Climate Zones Explained

Climate Zones

• Climate zones are areas with similar climates that form broad east-west stripes around the Earth, separated by lines of latitude.
• Climate differences are determined by latitude, continentality, atmospheric circulation (winds), precipitation patterns, and altitude.
• The uneven distribution of sunlight affects temperature and precipitation based on latitude.

Classification of Climates

• Wladimir Köppen's climate classification system divides climates into five main types based on seasonal precipitation and temperature patterns established in 1884.
• The main climate zones are tropical, dry, temperate, continental, and polar/alpine.
• Transitional climate zones include sub-equatorial, subtropical, and subpolar regions.
• Diverse climate types can exist within a zone; a subtropical desert, for example, can be located in both the tropics and subtropics.
• Some regions contain specific climates like continental, maritime, and monsoon climates.

Climate Zones and Biomes

• A biome is a bio-community characterized by organism adaptations to the specific physical environment.
• Biomes are large geographical regions having particular climates which sustain specific living communities.
• Each biome features distinctive plants and animals (ecosystems) best adapted to the physical environment in that location.
• The five major biomes are aquatic, desert, forest (tropical rainforest, temperate, coniferous/taiga), grassland (tropical/savannah, temperate, Mediterranean), and tundra (polar).
• Terrestrial biomes account for less than 30% of the Earth's surface; aquatic biomes compose the remainder.

Ecosystems

• Large biomes contain variations of different ecosystems like taiga forest, temperate forest and tropical forest ecosystems within the forest biome.
• An ecosystem involves interactions between plants and animals within their natural environment.
• Each element in the ecosystem is interdependent, connected by complex relationships between living (biotic) and non-living (abiotic) components such as climate, soil, water, and light.
• Plants (producers) use sunlight, water, and soil nutrients to produce food through photosynthesis.
• Animals, or consumers, feed on plants (herbivores) or other animals (carnivores).
• Fungi and bacteria (decomposers or saprophytes) break down dead material, recycle nutrients for plant use, so without plants, all other living things cannot survive.
• Energy transfers from the Sun to producers, then herbivores, and finally carnivores/omnivores.
• A habitat is the natural environment where a plant or animal lives and grows.

Deserts

• Deserts do not necessarily mean "no rainfall" and can have rainfall variations with some parts of the year being very wet.

Climographs

• Note the length of winters/summers or months below 0°C to effectively match climographs to biomes.
• Reasoning can be explained by stating how parts of the climograph align with the biome description.
• Biome distribution is linked to climate in terms of precipitation and temperature.

Tropical Biomes

• Tropical biomes exist in the tropical zone belt between X°N and X°S with distinct precipitation and temperature characteristics.
• Tropical biomes thrive in wet and hot conditions and exist in the tropical zone belt.

Adaptations in the Physical Environment

• Adaptations are physical or behavioral characteristics that help an organism survive better in its environment or habitat.
• Desert plants have special adaptations to survive hot, arid conditions with minimal rainfall and sandy/stony soil.
• Desert plants adapt by having a short life cycle to avoid drought; seeds germinate in autumn, grow in winter, flower in spring, and die in summer (annuals); slow growth, using less food and water during photosynthesis including special methods (Crassulacean Acid Metabolism); extensive root systems with long taproots to absorb dew and groundwater; toxic, small leaves (spines and thorns) to protect against herbivores; glossy/waxy leaves to minimize water loss; thick stems/leaves to store water (succulents).

Tropical Forests

• Tropical forests ecosystems include rainforests, mangrove forests, and monsoon forests.
• Describing and explaining adaptations involves describing the characteristic and its functions as well as explaining adaptations with reference to the environment.

Tropical Rainforests

• Tropical rainforests are located in the tropical equatorial zone (between 10°N and 10°S of the equator).
• Tropical equatorial climates are hot and wet with high temperatures and rainfall throughout the year.
• High annual temperatures average 27°C with little temperature range (2°C-3°C) and high, evenly distributed precipitation (above 2000mm).
• Rainforests have soils rich in iron and aluminum oxides, but low in natural fertility and mineral nutrients.
• Heavy rain causes topsoil to leach and washes out most nutrients and organic material.
• Although dead organisms have nutrients, they get quickly absorbed by plants/swept away, leaving only a small amount of nutrients stored in the soil.

Layered Structure of Rainforests

• Rainforests have four layers: emergent, canopy, understory, and forest floor.
• Tallest emergent trees reach 40-50m tall, and have mushroom-shaped crowns to absorb most water and grow best.
• Closely spaced trees in canopy layer form a dense umbrella that blocks sunlight and rainfall from lower layers and reach 20-30m.
• The humid, still, and dark understory layer is 5-15 m tall with lianas and epiphytes.
• The forest floor has sparse vegetation with saprophytes living on dead matter.
• Other plants include Lianas which grow in the ground and climb trees for sunlight and Epiphytes that grow on trees with the advantage of height (non-parasitic) and support photosynthesis and reproduction and Creepers and climbers with weak stems that curl around tree trunks to reach higher up for more sunlight.

Biodiversity in Rainforests

• Rainforests cover less than 2% of the Earth's surface but house over 50% of all terrestrial plants and animals.
• Equatorial climates are highly favorable environments in regards to thriving species that include, long growing seasons, high sunlight intensity.
• Interlocked tree canopies support an abundance of habitats for plant and animal life.

Roots in Rainforests

• Shallow and widespread due to constant rainfall where nutrients are found closer to leaf litter in the topsoil.
• Buttress roots are exposed above ground(1-5m) to support and stabilize the heavy weight of tall trees and Aerial roots increase exposure to air and absorb water.

Trunks, Branches and Bark in Rainforests

• Tall, thin trunks indicate tree competition and a need for maximum height/sunlight.
• Branches are at the top one-third of trees for efficient energy and maximum light as lower layers are dark with little light.
• Smooth, thin, flaky bark allows water to flow down to roots easily and is shed constantly to prevent excessive growth of mosses, fungi, and parasitic plants.

Flowers and Fruits in Rainforests

• Colorful flowers and sweet-smelling fruits attract animals for pollination.
• No specific blooming season as there is sufficient water to grow flowers and fruits which ensures higher chances of reproduction.

Leaves in Rainforests

• Rainforests have evergreen forests that sustain photosynthesis all year.
• Smooth, waxy leaves with drip tips allow excess water to runoff easily.
• Thick and leathery leaves reduce water loss and Broad and green leaves provides maximum surface area and Flexible petioles help leaves adjust.

Tropical Monsoon Forests Climate

• Tropical monsoon forests are located in the tropical zone (between 10°N - 25°N and 10°S - 25°S).
• Consistently maintain an average temperature above 18°C.
• Experience a small annual temperature range of 3-4°C; High total annual precipitation of about 1500mm with distinct, uneven wet and dry seasons.

Tropical Monsoon Nutrient Poor Soils

• During the dry season, more nutrients stay in place.

Tropical Monsoon Forest: 3 Layered Structure

• The canopy is shorter in trees (20-30 m tall) that are sparse and open in spacing because of insufficient water supply.
• An understory ranges from 6-15 m in height.
• The Ground has a dense undergrowth as more sunlight may reach the forest floor.

Tropical Monsoon Lower Biodiversity

• Biodiversity is moderate with only (30-40 species/hectare of land).

Leaves of Tropical Monsoon Forests

• Most Tropical monsoon forests are deciduous forests and trees shed their leaves during the dry season (1.5-2 months) to focus on trunk survival. The leaves grow back quickly during the rainy season.
• It is very vital to promote water runoff with its smooth, waxy leaves with drip tips and prevent fungi growth in its plant.

Tropical Mangrove Forest Climates

• Mangrove forests are in a tropical climate zone (between 23.5°N and 23.5°S) that is high in termperature and precipitation.
• Mangroves grow at the interface between land and sea -> inter-coastal areas with salty and brackish water , with muddy, waterlogged and oxygen poor conditions.

Tropical Mangrove Forest Adaptations

• Trees have adaptations to be halophytic (salt-tolerant) with a complex salt filtration system and complex root system to cope with saltwater immersion (for aeration) and wave action for anchorage.

Mangrove Communities:

• Three Communities Include: Bruguiera Inland Zone(best in drier parts of mangrove belts), Rhizophora Middle zone and Avicennia and Sonneratia Coastal Zone (tolerant to most salt).

Important Factors for Distribution of Mangroves

The Important Factors: Climate, salt water, tidal fluctuation and soil type are all relevant.

Mangrove Locations

• Global distribution of mangrove forests cover more than 240,000 sq km of coastal land.
• A main location is the Sundarbans forest: mouth of the Ganges, Brahmaputra, and Meghan Rivers in Bay of Bengal fronting India and Bangladesh
• Smaller patches include mangrove forests and fringe mangroves (e.g. Pulau Tekong, Sungei Buloh, Sungei Mandai) in Singapore.

Mangrove Structure

• There is a Horizontal zonation (not vertical); mangrove forests thrive from the distribution and location in the intertidal zones.

Mangrove Leaves Adaptations

• Broad and green leaves allow for capture of more sunlight and photosynthesis production.
• Thick and leathery leaves withstand heat and reduce evapotranspiration.
• Smooth and waxy leaves Enable excess rainwater as they run and drip off avoiding moist surfaces of mould growth.
• Specialized adaptations due to high salt levels can influence high concentrations of salt as well as salt secretion and accumulation/exclusion.
• Salt Exclusion: The genus Avicennia secretes excess salt, with water evaporating salt crystals.
• Salt accumulation: Unwanted salt can be stored in leaves, fall off, and taken away with them.
• Non-salt secretors (Bruguiera, Rhizophora, Sonneratia) use ultrafiltration at the root level to exclude salt Evergreen leaves indicate it is evergreen with trees all year by photosynthesizing all though a single portion.

Mangrove Root Adaptations

• Aerenchyma: Transports air, provides air and is spony,
• Aerial roots: Supply oxygen, grow, and are above.
• Knee-like (Kneed) roots: Improve help aeration in Bruguiera
• Rhizophora: Improve Oxygen

Sonneratia+ Avicennia

• widespread flat root system with pneumatophores (upwards) and anchor roots (downwards)
• shallow and horizontally widespread

Mangrove Fruits and Flower Adaptaions

• seeds germinate when attached to parent tree, increasing chance of survival Adaptations Sharp ends to anchor firmly after dispersal. Avicennia has buoyant fruits that take root after floating in water Not a conducive environment for seeds to germinate. Seeds are able to germinate because of parent. buoyant/float - increase the chances of survival seedling.