2.4 - Biomes, Zonation And Succession Flashcards
Define biome
Collection of ecosystems sharing similar climate conditions
List some types of biomes
Aquatic
Deserts
Forests
Grasslands
Tundras
How does isolation affect photosynthesis
The greater the isolation the higher the rate of photosynthesis
How does temperature affect the rate of photosynthesis
The greater the temperature the higher the rate of photosynthesis
How does precipitation affect the rate of photosynthesis
The greater the precipitation the higher the rates of photosynthesis
What can influence the distribution of biomes
Latitude and altitude
State a type of biome
Desert
Name 3 biomes
Tropical rainforest - the amazon - Brazil
Tundra - islands of artic - artic and alpine
Describe how latitude affects isolation and temperature
It generally gets colder as you increase the latitude. This is because at the equator solar radiation into the earth at 90 degree angle so its is more intense as you move away from the equation the rays hit the earth at a more acute angle so are spread out over a greater surface area
Why does a higher perceipitation to evaporation ratio result in a high p/e results and low soil fertility
It rains or snows al or and evaporation rates are low. Then there is leaching in the soil when soluble minerals are washed downwards
Precipitation to evaporation ratios influence soil conditions. Explain why a low p/e results in salinisation of soil
Water moves upwards through the soil and evaporates from the surface. This leaves salts behind and the soil salinity increases
LOOK AT THE TRICELLULAR MODEL
Outline the changes that are occuign worldwide as a consequence of global climate change
With changes in global temperatures in the future models suggest a north/south shift in biomes relative to to the equator. Biomes will also move up slopes as on mountains. Low lying biomes e.g. mangroves may be lost due to sea level rise
Briefly explain the ways some species are moving in response to climate change
Plants can only migrate very slowly as seeds are dispersed by wind or animals. Animals can migrate longer distances - they will move towards the poles where it is cooler, higher up in the mountains where it is cooler, towards the equator where it is wetter
Summarise the limits to species movements and migration
There are natural obstinaos to migrantion like mountain ranges and seas and ones caused by human activities such as roads, agriculture fields and cities.
Define zonation
Is the change in community along an enviromental gradient due to factors such as changes in altitude, latitude, tidal level or distance from shore/coverage by water. Tends to occur in parallel lines
Who does temp vary with altitude
Temperature, decreases as altitude increases
Who does precipitation change with altitude
On mountains, most rainfall is at the middle altitude and plants have to adopt
How does soil type change with altitude
In warmer zones, decomposition is faster so soils are deeper and more fertile. Higher up decomposition is slow and the soil tends to be more acid
How does interaction between species change with altitude
Competition may crowd out some speacies and grazing may alter plant composition
What is meant by succession
Is the process of change over time in an ecosystem involving pioneer, immediate and climax communities
Distinguish between primary and secondary succession
Primary succession occurs on bare ground where soil formation starts the process
Secondary succession occurs where soil has already been formed but the vegetation has been removed.
When might primary succession occurs
New land is created or uncovered
What is a circumstance when secondary succession might occur
Established community destroyed fire, flood …
Describe the change in both NPP and GPP that occur throughout succession
Early stages : low gpp but high percentage NPP
Middle stages : high gpp, lower NPP
Later stages : high gpp, NPP reaches zero
Explain the changes in both NPP and gpp that occur through succession
In the early stages the Gpp is low because of the law density of producers duc to lack of soil water and nutrients.. The Npp is high as the portion of energy lost during community respiration is low. (the elcosystem is growing and biomass is accumulating)
The specific climax community that is formed from succession will vary. Explain why this is.
In a climax community there are continuing inputs and outputs of matter and energy but the system as a whole is in more or less steady state equilibrium, This equilibrum will vary depending on the climatic factors, propertics of the local soil and a range of random events.
List the ways in which humans can disrupt the process of succession.
Agriculture, hunting, forest vlearing, burning and grazing - all divert the progression of succession b an alternative stable state - onginal llimax hot reached
When succession is disrupted, the system may recover quickly or slowly from the disruption, depending on its resilience. Explain what is meant by ecosystem resilience.
The ability of a system to retum jo its inial state after a disturbance.
The mae complex and diverse an ecosystem, the more resilient it will be as there are more interauhons behween diflerent speues.
LOOK AT THE STAGES OF PRIMARY SUCCESSION
