Topic 8 - Forests Under Threat Flashcards
What are the stratified layers of the rainforest?
Ground layer Shrub layer Under canopy Main canopy Emergent layer
What are the features of the shrub layer?
Between 0-10 metres
Made up of smaller plants
Alligators, jaguars, snakes, insects, orchids
What are the features of the under canopy?
10-20 metres
Young trees competing for sunlight
Insects, sloths, halo monkeys
What are the features of the main canopy?
20-30 metres
Lots of birds
Trees that are tall and straight with few branches
Butress roots
What are the features of the emergent layer?
30-40 metres
Tallest trees
Wide butress roots
Birds, insects and butterflies
What does interdependent mean?
Interrelated / depend on each other.
What are biotic factors?
The living parts of an environment, such as plants (flora), animals (fauna) and microorganisms.
What are abiotic factors?
The abiotic factors are the non-living parts of an environment.
What biotic and abiotic factors are interdependent?
- Climate
- Soil
- Water
- Plants
- Animals
- Humans
What’s an example of interdependence?
Sunlight and rain (abiotic-climate) keep plants alive and growing.
How are plants adapted to the climate?
- Stratified layers
- Butress roots
- Drip tips
What are the features of the ground layer?
Very dark, very steamy
2% of light reaches it
Dead and decaying plant matter
Infertile (no nutrients) soils
What are butress roots?
Stretch from the ground to 2 metres or more up the trunk, which help anchor the tree to the ground to stop them falling over and ensure they take in as many nutrients as they can.
What do drip tip leaves do?
Thick waxy leaves with pointed tips.
Pointed this channel the water to a point so it runs off, so the weight of the water doesn’t damage the plant.
Waxy leaves stop algae or moss growing over the leave surface which would block sunlight preventing photosynthesis.
What ways are animals adapted to the tropical rainforest?
- Strong limbs - spend day climbing and leaping
- Flaps of skin to glide between trees
- Camouflaged
- Nocturnal (night is cooler so save energy)
- Adapted to low light levels - sharp sense of smell and hearing
- Can swim to cross river channels
What are the 3 stores in the nutrient cycle?
- Biomass (living organisms)
- Litter
- Soil
What are the ways nutrients are lost?
- Surface run off
* Leaching
What are the inputs in the nutrient cycle?
- Breakdown of rock
* Rain
Why are nutrients cycled quickly in tropical rainforests?
- Trees are evergreen, so dead leaves and other matter fall all year round.
- Warm, moist climate means that fungi and bacteria decompose the dead organic matter quickly. The nutrients released are soluble and are soaked up by the soil.
- Dense vegetation and rapid plant growth means that nutrients are rapidly taken up by plants roots.
Why do rainforests have high levels of biodiversity?
- Not much climate change so there has been lots of time for plants and animals to evolve to form new species.
- Layered structure provides lots of different habitats - plants and animals adapt to become highly specialised to there particular environment and food source so lots of different species develop.
- Hot and wet all year. Very productive because of high rate of nutrient cycling. Plants and animals don’t have to cope with changing conditions and there is always plenty to eat - so they are able to specialise.
What do food chains show?
What’s eaten by what in an ecosystem.
What do food chains start with?
A producer.
Producers make there own food using energy from the sun.
What are producers eaten by?
Primary consumers
What are primary consumers eaten by?
Secondary consumers
What are secondary consumers eaten by?
Tertiary consumers
What happens when these organisms die?
They get broken down by decomposers.
What do food webs show?
How all the food chains overlap.
Ecosystems usually contain many different species - which means lots of different possibile food chains.
Why are food webs in the tropical rainforest very complex?
- So many different species so loads and loads of links.
* Some animals can be both primary and secondary consumers.
What are causes of deforestation?
- Local demand for fuel wood
- Mineral resources
- Electricity (HEP)
- Commercial hardwood logging
- Commercial farming
- Subsistence farming
- Demand for biofuels
Why does local demand for fuel wood cause deforestation?
Local people chop down trees to use for fuel for cooking or to burn to make charcoal.
Why does Mineral resources cause deforestation?
Gold, copper and iron ore are often found in tropical rainforests. Explosives are sometimes used to clear earth or deep pits are dug to reach the deposits.
Why does electricity (HEP) cause deforestation?
Many tropical rainforest have large rivers. Building dams to generate hydroelectric power floods large areas of forest behind the dams.
Why does commercial hardwood logging cause deforestation?
Trees are felled to make furniture and for construction. Road building for logging also requires more tree clearance.
Why does commercial farming cause deforestation?
Forest is cleared to make space for cattle grazing, or for huge palm oil or soya plantations.