3.1.2.2 Tropical rainforests Flashcards
What is the climate like in tropical rainforests?
Same all year round, no definite seasons:
- Hot (20-28C) doesn’t vary much (sun is overheard
all year round)
- Rainfall is very high (rains every day, usually in afternoon)
Why is the climate hot?
Because it’s near the equator
What is the soil like?
Not very fertile
Why is the soil not very fertile?
Heavy rain washes nutrients away
Where are the nutrients found in the soil and why?
At the surface due to decayed leaf fall
Why is the layer of nutrients found on the soil very thin?
As decay is fast in warm, moist conditions
Why type of trees are most of the trees and why?
Evergreen - to take advantage of the continual growing season
Why does very little light reach the forest floor?
Trees are really tall and vegetation cover is very dense
What types of plants are there lots of?
Lots of epiphytes e.g. Fern, orchids
What are epiphytes?
Plants that grow on other living plants and take nutrients and moisture from the air
How many animal species are there?
Contains more animal species than any other ecosystem
All parts of rainforest are … on another
All parts of rainforest are dependent on another (interdependent)
The warm and wet climate means …
That dead plant material is decomposed quickly by fungi and bacteria on forest floor
What is the effect of dead plant material being decomposed quickly?
Makes the surface soil high in nutrients = plants can grow quickly and easily
How do animals get their nutrients?
By eating plants
Why are animal populations high?
Dense vegetation provides lots of food
How can deforestation lead to climate change?
Reducing amount of CO2, being absorbed from the atmosphere, adding to the greenhouse effect and changing the climate
How do trees provide moisture for further rainfall?
Trees intercept and take up loads of water and release back into the atmosphere
What can deforestation increase the risk of, if there’s less trees to intercept water?
Can increase the risk of drought
What is biodiversity?
It’s the variety of organisms living in particular area (plants and animals)
Why are rainforest are stable and productive environments?
Because it’s hot and wet all year round ∴ plants and animals don’t have to cope with changing conditions = always plenty to eat
Why are many species only found in a small area?
Organisms have evolved to depend on a few species for survival - are very specific to a particular habitat and food source
What is the biodiversity like in tropical rainforests?
Extremely high biodiversity - contains 50% of world’s plant, animal and insect species (may contain half of all life on earth)
What is the effect of deforestation on the ecosystem?
Likely extinction of species + loss of biodiversity
What are plants are adapted to cope with?
High rainfall, high temperatures & competition for light
What do tall trees competing for sunlight have?
Have big roots called buttress roots to support their trunks
How are plants’ leaves adapted and why?
Plants have thick, waxy leaves with pointed tips = pointed tips (drip-tips) channel water to a point do it runs off. So the weight of the water doesn’t damage the plant + no standing water for fungi an bacteria to grow in & waxy coating of leaves helps repel the rain
Name the distinct layers of plants (with different adaptations) that rainforests have (from the top to bottom)?
- Emergent layer
- Canopy layer
- Understory/shrub layer
- Forest floor
How are plants adapted in the emergent layer?
Plants only have branches at their crown (where most light reaches them)
How are plants adapted in the undercanopy?
Have large leaves to absorb as much light as possible
How are climbing plants adapted?
Climbing plants (e.g. Lianas) use the tree trunks to climb up to the sunlight
Why do plants drop their leaves gradually throughout the year?
So they can go on growing all year round
How are animals adapted?
Are adapted so they can find food and escape predators