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From sponges to echinoderms, animal body structure shows a pattern of increasing complexity — new features improve feeding, movement and protection, but often introduce new challenges. This pattern helps explain survival in diverse environments.
6. An earthworm (annelid) and a beetle (arthropod) both have segmented bodies, but the beetle has a hard external skeleton. This exoskeleton protects the body, reduces water loss and supports muscles , helping the beetle survive in dry, exposed environments.
- Protochordates (like Amphioxus ) possess a notochord at least once in life — a primitive step showing how animals with a notochord may have arisen.
- Vertebrates possess a vertebral column (backbone) that supports the body and protects vital organs like the brain and spinal cord.
- This internal framework allows a larger body, efficient movement and complex organ systems.
- Vertebrates are classified into five groups — fish, amphibians, reptiles, birds and mammals .
- They are grouped by broad patterns of habitat use, body covering and reproduction .
- Adaptations like fins and gills (fish), feathers and hollow bones (birds), fat storage (camels) and mammary glands (mammals) suit each group to its environment.
Forests rich in diverse flora and fauna work as barriers that reduce disasters. Mangroves lessened destruction during the 1999 Odisha super cyclone; rich forest diversity in the Western Ghats acts as a biological barrier against Kyasanur Forest Disease (Monkey Fever); and diverse soil microorganisms and mangrove soils trap pollutants and heavy metals, protecting water and ecosystems.
- Monera — the kingdom of single-celled prokaryotes such as bacteria and cyanobacteria.
- Protista — the kingdom of single-celled eukaryotes such as Amoeba and Paramecium.
- Fungi — the kingdom of heterotrophic eukaryotes with chitin cell walls that absorb nutrients.
- Mycelium — the network of fine fungal filaments that absorb nutrients.
- Saprophyte — an organism that feeds on dead and decaying organic matter.
- Notochord — a flexible rod-shaped structure; its presence separates chordates from invertebrates.
- Invertebrate — an animal that lacks a notochord and a backbone.
- Vertebrate — an animal with a vertebral column (backbone).
- Exoskeleton — a hard external covering, as in arthropods.
