Ecosystems Flashcards
Describe characteristics of desert plants.
- Short lived with a fast lifecycle or long lived with dormant seeds.
- Waxy leaves with few stomata
- Large underground or above ground water storage bodies
- Slow growing to tolerate stress and not to overuse resources
How do desert plants reduce competition for water?
They partition root space so that adjacent plants alternate between wide reaching shallow roots and deep reaching straight roots so that adjacent plants are not competing as much for the available water.
Give one adaptation for each a camel, kangaroo, budgerigar and gemsbok have to be adapted to the desert environment.
- Camel has a hump fat for storage.
- Kangaroo concerts the hydrogen by-product of fermentation into acetate (not methane) which is used to provide further energy
- Gemsbok can withstand high body temperatures
- Budgerigars are nomadic- stay for the good times and leave for the bad
What behavioural adaptations do desert organisms have to survive in their conditions?
- Gular fluttering- flapping wings near gulag (throat) to avoid overheating
- Increasing surface area to radiate as much heat as possible (e.g. large ears to dissipate heat)
- Some birds can carry water in breast feathers after long distance flights to water
- White to reflect the sun which would increase the temperature
- Loosely packed feathers to prevent insulation and air moving between feathers
Describe the trends of grasslands and compare it to savannahs
- 4 seasons
- Monthly average temps go up and down over the course of a year as not inside tropical zone
- Temperate grasslands receive rain every month unlike savannahs which experience annual drought.
- Rainy when its hot and less rainy when its cool
What are granivores and give an example.
Animals that eat seeds and grain. Eg Quelea quelea
Compare the trends for tropical savannah and tropical rainforest.
- Savannah does not receive monthly rain like rain forests
- Seasons are marked by rainy and dry in savannahs
- Savannahs are tropical and subtropical grasslands with scattered trees and shrubs
A typical tree in the savannah is an acacia tree. Describe how it is adapted to the savannah conditions.
- Some have deep tap roots
- Thorns to minimise herbivory
- Leaf form is pre adapted to heat and water stress
What are:
- Obligate grazers
- Bulk grazers
- Selective grazers
Selective grazers – eat fewer species, typically more nutritious species
Obligate grazers- confined by certain parameters
Bulk grazers- eat anything, usually all species of grasses. Zebra are examples of this.
Describe two ecosystem engineers in savannahs.
Elephants- keep the savannah open by moving logs and trees
Termites- main grazer in african savannah. They eat lignin and plant material which does a lot of damage.
How does solar energy drive surface air patterns?
IT heats the air and causes local convection currents
How do elevation and attitude determine distribution of major vegetation zones?
The adiabatic lapse rate determines that every 100m gained in altitude decreases the temperature by 0.6˚C which therefore causes the organisms present to change
Describe how the vegetation changes from the equator to the Arctic.
Arctic circle
Polar ice Tundra Boreal forest Temperate forest Tropical rain forest
Equator
Describe the dominant plants in
- tropical evergreen forest
- tropical deciduous forests
- temperate deciduous forest
- boreal and temperate evergreen forest
-tropical evergreen forest
> trees and vines
-tropical deciduous forests
>deciduous trees
-temperate deciduous forest
> trees and shrubs
-boreal and temperate evergreen forest
>trees, shrubs and perennial herbs
Describe the features of a tropical evergreen forest.
- Major producer of oxygen
- Greatest source of biodiversity (both plants and animals)
- Lots of rainfall each year
- 2˚C temperature range
Describe the features of a tropical deciduous rainforest.
- Rainfall is an important abiotic factor
- Deciduous trees in the dry season
- Little temperature range- 5˚C
- Hot dry winters and hot wet summers.
Describe the features of a temperate deciduous forest.
- Cold snowy winter and warm moist summer
- 31˚C temperature range
- Rich in animas, rich biota
Describe the features of boreal and temperate evergreen forest.
- Tall trees
- 41˚C temp range
- Low species richness but trees preserve biodiversity but low diversity as few trees are able to survive at these temperatures
- Migrant birds move away when cold
- Tree lines common separating forest and tundra
- Most species conical and evergreen so snow falls off
- Leaves are waxy needles
- Mycorrhizae allow trees to obtain limited soil phosphorous
Describe the features of tundra.
-Range of 28˚C
-Short growing season due to low temperatures meaning plants can only grow a few months a year
-Permafrost (permanently frozen ground)
-Perrenial herbs and small shrubs
-
How does topography help plants survive in the tundra?
The cushioned topography of plants allows them to shelter from the wins and allows a microclimate to be created which is more favourable for the plant to survive
why does tundra have a low net primary productivity?
Because if the low nutrients, low temperatures and short growing seasons
Why is the low soil nutrients in tundra?
Low inputs from slowly decomposing plant litter
Why is soil thin in tundra?
Only a thin layer of permafrost melts each year, making soils thin and poorly drained. Also due to slowly decomposing plant litter so not much time for accumulation.
Why are bryophytes abundant in tundra?
They are non vascular plants so survive well due to the permafrost restricting the abundance of tracheophytes.
Why do plants in tundra tend to reproduce by budding an division rather than sexually by flowering
Because its energetically more expensive to produce flowers and pollination is hard due to large distances between plant groups and lack of pollinators.
How are arctic and alpine tundra differentiated?
Alpine tundra has better drained soil as little permafrost so soils are drier
How do cushion plants harbour their own compost heap?
They group together to insulate heat and so no mineral nutrients gets blown away from the cushion’s personal “compost pile”
Describe 3 important properties of water.
- High freezing and boiling point- allowing water to retain heat well and H bonds being in closest association at 4˚C
- Is a universal solvent, important inorganic materials available
- Transport and reaction system, fundamental to cellular life
Describe the turnover rates in fresh and salt water. What is a turnover rate. Why is there a difference between salt and fresh water.
The process of turnover occurs in autumn when the thermally stratified layers of the lake, the epilimnion cools and becomes more dense and sinks, causing “turnover” of the water in the lake.
Fresh water high turnover and salt water has a low turnover.
The difference is due to fresh water mainly occurring in lakes which can become thermally stratified in summer, allowing turnover as water cools in the autumn whereas salt water is usually in the oceans which flows and therefore does not undergo stratification so there is little turnover.
Describe the salt accumulation patterns in salt (ocean) and fresh waters.
Ocean has a concentration of salt due to evaporation. Fresh water has little salt accumulation due to liquid outflow.
Why is there lower biodiversity in fresh water?
In oceans there is less disruption so species can differentiate more easily- longer timescale for species differentiation
In fresh waters there is more (seasonal) disruption (due to turnover) which causes discontinuity and no escape, especially in lakes .
How does the depth of a lake influence habitat stability?
Shallow waters:
-Shallow water dries out so therefore is better suited to generalists to cope with the changing conditions and range of food
Deep waters:
-Never dry out so therefore fish are more specialist and resources are finely partitioned as small niches can be maintained
How did glacial periods affect dispersal and colonisation?
Glaciers caused changes in geomorphology that were important in shaping temperate freshwater communities (shaping their distribution )
Eg after the last glaciation, eastern rivers of England were connected to continental Europe
Describe the diversity in the UK due to the glacial period.
Eastern England most diverse and Ireland least diverse because it separated first (separated from glacier)?
