Invertebrates

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Activity 3
Activity 4
Activity 5
Activity 6
Activity 7
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When most people think of animals, the images that come to mind are birds soaring overhead, dolphins gliding through the ocean, or lions prowling the savanna. Yet these vertebrates represent only a small fraction of the animal kingdom. In reality, nearly 97% of all known animal species are invertebrates — animals without a backbone. These creatures are everywhere: crawling in the soil beneath our feet, swimming in the deepest oceans, buzzing through the air, and sometimes even living inside us. Despite their small size and quiet presence, invertebrates are essential to the balance of our ecosystems, contributing to nutrient cycling, pollination, decomposition, and marine food webs.

Let’s explore the seven major groups of invertebrates.

Activity 1 – Insects

Insects are by far the most diverse and numerous animals on the planet, with over one million species formally described and many millions more believed to be undiscovered. All insects share a basic body plan: three main parts (head, thorax, and abdomen), six legs, and often one or two pairs of wings. They are found in nearly every habitat on Earth, from the lush canopies of the Amazon rainforest to the icy fringes of Antarctica. Some, like the monarch butterfly, undertake annual migrations spanning thousands of miles across North America, while dung beetles in Africa play a crucial role in cycling nutrients in grassland ecosystems. Insects are responsible for pollinating most of the world’s food crops, breaking down organic matter, and serving as a crucial food source for other animals. It’s estimated that insects account for more than 80 percent of all animal species on Earth.

If insects suddenly disappeared, what would happen? Draw six different insects; label them, and upload them to the gallery!

Activity 2 – Arachnids

Arachnids are a class of eight-legged arthropods that include spiders, scorpions, ticks, and mites. Unlike insects, arachnids have two body segments and lack wings and antennae. They are mostly predators, using venom, stealth, or webs to capture prey. Spiders produce silk that is stronger than steel by weight, while scorpions possess a glow-in-the-dark exoskeleton that can be seen under ultraviolet light. Ticks, although tiny, can cause significant health issues by transmitting diseases such as Lyme disease, particularly in the northeastern United States. Scientists record 120,000 plus known species of arachnids. They are found in deserts, forests, grasslands, and even our basements.

Would you rather be bitten by a mosquito or a spider? Why? Think about function, not fear. Draw three different spiders and label them.

Activity 3 – Mollusks

Mollusks are soft-bodied invertebrates, many of which are protected by hard shells. This group includes snails, slugs, clams, squids, and octopuses. Found in marine, freshwater, and terrestrial environments, mollusks play a range of roles from filter feeders to active hunters. One of the most fascinating members of this group is the octopus, an animal with a complex nervous system, problem-solving skills, and the ability to use tools. Octopuses have been observed opening jars, escaping through tight openings, and even decorating their shelters with found objects. The giant squid, lurking in the depths of the Atlantic Ocean, can grow up to 40 feet long and has eyes the size of basketballs. Cone snails, on the other hand, deliver venom that can be fatal to humans. These venoms are being studied for their potential in developing new medications. Over 85,000 mollusk species have been described, with many more awaiting discovery.

If you had power, would you choose speed like a squid or armor like a clam? Why? Draw four different mollusks and uoplaod them to the gallery.

Activity 4 – Crustaceans

Crustaceans are aquatic arthropods with hard exoskeletons and jointed legs. This group includes crabs, lobsters, shrimp, and barnacles, many economically significant to coastal communities. Crustaceans vary dramatically in size and function in rivers, lakes, and oceans. The Japanese spider crab, for example, has a leg span of over 12 feet and lives in the deep sea. Native to Indo-Pacific coral reefs, mantis shrimp deliver powerful punches. They also have a highly complex vision that can see polarized light and ultraviolet colors. Crustaceans are also crucial to fisheries and aquaculture industries in Maine, Nova Scotia, and Norway, contributing billions of dollars annually. If crustaceans vanished, how would coastal economies and your seafood menu change?

Research a picture of a Coral reef and draw it in color; upload it to the gallery!

Activity 5 – Worms

Worms may not be visually striking, but their ecological roles are indispensable. Earthworms, flatworms, roundworms, and leeches all fall under this category. Earthworms are crucial to the health of our soil. Worms decompose organic matter, recycle nutrients, and aerate the soil. A single acre of productive farmland can contain over one million earthworms. In regions such as Iowa in the United States and Punjab in India, healthy worm populations are essential to agriculture. On the other hand, parasitic worms can inhabit human and animal hosts, often causing disease in areas with poor sanitation and limited healthcare. Despite their simple appearance, worms influence agriculture, health, and ecosystems globally.

Draw a short scene imagining a world without earthworms, what happens to the soil, the plants, and the food we eat?Then draw a soil section with active worms. Upload the two drawings to the Gallery!

Activity 6 – Cnidarians

Cnidarians are a group of simple aquatic animals that include jellyfish, sea anemones, and corals. They possess stinging cells called cnidocytes, which they use to capture prey and defend themselves. Despite their simplicity, cnidarians can form complex and beautiful ecosystems. Coral reefs, built by colonies of tiny coral polyps, support approximately 25 percent of all marine life yet cover only 1 percent of the ocean floor. Coral reefs form over thousands of years accumulating limestone skeletons. Tropical coral reefs, shallow water ecosystems, support diverse marine biodiversity. Often called the “rainforests of the sea”, their incredible richness of life, includes colorful fish, sea turtles, crustaceans, and countless invertebrates. The Great Barrier Reef of Australia is the largest living environment in the world covering. The Great Barrier Reef is a site of remarkable variety and beauty on the north-east coast of Australia. It contains the world’s largest collection of coral reefs, more than 250, with 400 types of coral, 1,500 species of fish, 4,000 types of mollusk, and 240 species of birds. The Great Barrier Reef also supports a great diversity of sponges, anemones, marine worms, crustaceans, and other species. It holds great scientific interest as the habitat of species such as the dugong (‘sea cow’) and the large green turtle, which are threatened with extinction. Jellyfish, like the deadly box jellyfish, are found in oceans near Australia and Southeast Asia and can deliver venomous stings that may be fatal to humans. Sea anemones form mutualistic relationships with clownfish, offering shelter in exchange for food and protection.

Draw a healthy coral reef teeming with life. Upload it to the gallery!

Activity 7 – Sponges

Sponges are among the simplest multicellular animals. They lack tissues and organs, but their porous bodies allow them to filter large volumes of water, removing bacteria and organic matter. Found in oceans and some freshwater environments from the Caribbean to the deepest parts of the Pacific Ocean, sponges are stationary filter feeders that support water clarity and marine biodiversity. Some species can filter over 1,000 liters of water per day. In ancient times, natural sponges were used for bathing and cleaning. Today, they are still used in cosmetic and biological research. Scientists are exploring their potential in producing new antibiotics and anti-cancer compounds.

If you could design a water filtration system inspired by sponges, where would you use it in real life?