Tentacles: a flexible body part that is used for feeding, grasping, or moving Make copies of the Coral Polyp handout and the Analogy Map worksheet (1 per student).
Introduce the activity's essential question by writing this on the board: “Is coral a plant, animal, or something else?” Give students some time (~1 minute) to brainstorm a short list of some key differences between plants and animals.
Ask students to share some big differences between plants and animals. Create a table on the board to keep track of the key differences between plants and animals.
Explain that they are going to make a simple representation of coral polyp using everyday materials. The TEACHER GUIDE shows what to draw on the board while students build their polyp.
You can reassure students that they will get a chance to consume their coral polyps at the end of the lesson. Begin the lesson by reminding students of the ideas that they discussed in Part 1.
Once students have finished assembling their coral colonies, draw their attention back to the guiding question. Give students time (~5 min) to think-pair-share on the question, based on what they learned from building their polyp.
Tell students they can pretend to be predatory fish, such as parrot fish, that eat coral polyps. GNSS SCIENCE AND ENGINEERING PRACTICES CONNECTION: This portion of the lesson connects to the Practice of Constructing Explanations because students are asked to explain why they think coral is a plant, animal, or something else.
Students' explanations should come from the observations they made while building the representation of a coral polyp, and from the plant vs. animal brainstorm in Part 1. Have students share their ideas about what the representation accurately shows (the basic parts of a coral polyp's anatomy) and what it doesn't show accurately (cellular structures, how corals move to catch food).
Tell students that they will be making observations of coral in the real world to help deepen their ideas. Teacher Tip: You can pause the video at 7:16, 7:18, and 8:43 to see some really great, close up views of polyps.
In small groups, have students discuss the ideas that are generated by this question. Tell students they will organize their reflections about their coral polyps using a tool called an Analogy Map.
Explain the parts of the Analogy Map, and give one copy of the worksheet to each student. The name “Cnidaria” comes from the Greek word “UNIDO” which means stinging nettle.
The tentacles have specialized stinging structures called nematocysts that are used for protection and to capture prey. Hard corals are classified within the subclass Hexacorallia because their tentacles are arranged around the mouth in multiples of six (hex = six).
They are called hard corals because they extract calcium and carbon from the ocean water and deposit a hard calcium carbonate skeleton that surrounds the lower portion of the body. Coral polyps fuse their skeletons together and form large coral colonies.
When hard coral polyps die, the calcium carbonate skeleton remains intact. Soft corals are classified within the subclass Octocorallia because their tentacles are arranged around the mouth in multiples of eight (onto = eight).
Soft corals do not produce a hard external calcium carbonate skeleton and therefore do not contribute significantly to the building of reefs. Zooxanthellae that live inside corals have a mutually beneficial symbiotic relationship with their host.
Because zooxanthellae need sunlight to perform photosynthesis, they are the reason why corals need sunshine to survive. K-2: Make observations (firsthand or from media) to construct an evidence-based account for natural phenomena.
3-5: Use evidence (e.g., measurements, observations, patterns) to construct or support an explanation. Different animals use their body parts in different ways to see, hear, grasp objects, protect themselves, move from place to place, and seek, find, and take in food, water and air.
Plants also have different parts (roots, stems, leaves, flowers, fruits) that help them survive and grow. Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior, and reproduction.
Each polyp has a saclike body and a mouth that is encircled by stinging tentacles. The polyp uses calcium carbonate (limestone) from seawater to build a hard, cup-shaped skeleton.
Corals are sessile animals that “take root” on the ocean floor. When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white.
Corals are sessile, which means that they permanently attach themselves to the ocean floor, essentially “taking root” like most plants do. Corals actually comprise an ancient and unique partnership, called symbiosis, that benefits both animal and plant life in the ocean.
Corals have tiny, tentacle-like arms that they used to capture their food from the water and sweep into their inscrutable mouths. Because of this cycle of growth, death, and regeneration among individual polyps, many coral colonies can live for a very long time.
More than merely a clever collaboration that has endured between some of the tiniest ocean animals and plants for some 25 million years, this mutual exchange is the reason why coral reefs are the largest structures of biological origin on Earth, and rival old-growth forests in the longevity of their ecological communities. Corals are marine invertebrates with bright and vivid colors, and coral polyps have clear bodies.
Their wide variety of colors come from zooxanthellae, tiny algae, living inside the tissues of polyps. Named as”China's Hawaii”, the entire Hainan Island is also on the way to be a free trade port.
Y:Corals are members of the Animal Kingdom. As larvae, called plane, they're free-swimming. An individual mature coral animal is called a polyp. This sea anemone-like creature is structured like a tiny hollow sack. Around its mouth are stinging tentacles that enable it to capture food. A Paula may also attach to a rock and possibly begin a reef of its own. After settling and becoming a polyp, it will asexually reproduce to form a series of interconnected polyps, making a colony. Once a colony is big enough, it will have energy to reproduce sexually, forming free-swimming plane that may settle away from the group.
Y:Yes. Not only does this communal skeleton protect polyps from potential predators, like fish, but it enables them to share food too. Polyps can eat tiny animals, but they largely subsist on nutrients produced by algae that live sandwiched between coral tissue layers. Inside the communal skeleton is a gastrovascular network by which the colony shares these nutrients.
A reef of corals, in effect, share a communal skeleton, as well as other things like food. A Paula builds its skeleton by secreting calcium carbonate from its base.
Once a colony is big enough, it will have energy to reproduce sexually, forming free-swimming plane that may settle away from the group. Not only does this communal skeleton protect polyps from potential predators, like fish, it also enables them to share food.
Polyps can eat tiny animals, but they mostly subsist on nutrients produced by algae that live sandwiched between coral tissue layers. Inside the communal skeleton is a gastrovascular network by which the colony shares these nutrients.