Chapter 26: Some Major Ecosystems

Weather: Short term fluctuations in temperature, humidity, cloud cover, wind, and precipitation over periods of hours or days.

Climate: Overall pattern of weather in a year or longer in a particular region.

Systems in water. Types: Freshwater (Rivers, Lakes) and Marine (Oceans). Fresh water covers 1% of earth surface.

Properties

• Temperature: Water changes temperature slower than air. Moderate environment.
• Absorption of Energy: Decreases with depth. Determines Photic (light) and Aphotic (no light) zones.
• Nutrients: Concentrated near bottom (sediments).
• Productivity: Depends on light and nutrients.

Lake Ecosystem Zones

• Littoral Zone: Shallow, near shore. Rooted plants (water lilies), Phytoplankton (Cyanobacteria), Zooplankton (Protozoa, Crustaceans).
• Limnetic Zone: Open water, light penetrates. Phytoplankton (Cyanobacteria, Volvox), Zooplankton, Fishes.
• Profundal Zone: Deep, no light. Decomposers (Bacteria, Fungi), Detritus feeders. No producers.

Human Impact: Eutrophication

Enrichment of water bodies with nutrients (Phosphates/Nitrates from sewage/fertilizers) causing algal blooms. Depletes oxygen (decomposition of dead algae), killing fish.

Ecosystem on land. Factors: Light, Nutrients (Soil), Water (Limited), Temperature (Variable), Air (Constant O2/CO2).

Adaptations

• Water Conservation: Waxy cuticle, storing water (Cactus), concentrated urine (Camel/Kangaroo rat).
• Temperature Regulation: Bark in plants, skin/fur in animals.
• Support: Vascular bundles in plants, Skeleton in animals.

Temperate Deciduous Forest

Location: Neelam Valley, Shogran (Pakistan). Trees shed leaves in autumn.

• Climate: Moderate temp (4-30°C), Rainfall 750-1500mm. Warm summers, cold winters.
• Plants: Taxus baccata, Pinus, Herbs, Ferns, Mosses.
• Animals: Rhesus monkey, Black bear, Leopard cat.
• Soil: Brown, fertile, rich in organic matter.

Coniferous Alpine & Boreal Forests (Taiga)

Location: Upper Kaghan, Dir, Chilas, Swat (Pakistan). Northern Hemisphere (Eurasia, N. America).

• Climate: Harsh, cold winters, short growing season. Temp below freezing.
• Plants: Conifers (Pinus wallichiana, Abies pindrow) with needle-like leaves (waxy cuticle) to reduce water loss.
• Animals: Snowshoe hare, Marco Polo sheep, Crossbills.

Types: Prairies (Temperate, no trees), Savanna (Tropical, with trees).

Location: Gilgit, Waziristan, Chitral (Pakistan).

• Rainfall: 250-750mm. High evaporation.
• Plants: Grasses (Tall, Mid, Short), Legumes, Composites. Layering present.
• Animals: Grazers (Zebras, Bison), Insects (Grasshoppers), Reptiles, Predators (Foxes, Wolves).
• Impact: Overgrazing leads to desertification.

Location: Thal (Western Punjab), Thar (Sindh). Rain shadow areas.

• Rainfall: Very low (< 25-50cm).
• Plants (Xerophytes): Cactus (Succulents), Perennials (shed leaves). Small leaves, few stomata, deep roots.
• Animals: Reptiles (Horned lizard), Kangaroo rat (doesn't drink water), Camels. Nocturnal behavior to avoid heat.

Arctic Tundra (Last biome before polar ice caps). Treeless.

Location: Kara Koram, Hindukush (Pakistan).

• Plants: Dwarf willows, Lichens, Mosses, Grasses. Short growing season.
• Animals: Mosquitoes (in standing water), Caribou, Reindeer, Musk oxen, Arctic fox, Snowy owl.
• Human Impact: Fragile ecosystem, long recovery time (centuries).