Living World Flashcards
Ecosystems, Tropical Rainforests, Hot Deserts
Ecosystem
An environment in which a community of plants and animals (biotic) interact with non-living (abiotic) things (eg, soil). Large ecosystems are called biomes (eg, tundra, desert, coniferous forest).
Producers/plants
Green plants that use photosynthesis and take nutrients from the soil, using their roots
Primary consumers/herbivores
Plant-eating animals
Secondary consumers/carnivores
Animals that feed on herbivores
Top carnivores
Animals that hunt and eat other carnivores in the ecosystem, as well as herbivores
Food chains vs food webs
A food chain shows only one path. A food web shows many food chains.
Weight of biomass decreases at each level in the food chain
- Animals don’t eat all parts of a plant or animal (eg, bones and roots)
- Much of what the predators eat is excreted
- 10% energy is lost at each level —> hunters use kinetic energy to chase and catch their prey. Herbivores search for plants to eat. Energy is also constantly used for respiration.
Decomposers
Decomposers return nutrients to the soil in the form of an organic substance called humus
Physical factors affecting balance of ecosystems
Imbalanced food chains; Hurricanes; Forest fires; Coral bleaching; Desertification; Climate change
Human factors affecting balance of ecosystems
Hedge row removal;
Eutrophication;
Deforestation
When one species increases or decreases in population…
When one species decreases in population, the population of its predator will increase because it is eating more of its other prey. The species’ prey increases because the prey has no predator. Vice versa occurs for increase of population.
Distribution and Characteristics of Tropical Rainforests
Located on the Equator between Tropics of Cancer and Capricorn —> Central America, northern South America, West Africa, South East Asia;
High temperatures (25º+) and heavy rainfall (2000mm+/year);
Humid, dense forest, rich in biodiversity —> half of world’s species
Distribution and Characteristics of Mediterranean
40º-45º North of Equator —> Italy, Spain, California, Morocco;
Temperatures range from 10ºC (in winter) to 30ºC (in summer), rainfall of 200-500mm;
Hot, sunny/dry summers, mild/moist winters;
Shrubs, low-lying vegetation —> adapted to drought conditions (eg, olive trees, dry herbs — rosemary)
Distribution and Characteristics of Deciduous Forests
25º-50º N/S of Equator —> Eastern USA, Western and Central Europe, North East Asia;
Temperatures range from -10ºC (in winter) to 20ºC (in summer), rainfall of 700-1500mm, well-defined seasons;
Broad-leaved trees, fertile soil enriched by decaying litter, trees lose their leaves during winter months, animals hibernate
Distribution and Characteristics of Coniferous Forests
50º-60º North of Equator —> Canada, Scandinavia (largest biome on earth);
Temperatures range from -50ºC (in winter) and 21ºC (in summer), snowfall of 100mm;
Evergreen trees, predators (eg, lynx, wolverines, minx)
Distribution and Characteristics of Savanna Grassland
40º-60º N/S of Equator, away from coasts/sea;
Dry for half the year;
Flat plains, limited vegetation, close to desert
Distribution and Characteristics of Deserts
15º-30º N/S of Equator, near Tropics of Cancer and Capricorn —> Africa, South West USA, Mexico, and India; Temperatures range from 50ºC (at day) and 0ºC (at night), rainfall less than 250mm/year; Little vegetation (can survive drought conditions and retain water, small animals that bury themselves in the sand
Distribution and Characteristics of Tundra
55º-70º North of Equator, coldest and driest biome;
Temperatures range from -70ºC to -28ºC, very windy;
Barely any vegetation, except for grass, bushes, no trees, some wolves, deer, hares, insects
Distribution and Characteristics of Alpine
North and South Pole;
Temperatures ranging from -40ºC to 10ºC, little precipitation, mainly as snow;
Most of ground is permafrost, creatures have thick layers and white fur
Why ecosystems are distributed globally
- Altitude — as altitude increases, temperatures drops
- Relief rainfall — windward side of mountain is wetter, leeward side is warmer as air is falling, ie. no clouds
- Ocean currents — warm ocean currents create evaporation and condensation, cold currents don’t, so it’s dry
Tropical Rainforest Examples
Amazon Rainforest, Congo Rainforest, Borneo Rainforest, Madagascar Rainforest, Queensland’s Tropical Rainforest, Ecuador’s Cloud Forest, Monteverde Rainforest, Sinharajin Forest, Sumatra’s Rainforest
TRF Climate
2000mm+ rainfall/year;
Average daily temperature of 28ºC;
Humid and hot atmosphere;
Climate is consistent all year round (no seasons)
TRF Soil
Not very fertile;
A thin layer of fertile soil where dead leaves decompose;
Red in color because it’s rich in iron;
Lots of leaching of the nutrients from heavy rainfall
TRF Plants and Animals
Warm, wet climate perfect conditions for plant growth;
Wide range of plant species supports many different animals, birds, insects;
Species have adapted to conditions
Structure of TRF
Emergent
Canopy
Under canopy
Shrub level
TRF Plant Adaptations: Lianas
Roots in the ground, climb up trees to reach sunlight, in the canopy
TRF Plant Adaptations: Tall Trees
Reach sunlight, bark is smooth to allow water to easily flow to roots
TRF Plant Adaptations: Drip Tips
Waxy surface, pointed tips to allow water to easily run off, prevents growth of algae which would block out sunlight
TRF Plant Adaptations: Buttress Roots
Shallow roots, expand surface area to get more nutrients, large roots also provide support for very tall trees
TRF Plant Adaptations: Stilt Roots
Shallow roots, provide support for tall trees
TRF Plant Adaptations: Leaf Angling
Leaved arranged as different angles to prevent shading its own leaves
TRF Plant Adaptations: Thin Bark
Don’t need thick bark to lose moisture because the climate is always wet and humid, smooth bark makes it hard for other plants to grow on tree
TRF Plant Adaptations: Epiphytes
Live on trunks and branches of other trees, reach sunlight
TRF Plant Adaptations: Red Leaves
Young leaves are red to protect from strong sunlight while their photosynthesis organs are still developing
TRF Animal Adaptations: Sloth
Camouflage, slow movement, hard for predators to spot
TRF Animal Adaptations: Spider Monkey
Long, strong limbs, climb though trees
TRF Animal Adaptations: Flying Frog
Webbed hands and feet, flap of looses skin that stretches between its limbs, which allows it to glide from plant to plant
TRF Animal Adaptations: Toucan
Long, large bill, reach, cut fruit from branches that are too weak to support its weight
Deforestation Threats: Farming
Pastoral farming global demand for meat increases cattle ranching, arable farming, growing cash crops, eg, soya beans
Deforestation Threats: Logging
Mahogany sold for timber to make furniture. Other trees cut down for making paper products
Deforestation Threats: Mining
Rich in iron ore, copper, tin, aluminum, manganese, gold. Development of mines —> Carajas mine in Brazil is world’s largest iron ore mine
Deforestation Threats: Roads
Construction of access roads for farmers, loggers and miners results easy access to more areas of the TRF
Deforestation Threats: Hydroelectric Power
Large areas flooded to create reservoirs and dams. Flooding of Balbina dam in Brazil led to 920 square miles loss of TRF
Deforestation Threats: Population
Population growth means land needs to be cleared to build houses and infrastructure
Deforestation Threats
- Farming
- Logging
- Mining
- Roads
- Hydroelectric Power
- Population
Impacts of Deforestation: Soil Erosion
No interception by trees so nutrients leached and lots of surface run-off. Nutrient cycle stops as no trees leave litter and nutrients to be recycled into soil. Soil is not fertile. Soil easily eroded, no roots of plants can hold the soil together.
Impacts of Deforestation: Loss of Biodiversity
Habitats lost, trees are habitats of birds and other animals like sloths and monkeys often live in them, plants are needed for producers to eat them, disrupts food web
Impacts of Deforestation: Climate Change
Trees absorb CO2 and turn it into oxygen through photosynthesis, less CO2 is absorbed, so enhanced greenhouse effect, leading to global warming and climate change
Impacts of Deforestation: Economic Development
Rich in resources: mines, farms, roads, logging. Creates jobs for rural-poor, increasing taxes, so money goes into government for more economic development in TRF and providing infrastructure and services (eg, healthcare, education)
Impacts of Deforestation (Evaluate, discuss, to the extent, assess)
- Loss of biodiversity
- Climate change
- Soil erosion
- Decline of indigenous tribes (loss of land)
- River pollution (mercury used for gold mining)
- Conflicts (indigenous, TRF conservation groups vs developers)
- Loss of plants (medicine)
- Tourists (see TRF)
+ Jobs
+ Taxes
+ Homes
+ Infrastructure
+ Economic development
Management of TRF: Selective Logging
Mature trees chosen, rainforest canopy is reserved, younger trees gain more space and sunlight to grow
Management of TRF: Replanting
For every tree that is felled, one is replanted
Management of TRF: Education
Local people, businesses, politicians understand importance of TRF
Management of TRF: Ecotourism
Sustainable tourism, creates jobs for locals, money is still generated, goes into government through taxes, while still protecting and conserving TRF for future generations to enjoy
Management of TRF: Intergovernmental Agreements
Trade restrictions, timber must have registration number otherwise it’s illegal logging
Management of TRF: Debt-for-Nature Swaps
Debt from debtor country is swapped into conserving the TRF through third-parties/NGOs buying debt and sell to a creditor country who will help protect the TRF
Management of TRF: Conservation Groups/NGOs
Provide education and training, buy threatened areas, create nature reserves,
Management of TRF: National Governments
Use satellites to monitor activity, high-tech rangers, fines to illegal loggers and miners, create more protected areas
Management of TRF: Agro-Forestry
Growing trees and crops at the same time to maintain fertile soil and still sell crop yield
Hot Deserts Examples
Sahara Desert (N. Africa), Arabian Desert, Atacama Desert (W. South America), Namib Desert (S. Africa), Kalahari Desert (S. Africa), Mexican Desert, Thar Desert (±India), Great Sandy Desert (Australia)
Hot Desert Climate
Hot, dry —> <250 mm rainfall/year;
Summer = +40ºC (day), 0ºC (night);
Winter = 20-30ºC (day);
Hot Desert Soil
Thin, sandy, rocky, gray;
Dry, soak water quickly;
Appear crusty, evaporation of water leaves salts on surface of soil.
Hot Deserts Plants: Small Leaves
Less water loss through transpiration, smaller surface area
Hot Deserts Plants: Tap Roots
Long roots (7-10 m long), larger than plant, reach underground water supplies
Hot Deserts Plants: Spines
Spines lose less water, prevent animals from eating plant
Hot Deserts Plants: Waxy Skin
Thick, reduces water loss by transpiration
Hot Deserts Plants: Water Storage
(Succulents) store water in stems, leaves, roots, or fruits. Also will have thick waxy skin to prevent water loss.
Hot Deserts Animals
- Thick skin on soles of feet to prevent burning from sand
- Light-colored fur to reflect light
- Get water from food rather than water
Causes of Deforestation: Population Growth
Increased population means a greater demand on resources such as wood and water. Increased population from mining and tourism for more jobs
Causes of Deforestation: Removal of Wood
In developing countries, wood is used for cooking. Population growth means more greater demand for wood. Land is clearer of trees, roots no longer hold soil together —> soil erosion
Causes of Deforestation: Overgrazing
Population growth —> more land used for farming. Sheep, cattle, goats eat vegetation, exposing soil to erosion
Causes of Deforestation: Soil Erosion
Made worse by overgrazing and wood removal. Population growth responsible
Causes of Deforestation: Climate Change
Temp. increase —> desert gets warmer and drier. Less rain now than there was 50 years ago.
Strategies to Reduce Desertification: Solar Cookers
Cheap, reduces carbon emissions;
Reduces amount of wood used;
Cannot be used in the morning, very windy days;
Slow method of cooking;
Reduced chance of deforestation, soil erosion, desertification
Strategies to Reduce Desertification: Sand Dams
No evaporation;
Water naturally gets filtered;
No mosquito larvae —> no spread of diseases (malaria);
Saves time —> children can go to school, parents can work;
Provides water for 1200 people;
Holds 2-10 million liters water
Strategies to Reduce Desertification: Water Pumps
Appropriate technology; Easy to use and maintain; No electricity needed; Saves time —> children can go to school, parents can work; Health improves; — Could encourage over cultivation
Strategies to Reduce Desertification: Magic Stones
Contour lines 40m high; Reduces soil erosion and leaching; Allows water to infiltrate; Easy to build and cheap; Sustainable; Increases crop yield by 40%; — Takes time to be effective — Best with manure, but expensive — Takes effort
Strategies to Reduce Desertification: Fruit Trees and Bushes
Branches for firewood —> reduces deforestation; Better nutrition from fruits and berries; Good soil anchor —> less soil erosion; Leaves feed goats; Raises status of women; Protects watershed of the area; — Takes time to grow — Can’t solve desertification on its own
