Section 1
Invertebrates Thrive Without Backbones
Nearly one million invertebrate species inhabit Earth in diverse environments. These animals lack backbones and bone tissue, yet adapt successfully to water, land, and even inside other organisms.
Grade 7 Life Science students explore the concept of invertebrates in Chapter 12, learning that invertebrates are animals without backbones and examining the six major groups: sponges, cnidarians, worms, mollusks, echinoderms, and arthropods. The lesson covers the diversity and habitats of invertebrate species, from Arctic tundra to tropical oceans, and takes a closer look at sponges as sessile, multicellular organisms that filter-feed on plankton. Students also investigate what defines an animal and how scientists classify organisms like sponges that lack familiar animal features.
Section 1
Invertebrates Thrive Without Backbones
Nearly one million invertebrate species inhabit Earth in diverse environments. These animals lack backbones and bone tissue, yet adapt successfully to water, land, and even inside other organisms.
Section 2
Sponges Filter Food Through Specialized Cells
Sessile sponges remain fixed in one spot, using specialized cells to move water through their bodies. Pore cells create openings, flagella cells circulate water, and other cells capture food particles.
Section 3
Six Groups Form the Invertebrate Kingdom
The invertebrate kingdom includes sponges, cnidarians, worms, mollusks, echinoderms, and arthropods. Each group has unique body structures, from the simple sponge to complex arthropods with legs and wings.
Section 4
Sponges Reproduce Through Multiple Methods
Sponges create new individuals asexually through budding or sexually through egg fertilization. After fertilization, swimming larvae develop and move away before attaching to surfaces and becoming sessile adults.
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Section 1
Invertebrates Thrive Without Backbones
Nearly one million invertebrate species inhabit Earth in diverse environments. These animals lack backbones and bone tissue, yet adapt successfully to water, land, and even inside other organisms.
Section 2
Sponges Filter Food Through Specialized Cells
Sessile sponges remain fixed in one spot, using specialized cells to move water through their bodies. Pore cells create openings, flagella cells circulate water, and other cells capture food particles.
Section 3
Six Groups Form the Invertebrate Kingdom
The invertebrate kingdom includes sponges, cnidarians, worms, mollusks, echinoderms, and arthropods. Each group has unique body structures, from the simple sponge to complex arthropods with legs and wings.
Section 4
Sponges Reproduce Through Multiple Methods
Sponges create new individuals asexually through budding or sexually through egg fertilization. After fertilization, swimming larvae develop and move away before attaching to surfaces and becoming sessile adults.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter