pa3 , another section Flashcards
what is biodiversity
biodiversity is the number of different plants and animal species in an area
why is biodiversity so high in rainforests
- Good climate for all year round growth and reproduction
- Rainforests are ancient and have a stable climate so thousands of different species evolved
- Multiple layers provide numerous different, specialised habitats, plants and animals have evolved to take advantage of these
how sloths are adapted
- huge claws allow to hang upside down from branches
- fur grows away from their feet to help shed rain when upside down
- green algae growing in their fur helps camouflage them from predators
how big cats are adapted
jaguars, tigers, leopards all have camouflaged fur ‘= dark and light
fur blends with sun/shade on the forest flaw
how birds are adapted
- loud : calls to hear mate rather than see them in the dense canopy
- parrots and macaws have powerful banks to open nuts
how primates are adapted
lemurs and monkeys evolved to live in the canopy where most food is
long tails used for balance
strong claws to grip trees and branches
how evergreen hardwood trees are adapted
tall slender trunks with no branches but huge triangular buttress roots to support weight leaving leaves and branches on top where sunlight is
how epiphytes are adapted
these plants live in the tree canopy
evolved to get nutrients from the soil as roots dangle in mid air
how lianas adapted
climbing plants use tree as their trunk - their stems cling to trees and climb up to sunlight in the canopy while getting water and nutrients from the soil below
how drip tip leaves are adapted
most rainforest plants have thick, waxy leaves with drip tips which shed water. quickly to prevent leaves rotting
how soil supports biodiverse forests
via the nutrient cycle
what do all plants need to grow
nutrients
external factors affecting the nutrient cycle?
Nutrients can be added to an ecosystem by precipitation and weathering
they can also be removed by runoff of leaching (when nutrients are washed out of soil by water moving through it)
They are taken up from soil as plants (on biomass) grow
They are returned to it when they die, first as litter (or decaying leaves and twigs) on the soil surface and then back into the soil as litter clays
therefore
nutrients move between biomass, litter and soil in a continuous cycle that keeps both plants and soil healthy
in the TRF , the nutrient cycle is…
RAPID
Most nutrients in the TRF are stored in biomass so if forest is cut down, most nutrients are destroyed…effects?
Without forest to protect it, litter and soil is easily eroded by heavy rains
As rainforest soils contain few nutrients, land cannot be formed for long before having to move on
Taiga location
between 50 degrees and 70 degrees latitude, mostly in the northern hemisphere
Huge areas of Russia and Canada are covered
how have coniferous (evergreen) trees adapted in Taiga
They have adapted to the cold climate - their shape allows snow to fall, instead of weighing on the branches, and their pine needles prevent damage by wind or snow
Taiga weather
short, wet summers of three months when temperatures rise to 20 degrees celsius
Long cold dry winters with several months below freezing, as low as-20 degrees celsius
Low precipitation
Snow on ground for many months
why is biodiversity so low in the taiga
- only reptiles and amphibians are adapted to cold climate and they are quite rare
- Growing season only 4-5 months so little food int he winter
why must animals adapt to cold. winter in taiga
plants stop growing
snow cover makes grazing difficult even for dead plants
Temperatures are bitterly cold
mammal adaptations to taiga
thick, oily fur to help retain heat and provide waterproofing
Because food is hard to find, some hibernate eg bears
Many birds only live in taiga in summer then migrate for winter due to lack of food.
what is NPP (net primary productivity)
A measure of how much new plant and animal growth - or biomass - is added to a biome each year, measured in grams per square metre per year
when is productivity greater
when there is plenty of sunlight
high temperatures
precipitation
direct threats to the TRF
Deliberate cutting down of trees for timber to make roads or to convert the forest into farmland
- Cattle ranches (60 percent)
- small scale subsistence agriculture(30 percent)
- fires, mining, urbanisation, road construction, dams (3 percent)
- Logging, legal and illegal (3 percent)
- Large-scale commercial agriculture including soybeans (1 percent)