling Harbour to go whale watching.

Cockle Bay Marina

Cockle Bay Marina

We were a bit early for our 2pm adventure, and one of the guys running the tour told us it was quite choppy out there, so “be prepared.” Whatever that means… Come to find out that earlier in the morning, the whale watching tour group ended up with everyone getting seasick and wanting to come back in. Mom and I had no idea what a rough ocean meant. The most we had done prior to this was go fishing on Lake Michigan. They said if they had enough people up for it, they’d still take us out to see the whales, so out we went.

The swells were massive! I’ve never seen anything like it! Later, we found out they were 6-8 meters (about 20-26 feet)! Our boat was sturdy, but small (it maybe fit 20 people). We were literally flying through the air over the swells and crashing back down on the water. It was fun at first, but after the 10th time of slamming down on the seat and metal arm rests, your body starts to get annoyed.

At one point, a wave actually washed over the front of the boat. Mom, my camera, and I were all soaked! I had my rain jacket on, but it was open. Lesson learned! I had a two second freak out moment that my nice DSLR camera was wet, but there was nothing I could really do but shove it under my layers of clothing and hope something would dry it out. Thank goodness no damage was done!

We made it out there though and managed to find three humpback whales and followed them. They didn’t breech or lift their tails for a really good view, but they were awesome nonetheless. They would surface for a while and then dive back down. We followed them by looking for the mist from their blow-spout when they surfaced.

65309_10151554958038403_1803849043_n

1003268_10151554957948403_1175605128_n

1012200_10151554958123403_1737806633_n

After about two hours, it was time to head back in. Those waves and the whales made for a pretty memorable experience.

Whale watching battle scars on my elbow (from the crashing down on the metal arm rests).

Whale watching battle scars on my elbow (from the crashing down on the metal arm rests).

The next day we walked to Circular Quay to catch the ferry to Manly Aquarium so I could do the Xtreme Shark Dive with the Grey Nurse Sharks. We got there early to wander around the aquarium for a bit.

Octopus

Octopus

Giant Cuttlefish

Giant Cuttlefish

Fairy Penguins

Fairy Penguins

When it was 1pm, we met my dive guide. Mom passed on this experience because she was worried she’d have more problems with her ear and equalizing. There were two other girls I dove with, both named Hannah. For one girl it was her 21st birthday surprise and the other was on a cruise with her family (She said that the day before, everything was rolling around the cruise ship with the crazy swells. Apparently dinnerware doesn’t like to stay still on a tippy ship.). They took us downstairs to the shark tank to walk us through what we would be doing with our families in tow. We were given a briefing (in the form of a video) and filled out some forms before suiting up for our dive. They gave us three layers of suit to wear: a shirt, cut-off wetsuit, and full wetsuit. The water was still freezing! It was 14-16˚C (or 57-60˚F).

When we got in a little holding tank in the back, we had to prove that we could empty our mask if it filled when we were underwater, remove and retrieve our regulator underwater, and equalize. Then they gave us gloves and we walked through a little doorway into the main tank.

getting into the tank

getting into the tank

Once we were all ready, we jumped over the tunnel and walked through a divider into the second half of the shark tank. It was divided in order to prevent related nurse sharks from mating during the breeding season. As we walked though the divider, we passed a sleeping Green Sea Turtle.

walking through the divider

walking through the divider

Once we reached our destination, we stood on the edge of the tunnel and watched the Grey Nurse Sharks swim all around us. It was pretty neat to see them swim overhead, right in front of us, and every now and then sneak up behind us.

998691_10151554958633403_1565650100_n

533571_10151554958723403_1456223956_n

1002103_10151554958678403_929648525_n

954720_10151554958848403_947473153_n

There were also some sting rays.

There were also some sting rays.

After watching for about 30 minutes, it was time to hop out and warm up! As we walked out, our guide pointed out a shark attack survivor fish to me, and there was also a stingray trying to swim up the side of the tank to get a piece of lettuce he could see that he was about to be fed. Those stingrays are massive!

Time to go...

Time to go…

I couldn’t stop shivering when we got out of the water! It makes it difficult to get dressed when your hands are shaking all over the place, but I finally managed and we headed back to the hotel for a hot shower! The dive was a good refresher before we jumped in to see the reef in Cairns and it was a neat experience. Between the rain and the dive, I’m pretty sure I spent a good 70% of the day semi-wet!

The next day we had the Sydney Harbour Bridge Climb at 3:50pm. It was still raining in the morning, so we just chilled at our hotel until about noon and headed out into the streets. Because we were so early, we sort of wandered around a bit on our walk to the Bridge Climb. I had found a coupon in a Sydney tourism book in our hotel room for a free gift. Apparently this opal store/museum would give you a souvenir of you brought you passport in to prove you were a traveler.

We found the opal store and checked out the museum. It was sort of neat to see the fossilized opals they had on display. We had some fun posing with the dinosaurs too. Once I get my mom’s pictures I’ll be able to post them. I didn’t realize opals could be colors other than white. I guess red is the rarest and most expensive color, blue and green are in the middle, and white is the most common.

opal fossil

opal fossil

Our free gift turned out to be a kangaroo pin with a small opal fragment. It’s nothing fancy, but it’s a neat Australian memento… plus, it was free!

In a part of Sydney near Circular Quay, there’s an area known as The Rocks. It’s popular for its shopping, and we happened to come across a weekend market that they had set up. There were some neat little homemade odds and ends that people were selling. This one lady used five photographs, cutting out portions from each photograph and staking them up to make a 3-D image of various landmarks. There were also homemade chocolates, wood carvings, etc.

The Bridge Climb building proved pretty difficult to find, especially in the rain. After several attempts to open a door near flags that said “Bridge Climb” we finally asked a bartender down the street. She said we were in the right place, so back we went. We had completely missed the large glass doors and had been trying to get in what seemed to be employee entrances… oops!

Sydney Harbour Bridge

Sydney Harbour Bridge

Once we went in the correct entrance we checked in and waited for our 3:50pm start time. They gave us tickets to check out the Pylon Tower for free sometime in the future. We were in a group with six other people. We signed some waivers and were given our outfits for the climb. There was a jumpsuit we had to wear over a layer of our own clothing. We were also given rain pants.

jumpsuit

jumpsuit

Once we were dressed, we met our climb guide and strapped ourselves into our safety belt. Mom and I were given glasses holders to keep our glasses attached to our jumpsuits in case they fell off in the breeze. Everything we wore somehow snapped/attached to our jumpsuit. We had so many clips! Once our safety belts were on, we were given a fleece and rain jacket that were in pouches on our hips. We also had a winter hat or cap to choose from, gloves, and radio so we could hear our guide. I felt like a pack mule.

Once we were all geared up, we walked up to the starting point for the tour and clipped our safety harness to the bridge wire. I get that it was for safety, but the harness wasn’t my favorite. Every now and then there would be a little wire guide for your harness, and its purpose was to support the wire all the way across the bridge, but my harness would always get stuck at these points. I got jerked backwards a few times before I learned to guide my harness with my hand. I wasn’t the only one either!

The climb itself was wet, but interesting. Our guide talked a bit about the history of the bridge and how it was built. By the time we reached to top, it was quite dark. The city lights were beautiful. Our walk took us up the lower arch of the bridge and then up some stairs to the bridge’s summit. We took a group photo and made our way back down the bridge.

other groups climbing the bridge... just to give you an idea of where you climb the bridge... we were on the lower arch though for most of our climb

other groups climbing the bridge… just to give you an idea of where you climb the bridge (see the little group of blue people halfway up the right side of the arch?)… we were on the lower arch though for most of our climb

It was a soggy and beautiful experience. The only thing I didn’t particularly like about the climb was that I felt extremely rushed getting ready for the climb and getting all the gear off at the end. I get that they have other groups too, but it was so much gear! I could have used a few seconds more to figure everything out, but oh well! Thank goodness mom and I had each other to figure everything out and aid in working the clips! I’d still be tangled in knots!

The next day we headed out into the rain for our tour of the Sydney Opera House.

6270_10151554959443403_1196132114_n

Our tour started at 1pm, so we had time to wander around before our tour. There were some events going on for young dance groups.

inside the opera house

inside the opera house

When our tour began, we were once again given radios to hear our guide. We couldn’t go in very many theaters or take pictures because of copyright laws with the different sets and stage productions, but it was still interesting.

Mom and I decked out in our radios.

Mom and I decked out in our radios.

To begin our tour, we watched a video about the construction. The design proved to be quite a challenge for the architects, but eventually they figured out how to use buttresses to make the odd shape work.

buttresses

buttresses

Our guide talked about several of the productions taking place in the various theaters we visited. She also talked about the technology of each room and how they are able to create the sets. For example, most of the rooms have an orchestra pit that can be raised or lowered and sections of the stage can be extended according to the productions needs. The one room we could take pictures of was the Utzon room, named after and designed by the architect who figured out how to build the opera house. Utzon designed this mural for the room which is supposed to represent what he sees when he listens to music with his eyes shut.

Utzon Room

Utzon Room

Apparently, the government switched during the building of the opera house, and they determined that it was costing too much money and taking too long to complete the project. Before the interior was completed, they told Utzon that he could either step down and become part of a team to help with the construction or resign. He ended up resigning and returning home to Denmark, never to see the opera house completed.

Our guide also talked about the panels covering the opera house. Apparently there are multiple shades of cream used. Cream is used instead of white to prevent the opera house from being too bright when in full sun.

panels

panels

After our tour, we decided to take advantage of our free tickets to climb the Sydney Harbour Bridge Pylon. It would have been an $11 climb, so I’m glad it was free. It was a nice view, but not worth $11 out-of-pocket.

view from the pylon

view from the pylon

They also had little captions throughout the tower explaining more about the history of the bridge and how it was built.

view of Circular Quay from the pylon (where we got on the ferry for Manly Aquarium and the Taronga Zoo)

view of Circular Quay from the pylon (where we got on the ferry for Manly Aquarium and the Taronga Zoo)

Our last full day in Sydney, we had a behind the scenes tour of the Taronga Zoo scheduled. We caught the ferry super early and arrived at 8:45am. The doors to the zoo didn’t open until 9:30am, so we tried to find the skyrail that was supposed to take us up to the zoo. At first, we wandered down this pathway that we thought led to the building… but it turned out to lead to a beach. After turning around, we found the stairs that led up to the building, but it was still closed. There was another pathway that branched off to the side, so we followed that instead. This path led to a door that said no entry, but it was open, so Mom poked her head in. We went through the door and found ourselves inside the zoo! We knew that wasn’t right either, so we were just going to walk up to the entrance and explain what happened, but technically the zoo wasn’t even supposed to be open yet! We didn’t know if they’d be able to let us out to actually get to the entrance, so we turned around instead. It was mass confusion.

We ended up walking back down the path and up the road, where we came across the back entrance of the zoo. No one was there, so we waited for a while. Mom thought she saw someone go in, so we opened the door to the gift shop and walked in. One of the employees told us that they weren’t open yet and they needed to count money, so we’d have to wait outside yet… I’m still not sure why the door was unlocked if guests weren’t allowed to come in yet. Eventually, however, the zoo did open and we were able to go through the appropriate entrance. We ended up walking into the zoo where we had accidentally entered earlier and down to the now unlocked skyrail building. What an adventure, and it wasn’t even lunch time yet!

The skyrail basically runs from the back of the zoo to the front, so you get a bird’s eye view of the place before you walk around. Once we checked in at the front, we met up with our tour group and keeper guide, Jenny, to check out the animals. Our first stop was the tree kangaroo. Apparently Jenny had been cleaning the cage earlier in the morning and bent over. The kangaroo mistook her for a stump, and pounced on her to get down from the tree. I guess Jenny and the kangaroo were both rather surprised that morning, Jenny with the bruises to prove it!

tree kangaroo

tree kangaroo

I was rather excited that we got to see the platypus. Jenny said it’s usually a rather reclusive creature, so she fed it in order to encourage it to swim into the viewing area. My picture isn’t very good, but it was rather dark in there and difficult to get a shot. I was just excited to see one. They’re much smaller than I imagined. Mom was surprised to learn that the males have venomous spurs.

platypus

platypus

Our next stop was inside the quokka and echidna enclosure. We each took a turn petting the echidna. They’re adorable little spiny creatures.

Quokka

Quokka

echidna

echidna

Afterwards was my favorite part of the tour, entering the koala enclosure for some pictures!

1010829_10151554960553403_871805341_n

They sleep 20 hours a day, and since the eucalyptus they eat is not very nutritional, they need every waking moment to feed. For that reason, we were not allowed to actually touch the koalas, but we were allowed to get pretty close for some nice shots.

1003444_10151554961008403_1786873634_n

Two koalas meet on a branch... now what?

Two koalas meet on a branch… now what?

Our next stop was feeding the kangaroo and wallaby. Apparently the kangaroo love Sultanas (raisins) and the wallaby prefer peanuts. An emu came to check out what was going on too. Then we headed backstage at the zoo’s nocturnal exhibits. We got to peek inside the kitchen before heading off to feed an owl live mealworms.

nocturnal animal kitchen

nocturnal animal kitchen

The owl would make these noises of contentment that almost made it sound like it was growling. They’re gorgeous animals. Apparently this particular owl used to be in the bird show at the zoo. She tended to get picked on by the other birds, so they moved her to the nocturnal enclosure. One might think that she would be unhappy in a smaller, indoor area, but it turned out to be exactly the opposite. They know this because of the owl’s behavior. They used to think the owl was a boy, because it hadn’t laid an egg in the 7 years it was part of the bird show. When they separated it from the other birds, however, she started laying eggs (which is a sign of comfort and contentment… they only lay eggs when their nutritional needs are met an they feel safe enough to do so).

owl

owl

We also got to hold a feather glider, which was incredibly tiny and vibrated constantly because of its high metabolic rate, almost like a hummingbird. They’re named after their feather-like tails.

feather glider

feather glider

Our keeper guide also let out two of the bandicoots for us to see. She explained that they don’t run in a straight line, which is a natural, hereditary behavior used in order to evade predators. They’re also incredibly endangered creatures. Around Easter time here, they actually sell chocolate bandicoots (sort of like chocolate bunnies) to raise awareness for the species and help fund conservation efforts.

bandicoot

bandicoots

We also got to see the Tasmanian devil at its enclosure before our tour came to an end at a cafe. We were given a choice of free bakery items and beverage (Mom and I sampled the orange poppy seed muffins… I had never though of using orange in place of lemon, but it was tasty and seems to be quite popular around here!)

For the rest of the day mom and I wandered the zoo, checking out the animals until it closed at 4:30pm. We still didn’t get to see everything the zoo had to offer, but we managed to get to the things we really wanted to do. The sea-lion show and spider keeper chat were rather interesting. They brought out an Australian funnel-web spider, black widow spider (or red-backed spider), and huntsman. We also saw the binturong, which is a rather unusual prehensile creature. They’re also known as a bear cat.

binturong

binturong

I didn’t mention all of the animals that we saw, simply because there were quite a few! We spent quite a long time watching the elephants. They’re such fascinating creatures. We also checked out the reptile house. We literally stayed at the zoo until they announced it was time for people to clear out for closing. We headed back to the skyrail, onto the fairy, and back to the hotel. It was time to get ready for our flight to Cairns! Our 6:00am flight meant our alarm clocks would be going off at 3:30am… hurrah for early mornings! Stay tuned for Part 2 of our vacation…

1005292_10151554963023403_1389706379_n

Advertisements

Echinodermata: Those With the Spiny Skin

Time to examine some echinoderms! This phylum was our last group of marine animals to examine. We made it through algae, annelids, mollusks, and arthropods. Echinoderms are a pretty unusual and beautiful group. Starfish, brittle stars, sea urchins, and sea cucumbers make up this phyla. They’re named after their rather pokey exterior,  coming from the Greek term for “spiny skin.”

One of the identifying characteristics, most clearly seen on some starfish, is pentamerous radial symmetery. This simply means that the body is composed of 5 identical sections, and these sections radiate outward in a circle (like the arms on the clock). Pixar demonstrated this quite well in their creation of the character Peach. See how she has 5 identical arms? Starfish can have more than 5 arms, but you will usually be able to subdivide the body into 5 repeated sections.

They also have a rather interesting system to assist with movement, called the water vascular system.

Basically, water enters their body through the medreporite. From there, it flows into an interior closed system of canals. These canals originate from the central ring canal and radiate out into each of the appendages. The lateral canals connect with the tube feet.

The tube feet are controlled by the pressure within the water vascular system. It’s a bit like filling a water balloon with water. When the balloon is empty, its limp and floppy, but when it’s filled with water, it’s tight and contracted. Protractor muscles control the amount of water pressure (found in the balloon-like structure in the image below). In order to control the motion of each individual tube foot, echinoderms have postural or orienting muscles (located at the top of the foot).  These work to swing the entire foot from one side to another (though still in a straight line). In order to bend the foot retractor muscles are used (found at the bottom of the foot).

In the end, this system allows echinoderms to use their tube feet for locomotion, feeding, and respiration.

Another cool feature is the ossicles that cover their bodies. These are calcareous, bony plates that make up the echinoderms internal skeleton. Depending on the species, their structure can be fused together into a solid “shield-like” structure (called a test) or hinged together to function like joints. On the image of the sea urchin test below, the spiny bumps you see are created by the ossicles.

Okay, now that we’re familiar with the basic characteristics, we can start looking at the individual classes of this interesting phyla.

Class Asteroidea

That’s starfish in plain English! They classically represent the echinoderms. They have a central disc with 5 arms (though they can sometimes have more), tube feet used for movement (usually 2 or 4 rows), and spines. Some features, however, are rather unusual. For example, when starfish feed, they extrude one of their 2 stomaches. The first stomach is pushed out through their mouth, and envelopes their prey (or a portion of the prey) and digestive enzymes are used to break down the food. Once they’re done slurping up their soup of a meal, the stomach is pulled back in and the second stomach continues digesting the meal. Check it out:

Starfish also have  pedicillariae, which are super tiny claw-like structures that cover the outside of the body. Their use is largely a mystery in some species, but for the most part, they have 2 types: cleaning and one for feeding. The image below shows a close-up of a starfish. The little pinkish-white bumps you see are the pedicillariae.

And this is an example of what it looks like up close (though it varies from species to species):

They also have papulae. (Has anyone else noticed that science has waaaaay too many terms that start with “p”? Pedipalps, papulae, pedicillariae, pleopods… By time I’m done with this exam, saying supercalifragilisticexpialidocious backwards will be a cinch!) Papulae are used for gas exchange and to get rid of wastes. They’re little tube-like structures covering echinoderms body surface, increasing surface area. This increased surface area helps expose them to more water at a time, allowing their bodies to absorb oxygen at an increased rate.

We also looked at various stages of starfish larval development under a microscope. This video illustrates the development, showing a flow of each of the stages:

We first examined the gastrula, which looked a lot like this:

You can see at the top of the image how the body has sort of caved inwards. The technical terminology for this is the “invagination of the blastopore.” This particular part of the body will become the anus.

a labeled image fo the gastrula Image from http://utweb.ut.edu/

a labeled image fo the gastrula
Image from http://utweb.ut.edu/

The next stage is the free-living larval stage. At this point, the starfish has started to develop coelomic sacs, oesophagus, mouth, stomach, intestine, and anus.

The large, purple central core is the stomach. At the top of this structure is a tube (oesophagus) and opening (mouth) that leads to the exterior of the body. At the bottom of the stomach is also a tube (intestine) and opening (anus). The little sacs that look like deflated balloons at the top of the stomach are coelomic sacs. These will basically become the starfish’s guts.

After this, the starfish larvae moves into a planktotrophic stage (meaning it lives among and eats algae in the water column). The first of these planktotrophic stages is the bipinnaria.

The darker boarders around the larvae are the ciliated bands. The starfish has also begun to develop stubby little arms (the points on the bottom of the triangular region of the larvae). The round ball that the black arrow is pointing to is the stomach, and the tubes branching off of it make up the digestive system. This next image helps to identify the individual parts. You can see the mouth is made up by loop-like structure at the top that connects to the stomach. The anus is also visible.

From the bipinnaria stage, the starfish develops into the second planktotrophic stage, known as brachiolaria. It’s somewhat difficult to believe that these guys eventually end up turning into starfish.

They start to sprout stringy 3 more stringy appendages. These all develop around a sucker. Here’s a labeled diagram to help orientate you:

With its 3 arms and sucker, the brachiolaria larva is able to attach itself to the substrate. This is where the real magic begins. It starts to break down the larval tissues and undergo metamorphosis. The structures are rearranged and remade (digestive system, arms, tissues, etc.).

And a juvenile starfish is formed…

It’s interesting to note that the brachiolaria larva has bilateral symmetry, meaning that one half is identical to the other half, while the adult starfish has the classic echinoderm radial symmetry. The body plan completely changes during metamorphosis. You can see that the tube feet have begun forming on the arms along the canals of the water vascular system. Overall, the process from egg to reproductive starfish takes about a year, depending on the species and water temperature.

Class Ophiuroidea

Have you ever been to an aquarium and seen these guys?

They look sort of like starfish, but their arms are quite alien looking. They’re brittle sea stars, belonging to the class Ophiuroidea. They’re related to starfish, but slightly different. They have a central disk with 5 distinct arms. These arms, unlike that of starfish, are jointed, giving them a squiggly appearance. They sort of remind me of Medusa’s hair.

Another difference is the location of the madreporite (the spot where water is taken in for the water vascular system) and the presence/absence of abulacral grooves. In starfish, the madreporite is located on the aboral surface (the side opposite the mouth) and they have abulacral grooves.

Brittle sea stars, however, have the madreporite on the oral surface (the same side as their mouth) and do not have abulacral grooves.

Brittle sea stars are also different in the fact that they do not use their tube feet for movement. Instead, their jointed arms and spines can have rapid movement. They also have bursae, areas in the body wall that cave inward, forming a sac.

If you look on either side of the arms, it looks a bit darker and shaded. These are the bursal slits. They’re used in reproduction. The mouth is the star-shaped structure in the center of the body, and is surrounded by skeletal plates. They also have a ophiopluteus larva, meaning they have 4 pairs of extra-long arms with cilia and supported by calcium-based rods.

This video, albeit a bit long, helps to demonstrate how quickly the brittle stars can move. It’s of two brittle stars fighting over a dead shrimp at the bottom of the ocean:

Class Echinoidea

Sea urchins! These spiny guys are rather interesting (and smelly to dissect!). Their body is centralised around a sphere or disk shape (sand dollars are also echinoids), and they have no arms. The bony-like ossicles that make up their body are fused together into a solid test. Like starfish, they have moveable tube feet in order to get around. They can also move their spines to aid in this respect. The spines are attached in a ball-and-socket-like joint, and are flexible but to a point. Just like our arms and legs.

photo 1

Urchins also have pedicillariae. This video gives you a good idea of what they are and what they look like:

For an even better view of the translucent pedicillariae, check out this link: Predators and Defenses. About halfway down the page, there’s a link to a video of the little pedicillariae in a pincer action!

We examined dried and preserved sea urchins, looking for the ambulacral and interambulacral areas. This image gives you a good idea of where those areas are (click on the image to see a larger view):

In the ambulacral zone, you can see the small holes where the tube feet come out.

They also have a rather strange mouth surrounded by 5 pairs of gills (the mouth is the white thing in the center of the body).

photo 2

The unique structure is known as Aristotle’s Lantern, and when removed from the urchin, it looks like this:

We were also given an urchin from the bait shop to dissect. When we did it, we were instructed to use our scissors to cut around the “equator” of the urchin and pull it apart. Of course, my intestinal tract (and everyone elses) ended up quite emaciated as a result.

photo 3

After doing a bit of a YouTube search, this seems like a better method (she also explains the location of the madreporite and anus):

The orangey stuff you see in my photo above is roe, or urchin eggs. It’s also known as “uni” and typically eaten in sushi and Korean food. The black stuff is mainly the guts. Since mine had burst open, I ended up having lots of green specks bursting from the intestine. The specks were algae… it was basically urchin poo. I’m quite sure I won’t forget the smell of urchin guts for quite some time.

This video gives you a good look at the intestines if you’re interested (plus, I’m pretty sure she’s wearing a Mickey Mouse shirt…):

Sea stars have much shorter intestines, since they are feeding upon animal prey. Urchins, on the other hand, eat algae and need the longer digestive system in order to take the time to break down the tough cell walls of their dinner.

Urchin larvae is echinopluteus. They have 3-4 arms with cilia.

This BBC video clip talks about all 3 of the classes we’ve discussed so far (Asteroidea, Ophiuroidea, and Echinoidea) and a bit about how they interact in the ecosystem:

Class Holothuroidea

Sea cucumbers are, in my opinion, some of the oddest creatures on the planet.

They have an elongated body with no arms. Their skeleton is largely reduced, so they have a more fleshy appearance. To feed, they use tentacles that can be found around their mouths. These tentacles are actually modified tube feet. The tube feet that are used for movement run in 5 horizontal rows along the body. Internally, they have “respiratory trees” that are used to collect oxygen. The madreporite (where they take water into the water vascular system) is found floating free in the coelom (body cavity).

If the cucumbers themselves aren’t strange enough, check out the pearl fish:

Class Crinoidea

This class consists of feather stars and sea lilies. Sea lilies are  made up of a stalk (which may have cirri, little appendage-like structures) and a crown (which is a reduced central disk and arms). Feather stars are lacking the stalk portion.

The arms are branched with pinnules, or secondary branches.

The tube feet have a mucus on them and are found on the pinnules. They’re used in filter feeding.

The basal calyx, or the bottom of the flower-like part, is where the mouth is located. This image helps to illustrate that (click the photo for a larger view):

They  have a lecithotrophic vitellaria larval stage. Lecithotrophic means that the larvae have a yolk that they feed upon for nutrients, instead of relying upon plankton. Vitellaria is the group of glands that secrete the yolk.

And that’s it for echinoderms and the end of our Marine Biodiversity labs for the semester! Now it’s time to study the groups of  algae, annelids, mollusks, arthropodas, and echinoderms for our final exam. But first, which phylum was your favorite? Vote in the poll below!

Searching for Nemo… in Cairns!

As I mentioned in an earlier post (P. Sherman 42 Wallaby Way, Sydney!), my mom and I will be heading to Cairns after our Sydney adventures. Cairns (pronounced “Cans”) is a tropical city located in the northern state of Queensland. From what I hear, it’s one of the best places to don a snorkel and wetsuit, getting up close and personal with the Great Barrier Reef!

Cairns, named after Sir William Wellington Cairns, was officially founded in 1876, and the discovery of gold in the area largely contributed to the city’s development. The area had been discovered in 1770 by Captain James Cook and  his crew. Though Aborigines originally inhabited the area, the reef, channels, and mangrove swamps made the region and survival rather difficult for European settlers. During World War II, Cairns was used by the Allies as a base for operations in the Pacific, thereafter evolving into a tourist destination.

Once Mom and I arrive, Dad will be flying over to spend a few days with us. Yay!

We’ll be spending one day on a dive boat, doing 3 dives and hopefully seeing lots of amazing critters on the Great Barrier Reef. It’ll be the first time any of us has had the opportunity to dive in ocean water! We were all certified in lakes in Wisconsin, and I can’t wait to get in the salty sea and find me some cuttlefish! One of the other international students I know had the opportunity to go snorkeling in Cairns, and she happily reported she saw a few!

Our hotel has a deal with Tusa Dive, so we’ll be going on a trip with them to 3 different dive sites. They provide all of the equipment, which is awesome! It’s a bit difficult to fit boots and fins in your carry-on, plus all the clothes you need for a 2-week trip…

The trip would be even more perfect if I could find a sea turtle! Chances of seeing my beloved leatherback are pretty much nil, but I’d be satisfied finding any sort of sea turtle! I’ve been dreaming of seeing the reef ever since I first learned about it in 2nd grade (and we transformed our classroom to make a mock-flight to Australia… so fun!), and now it’s finally almost time!

Did I mention I’m super excited??? I’m assuming we’ll see lots of fish and other species too. We’ll have to see how many we recognize from Finding Nemo! Starfish, surgeonfish, clownfish, pufferfish, stingray… any and all would be awesome!

We’ll also be taking a day to explore the Daintree Rainforest. Our hotel also works with Billy Tea Safaris, and we’ll be going on their 1 Day Daintree Rainforest, Cape Tribulation & 4wd Bloomfield Track Day Tour.

Our day begins rather early with a drive along the Coral Sea and a guided cruise on the Daintree River. We’ll be learning about the Estuarine Crocodiles, checking out the mangrove forests, and searching for other wildlife.

We then head over to Alexandra Range for a walk on the boardwalk and  find a Southern Cassowary! In all honesty, this is the major reason I chose to do this tour! I love cassowary! They’re such ancient-looking and unique birds. I’m really hoping we see one!

They’re not birds you want to mess with though. They have a rather convenient dagger-like middle claw on their three-toed feet that can be up to 5 inches long!

For those familiar with dinosaurs, they rather earily bring up images of a velociraptor… Check out those feet!

Cassowary are obviously not defenceless, but have become classified as vulnerable due to human actions. Rainforest destruction for agriculture and development, fragmented populations, increasing traffic and car accidents, and pets (attacking the young) have all become a problem for this beautiful bird.

Lync Haven is our next destination, where we’ll be able to feed kangaroos, visit “Boris the crocodile, and have lunch. Then we drive along the Bloomfield Track to Emmagen Creek where we’ll have time to explore, swim, and sample traditional Billy Tea from the Daintree Tea Plantation.

Kangaroo Feeding

Kangaroo Feeding

Afterwards, we stop at Cape Tribulation Beach before crossing the Daintree River by cable ferry and heading back to the hotel. Much of the tour is centered around visiting the National Parks, which I love!

Other than that, we’re planning on relaxing on the beach and enjoying the tropics! I’m looking forward to seeing my familia! Looking back, time has gone by pretty quickly, but it seems like forever since I’ve seen them!

With this trip planned and set, it’s time for another! I just finished booking my tour for the break during Trimester 2! It looks like I’ll be headed to the Outback in August! Stay tuned for a pre-trip report!

It’s sure to be an adventure Down Under!

Arthropods: The Creatures with the Jointed Feet

Up next in our Marine Biodiversity labs was the phylum Arthropoda! (As a forewarning, besides blogging to share my  experiences, I use my lab blogs as a way to study and review what we learned for upcoming quizzes. There’s a lot of terminology, but I hope I explained it in a way that makes sense! If you do have any questions, don’t hesitate to ask me in the comments!)

Arthropods cover a wide range of species that can be found anywhere from the bottom of the seas to flying though our skies. Arthropoda means “jointed foot” and, as with the other phyla,  these creatures come in various shapes and forms but have certain characteristics in common. Insects and crustaceans belong to this massively diverse group. Even my tarantula, Archie, is an arthropod.

Archie makes a rare appearance

Archie makes a rare appearance

Though most people prefer crustaceans…

Image from http://disney.wikia.com/

Poor Sebastian…
Image from http://disney.wikia.com/

One of the most noticeable Arthropod characteristics is their metameric body segmentation. In other words, they have sections of their body that seem quite similar in structure and repeat themselves. This can most clearly be seen when examining their legs, since they have a single pair of jointed appendages that go along with each segment. The body of an Arthropod is covered by an exoskeleton. They have no bones inside their body, but are instead covered by a hard, chitinous shell that serves largely for protection. Because of the rigidity of the exoskeleton, when an Arthropod grows, it needs to completely shed and replace its covering, called molting. Basically, they crack their old exoskeleton, push it off, and allow their new exoskeleton underneath their bodies to harden. It’s quite the interesting process. Here’s a video of a molting horseshoe crab to give you more of a visual:

When the animal first molts, its new exoskelleton has not yet hardened, and it is extremely vulnerable. For example, soft-shell crabs can be quite popular for consumption, allowing diners to enjoy their dinner without the time-consuming task of removing the shell. These crabs are actually blue crabs that have freshly molted. They’re shells simply havent had time to harden yet.

Arthropods are coelomates. (They have internal body cavities separated from the exterior of the animal by a fluid and connected by tissue. Humans, for example, are also coelomates. Check out my Annelids: A Rather Squirmy Lab blog for a bit more information on the subject.) They also have an open circulatory system. This means that instead of blood vessels running through their bodies, their blood is pushed through a hemocel, a blood containing body-cavity where the blood is diffused through cell walls.

closed circulatory system Image from http://www2.gsu.edu/

closed circulatory system
Image from http://www2.gsu.edu/

open circulatory system Image from http://www2.gsu.edu/

open circulatory system
Image from http://www2.gsu.edu/

Once we established the main characteristics of an Arthropod, it was time to get more detailed.

Within the major phylum Arthropoda, there are 3 subphylum: Trilobitomorpha, Chelicerata, and Crustacea.

Trilobites are all extinct. Their 3-segmented bodies (head, thorax, and telson) and seemingly unspecialized, decorative appendages can only be seen today in their fossilized form. While I was working at the Houston Zoo, I took a Saturday to explore the Houston Natural Science Musume’s Hall of Paleontology. They had quite a few of these awesome little critters on display.

trilobites

trilobites

IMG_1090

IMG_1089

IMG_1097

They’re pretty fascinating.

The next subphylum, Chelicerata, is extant (still around today). They have a body that is divided into 2 distinct sections: the cephalothorax (front) and abdomen (rear). Chelicerae is the term given to their first pair of appendages. These are the claws they use for feeding. The second pair of appendages are the pedipalps, which are modified for different functions depending on which animal you’re looking at. Members of this subphylum also lack antennae.

Class Merostomata

The living representation of this group is the horseshoe crab. They’re pretty neat tank-like animals that have an interesting clotting agent in their blue blood. When their blood comes in contact with bacteria, it clots. The blue color comes from the copper it contains. Because of its special properties, these crabs are “milked” for the biomedical community, removing about 1/3 of their blood before returning them to the water. The practice is somewhat controversial. It is still largely unknown how they are affected by the stress and physical demands of the process.

If their unusual body and shell shape isn’t enough of an identifying marker, you can always count on their gills and  telson. They have 6 pairs of normal appendages, and 5-6 pairs of appendages towards the rear of their bodies (abdomen) that are modified as gills. At the very end of their body, you can see the spike-like telson. The telson is used for steering and to right themselves if they become flipped upside down.

Class Pycnogonida

More commonly known as sea spiders, this class is entirely marine. They have 4-6 pairs of legs and no antennae.

Their trunk, or main body has lateral processes that join with the legs (see the diagram below). They also have 4 eyes, a short abdomen, and a proboscis. Males and females can be identified by their ovigerous (or egg-bearing) legs. Interestingly, males are actually responsible for carrying the eggs in this class of animals. The ovigerous legs in females are often much smaller.

The final subphylum, Crustacea, is distinctively different from Chelicerata. For instance, crustaceans have 2 pairs of antennae. They have 3 pairs of mouthparts, consisting of mandibles (used for biting, cutting, and holding food), and the 1st and 2nd maxillae (used for tasting and manipulating food). Their limbs are biramous, meaning they are branched in two (which you’ll be able to see more clearly in the prawn dissection below). These appendages are usually specialized according to the function required by the animal. Their trunk is divided into a thorax (between the head and abdomen) and abdomen. Their thorax may also bear a carapace, the shell or exoskeleton on their back. This exoskeleton is made from chiton, as with other arthropods, but may also contain calcium salts and proteins.

Class Ostracoda

This class of organisms is more commonly known as seed or mussel shrimp. They are very round and tiny, but they can range in size from smaller than a poppy seed  to as large as a meatball.

Under the microscope, it was a bit difficult to see their individual parts. Besides the antennae, legs, and the black dot of a naupliar eye (a simple eye that first appears in the larval stage), you can’t see much. They have a bivalve carapace (two shells covering their body like a mussel) that does a great job of concealing their insides. These images, however, help with that:

The body is largely composed of the head with a very reduced trunk, segmentation, and few appendages. They usually have less than 2 pairs of legs. The 2 pairs of antennae are used for movement, while the legs and body are covered in  sensory hairs.

Class Copepoda

The word “copepoda” originated from Greek terminology translating to “oar-foot.” When examining the swimming behavior of a copepod, their name makes complete sense. They have a pair of appendages on the same body segment that they move together, thus using their legs like an oar to “row” through the water.

The body is larger at the front than at the back, and the head has one eye. They have 6 pairs of legs, with the first (maxillipeds) being modified for feeding. The abdomen consists of the 5 body segments and 5 pairs of swimming legs. Their enormous antennae extend from the body at a 90˚ angle. These antennae can actually be used to distinguish male from female.

If you examine the antennae right copepod, the male, you notice that the right antennae is slightly bent towards the end. That is because it is slightly modified to help him grasp the female. He also has a slightly longer 5th pair of legs, helpful for transferring his spermatophore to his mate. Females are often much larger than males, and sometimes trailing egg sacs give them away.

Class Cirripedia

Barnacles! These guys are another creature you might not immediately classify as an animal. You’ll only find them in the ocean, sessile on the ocean bottom or living on larger animals.

Their antennae are smaller and they have specialized mouthparts. When they attach to something, they settle down headfirst, suspending their 6 pairs of legs in the air. These legs have setae (little bristles) used to bring in food. They tend to colonize together, waving their little legs in the air to create miniature currents and bring in organic particles. Here they are, hard at work:

Interestingly, they are also hermaphrodites, containing both male and female reproductive organs. In order to maintain genetic diversity, they can sexually reproduce with their close neighbors. This video isn’t the highest quality, but they explain the process well:

Recently, I came across an article, “Finally, the truth about barnacle sex is revealed: Genetic analysis shows that the sessile crustaceans can broadcast sperm in water,” that  described an alternative method of reproduction. They discovered that their sperm can also travel through the water to fertilize more distant barnacles. It’s not a very reliable method, but it works! (Click the link above to check out the article.)

About 1/3 of barnacle species are parasitic, showing no features expected of crustaceans, but having the cyprid larval stage of other barnacles (a non-feeding stage in which the larvae look for a place to settle).

Class Malacostraca

This is a the largest class of crustaceans, all consisting of an 8-segmented thorax, 6-segmented abdomen, and telson (tail). On all of these body segments you will find appendages. Their first few legs (usually the first 1-3 paris) are maxillipeds (legs used for feeding). The rest are called pleopods and are used for swimming, burrowing, carrying eggs, etc. Because the class is so large, we looked at further subdivisions.

Quick refresher on taxonomy– organisms are classified in each of the following categories: domain, kingdom, phylum, class, order, family, genus, species. Domain is the least specific and broadest classification, while species is the smallest and most specific.

To complicate things a bit further, you can also have super- or sub- classifications within the categories. Super- would refer to a ranking above that categories, while sub- refers to a ranking below that category. Confused yet? Hopefully that made a bit of sense, or maybe this diagram will help out a bit. It does not contain super- classifications, but it at least gives you an idea to the overall flow.

So… within the Class Malacostraca, we looked  at 2 different superorders, Eucardia and Peracardai, and orders within each of those groups.

Superorder Eucardia

These organisms all have compound eyes that are stalked, and the carapace is fused with the body segments of the thorax.

  • Order Decopoda

Decapoda, meaning 10 feet, all have 10 or more legs. In addition, they have 3 pairs of maxillipeds (feeding legs). For this part of the lab, we partially dissected a prawn, plucking off each of its individual legs on one side of the body  and antennae and identifying each.

prawn and the legs

prawn and the legs

I a bit morbid, like a kid with ants and a magnifying glass, individually pulling off the legs, but it was interesting to see how they were designed differently according to their use.

Crabs also fit into this order, and we were able to examine specimens on ice.

crab

crab

The abdomen in these guys is reduced and folded up under the thorax (it’s the triangular part you see in the center of the body.) The shape of the abdomen can be used to identify males versus females.

The female (on the left) has a much wider abdomen, while the male (on the right) is much more narrow and triangular. The wider shape allows females to carry and brood their fertilised eggs here.

Chelipeds are the large claws you see. They can be used for feeding, defense, grabbing things, or for attracting a mate. The fiddler crab has taken this enlargement to the extreme.

The pleopods (other legs) are not used for swimming but mainly for reproduction and scuttling. Their back legs, however, may be modified to help with swimming.

Superorder Peracardia

The 2nd superorder we looked at is characterized by their small size. They’re almost never larger than 2cm. A naupilar eye (simple, larval eye) never develops, and the females have a brood pouch.

  • Order Isopoda

Growing up, I knew these guys as roly-polys! We would find them all the time looking for bugs when we rolled over the logs my mother used to border her flower beds. For some reason, she never appreciated it much… Sorry, Mom! But that  where all that bug-exploring experience has gotten me!

Image from http://eol.org/

Image from http://eol.org/

These guys are dorso-ventrally compressed. This means that they’re flattened in appearance, with their length being much longer than their height. Their pleopods (legs) have been modified into abdominal gills, and their eyes are not stalked (like those of a crab). The thorax and abdomen do not have a distinctive start and stop point, making it look like one connected body, and it doesn’t have the hardened carapace we see with other crustaceans. For appendages, they have one pair of grabby mouthparts (maxillipeds) and 7 paris of legs.

This is the largest order of crustaceans, and there are even some parasitic forms, like this guy:

Say hello to Cymothoa exigua, the tongue eating parasite. This video helps to explain them a bit:

  • Order Amphipoda

Amphipods are, as their name suggests, distinguished from isopods by their legs. Amphi- meaning 2, and poda- meaning legs or feet, refers to the different types of legs they have. Iso-, meaning one or equal, refers to the identical appearance of the isopods legs. (I feel like if I spoke Greek or Latin I would be so much better at identifying these animals!) Though they look different they have the same overall number of legs (1 pair of maxilipeds and 7 pairs of regular legs).

Their bodies are laterally compressed (flattened side-to-side) and their gills are found on their thorax. Like isopods, they have non-stalked eyes, and the thorax and abdomen are not clearly defined.

Amphipods are a very diverse group too, with some surviving even in Antarctica. Check out the video below to get a close up of these guys… they’re kinda cute:

Okay, phew! That’s it! That’s what we covered for Arthropods! Now who’s ready for the next  lab: the phylum Echinodermata! Get ready for starfish, sea urchins, and sea cucumbers!

P. Sherman 42 Wallaby Way, Sydney!

The end of the trimester is rapidly approaching, and I’m really starting to look forward to the break! I’m planning on checking a few more things off of My Top 5 Australian Must-Do’s, and first up is Sydney! When I first flew in to Australia, I did land in Sydney briefly before boarding a plane to Melbourne. I can say I have seen the Sydney Opera House, but I’m pretty sure that doesn’t account for much when you’re a few thousand feet in the air!

sydney

My mom is flying in to Sydney at the end of exams, and I’ll be meeting her there. I did some research and after a few Skype conversations we were able to narrow down our options and choose our favorite sites and tours. Technology definitely comes in handy sometimes!

I have always been fascinated with the ocean (hence the Marine Biology major) and passionate about ocean critters. Lately, I’ve also done a lot of research and reading about cetaceans (whales, dolphins, and porpoises). Their intelligence and communication structures are simply fascinating! Despite my interest, I have never seen one in the wild! I remember going to Sea World and seeing the orca when I was quite young, and I have seen the dolphins multiple times at The Seas with Nemo & Friends, but somehow I don’t think that’s quite the same as seeing a humpback whale surface from the depths.

The first full day we have in Sydney, Mom and I will be going on a 2 Hour Whale Watching Adventure Cruise! I have been practicing my whale-speaking skills with Dory, so hopefully we’ll be able to see some!

Humpback whales are reportedly seen on almost ever trip, since about 20,000 of them migrate past the coast of Sydney each year from May to December. It’s one of the longest whale migrations in the world. I have a feeling I’m going to be shocked at how large they are. It’s so difficult to imagine something that massive if you’ve never seen it before. From May to August the whales are on their Northern Migration, moving from the southern antarctic waters to their breeding grounds near the equator. Apparently, there are a lot of breaching whales (jumping) and the males are quite active, showing off to the females in attempt to seduce them.

Other species do make an occasional appearance. There’s about a 50% chance to see dolphins such as the Bottlenose and Common Pacific. Southern Right whales, Blue whales, Minke whales, and  orca can make a rare appearance. I would flip if we see an orca! (I have a special interest in them). Right whales generally start to make an appearance in July, and we’ll be there at the very end of June, so maybe we’ll have a chance to see some! Fur Seals, Sea Birds, and other species such as sharks, False Killer whales, Pilot whales, sun fish, rays, and turtles might also show up. It seems like a flip of the coin as to what animals we’ll see, but as long as we see some sort of cetacean, I’ll be happy!

One of the neat things about the company we’ll be whale watching with is the research they’re supporting with Professor Robert Harcourt and Megan Kessler at Macquarie university. They’re working to examine the Australian whale watching guidelines in relation to the anthropogenic (human) impact whale watching has on the whales. For example, they’re working to answer questions like, how close should a whale watching vessel get to the whales? How does it impact their behavior? They’re also focusing on other aspects of whale behavior, communication, and anthropogenic noise pollution. For more information about their research, check out their website hyperlinked to the researchers names above.

Okay, enough about whales! I could probably go on forever…

The next day, we’re planning on heading over to Manly SEA LIFE Sanctuary. They have a diving program, called Shark Dive Xtreme where you can dive with their Grey Nurse sharks, turtles, and stingrays.  I’ll be suiting up and jumping in for this one, while mom enjoys the dryness and less-toothy observation area. I’ll be doing the Tune-Up Dive, which is targeted for people who have logged less than 15 dives or haven’t dived in the last 6 months. I fit both categories! I haven’t dived since I did my open water dives in 2011, so it’s time for a refresher course! I thought it might be a good idea to run through everything again before heading out to the open ocean and checking out the Great Barrier Reef! This dive includes a refresher training course, reminder of the SCUBA equipment, and run through of the dive skills. You are required to demonstrate your skills to an instructor in a training pool before going on a 30 minute dive in the aquarium.

Grey Nurse sharks are an endangered species, and it is estimated that less than 500 remain along the east coast of Australia. Hunting has been the major pressure on their populations. Sharks often have a fearsome reputation due to their predatory nature, but they’re not all man-eaters. Looking at the situation in reverse, humans hundreds (if not thousands) more sharks each year than sharks kill humans. Often, when shark attacks do happen, it’s a bite and release phenomenon. Sharks don’t have hands like we do to investigate things. Their mouth is what they rely upon to tell them what things are. Much of our fear of them comes from misunderstanding and media-skewed perspectives. Grey Nurse sharks cannot actually prey upon large, fleshy items. In fact, their teeth are designed to grab fish and anything much larger than that will not fit into their mouths.

Diving with sea turtles is a plus too!

Day #3, we’re planning on doing the Sydney Bridge Climb! I don’t know much about it, other than you climb the bridge, and everyone I’ve talked to who has done it in the past has highly recommended it!

We’re planning on doing The Discovery Climb at night. The entire climb takes about 3.5 hours, walking up the lower arch of the bridge to the upper arch over Sydney Harbour. It looks like we’ll have some spectacular views.

And how can you go to Sydney without visiting the Sydney Opera House? On our 4th day, we’ll be going on a 1 hour walking tour of this iconic landmark. On the tour you get to take a peek inside the buildings multitude of rooms and corridors, hearing stories and secrets along the way. They talk about the architectural design and the vision of the architect, Jorn Utzon. I’m not one for opera, but looks like it’ll be pretty interesting.

For our 5th and last full day, we’re going to head over to the Taronga Zoo to participate in their Wild Australia Experience. We’ll have the opportunity to get a behind-the-scenes glimpse at the inner workings of the zoo.

It includes a tour of the zoo’s kitchen, Australian Nightlife house, hand-feeding kangaroos and wallabies, and a photo opportunity with koalas in their enclosure. It also includes all-day access to the zoo and the Sky Safari cable car. Overall, it looks like an interesting experience. I’m crossing my fingers for being able to hold a koala! (If my Grandma Betty were still alive, I’m pretty sure she would totally fly over to Australia just for that experience! She absolutely loved koalas.)

I’ve heard the zoo is pretty awesome too from multiple sources, so I’m looking forward to having the time to check it out. It’ll be interesting to see how Australian and American zoos compare.

And that wraps up our trip to Sydney! Before you ask, I did google P. Sherman 42 Wallaby Way, Sydney, and no, it does not appear to exist outside of Finding Nemo. Oh, well! I think we’ll be busy enough with our little excursions! Hopefully I’ll be blogging again soon with some of my own pictures to illustrate our adventures!

After Sydney, mom and I will be flying to Cairns. Dad’s planning on flying over to meet up with us for a few days, so now it’s time to nail down the planning for Cairns and the Great Barrier Reef!

Mollusca: The Soft-Bodied Phylum

This past week, our Marine Biodiversity lab focused on Molluscs! The phylum name, Mollusca, originated from the term “molluscs,” the Latin word for soft. Many of the members of this phylum, however, are covered and protected by a calcareous shell. Squid, mussels, slugs, and snails are a few familiar faces from this diverse group of animals. They can be found in all sorts of environments, from land to the salty seas. Though these creatures can be quite different, they all maintain a few characteristics specific to their phylum. In order to move, they all have a strong muscular foot on the ventral side (toward the belly) of their bodies. They usually have gills, called ctenidia, and a radula, or membrane with little “teeth” used for feeding.

We looked at each individual class in order to gain an understanding of their specific characteristics to be able to identify them in the future.

Class Polyplachophora

These guys are the most primitive class of Mollusks. Chitons are found only in marine environments, and have a shell made up of  eight plates covering their body.

chiton

chiton

They live in rocky intertidal areas under rocks and ledges. Because of the powerful nature of tides and waves in these regions, they have adapted the ability to securely attach themselves to surfaces. They use their flat, broad bodies and muscular foot to crate a vacuum and suction themselves onto the rocks. They lack a well-developed head and don’t have any eyes, preferring to feel around for algae rather than hunt for prey. When you flip them over, you can see the pallial grove lined with ctenidia (gills). The dark red-ish area in the photo below is the pallial groove, and the gills are a bit difficult to see (mostly due to the fact that they were mostly broken off in this ancient specimen).

underside of a chiton

underside of a chiton

To help orient you, mouth of the chiton is the small dot at the bottom of the picture. Water runs under the body along this pallial groove and over the gills, allowing the chiton to extract oxygen. The foot is the large muscular looking mass in the center of the body.  Apparently, as chitons age and grow longer, they have more pairs of gills. Counting the gills can be used as one method to identify or compare the ages of individuals.

Class Gastropoda

Time for some gastropods! This class consists of garden snails, slugs, sea slugs (or nudibranchs), limpets and periwinkles. Most of the species are marine, but there are a few found on land and around freshwater. They’re unique in that they’re the only class of mollusks that show torsion. This basically means that their rear end does a 180˚ as they develop,  ending up above their head. The diagram below helps to illustrate stages of this process:

gastropod torsion Image from www.biog1105-1106.org

gastropod torsion
Image from www.biog1105-1106.org

Their heads are well-developed, and they have eyes and tentacles. Most of their bodies are contained within their shell. This coil is usually to the right-hand side and asymmetrical. There are three different subclasses that make up this class:

Subclass Prosobranchia

This is the largest subclass and consists mainly of marine gastropods. They have normal ctenidia and have an operculum (almost like a door) to protect them when they withdraw into their shells. Cominella, a predatory snail species, has osphradia, or olfactory organs. This might help them “sniff” out food particles in their marine environments.

Cominella

Cominella
Image from www.mollusca.co.nz

Subclass Opistobranchia

Sea hares, sea slugs, and planktonic pteropods make up this subclass. They show torsion and they detorsion as adults, where their body returns to its normal position. They have a reduced mantle cavity, which is the area where the respiratory organs can be found. They do not have a fully developed shell; it is partial or lost completely. They have dorsal external gills to breathe instead of the normal ctenidia, and usually have rhinophores, a second pair of tentacles. They’re often brightly colored. A book I was reading recently, “Sex, Drugs and Sea Slime” by Ellen Prager,  had a pretty accurate description:

“It is as if Mother Nature asked a children’s art class to design the sea slug and gave them instructions to use all the colors of the rainbow, to attach any sort of paper cutout for decoration, and most especially, to use their imaginations with abandon.”

Check it out:

Subclass Pulmonata

Our final subclass consists of mostly terrestrial species. Instead of ctenidia, these guys have a vascularized mantle which acts as a lung. They also lack an operculum.

Class Bivalvia

This class of animals are commonly seen upon dinner plates: oysters, mussels, scallops, and clams. The name bivalve comes from the two valves that comprise their shell and are found on the dorsal (or back) surface. They have quite a large mantle cavity but a reduced head. the visceral mass and foot are laterally compressed, or flattened. They do not have a radula but are filter feeders, using their ctenidia (gill) to filter out particles.

We looked at Mytilus, a mussel, trying to identify the dorsal hinge, anterior and posterior ends, and left and right valves.

Insides of Mytilus

Insides of Mytilus

Mytilus is also interesting because they have a slightly smaller foot and byssal threads. These threads are made up of proteins and begin in a liquid form, are secreted by a special gland. Once secreted, it sticks to a surface and hardens. Mytilus secretes hundreds of these threads, securely attaching itself to a surface. You can see the yellow-ish threads in the photo below:

We also looked at Soletellina alba. One of the professors here studied these guys for his PhD, and there are lots of them in the nearby Hopkins River Estuary.

Soletellina alba

Soletellina alba

When in the sediment, Soletellina stick their foot out, turn sideways, and dig down into the sediments with a wiggling motion to bury themselves. It can be a bit of a slow process (depending on how motivated the bivalve is), but this video shows how it works:

Class Cephalopoda

This is the most advanced group of Mollusks and my personal favorite! Octopi, squid, cuttlefish, and nautili all belong to this class. They have a well-developed head and complex eyes. It is believed, however, that these eyes cannot detect color, which is amazing given their awesome color-matching camouflage abilities!

Their “foot” is highly modified and consists of their tentacles and the funnel which they shoot water through for movement. Their shell is reduced and internal, with the exception of nautili.

nautilus shell

nautilus shell

They also have an extremely powerful beak (think parrot) which contains a radula that pulls the food into the mouth. We had the opportunity to dissect a squid to get a better look at their internal organs and structure.

before dissection

before dissection

We started by removing the eye and looking for the cornea, lens, ciliary muscle, iris, retina, and optic nerves.

cephalopod eye diagram

cephalopod eye diagram

Our next project was to flip the squid on its dorsal side (so the funnel was facing us) and slice up the mantle cavity. I’m pretty sure the only thing I’ve ever dissected was a frog in 7th grade, so I was excited to finally use my dissection kit and open up a squid!

open mantel cavity

open mantle cavity

In the middle of the body, you can see the black ink sac. Immediately behind the ink sac is where the stomach is located (you can see it as the white mass sticking out on either side). The two clear-ish structures that stick out from the center of the body are the ctenidia (gills), and the top half of the body contains all of the reproductive organs. I believe the orange coloration was the beginning stages of eggs. We were also able to open up the stomach (nothing but digested orange gunk in ours) and the ink sac. The ink was much more gelatinous than I expected. This video, it’s a slightly different squid from the type we dissected,  points out the structures in more detail:

Squid have eight arms plus two more that are much longer and used to capture prey. Males can be identified by their single copulatory arm that is used to collect and transfer spermatophores to the female.

At the end of our dissection, we removed the beak.

squid beak inside the body Image from http://scienceblogs.com/

squid beak inside the body
Image from http://scienceblogs.com/

It was a slimy process, but really neat to see! The two pieces were actually shaped differently to fit together and work like a hinge.

beak

squid beak

After we were done I washed my hands a few times and sanitized, but they still smelled like fish bait for the rest of the day! I can’t say I minded too much though, I dissected a squid! Definitely the highlight of labs so far.

Molluscan Radulae

We also had to look at the different radulae that exist in mollusks. I mentioned earlier that radula a radula is a membrane with little “teeth” used for feeding. It’s shaped differently depending on what type of food the animal eats.

The first type we looked at was relatively smooth. It was from Bembicium, a sea snail that eats algae.

Image from http://www.helicina.de/

radula similar to Bembicium           Image from http://www.helicina.de/

We also looked at the radula from Nodolitorrina, which was slightly more pointed and toothy.

radula similar to Nodolitorrina Image from http://www.scielo.br/

radula similar to Nodolitorrina
Image from http://www.scielo.br/

Next up was Cellana, which was even toothier…

radula similar to Cellana Image from http://scienceblogs.com/

radula similar to Cellana
Image from http://scienceblogs.com/

And finally, we have the lethal radula of  a cone snail…

cone snail radula Image form http://www.newark.osu.edu/

cone snail radula
Image form http://www.newark.osu.edu/

You don’t want to mess with these experienced hunters.

Here’s a comparison of all the different types of radula:

Radula_types

Pretty crazy, huh? It’s amazing what you can see sometimes when you put it under a microscope!

We also had a few preserved mollusks to look at and some shells to investigate.

shells

shells

squid

squid

dumbo squid

dumbo squid

Hard to guess how it got its name, huh?

octopus

octopus

And that was the end of lab! By the end I was feeling pretty comfortable identifying the various parts of the mollusks, now I just have to memorize all those funky class and subclass names!

Annelids: A Rather Squirmy Lab

Our Marine Biodiversity lab this past Friday focused on Annelids, the worms of the animal kingdom. Our main goal was to become familiar with the various body types and structures, providing us with the tools to identify the various squirming creatures we collected on a field trip a few weeks ago. This blog is as much as a photo study guide for me as to share what we’re learning, so get ready for lots of lovely worm info!

First of all, we had to understand the three different body types of worms: acoelomate, pseudocoelomate, and coelomate. A coelom is a fluid-filled body cavity that serves as a “cushioning” between the outside of an animal and it’s guts. It also allows for separation and compartmentalization of organs and other body features. Animals lacking a coelom, such as Planaria (a flatworm) are considered more primitive and are labeled as acoelomates.

We were able to look at a cross-section of Planaria under the microscope to see this body structure.

You can see that there’s really nothing separating the outside of the outside (epidermal) layer of the animal from the gut cavity. Everything is filled by parenchyma, or the tissues of the various organs.

The next body type is pseudocoelomate, or “false” coelomate. These animals have more of a space in their body cavity, but there is no connective tissue or muscle to support the gut within the fluid of the coelom.  There is still no membrane surrounding the gut and internal organs, or peritoneum. For this reason, it is known as a false coelom.

We were able to look at the cross-section of Ascaris (parasitic nematode worms). You can see that the body structure is slightly more complex.

Finally, coelomates make up the last body type. These animals, like humans, have a lined body cavity that provides support for the coelom.

We examined a polychaete worm known as Nereis, noting the muscle bands, nerve cords, and other internal body structures.

They phylum Annelida is represented by coelomates. Though there are other worms that have aceolomate and pesudoceolomate body structures, they belong to other phylums. Their body is composed of repeating segments, and they have a circulatory system. Our lab focused on the class known as Polychaeta, which are almost entirely marine. These guys have a pari of parapodia (leg-like structures) with many setae (hair-like structures) on each segment. Their head is usually well-developed and contains sense organs.

Okay, here we go!

Family Arenicolidae

These worms, also known as lugworms, do not have appendages, but like to burrow in the sediment, looking for deposited organic materials to feast upon. In their mid-section, you can see the little parapodia and gills on each segment.

Family Orbiniidae

Orbiniidae are also deposit feeders that burrow in the sediment of tidal sand and mud flats. Their bodies, however, are divided more distinctly. The thorax makes up the first section of the body (on the left), and you can see the little parapodia (leg-like structures) coming off of the abdomen (which makes up the rest of the body). The very first segment of the head is known as the prostomium, and the peristomium is the second. The prostomium comes to a point or is truncated, unlike ArenicolidaeThe head also has no palps (appendage-like mouthparts).

Family Eunicidae

Image from http://www.stroembergiensis.se/

Image from http://www.stroembergiensis.se/

The name of this polychaete literally means “many bristles,” and they can be found in the crevices and algae holdfasts (or root-like structures) in the temperate rocky reefs of marine environments. As you can see, they have very large jaws. This allows several members of this family to be carnivorous, though there are also many omnivores. A few Eunicidae species can grow to be longer than a meter in length, and they are amongst the largest Polychaetes. They can be identified by their rounded prostomium from which projects five appendages, two palps and three central antennae. Bright red gills also extend from the parapodia. It’s a bit difficult to see since they are very small, but the photo does show little red, feathery gills along each little leg-like structure on the body.

Family Nerididae

Nereididae reminded me of the millipedes we used to carry around in bug boxes in Disney. These guys had lots of little legs that worked together in a wave-like motion. Their main characteristics are their well-developed sense organs. Their prostomium has two anterior tentacles, two jointed palps, and four eyes.

Family Syllidae

This family is the most diverse of the polychaetes and its species are found in all types of marine environments. The main feature used to identify this group is the proventricle (a little round spot that is part of the digestive tract). In the photo above, you can see a little brown spot behind the head– that’s it. They also have three antennae on their first body segment and a toothed pharynx (an organ by the mouth used to eat).

Family Serpulidae

Tube worms are some of my favorites. These guys form calcareous tubes and live together in groups, working collectively to fan in and filter out sediments with their feather-like tops. We were supposed to focus on the various body sections: the head, thorax, and abdomen. The thorax has a sort of collar that distinguishes it from other worms. They also have an operculum, which is used as a sort of “door” when the worm pulls itself inside the tube to hide. A central grove runs along the ventral surface of the body and curves up towards the thorax. As you can imagine, living in a tube makes waste disposal a slightly more complex process, and this grove helps with that.

Family Sabellidae

Representing this family, we had some rather large feather duster worms! These guys are different from Serpulidae because they lack an operculum to protectively “close” their body cavity when they pull inside their tubes. The tubes for this family are made from mucilage (a snot-like substance) and sand from the sediment. If you poke the tube it’s rather squishy and a bit spongy. It’s almost like squeezing a cattail. They’re rather interesting little creatures.

Family Spionidae

Found throughout soft-sediment environments, Spionidae are identified by their  large, grooved feeding palps extending from the top of the head. Their prostomium is also rather prolonged, and you can see it in the photo extending almost like a lengthy nose structure. supposedly, on either side of the head they have notopodia (larger parapodial lobes behind the head) and gills, but I had difficulty seeing these structures.

Family Cirratulidae

I’d describe this family as quite the mess! When I first looked at our specimen, it took me a few seconds to find the body underneath its wriggling mass of tentacles. They like to burrow and crawl in the sediments and are often found in seagrass beds and the enriched sediments of estuaries. Along their body, they have a pair of gills per body segment, and the tentacular filaments may almost cover the body.

Family Terebellidae

photo

I actually took the photo of this one! Spaghetti worms, one of the sci-fi stars of the ocean world (of which there are many)! Those thin little tentacles are non-retractable. They’re deposit feeders, so they sift through organic materials deposited in the sediments and consume them. When I looked under the microscope I could actually see little particles trapped in the tentacles which were slowly being worked towards the mouth. It was freaky and fascinating all at the same time. If one of those spaghetti-like appendages is lost, they can actually regrow them. Handy, huh?

At the end of lab, we had time to identify the worms we had managed to collect in our lab in the weeks prior. My group found very few species in the area we surveyed. I’m not sure if it was because we picked a poor spot or if it was due to some other reason, but we found three worms in our samples overall. Two of them we found to be Syllidae and the other seemed to belong to the family Magelonidae. We didn’t look at this family in our lab, but the worm had characteristics described in the literature that matched this group (a tube-like structure on the bottom half of its body and  large palps). They’re also common to the sandy sediments we were sampling.

At the end of the day I found myself carrying around much more knowledge about worms than I ever thought I would need. Next week we’ll be focussing on another phylum. I think I found myself most fascinated with the spaghetti and feather duster worms this week. Which Annelid was your favorite?