Topic 8 Flashcards
Agouti
The Agouti are one of the few animals who can crack ppen the hard seed pod of a Brazil nut, sometimes the Agouti bury the nuts, that then sprout into new seedlings. If the agouti were to became extinct,the Brazil nut trees and all the animals surviving off them would become extinct.
Biodiversity is high in rainforests, because:
The climate is perfect for year-round growth and reproduction.
Rainforests are ancient and have a stable climate, so thousands of different species have evolved.
The multiple layers in a tropical rainforest provide numerous different, specialised habitats, with plants and animals evolving to take advantage of these.
Biodiversity in tropical rainforests
In Amazonia there are 16000 different tree species, over 40000 other plant species, 1300 bird species and six different species of sloth. In comparison, the UK has only 30 native tree species.
Climate in tropical rainforest areas
Equatorial climate(helps tropical rainforests to grow continually):
No dry season, with at least 60mm of rainfall each month, some get three metres of rain each year.
Temperatures are high(26-32C all year round), so there’s no summer or winter
Structure of a tropical rainforest
From top to bottom:
1) Emergent layer
2) Canopy layer
3) Understorey/undercanopy layer
4) Forest floor/shrub layer
Emergent layer key features
Hardwood, evergreen trees that have broken through the dense canopy layer below to reach the sunlight. Monkeys and birds live up here.
Canopy layer key features
Is a continuous layer of trees
Home to tree snakes, birds, tree frogs and other animals, because there’s so much food available.
Waterlogged conditions and competition for space at the forest floor
Approximately 30-40 metres high
Dense canopy
Trees only have leaves at the top % dense layer of leaves shades the rest of the forest
Understorey layer key features
This layer contains young trees(yet to reach their full height) and those with large leaves, to capture sunlight: huge numbers of insects live in the understory layer.
The trees can only survive when there are breaks in the canopy to let light through.
Forest floor/shrub layer key features
The darkness of the forest floor means shade-loving ferns with large peaves live here along with mammals like the jaguar.
Shrubs have large, broad leaves to absorb as much of the available light as they can.
Examples of plant adaptations in the rainforest
Evergreen hardwood trees
Epiphytes
Lianas
Drip tip leaves
Emergents
Buttress roots
Minimal shrub growth
Dark, large leaves at the forest floor
Examples of animals that have adapted to the tropical rainforest
Sloths
Primates
Big cats
Birds
Flying squirrels
Jaguars
Howler monkeys
Leaf tailed geckos
Anteaters
Evergreen hardwood tree adaptations
Mahogany, teak and ebony trees have tall slender trunks with no branches on them, but hige triangular buttress roots. The roots support the enormous weight of the trees, and leaves and branches are only at the very top, where the sunlight is.
Epiphytes adaptations
These plants live in the canopy on trees and have evolved to get all their nutrients from water and air rather than the soil, so their roots dangle in mid-air.
Can reach sunlight quickly and without competition.
Not parasitic - get nutrients from air and pools of water where dead organic material is rotting down
Don’t have access to nutrients in the soil - they’re dependent on rainfall to provide water and nutrients
Liana adaptations
These climbing plants use trees as their trunk - their stems cling to trees and climb up to the sunlight in the canopy, while getting water and nutrients from the soil below.
Quick growing
Use tree trunks to climb up to the sunlight.
Doesn’t use energy growing strong(weight supporting) stems
Drip tip leave adaptations
Most rainforest plants have thick, waxy leaves with pointed drip tips(these shed water quickly to prevent leaves rotting).
Ensures photosynthesis can continue.
Prevents mould growth - no standing water for fungi and bacteria to grow in
2000mm rain a year
Helps drain water from leaves - drip tips channel the water to a point so it runs off, and the weight of the water doesn’t damage the water. Waxy coating of the leaves helps repel the rain.
Sloth adaptations
Huge claws allow sloths to hang upside down in the branches, while the fur grows away from their feet to help shed rain when upside down. Green algae growing in their fur helps camouflage them from predators.
These animals are nocturnal(active at night). They sleep through the day and feed at night when it’s cooler - this helps them to save energy.
Primate adaptations
Lemurs and monkeys have evolved to live in the canopy where most food is: their long tails are used for balance and most have strong claws to grip trees and branches.
Big cat adaptations
Jaguars, tigers and leopards all have camouflaged fur: the dark and light fur patches blend in with the shade and sunlight on the forest floor
Bird adaptation
Rainforest birds often have very loud calls, because it’s easier to hear a mate than see them in the dense canopy: parrots and macaws have powerful beaks to break open nuts.
Emergent adaptations
Emergents reach through the dense canopy for light.
Slow growing trees reach the top(hardwoods)
Tallest trees can be almost 65 metres high.
Big buttress roots to support their trunks
Straight trunks - only have branches and leaves at the top where they can get light
Buttress root features
Wide(10 metres) to support the tall trees
Shallow roots to capture nutrients close to surface
Infertile soils
Minimal shrub growth features
Carnivorous plants/insectivorous plants as a result of soil depth and quality.
Less than 2% of light reaches the floor
Soft wood shrubs
Waxy/jagged leaves to prevent consumption from herbivores
Dark large leaves at the forest dloor features
Greater levels of chlorophyll
Absorb/capture more light
Less than 2% of light reaches the floor
Biodiversity
The number of different plant and animal species in an area
Why is biodiversity in the rainforest so high?
Climate allows for year round growth and reproduction.
Rainforests are ancient, stable climates.
The different layers of the rainforest
provide numerous different habitats for a variety of plants.
What structure do tropical rainforests have?
A layered structure(are stratified)
Nutrient cycle(normal)
1)Precipitation(rainfall adds nutrients)
2) From biomass, dead plants and animals become litter to the soil surface.
3) Litter decomposes returning nutrients to the soil.
4) Runoff - Water washes litter away, removing nutrients.
5) As plants grow, they take nutrients from the soil(uptake)- so nutrients are transferred to the biomass
6) Biomass - Fallout: Dead plants and animals become litter on the soil surface.
7)Leaching - Nutrients are washed out of the soil as water moves through
8)Weathering - The chemical breakdown of rock adds nutrients to the soil.
Nutrient cycle
Describes how nutrients are transferred around an ecosystem
External factors affecting the nutrient cycle
1) Nutrients can be added to an ecosystem by precipitation and weathering.
2) They can also be removed by runoff or leaching(when nutrients are washed out of the soil by water moving through it).
3) Nutrients are taken up from the soil as plants/biomass grow.
4) Nutrients are returned to the soil when they die: first as litter(or decaying leaves and twigs) on the soil surface and then back into the soil as the litter decays.
Nutrient cycle in tropical rainforests(differences from a normal nutrient cycle)
Larger biomass store - Layers of vegetation and huge trees store large amounts of nutrients.
Smaller litter store and larger decay transfer - In hot wet conditions bacteria and fungi decay dead matter quickly, returning nutrients to the soil.
Large growth transfer - Plants grow all year, so draw nutrients up from the soil rapidly.
Larger weathering input - Chemical weathering processes(e.g. solution) are faster in hot wet climates, so release nutrients into the soil from rocks.
A larger leaching output - Heavy rainfall throughout the year brings in nutrients, but the constant flow of water through the soil removes them(leaching).
Effects of deforestation
Nutrients are destroyed:
Without the forest to protect it, litter and soil are easily eroded by heavy rains.
As rainforest soils contain few nutrients, land can’t be farmed for long before having to move on.
Energy source for all food webs
Sunlight - Plants convert sunlight into energy in the form of carbohydrates, through photosynthesis. As one organism feeds on another, energy passes between them.
Food webs(how energy passes) in a rainforest
Primary producers: Primary consumers: Secondary consumers:
Tertiary consumers: Detrivores
Examples of primary consumers in a tropical rainforest
Herbivores(sloths, ants, butterflies)
Examples of primary producers in a tropical rainforest
Plants(trees, ferns, flowersJ
Examples of secondary consumers in a tropical rainforest
Carnivores(birds, frogs)
Examples of tertiary consumers in a tropical rainforest
Top carnivores(snakes, jaguars)
Examples of detrivores in a tropical rainforest
Decomposers(fungi, bacteria)
Biotic components
Living components of rainforests(plants, animals and people)
Abiotic components
Non-living components of rainforests(climate, soils, water)
How can a lack of wind near the forest floor affect the biotic components of rainforest?
The lack of wind near the forest floor means many plants there have to rely on bees, butterflies or other animals for pollination
Symbiotic relationships hetween plants and animals
Relationships where animals and plants depend on each other for survival, very common in tropical rainforests e,g. Agouti
Rainforest - plant other adaptations
Trees have smooth, thin bark, so there’s no need to protect the trunk from cold temperatures. The smooth surface also allows water to run off easily.
Plants drop their leaves gradually through the year - can grow all year round.
Howler monkey adaptations to tropical rainforest
They have strong limbs, so they can spend all day climbing and leaping from tree to tree
Flying squirrels adaptation to tropical rainforest
They have flaps of skin to glide hetween trees.
Leaf-tailed gecko adaptation to tropical rainforest
Are camouflaged as leaves so they can hide from predators.
Anteater adaptations to tropical rainforest
Have a sharp sense of smell and hearing, so can detect predators without seeing them
Jaguar adaptations to tropical rainforest
Can swim, which allows them to cross river channels.
In an ecosystem, how are nutrients stored:
Living organisms(biomass)
Dead organic material e.g. fallen leaves(litter)
The soil
Why is the transfer of nutrients very rapid in tropical rainforests
1) Trees are evergreen, so dead leaves and other material fall all year round.
2)The warm, moist climate means fungi and bacteria decompose the dead organic matter quickly. The nutrients released are soluble(dissolve in water) and are soaked up by the soil.
3)Dense vegetation and rapid plant growth mean nutrients are rapidly taken up by plants’ roots.
Rainforests have high biodiversity, because:
1) The rainforest biome has been around for 10s of millions of years without the climate changing very much, so there’s been lots of time for plants and animals to evolve to form new species.
2) The layered structure of the rainforest provides lots of different habitats - plants and animals adapt to become highly specialised to their particular environment and food source(ecological niche) so lots of different species develop.
3) Rainforests are stable environments(hot and wet all year round), are productive(the plants grow quickly all year round, producing lots of biomass) due to the high rate of nutrient xycling and means plants and animals don’t have to cope with changing conditions.
Examples of interdependence in taiga forests
1) Plants gain their nutrients from the soil and provide nutrients to the animals that eat them.In turn, animals spread seeds through their dung, helping the plants to reproduce.
2) The cold climate causes plants to grow and decompose slowly, meaning the soil’s low in nutrients, inhibiting the ability of the plant to grow.
3)Herbivores like reindeer that rely on plants like mosses to survive will migrate to areas where plants are able to grow food,and carnivores like wolves have to follow the reindeer.
4) In summer, the trees absorb heat from the sun and shade the ground below - preventing the permafrost(which provides water for plants) from thawing.
5)
Changes to components of the ecosystem(e.g. chopping down trees) causes permafrost to melt. Melting permafrost can flood land,
preventing plants from growing and this also releases greenhouse gases, leading to global warming and changes to the climates of cold environments(including plants and animals).
Climate in taiga forests
Taiga(boreal) forests are part of the boreal biome - the climate is cool, dry and highly seasonal
Features of taiga forest
Found between 50-70 degrees latitude, mostly in the northern hemisphere.
Huge areas of Russia and Canada are covered by Taiga.
The trees are coniferous(evergreen) and have adapted to a cold climate - their shape allows snow to fall, instead of weighing on branches, and their pine needles prevent damage by wind or snow.
Taiga climate
Short, wet summers of three months when temperatures can rise to 20C.
Long cold, dry winters with several months below freezing, as low as -20C.
Low precipitation - below 20mm for five months and only 350-750mm per year.
Snow on the ground for many months.
Why is biodiversity low in the Taiga Forest
1) Plants and animals can only survive if they’re specially adapted to the cold climate, this means reptiles and amphibians are rare.
2) The growing season is only 4-5 months long, meaning in winter there’s little food.
Animal adaptations to cold winters(taiga climate)
1) Many mammals have thick, oily fur(e.g. black/brown grizzly bears, wolves, moose and lynx) to retain body heat and provide waterproofing.
2)Because food is hard to find - some taiga animals hibernate e.g. brown bears and some species of mice, bats and squirrels
3) 300 species of birds live in the taiga in the summer, eating insects and breeding. However, another 270 species migrate away for winter because of the cold and lack of food. For example, many of the larger mammals like caribou move long distances through the forest in order to find food.
Structure of taiga vegetation
Simpler than tropical rainforest - really only one layer of vegetation
