Forests Under Threat Flashcards
Why are forest biomes important on Earth?
They absorb and store huge levels of carbon, release oxygen into the atmosphere and provide habitats for many plants and animals,
however, they are increasingly under threat from human activities
What is a tropical rainforest?
A warm, wet ecosystem located between the tropics with dense vegetation
What is the rainfall like in a tropical rainforest?
Extremely high rainfall, exceeds 2000mm a year
Usually seasonal with a distinct wet season
Low during summer months
What is the temperature like in a tropical rainforest?
Very high (~26-27C)
Temperatures are consistent throughout the year,
This is due to the sun shining directly on the equator throughout the year
What is the soil like in tropical rainforests?
Extremely nutrient deprived and infertile because nutrients are washed and dissolved away very quickly by intense rainfall (leeching), leaving an infertile, iron rich soil (latosol)
How do plants get nutrients in tropical rainforests?
From the layer of decomposing organic matter that sits on top, decomposition is sped up by the hot and humid conditions and decomposers. The products are then quickly absorbed by the roots and put back into the living ecosystem
Describe the nutrient cycling in tropical rainforests
Vegetation and trees grow rapidly and shed leaves continuously as conditions are perfect →
Vegetation decays and decomposes rapidly dues to favourable conditions and decomposers in the system→
Nutrients enter the topsoil, but are either quickly picked back up or leeched away by rain, so do not penetrate deep into the ground→
Shallow roots take up nutrients and use them to grow
What are the 4 layers of the tropical rainforest and where are they found?
Forest floor (0-15m)
Understorey (15-30m)
Canopy (30-45m)
Emergent layer (>45m)
What type of life does each layer of the rainforest support?
Forest floor - rodents, large mammals, decomposers
Understorey - insects, frogs, snakes (away from predators)
Canopy - mammals such as monkeys
Emergent layer - birds and flowers
What are 5 adaptations of plants in the tropical rainforest?
Buttress roots
Drip tips
Flexible stems
Lianas
Epiphytes
What is the purpose of buttress roots?
They are roots above ground, adapted for the waterlogged, nutrient deprived soils.
They ensure tall trees are kept stable without going too far into the soil
Describe the leaf adaptations in tropical rainforests
Drip-tips - allows excess rainwater to quickly drip off the leaf, which ensures plants won’t be too wet (prevents rotting)
Flexible stems - move to find light as the dense canopy blocks light
Describe the adaptations of lianas
Woody vines adapted to the dark lower levels.
Roots that grow in the ground, but their vines go high up and wrap around trees (symbiotic relationship), meaning they have access to nutrients from the soil and sunlight from the canopy
Describe the adaptations of epiphytes
Live on the surface of other plants, receiving their nutrients. Adapted to grow on trees high in the canopy so they can receive more sunlight
, but feed off of the nutrients of their host plant (parasitism)
What are some adaptations of animals in a tropical rainforest?
Poisons and venoms
Physical characteristics
Camouflage
Size
Describe the adaptation of poisons and venoms on animals in a tropical rainforest
Poisons and venoms prevent the animal from being eaten.
Many spiders/ snakes can paralyse and kill other animals. Some sting or bite if threatened.
Some are poisonous to eat
Describe the physical adaptations of animals in a tropical rainforest
Primates have developed long limbs and strong tails to help the swing between branches and avoid predators
Some animals have strong claws to help them climb trees e.g. geckos have special pads that stick to branches
Describe the adaptation of camouflage on animals in a tropical rainforest
Camouflage enables the animal to hide from predators
Describe the size of animals in a tropical rainforest
Smaller - easier to move through dense vegetation
Why do tropical rainforests have high levels of biodiversity?
Rapid rate of nutrient cycling means there are always nutrients readily available to support biodiversity.
Hot and humid climate is favourable
Describe the nutrient cycle of a tropical rainforest
Biomass - very large due to dense, layered vegetation with high biodiversity
Fallout - consistent
Litter - small as decay is so rapid in hot, moist conditions
* majority of nutrients are stored in the topsoil and the rest of the soils are nutrient deprived and heavily leeched
Plant uptake - high
Runoff - continuous throughout the year
What are the nutrient additions in a tropical rainforest?
Precipitation
Chemical weathering due to hot, wet conditions