The Living World

• Ecosystem

  A system in which organisms interact with each other and with their environment
• Ecosystem's Components

  • Abiotic (non-living, such as air, water, heat and rock)
  • Biotic (living, such as plants, insects, and animals)
• Flora

  Plant life occurring in a particular region or time
• Fauna

  Animal life of any particular region or time
• Biome

  A large geographical area of distinctive plant and animal groups, which are adapted to that particular environment
• Biomes

  • Coniferous forest
  • Deciduous forest
  • Tropical rainforests
  • Tundra
  • Temperate grasslands
  • Tropical grasslands
  • Hot deserts
• The most productive biomes – which have the greatest biomass- grow in climates that are hot and wet
• Biome's climate and plants

  • Tropical rainforest (Centred along the Equator, Hot all year, Very high rainfall, Tall trees forming a canopy; wide variety of species, Greatest range of different animal species. Most live in canopy layer)
  • Tropical grasslands (Between latitudes 5°- 30° north & south of Equator, Warm all year, Wet + dry season, Grasslands with widely spaced trees, Large hoofed herbivores and carnivores dominate)
  • Hot desert (Found along the tropics of Cancer and Capricorn, Hot by day, Cold by night, Very low rainfall, Lack of plants and few species; adapted to drought, Many animals are small and nocturnal: except for the camel)
  • Temperate forest (Between latitudes 40°-60° north of Equator, Warm summers + mild winters, Variable rainfall, Mainly deciduous trees; a variety of species, Animals adapt to colder and warmer climates. Some migrate)
  • Tundra (Far Latitudes of 65° north and south of Equator, Cold winter + cool summers, Low rainfall, Small plants grow close to the ground and only in summer, Low number of species. Most animals found along coast)
  • Coral Reefs (Found within 30° north – south of Equator in tropical waters, Warm water all year round, Wet + dry seasons, Small range of plant life which includes algae and sea grasses that shelters reef animals, Dominated by polyps and a diverse range of fish species)
• Nutrient cycle


  1. Plants take in nutrients to build into new organic matter

  2. Nutrients are taken up when animals eat plants and then returned to the soil when animals die and the body is broken down by decomposers
• Litter

  The surface layer of vegetation, which over time breaks down to become humus
• Biomass

  The total mass of living organisms per unit area
• Tropical rainforests are centred along the Equator between the Tropic of Cancer and Capricorn. Rainforests can be found in South America, central Africa and South-East Asia. The Amazon is the world's largest rainforest and takes up the majority of northern South America, encompassing countries such as Brazil and Peru
• Climate of Tropical Rainforests

  • Evening temperatures rarely fall below 22°C
  • Due to the presence of clouds, temperatures rarely rise above 32°C
  • Most afternoons have heavy showers
  • At night with no clouds insulating, temperature drops
• Rainforest nutrient cycle

  1. The hot, damp conditions on the forest floor allow for the rapid decomposition of dead plant material

  2. This provides plentiful nutrients that are easily absorbed by plant roots

  3. However, as these nutrients are in high demand from the many fast-growing plants, they do not remain in the soil for long and stay close to the surface

  4. If vegetation is removed, the soils quickly become infertile
• Layers of the Rainforest

  • Emergent (Highest layer with trees reaching 50 metres)
  • Canopy (80% of life is found here as It receives most of the sunlight and rainfall)
  • U-Canopy (Consists of trees that reach 20 metres high)
  • Shrub Layer (Lowest layer with small trees that have adapted to living in the shade)
• Tropical rainforest cover about 2 per cent of the Earth's surface yet they are home to over half of the world's plant and animals
• Food chain


  Simple food chains are useful in explaining the basic principles behind ecosystems. They show only one species at a particular trophic level
• Food web


  Food webs however consists of a network of many food chains interconnected together
• The term deciduous means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves
• Components & Interrelationships in a Deciduous Woodland

  1. Spring: Flowering plants (producers) such as bluebells store nutrients to be eaten by consumers later

  2. Summer: Broad tree leaves grow quickly to maximise photosynthesis

  3. Autumn: Trees shed leaves to conserve energy due to sunlight hours decreasing

  4. Winter: Bacteria decompose the leaf litter, releasing the nutrients into the soil
• A rainforest works through interdependence. This is where the plants and animals depend on each other for survival. If one component changes, there can be serious knock-up effects for the entire ecosystem
• Malaysia is a LIC country is south-east Asia. 67% of Malaysia is a tropical rainforest with 18% of it not being interfered with
• Malaysia has the fastest rate of deforestation compared to anywhere in the world
• Causes of deforestation in Malaysia

  • Logging (Most widely reported cause of destructions to biodiversity, Timber is harvested to create commercial items such as furniture and paper, Violent confrontation between indigenous tribes and logging companies)
  • Agriculture (Large scale 'slash and burn' of land for ranches and palm oil, Increases carbon emission, River saltation and soil erosion increasing due to the large areas of exposed land, Increase in palm oil is making the soil infertile)
  • Mineral Extraction (Precious metals are found in the rainforest, Areas mined can experience soil and water contamination, Indigenous people are becoming displaced from their land due to roads being built to transport products)
  • Tourism (Mass tourism is resulting in the building of hotels in extremely vulnerable areas, Lead to negative relationship between the government and indigenous tribes, Tourism has exposed animals to human diseases)
  • Energy Development (The high rainfall creates ideal conditions for hydro-electric power (HEP), The Bakun Dam in Malaysia is key for creating energy in this developing country, however, both people and environment have suffered)
  • Road Building (Roads are needed to bring supplies and provide access to new mining areas, settlements and energy projects, In Malaysia, logging companies use an extensive network of roads for heavy machinery and to transport wood)
• Adaptations to the rainforest

  • Orangutans (Large arms to swing & support in the tree canopy)
  • Drip Tips (Allows heavy rain to run off leaves easily)
  • Lianas & Vines (Climbs trees to reach sunlight at canopy)
• Many tribes have developed sustainable ways of survival. The rainforest provides inhabitants with food through hunting and gathering, natural medicines from forest plants, and homes and boats from forest wood
• Why are there high rates of biodiversity in rainforests?

  • Warm and wet climate encourages a wide range of vegetation to grow
  • There is rapid recycling of nutrients to speed plant growth
  • Most of the rainforest is untouched
• Main issues with biodiversity decline in rainforests

  • Keystone species (a species that are important of other species) are extremely important in the rainforest ecosystem. Humans are threatening these vital components
  • Decline in species could cause tribes being unable to survive
  • Plants & animals may become extinct
  • Key medical plants may become extinct
• Impacts of deforestation

  • Economic development (Mining, farming and logging creates employment and tax income for government, Products such as palm oil provide valuable income for countries, Loss of biodiversity will reduce tourism)
  • Soil erosion (Once the land is exposed by deforestation, the soil is more vulnerable to rain, With no roots to bind soil together, soil can easily wash away)
  • Climate Change (When rainforests are cut down, the climate becomes drier, Trees are carbon 'sinks'. With greater deforestation comes more greenhouse emissions in the atmosphere, When trees are burnt, they release more carbon in the atmosphere. This will enhance the greenhouse effect)
• Sustainability strategies for the Rainforest

  • Agro-forestry (Growing trees and crops at the same time. It prevents soil erosion and the crops benefit from the nutrients)
  • Selective logging (Trees are only felled when they reach a particular height)
  • Education (Ensuring those people understand the consequences of deforestation)
  • Afforestation (If trees are cut down, they are replaced)
  • Forest reserves (Areas protected from exploitation)
  • Ecotourism (tourism that promotes the environments & conservation)
• The Thar Desert is located on the border between India and Pakistan in Southern Asia. With India soon becoming the most populated country in the world in the next five years. With this, more people will plan to live in the desert
• Most of the world's hot deserts are found in the subtropics between 20 degrees and 30 degrees north & south of the Equator. The Tropics of Cancer and Capricorn run through most of the worlds major deserts
• Major characteristics of hot deserts

  • Aridity (hot deserts are extremely dry, with annual rainfall below 250 mm)
  • Heat (hot deserts rise over 40 degrees)
  • Landscapes (Some places have dunes, but most are rocky with thorny bushes)
• Climate of Hot Deserts

  • Very little rainfall with less than 250 mm per year
  • It might only rain once every two to three years
  • Temperate are hot in the day (45 °C) but are cold at night due to little cloud cover (5 °C)
  • In winter, deserts can sometimes receive occasional frost and snow
• People often live in large open tents to keep cool, Food is often cooked slowly in the warm sandy soil, Head scarves are worn by men to provide protection from the Sun
• Adaptations to the desert

  • Cactus (Large roots to absorb water soon after rainfall, Needles instead of leaves to reduce surface area and therefore transpiration)
  • Camels (Hump for storing fat (NOT water), Wide feet for walking on sand, Long eyelashes to protect from sand)

  
• Different parts of the hot desert ecosystem are closely linked together and depend on each other, especially in a such a harsh environment
• Opportunities in the Hot desert

  • There are valuable minerals for industries and construction
  • Energy resources such as coal and oil can be found in the Thar desert
  • Great opportunities for renewable energy such as solar power at Bhaleri
  • Thar desert has attracted tourists, especially during festivals
• Challenges in the Hot desert

  • The extreme heat makes it difficult to work outside for very long
  • High evaporation rates from irrigation canals and farmland
  • Water supplies are limited, creating problems for the increasing number of people moving into area
  • Access through the desert is tricky as roads are difficult to build and maintain
• Desertification

  The turning of semi-arid areas (or drylands) into deserts