Sea Slugs, Snails, and Sea Hares, Oh My!

I love slugs! They are one of my favorite animals, particularly if limiting the scope of the question to invertebrates. In my opinion, they are one of the most beautiful and fascinating organisms.

You’re likely thinking I have lost my mind. “You really think this guy is beautiful?” 

Sea Slugs, Snails, and Sea Hares

Pictured here is the banana slug

Yes, I do. Well, actually, in my mind I was picturing his close relative the sea slug or nudibranch. This summer, I have been volunteering at the new Marine Life Center at the Oregon Institute of Marine Biology and I’ve thereby had the opportunity to learn so much about these fascinating animals. Let me introduce you to the gastropods.

Class Gastropoda 

The Gastropoda or gastropods class, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. A very diverse group with 60,000 to 80,000 living species (second only to insects in number of species) that includes snails and slugs of all kinds and all sizes from microscopic to large. There are many thousands of species of sea snails and sea slugs, as well as freshwater snails, freshwater limpets, land snails and land slugs.

Sea Slugs, Snails, and Sea Hares @EvaVarga.net

How many sea slugs can you find in this picture?

The anatomy, behavior, feeding, and reproductive adaptations of gastropods vary significantly from one group to another. The class also inhabits an extraordinary diverse habitats including gardens, woodland, deserts, mountains, rivers and lakes, estuaries, mudflats, the rocky intertidal, the sandy sub-tidal, the abyssal depths of the oceans including the hydrothermal vents, and numerous other ecological niches, including parasitic ones.

Sea Slugs, Snails, and Sea Hares @EvaVarga.net

Gastropoda means the belly-foot animals

Snails & Other Shelled Gastropods

Commonly, snails are those species with a single external shell large enough that the soft parts can withdraw completely into it. Those with a shell into which they cannot withdraw are termed limpets.

The marine shelled species of gastropod include species such as abalone, conches, cowries, periwinkles, whelks, and numerous other sea snails. Each produce seashells that are coiled in the adult stage. In a number of families of species, such as all the various limpets, the shell is coiled only in the larval stage, and is a simple conical structure after that.

Sea Slugs, Snails, and Sea Hares @EvaVarga.net

Pictured here is Hermissenda crassicornis

Slugs or Gastropods Without External Shells

Those gastropods without a shell, and those with only a very reduced or internal shell, are usually known as slugs. The various families of slugs are not closely related, however, despite a superficial similarity in the overall body form.

Sea Slugs

The phrase “sea slug” is perhaps most often applied to nudibranchs and they come in an outstanding variety of shapes, colors, and sizes. With translucent bodies, they appear in just about every color on the rainbow. Of course, these bright colors are cause for warning to potential predators that they are poisonous with stinging cells. It is their colors that so fascinate me.

Like all gastropods, they have razor-sharp teeth, called radulas. Most have two pairs of tentacles on their head used primarily for sense of smell, with a small eye at the base of each tentacle. Many have feathery structures (ceratia) on the back, often in a contrasting color. These act as gills.

All species of sea slugs have a selected prey, that is specifically fitted for them to hunt. Amongst the diverse prey are jellyfish, bryozoans, sea anemones, sponges, and other various organisms including other sea slugs.

Sea Slugs, Snails, and Sea Hares @EvaVarga.net

Pictured here is Phyllaplysia taylori

Sea Hares

The sea hares, clade Aplysiomorpha, are often quite large and sometimes described as large sea slugs. They have a small, flat, internal shell composed of proteins. The name derives from their rounded shape and from the two long rhinophores that project upwards from their heads and that somewhat resemble the ears of a hare.

The greatly modified shape of the sea hare and the fact that it orients its body lengthwise along the leaves makes it almost invisible on the sea grass Zostera. An herbivore, it feeds by grazing the film of organisms, mainly diatoms, off sea grass leaves, leaving a characteristic feeding scar on the leaves.

Take it Further

Learn more about Phyla Mollusca in my earlier post, Echinoderms and Molluscs.  You might also be interested in my in-depth zoology curriculum specifically designed for middle school students.

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Junior Explorers Brings the World Ecosystems to You

I was recently sitting on the pool deck one afternoon waiting for our kids to finish swim practice. As summer was still just a few weeks away, a few moms and I got to talking about activities to keep the kids engaged through the hot summer.

One mom suggested a subscription kit. “Yeah, but there are so many available today,” one mom replied. “How does one choose?”

I was delighted to share with them my experience with Junior Explorers. When choosing a subscription box – either as a gift or as a curriculum enrichment – my suggestion is to keep the interest and passion of the recipient in mind.

While my son is in the target age, a child passionate about animals would be the ideal recipient for Junior Explorers. I knew the perfect little zoologist – my friend, Liam, who was recently promoted to first grade! I was delighted to be able to assign him his first mission, Mission Amazon.

I received the Junior Explorers mission kit in exchange for an honest review. All opinions expressed are true and completely our own. Please see my disclosure policy for more information. This post contains affiliate links.

Explore the World with Junior Explorers @EvaVarga.netLike many children, Liam loves animals and while waiting for his big brother at swim team, he will often role-play what he has learned in school or in the books he has brought along with him.

Junior Explorers helps foster that love to inspire the next generation of environmental stewards. Junior Explorers is a subscription program for kids 6-11 that teaches them all about wildlife and nature through exciting adventures that are sent home each month. Every month kids receive a kit in the mail sending them to a new ecosystem to solve a mystery in nature.

Each monthly mission focuses on a new ecosystem with real facts about wildlife and the environmental threats today. This can be a hard conversation to have with kids, but Junior Explorers introduces the topics in an easy-to-understand and solution oriented way.

The monthly kit contains cool collectibles like figurines, animal trading cards, temporary tattoos, stickers, and more. Every kit also includes a secret code to access a wealth of activities, games, and additional learning materials.

Liam loved the animal trading cards with facts about the featured animals best. “Did you know there are frogs that sweat poison?!” he exclaimed. I didn’t get a chance to elicit more details, he hopped off in delightful imaginary play.

Send your child on wild adventures with Junior Explorers subscription boxes! Join Now!

At the end of every mission, kids see a handful of not-for-profit projects doing front-line conservation in the ecosystem they just visited. Kids select their favorite real-world project and watch as their earned points are converted into a real dollar donation.

Junior Explorers is a certified B-Corporation and while this may not mean anything to Liam, us moms can smile knowing that the company has met rigorous standards and been designated as a company that is doing good for the world.

Shipping is only $2 per month to send your child on wild adventures with Junior Explorers subscription boxes! Join Now!

 

STEM Club: Bird Anatomy

To the delight of the kids, we’ve moved into vertebrate animals in our 10-week survey course this week. I created a chart (similar to the invertebrate chart I shared previously) with which the students could use to compare and contrast the five vertebrate animal classes as they took notes during the lecture portion of class.  However, I was surprised to discover that they could essentially fill it out without any input from me. They were experts on vertebrates.

Birds

Birds belong to a larger group of animals called vertebrates (animals with backbones) and they make up a special group or class of the vertebrates called Aves.  Aves is the Latin word for bird.  All birds share many characteristics.

Feather Lab

Birds are the only animals in the world with feathers. There are two main types of feathers: contour feathers, which are found on the bird’s body, wings, and tail; and down feathers, which are fluffier and softer and lie close to a bird’s body, under the contour feathers. I showed the class a contour feather and explained that the hard center tube is called the shaft and the rest of the feather is the vane.  The shaft is a hollow tube made of a very hard material called keratin (the same material of which a reptile’s scales and our fingernails are made).

The vane is made up of hundreds of barbs that look like skinny hairs coming offing the shaft in rows.  Under a microscope you can see that tiny barbules grow off each of the barbs.  These barbules have rolled edges on one side and tiny hooks on the other that interlock side by side much like a ziplock seal.  We observed a feather beneath the microscope and the kids were encouraged to sketch and label their observations.  Encourage the kids to sketch and label the parts of a feather in their notebook.

Download the lab notebook printable, Feather Lab.

Bird Anatomy

We then talked about the other characteristics that make a bird different from other animals – wings, bone structure, binocular vision, excellent hearing, poor sense of smell, air sacs attached to each lung, and a crop and gizzard to aid in digestion. We played a fun relay game and then focused on bird adaptations using a number of stations that were set up to simulate bird beaks.

fill the bill thumb

We discussed the shape and design of different bird beaks and how the design helps birds to survive.  Eight stations were set up around the room, each with a different type of “food” that fits one of the eight different types of beaks described (e.g. styrofoam peanuts in a small aquarium of water to represent fish, a test tube of water to represent flower nectar). At each station there were three tools (e.g. chopsticks, pipette, tongs, slotted spoon), each representing a different type of bird beak function – one tool that worked well to get the food and two that didn’t work so well.  The students were asked to visit each station and to decide which tool would be the most efficient.  They were then asked to identify which food different birds would eat based on the shape of their beak.

To accompany this activity, I’ve created a slide presentation, Fill the Bill, available as a free download to my subscribers (a thumbnail is shown above).  Following this activity, we gathered in teams to play a relay-style game called Pass the Part.  The kids had a lot of fun.  Both of these activities were adapted from activities described in Birds, Birds, Birds! (Ranger Rick’s Naturescope Series).

Extension Activities

To expand upon what we covered, I suggested many extenstion or enrichment activities and the students were encouraged to choose at least one to do at home.

  • Begin a bird life list and go on a bird outing. You can find numerous local bird checklists online. 
  • Consider entering the US Fish & Wildlife Federal Junior Duck Stamp Program and Scholarship Competition.
  • Find a picture of your favorite bird (or draw one of your own) and then label the parts of the bird (crown, rump, breast, belly, primary feathers, nape, crest, throat, mandible, chest, thigh, chin, eye-ring, tail feathers, etc.)
  • Draw pictures of birds in their nature journal – use a field guide to help with details
  • Use Barb’s Outdoor Hour Challenge as inspiration to observe and study bird feet – Woodpecker Bird Study
  • Do a research report on a bird of choice
  • Create a poster that compares/contrasts the five vertebrate animal groups
  • Do a bird survey in your backyard.  I’ve created a free notebooking page to aid in recording your observations.

Download the Bird Survey Data Form

bird survey notebooking page

I’d like to encourage everyone to do the bird survey.  This is a fun family activity and a great way to contribute to ongoing citizen science.  Get started now and become acquainted with the birds in your area.  You will then be very knowledgeable, and can easily identify most (if not all) of the birds in your backyard for the annual Great Backyard Bird Count in February 2014.  I will be sharing more about this wonderful citizen science project as we get closer.  I hope you will join us.

STEM Club: Arthropods

We wrapped up our study of invertebrates this week with a focus on the Arthropod Phyla.  I opened class with a short lecture portion, again encouraging the kids to take notes on the chart I had created the previous week or directly into their notebook.

Characteristics:

  • hard exoskeleton which they molt several times as they grow
  • bilateral symmetry
  • jointed appendages (legs and antennae)
  • largest animal phyla – more arthropods than any other animal

Examples:

  • insects – 3 pairs of legs
  • arachnids (spiders & mites) – 4 pairs of legs
  • crustaceans (crabs & lobsters) – 5 pairs of legs
  • millipedes & centipedes.

I had stations set up around the room introducing the kids to the diversity of insects (each station focused on a characteristic of a specific insect order).  Each station had a card (with printed instructions), a photographs, and at least one actual specimen to observe with a hand-lens.  I have created a slide presentation that you can use to simulate these stations with your students.  Though helpful and certainly of interest to the kids, the actual specimens are not required.  You can download the presentation here:  Insect Classification.

hands-on science activity

Upon concluding the first activity, I then introduced the inquiry portion of the lesson.  I had purchased in advance several live arthropods – 3 Madagascar Hissing Cockroaches (Class Insects, Order Blattodea), Bumblebee Millipedes, and a dozen or so pill bugs (Class Malacostraca [Crustacea], Order Isopoda).  The kids were divided into small groups and instructed to devise a simple experiment to test an experimental question.  For example,

What food(s) do the cockroaches prefer? 

What temperature do the pill bugs prefer?

Do pill bugs prefer light or dark?

isopod inquiry activity

Each group was allowed to utilize any number of the things I had on hand to set up their experiment – cardboard boxes, paper towels, ziplock baggies, aluminum foil, a variety of food (oatmeal, grapes, carrots, crackers, etc.)  I was delighted to see how well the kids worked together in the limited time we had to complete the activity.  Each group was able to quickly decide upon a question and devise a way to test their hypothesis.  However, we did not have the time to carry out different trials (repeat the experiment) and regardless, the sample sizes were too small to make any conclusions.  The activity provided me with a good understanding of what they understood about inquiry activities, however.

Nature’s Lesson Plans

While camping along the Rogue River recently, Papa Jens & Buddy enjoyed a little fishing and gold panning. Their endeavors have become a tradition to which they both look forward to each year. With their gold pans draped over their shoulders with a length of rope, small glass vials in their pocket, and a fishing pole and bucket in hand, they embark each morning after breakfast for the days adventure while the rest of us float the rapids in our inflatable kayaks.

fishingNature’s Lesson Plans

Their level of success varies every year but they never come back to camp without some reward in hand. This year was no different .. with nature providing lessons in geology, ecology, ichthyology, and economics.

Geology – Rocks & Minerals

Buddy was very excited this year to explore an abandoned mine shaft with which Papa was familiar. He had packed a head lamp especially for the occasion and was so persistent, Papa agreed to check spelunking off the list first. Upon locating the mine, they hiked in about 400 yards, though there were no big discoveries … only memories.

gold panning

Later that evening, they walked down to the river again with their gold pans.  This time, they did not return empty handed.  They proudly passed around their vials of tiny gold flakes.  Gold panning is a hobby my dad has enjoyed all his life and one he has certainly passed down to my kids. We haven’t struck it rich – but have certainly enjoyed the scenery.

I caught one

Ichthyology

The next day, their search for adventure brought them down to the river again where they baited their hooks with an earthworm and Papa gave instructions on how to cast properly.  There were a few entanglements and a lost weight, but all in all they were successful.  They caught three decent size northern pikeminnow (Ptychocheilus oregonensis), a large member of the minnow family, Cyprinidae. Until 1999, when the American Fisheries Society officially changed the common name to pikeminnow, the four species of this genus were known as squawfish (my dad, being of an older generation, referred to them as such).

Economics

The population of pikeminnow has flourished with the development of hydroelectric power systems. The reservoirs have provided excellent habitat and given them an advantage over depressed salmon and steelhead populations. While historically pikeminnow have not been of interest commercially nor to sport anglers, Washington and Oregon state fisheries agencies have placed a bounty on them to reduce predation on scarce salmon stocks.

Our annual camping trip to the Rogue River valley is a much anticipated endeavor.  We look forward to time with our friends and family but nature never fails to impress upon us valuable lessons that we carry forth.

 
Submitted to the Outdoor Hour Challenge Blog Carnival at Handbook of Nature Study.

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An Introduction to Entomology :: Free Online Workshop

When I was teaching in the public school, my favorite unit to teach was entomology.  Now that I homeschool, I have come to realize how much I miss teaching others and exploring our natural world together.  While my children and I actively engage in nature studies regularly, we have not been very consistent in incorporating more in-depth science studies into our curriculum.   I have discovered that I am more accountable when I provide opportunities to our fellow homeschooling community.  For this reason, I have decided to open this course to anyone interested in learning about insects along with us.

I have designed this unit so students will develop an appreciation for the diversity of insects in their local area as well as an understanding of the greater diversity the world over.  Participants will have the opportunity to use an identification or dichotomous key.  The course is open to all ages but the content is geared towards middle level students – parents and families are welcome to join in on the fun.  Any prior knowledge about insects is appreciated but not required.

The unit includes several labs and research assignments in addition to a long-term project. I will communicate weekly whereby I share videos and other media showcasing specific lessons and activities designed to teach insect anatomy, scientific classification, ecology, and inquiry.  I will also provide research suggestions, resources for study, and experiment ideas. 

See the course outline here, Entomology Course Outline

Participants will have the opportunity to participate in class discussions, contribute to data collection as citizen scientists, and do independent research on topics of interest.  Participants in the course are expected to keep a field journal or notebook of their work. Participants are also encouraged to come up with their own project ideas (videos, PowerPoints, art projects, field trips, photography, and more).

This free course will be six weeks in length and is scheduled to begin in May. For those interested in taking part, I ask that you subscribe to the Entomology Online Workshop newsletter via MailChimp.  You can find the subscription link in the right sidebar.  Upon receiving the verification email, you’ll want to click on “manage your preferences” and choose the list topics of interest to you; Entomology Online Workshop is listed as one option. I will then provide the necessary weblinks and/or pass codes required to access the course materials (via GoogleDocs, Flickr, and Project Noah) when the course begins next month.

Participants will have the opportunity to share documents via GoogleDocs, write blog posts (optional), and submit photographs of student work via Flickr.  Participants are also encouraged to collaborate with one another via my classroom on Project Noah.  Parents are expected to partner with younger children to read over and edit student presentations, checking for grammatical errors. Students working independently are asked to use spelling and grammar checks before submitting work. 

Each family or student that will be making home videos (strongly recommended) about class projects and activities should have a family or individual YouTube account. You can either use an already established account or start a new one for the class. Students wanting their own account must be 13 years old. Any videos made for class can then be uploaded to YouTube and the link given to me. Families are responsible for setting up desired privacy settings.