Habitats and environments: Macro
Certain habitats of the world have specific major environmental features which are worthy of study so that we can analyse the adaptations of the organisms living there. Deserts Desert plants have adaptations including extensive root systems, shiny waxy leaf cover, fewer stomata to reduce transpiration (see Plant systems A: Transport and support), thin spiky leaves to reduce surface area for water loss and drought resistant seeds.
Freshwater pond The majority of photosynthesis is due to microscopic producers (phytoplankton) in the water. Other plants are usually present in distinct zones. The emergent plants of the water's edge give way to free-floating and deep-rooted plants as well as submerged plants which use the sunlight filtering down to the bottom. Food chains include microscopic consumers (zooplankton), small crustaceans, insects (nymphs, larvae as well as adults), small molluscs (snails and mussels), fish and birds. In the muddy bottom, worms, fungi and bacteria are found, which decompose the remains of plants and animals. Marine habitats The ocean food chains are based on microscopic plants and animals (plankton) that drift in the surface waters. Light intensity and temperature decrease with depth but bottom-dwelling consumers can still survive on other animals or decomposing matter. Water provides buoyancy (uplift) supporting the body weight of even the world's largest organisms such as whales, which on land would collapse under their own weight. Due to the great size of the ocean, water temperature fluctuates very little except on the shore line and in rock pools. Intertidal rockpools are exposed to the force of breaking waves as well as daily variations in water availability, temperature and salt concentrations caused by the movement of the tides. Many animals have adaptations such as a hard shell and tight muscular foot allowing them to cling tightly to the rocks preventing dislodgment and drying out. Plants are also often firmly attached to rocks. Some have a structure called a "holdfast".
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