And each seed is a child being sent off by its mother.
“Goodbye, my dears! Fly safe, fly free, sleep well all winter snug in soil;
Come springtime……..think of me.”
— Amy Ludwig VanDerwater
Did you ever think of plants as great travelers? While it’s true that adult plants put down roots and die if they are removed from the soil, infant plants — what we call “seeds” — not only wander far and wide but will die if they don’t! When plants scatter their seeds we say they are “dispersing” them. Why do plants need to disperse or scatter their seeds? Think about what do plants need to grow. (Light, soil, water and air.) What would happen if seeds all fell right beside the parent plant?
Plants disperse their seeds in several ways. Some fly with wings while others are carried by down or fluff. Some seeds sail on the water. Others are eaten by animals and travel inside them for a while. Still other seeds are shot away from the parent plant, and some even hitchhike in order to get around!
Our Nature Study class is embarking on a new adventure into the world of traveling seeds — what Margaret Warner Morley calls Little Wanderers in her book by that name. I hope you’ll join us!
My favorite books on this topic (written for children, but I learned so much from them):
Little Wanderers by Margaret Warner Morley — http://www.amazon.com/Little-Wanderers-Illustrated-Yesterdays-Classics/dp/1599153173/ref=sr_1_1?s=books&ie=UTF8&qid=1445919370&sr=1-1&keywords=Little+Wanderer
Seed Babies by Margaret Warner Morley — http://www.amazon.com/Seed-Babies-Illustrated-Edition-Yesterdays-Classics/dp/1599153165/ref=pd_sim_14_2?ie=UTF8&dpID=51KazdYsalL&dpSrc=sims&preST=_AC_UL160_SR107%2C160_&refRID=18QGCCJ6GDQM5CC93PMQ
A Seed is Sleepy by Dianna Hutts Aston — http://www.amazon.com/Seed-Sleepy-Dianna-Aston/dp/1452131473/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=1445919480&sr=1-1
Flip, Float, Fly: Seeds on the Move by JoAnn Early Macken — http://www.amazon.com/Flip-Float-Fly-Seeds-Move/dp/054516348X/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=1445919608&sr=1-1
Because only then does one feel that all is as it should be and
that God wishes to see people happy, amidst the simple
beauty of nature. I firmly believe that nature brings solace
in all troubles.
– Anne Frank
The turtle’s always been inclined
to live within his shell.
But why he cares to be confined,
the turtle does not tell.
The turtle’s always satisfied
to slowly creep and crawl,
And never wanders far outside
his living room or hall.
So if you wish to visit him
in his domestic dome,
Just knock politely on his shell —
you’ll find the turtle home.
Steele Creek Park in Bristol, TN, was the site of this week’s nature study class. Hoping to surprise some turtles basking on a large fallen tree in the shallows, we began our time together by creeping quietly down to the lake. Our stealth was rewarded by finding several specimens of differing size bathing in the afternoon sun. After sharing some extremely corny “turtle jokes” (Why did the turtle cross the road? To get to the Shell station. What do you get when you cross a turtle with a porcupine? A slow poke.) we entered the Nature Center where several species of turtles are kept in huge tanks. After Jeremy Stout, manager of the Nature Center, fed the huge snapping turtle so we could watch it sneak up on its prey and POUNCE, the students each chose which species they’d most like to see “up close and personal” and I asked some questions to start their observations.
— Describe the turtle’s skin (what little you can see outside the shell). (Reptiles have dry, scaly skin (herpetology is the study of scaly things) and amphibians have smooth skin.)
— Compare the upper (carapace) shell with the lower (plastron). How are they shaped differently? (Most turtles have a curved carapace but in some species it’s flat.) Are the shells of different colors? Why might the carapace be darker and the plastron be lighter? (For purposes of camouflage. Predators or prey looking UP from the bottom of the body of water would see a light color like the sky, while those looking DOWN from above would see a darker color like the substrate.)
— Make a quick sketch of the upper and lower shell showing the shape of the plates that compose them. Where are the two grown together? (The carapace is grown fast to the backbone of the animal, and plastron to the breastbone.)
— Describe the turtle’s eyes. Does the turtle have eyelids? (Turtles’ eyes have nictitating membranes (“nictare” = Latin “to blink”) — a transparent or translucent third eyelid that can be drawn across the eye for protection and to moisten it while maintaining visibility. The turtle’s nictitating membrane comes up from below and completely covers the eye.)
— Do turtles have ears? (Turtles have 3 ears — 2 located on the sides of their head (small holes) and one on their nose. Turtles have “inner ear” mechanisms that other animals have. The outer ear gathers vibrations which makes the sound louder. While turtles can’t hear airborne sounds, they do sense and interpret vibrations within their environments. Meanwhile, the organs in a turtle’s ears do help them feel changes in water pressure that can warn them of the presence of predators.)
— Describe the turtle’s mouth. Are there any teeth? How does the turtle bite off its food? (The turtle has no teeth but strong, cutting jaws called a “beak.”) Describe the movement of the turtle’s throat. What is the cause of this constant pulsation? (The turtle is swallowing air for breathing.)
— Describe the shape of the legs. How many claws on the front feet? (5) On the back? (4) Are any of the toes webbed? On which feet are the webbed toes? Why should they be webbed? (To enable the turtle to swim faster.) Describe the way a turtle swims. Which feet do you think the turtle uses as oars? (Those which are webbed.)
I shared with the students that like all reptiles and amphibians, turtles are ectothermic (cold-blooded) animals, relying on their environment for warmth. Unlike some animals which hibernate (one lengthy period of inactivity) in winter, cold-blooded animals brumate (periodic awakening and temporary resumption of activity and feeding). In winter, water turtles may bury themselves in the ooze at the bottom of ponds and streams. Land turtles dig themselves into the earth for several short winter naps.
THE TURTLE SHELL
The shell is composed of hard, bone plates covered by scutes. The scutes are made of keratin, the primary substance in hair, nails and hooves. Pigments may form intricate designs and bright patterns in some species. Although the scutes form the familiar outer layer of the shell, it is the bony layer underneath which actually provides the shape, support and protective qualities of the turtle shell.
The vertebrae of the neck and tail are small, allowing for a high degree of flexibility, while the vertebrae of the central portion of the vertebral column are enormously elongated and inflexible, fused with the bony layer of the shell, acting as a support for the carapace. If the outer keratin is breached by infection or injury, the turtle can lose its protection and infection can proceed into the bony layer and the body cavity, threatening the turtle’s life.
RIDDLE: Alive without breath, as cold as death, clad in mail never clinking, never thirsty, ever drinking. (A FISH)
Bilbo Baggins didn’t stump Gollum with that riddle deep under the Misty Mountains, and I couldn’t stump my students with it either! To focus on fish, our nature study class met beside Little Limestone Creek at Mill Spring Park in beautiful, historic Jonesborough, Tennessee. It was a warm, overcast day, but the thunderstorms held off and at least the moms were able to stay relatively dry. The kids were another story — as you will see! We started off by collecting specimens from the creek in large, clear containers: Minnows, aquatic insects and even a crayfish. We brought them to the gazebo, spread out the quilts, got out our hand lenses, and sat down for a good, close look.
The fish usually has 7 fins, which play a different role in the fish’s movements:
Dorsal Fin – like a fan, protects the fish against rolling and assists in sudden turns and stops
Tail (Caudal) Fin — propels the body through the water like a scull
Anal Fin – used to keep the fish stable in the water
Ventral (Pelvic) Fins (2) – The pelvic fins assist the fish in going up or down through the water, turning sharply, and stopping quickly
Pectoral Fins (2) – help fish rise or sink in the water
Sight — The eyes of fish have no eyelid. Fish are nearsighted because the lens is spherical which enables the fish to see underwater.
Smell — The fish’s sense of smell is located in a little sac to which the nostril leads, but the nostrils have no connection whatever with breathing.
Taste — The tongue of the fish is very bony or gristly and immovable, and they have very little sense of taste. A fish’s teeth can be located on the jaws, inside the mouth, on the tongue and even in the throat! Fish without teeth expand their jaws and create a huge vacuum so they can literally inhale their food 😉 Check this out!
Hearing — Fish have poor hearing. They have only an inner ear and it has no exterior outlet. Instead, it is found inside the fish’s head behind the eye. Since fish have approximately the same density as water, sound passes right through their bodies. That doesn’t mean they don’t respond to auditory stimuli, though. Recent research indicates that fish may exhibit the Lombard Effect when exposed to loud or unfamiliar sounds. (The Lombard Effect is the involuntary tendency of speakers to increase their vocal effort when speaking in loud noise to enhance the audibility of their voices.) You read that right: Fish communicate out loud. Here’s a short video of minnows “growling” and “knocking”:
Touch – A fish’s “lateral line” consists of different scales that extend along the sides of the body containing small tubes connecting with nerves; it is used to detect motion and vibration in the water – like touch at a distance. This lateral line is especially important when fish need to gather and/or travel in “schools” because it allows each fish to sense the motions of its neighbors.
The shape, number and position of a fish’s teeth vary according to the food habits of the fish. Some have blunt teeth suitable for crushing shells; others have sharp teeth with serrated edges for harvesting vegetables, while some have incisor-like teeth who feed on crabs and snails. In some species there are several types of teeth, while others (goldfish and minnows) have no teeth at all. Fish teeth can be on the jaws but also in the roof of the mouth, on the tongue and in the throat.
The covering of fishes varies: Some have scales, others have a smooth skin. All fish are covered with a slimy substance which somewhat reduces friction as they swim through the water.
In order to understand how a fish breathes, we must examine its gills. They are filled with tiny blood vessels, and as the water passes over them, the impurities of the blood pass out through the thin skin of the gills and the life-giving oxygen passes in. A fish constantly opens and closes its mouth to draw water into the throat and force it out over the gills – the act of breathing. Fish can’t make use of the air unless it contains enough oxygen, so it’s important that the water they’re in have enough surface area (definitely NOT like Dr. Seuss’s McElligot’s Pool!)
I’ve been so pleased with the progress of our students in just a few short weeks! They’re paying closer attention and noticing so much more. Maybe these nature observation prompts we’ve been using (from John Muir Laws http://www.johnmuirlaws.com/natural-history/deep-observation) have helped played a role. For each journal entry they are asked to complete these thoughts:
I notice ______________. (Example: …this flower has five petals, red anthers and serrated leaves.) Requires close attention.
I wonder _____________. (Example: …how it disperses its seeds?) You can help them follow up with this.
It reminds me of ________. (Example: …the wild strawberries we saw growing by our boat dock.) This will eventually lead to classifying specimens by leaf shape, color, and other physical characteristics. It can also help us make connections to previous learning — a poem, story, work of art.
My 12yo son’s journal entry this week included a sketch and these observations:
I notice that this tree has shallow roots and the roots are in the creek.
I wonder why the bark is in vertical patterns? Maybe so rain water will run down to the roots?
It reminds me of elves. ( He’s a huge Lord of the Rings fan!)
It’s so important to take a moment to make a short sketch or note a small detail while you’re in the field. If you goal is a lovely nature journal page you can always flesh things out in living color later. But that tinge of blue on the tip of a wing or the dew drops collecting on an upturned leaf — those lovely bits may be forgotten if you don’t note them as you see/hear/smell them.
I’ll leave you with image of a single Cardinal Flower (Lobelia cardinalis) we found growing by the creek and a blue darner damselfly — so very lovely! (All photos in this post were taken by the lovely and talented Beth Waugh.)
Crayfish and salamanders and Hickory Horned Devils — OH MY! What a time we had today at our weekly Nature Study class! We visited a mountain stream at the foot of Bays Mountain in Kingsport, Tennessee to learn about crayfish. But we learned about so. much. more.
The greatest diversity of crayfish species is found in southeastern North America, especially Appalachia (that’s us), with over 330 species.
Crayfish are detritivores (they eat detritus = decomposing plant and animal parts) but they also eat living plants and animals such as worms and insects. Raccoons, snakes, opossums and muskrats are the crayfish’s most dangerous predators.
The crayfish breathe through feather-like gills and tend to inhabit water bodies that don’t freeze all the way through to the bottom. Some species are found in brooks and streams where there is fresh water running, while others thrive in ponds, swamps and ditches. Most crayfish cannot tolerate polluted water, so if they are present the water is probably pretty clean.
Crayfish burrow during the late summer, and spend most of the fall and winter underground in water-filled tunnels. Everywhere you see a crawfish chimney, there is a crawfish living in a burrow underneath. Their tunnels may extend down into the earth 3 feet or more and are full of water. Sometimes the color and texture of the chimney mud is different at different levels of the chimney. Why might this be? This is a sign that there are different types of soil layers below the surface, and the crayfish has burrowed through several layers.
As the crawfish burrows down, it brings up soil from different layers and deposits the pellets of mud at the top of the chimney. https://www.youtube.com/watch?v=DSIY5oUaUr4
During droughts, crayfish routinely plug the openings of their burrows with mud. As the water table drops, or when the temperature drops, the animal moves further down to warmer water levels. Over time, oxygen may be depleted in the burrow water. When this happens, the crayfish may position itself just above the water, thus keeping the gills wet and absorbing oxygen from the air in the burrow.
Crayfish also lay eggs in their burrows. After they mate in open water, (the male depositing sperm into a special sac on the female’s abdomen) the female (and sometimes the male as well) will dig a burrow where the female will lay the eggs, fertilize them with the stored sperm, and hold them attached to little appendages under the tail called swimmerets.
Once the eggs are laid, the male typically stays near the entrance and the female remains deeper in the burrow. As long as oxygen levels in the burrow water are high, the female keeps the eggs under water and swishes them back and forth to ensure aeration (air circulation). As the oxygen drops, the female keeps the eggs moist, but gets them out of the water, thus allowing them to absorb oxygen from the air. https://www.youtube.com/watch?v=XHCWiISnu_4
The eggs usually hatch in the burrows and begin to grow. Since there is a restricted amount of food available in the burrow, the babies eat infertile eggs and the bodies of dead babies. They will even kill each other to survive.
After the hatching, with her brood still attached, the female emerges from the burrow to find food. Once she is in open water, the hatchlings detach from their mother and begin living independently.
A young crayfish molts 11 times before becoming an adult. This takes about a year. They will live another year to mate and produce young. In this video, the carapace (shell) completely detaches about 5 minutes in: https://www.youtube.com/watch?v=mF6NgMBcNCM
In 2011 a new species of giant crayfish was discovered in Shoal Creek, a tributary of the Tennessee River. “A new species of giant crayfish [has] literally crawled out from under a rock in Tennessee, proving that large new species of animals can be found in highly populated and well-explored places,” Reuters reported. Aquatic biologists had been studying life in that little waterway for decades, but it appears these crayfish are not common (only 5 have ever been caught) and their preference for living under large rocks in deep water may have made them easy to overlook, especially in times of high water. After DNA testing and studying a ridge and unique spine between the crayfish’s eyes, the biologists knew they were looking at something entirely new, and named it Barbicambarus simmonsi (after TVA scientist Jeffrey Simmons — the guy who first spotted this giant).
Here’s a video about the discovery which gives some interesting insight into how these creatures are measured and catalogued. https://www.youtube.com/watch?v=e05nqc1ygYg
We spread out along the length of the creek. We haven’t had much rain lately so the water was low. Within 15 minutes the class had collected about 30 samples of crayfish at all different stages of development and a couple of baby salamanders.
Then a shout went up: Look what was found crawling along on the creek bank!
It’s a Hickory Horned Devil Caterpillar that will dig a hole in the ground and after pupating through two winters will emerge as a beautiful, huge Royal Walnut Moth!
And if that’s not enough, look who else came to call:
Did you know there are JELLYFISH in Bays Mountain Lake? Today our Nature Study class visited Bays Mountain in Kingsport, Tennessee, to learn about freshwater jellyfish. We even convinced a good-natured naturalist to take us on a barge ride around the lake to investigate! How in the world did they get there, you ask? Read on…..
Although we call them freshwater jellyfish, some argue that the Craspedacusta sowerbii is more closely related to the Hydra family than a “true” jellyfish, so many naturalists and scientists just call them Freshwater Jellies. The main difference between jellies and “true” jellyfish is the presence of a velum — a think circular membrane around the cap that helps propel the jelly forward. Freshwater jellies are transparent, gelatinous, umbrella-shaped creatures with a whorl of stringy tentacles around the edge of their bodies. Microscopic barbs called nematocysts run along the tentacles to help capture food and protect the jelly from predators. Luckily for us, jellies are quite small — adults are the size of a quarter — and their stings can’t even penetrate our skin.
Jellies have no head or skeleton, and contain no special organs for respiration or excretion. Their bodies are 99% water. Their large, flat reproductive organs are the only parts of the freshwater jelly that are not translucent, and this makes them easy to spot on sunny days when they tend to surface in large groups called “blooms.” They eat tiny microscopic animals called zooplankton that are found floating in the water. When they come into contact with prey, stinging cells in the jelly’s tentacles paralyze the organisms and then sway about moving the captured prey its mouth which is in the middle of the underside. The bell (body or umbrella part) of the jelly goes through several contractions to move the prey into the mouth and digestive cavity. The primary predators of freshwater jellies are crayfish and turtles.
Freshwater jellies have a multi-stage life cycle that includes two forms — the polyp and the medusa. The medusa form is more familiar, and it is during this adult stage that jellies reproduce sexually and fertilized eggs that develop into larvae detach from the medusa and drift away. This larvae form, now called polyps, will also reproduce — but it will do so asexually by dividing from one another. This is called “budding,” and the buds will then develop into adult medusa and the cycle repeats. During the winter the polyps contract and become “resting bodies” that are capable of surviving the cold temperatures. They are circular and fairly flat with no hooks or burrs, but there does seem to be some adhesive property which allows them to become attached to surfaces. Some scientists believe that the resting bodies are one way in which the jellyfish are transported — on aquatic plants, by aquatic animals, or on the feet of birds. When conditions become favorable and temperatures rise, the resting bodies develop into polyps and the life cycle continues.
Freshwater jellyfish can be found all over the world, but are not native to the United States. There are two schools of thought on their origins. Some believe they originated in the upper Yangtze River basin in China, and were first observed in the western world in water lily ponds in London’s Regents Park in the late 1800’s — having presumably arrived as polyps on the plants imported from China. Others say they originated in South America and made their way to the US in the bilge water of ships. However they got here, jellies spread rapidly and are now found all over the US in every state except North and South Dakota, Montana, Wyoming, Alaska and Hawaii. Why might this be? (Too cold in most of these places, and Hawaii just doesn’t have enough fresh water)
I asked the class how jellies might have gotten into Bays Mountain Lake. They can enter a body of water in many ways — in the water of bait buckets, through flooding from another site, on boat propellers. But we decided the most probable answer may be that they were carried in on the feet of migrating birds during the “resting body” stage of development.
The appearance of jellies is sporadic and unpredictable. Often they will appear in a body of water in large numbers even though they were never reported there before. The following year they may be absent and may not reappear for several years. It’s also possible for jellies to appear once and never appear in that body of water again. In some lakes they appear almost every single year. Why this difference? What triggers the appearance of medusa in certain places and at certain times? Temperature seems to play some role in triggering the medusa stage, which is why there is a freshwater jellyfish season, typically from August to September when water temperatures are highest.
Searching for jellyfish can be a fruitless venture, but the best time of year is NOW, and they are most likely to be found in calm bodies of water, which they prefer to rocky, fast-flowing rivers and streams. After walking across the dam and peering into the deepest part of the lake (which is what jellies usually prefer) we were unable to locate a single specimen. So Ranger Bob (sans the ponytail and facial hair he has sported for years) graciously treated us to a long ride on the barge so we could explore further. While we didn’t encounter any jellies (none of the naturalists we spoke with have seen them this year), we did see beaver dams, water lilies and lots of dragonflies. Definitely time well spent!