Life Processes In The Biosphere- Ecological Succession Flashcards
What is essential in all species life cycle to avoid extinction?
When movement to colonise new habitats takes place as changing conditions make the current location unsuitable for survival
How long can the period of survival be in an area?
It may last a long time or it may be very short
What is the most important thing species must do with in their lives?
Move, colonise, grow, breed then colonise and populate other areas
What happens when species moves to a new area?
It will change the habitats which may make it suitable for other species to colonise that could not have survived there before
What is the name for the sequence of events that occur when a new habitat is created?
The events that follow are called a SERE
Where is is it possible to see the full range of processes and stages in the changes to a habitat?
A newly created habitat which currently has no life
What are some examples of new habitats that wont have any life present?
A new pond
Bare rock- exposed by retreating glacier
A landslide
A volcanic eruption
What are all the types of SERE with their prefix?
Water- Hydrosere
Bare rock-Lithosere
Sand- Psammosere
What is the name for the changes that take place in a SERE?
Called ecological succession
What are the characteristics of the first species to colonise a new habitat?
Must be adapted to abiotic conditions which are very extreme then in a developed habitat
What are some of the more intense abiotic factors in a new habitat?
Less shelter from:
- strong winds
- brighter sunlight
- more extreme temperatures
What are the first species to colonise an area called?
Pioneer species
What do pioneer species do over time?
They change the habitat and makes it suitable for species that were not able to survive before
What happens to a newly created habitat when the pioneer species make it more suitable?
The new colonisers may out-compete the pioneer species which become less dominant and may die out eventually
What does the first colonisation after pioneer species do to the habitat?
The new colonisers also change the conditions making it more suitable and more species colonise
What happens as the changing abiotic factors become less extreme?
The adaptations needed for survival are increasingly based on biotic factors and inter-species relations
How is a climax community created?
After the cycle of colonisation, thriving, death continues a final community of specie develops which remain dominant as long as the climate does not change
What are the species controlled by in a climax community?
The climate
How do temperature extremes change during ecological succession?
High to low
How does water availability change during ecological succession?
Variable to reliable
How do light levels change during ecological succession?
High to lower (if shading occurs)
How does nutrient availability change during ecological succession?
Low to high
How does the rate of change change during ecological succession?
Rapid to slow
How does the main pollination method change during ecological succession?
Wind pollination to insect pollination
How does the main seed dispersal method change during ecological succession?
Wind dispersal to animal dispersal
How does the importance of inter species relations change during ecological succession?
Low to high
How does biomass change during ecological succession?
Low to high
How does biodiversity change during ecological succession?
Low to high
What are critical determinants of a biome?
Rainfall
Temperature
What is an example of rain and temperature determining a biome?
When water is available throughout the year a woodland will develop
High temperature will create a tropical rainforest
Moderate temperatures will develop a temperate deciduous forest
Cooler temperatures will develop a conifer forest
What is a SERE?
A sequence of stages in ecological succession during which an uncolonised habitat develops into a climax community
What is the first thing to colonise a newly created area of fresh water?
Single celled algae from the soil
What brings spores and seeds of algae, diatoms, and plants?
Birds- herons or ducks
Flying insects- water beetles or pond skaters
What rooting plants will first colonise the edges of the fresh water habitat?
Reeds
Lilies
Reedmace
Why are floating plants most likely the only plant currently in the open water?
The open water may be too deep for plants so floating plants live there
What happens as the plants grow and die in the fresh water habitat?
The water gradually fills with DOM as well as soil and sediments carried in forms he surrounding area
What happens as the water becomes shallower in a fresh water habitat?
Conditions continually change until rooted plants can survive
What is the name for plants with their leaves above the water?
Emergent plants
What happens when emergent plants start growing?
They shade the submerged plants which gradually die out
What happens as sediments fill the fresh water habitat?
The water recedes, aquatic species progressively disappear
What happens when enough soil accumulates in the fresh water habitat?
It develops to the extent that it can support the weight of much bigger plants, trees that can survive water logged soil
What trees can survive water logged soil?
Willow
Alder
What happens as the soil becomes drier? (Hydrosere)
Trees such as oak can colonise
How can the soil become drier? (Hydrosere)
Transpiration by trees
More sediment accumulates
What happens when oak colonises an area?
Larger trees create a denser canopy providing shade which inhibits the growth of smaller plants
What happens after large trees have stated colonising the habitat?
Will become dominated by larger trees with other plants and animals surviving under them
What is a lithosere?
The development of species on bare rock created by a cliff fall, glacial retreat or volcanic eruption
What are the initial abiotic factors like in a lithosere?
Very harsh and unsuitable for most organisms
What are the abiotic conditions in an early lithosere?
Temperatures are extreme
Water availability is severely limited
There is no soil
What are the first species to colonise bare rock?
Simple autotrophs- lichens and algae
What do autotrophs do in the habitat?
Break down rock and lead to an accumulation of DOM and rock
What is next to colonise bare rock after autotrophs?
Mosses
What do mosses do to bare rock?
Thy break down the rock and create a very thin layer of soil
What colonises the lithosere after mosses?
Grasses and ferns
What happens to abiotic factors in the lithosere as more soil layers form and plants get bigger?
The abiotic factors become less extreme
What are some examples of what abiotic factors are like after some development in the lithosere?
Never as:
- warm or cold
- wet or dry
Before development
How do seedlings of less hardy plants survive?
They can survive under the shade of larger plants
What can happen when pollinating insects become established? (Lithosere)
Flowering plants colonise and survive as pollination takes place
What are edaphic factors?
Soil factors
What happens when edaphic factors are suitable?
Trees can colonise
What are the first trees that usually colonise the lithosere?
Those with wind blown seeds such as birch
What trees will colonise later into development? (Lithosere)
Those that are dispersed by animals such as beech and oak trees
At what point are the Hydrosere and lithosere similar?
In the later stages of development as they are controlled by the climate of the region
What is Psammosere?
The ecological succession that starts on sand
Why is it hard for habitat development in sand?
Nutrients are not readily available
Drainage is rapid so water supplies are poor
Moving sand makes it difficult for plants to establish a good root hold without being covered and killed
What happens when plants succeed at colonising sand?
The sand is stabilised
Nutrient supplies increase
Organic matter builds up water becomes more available
What is a plagioclimax?
When human activity deflects the climax community regularly so the natural climax community does not have time to reform and a new plagioclimax community develops
What sort of habitats are plagioclimax?
Those that don’t seem to change
Grassland
Lowland heathland
Moorland
How is conservation os plagioclimax communities done in the UK?
Through the maintenance of the traditional activities that created them
How are lowland heathland managed? (Plagioclimax)
Grazing or burning
How are hay meadows managed? (PC)
Mowing
How are wet meadows managed? (PC)
Grazing
How is Upland Moorland managed? (PC)
Grazing or burning
How is arable field managed? (PC)
Ploughing
How is garden lawn managed? (PC)
Mowing
How is coppiced woodland managed? (PC)
Felling at intervals of 8 to 20 years
How are reedbeds managed? (PC)
Mowing or cutting
What happens if humans activities stop in a PC community?
Secondary succession will eventually re-establish the climax community
What is secondary succession?
When a human activity (Burning) takes place it might recreate or restart conditions suitable for previous species to colonise and the cycle of succession will start from there
Why is secondary succession faster than primary succession?
The soil does not have to develop an many seeds will already be present so there are fewer delays caused by time taken for species to colonise
