Ecosystems Flashcards
Biomass
The total weight of biotic material
Structure of an eco-system
Inputs – seeds blown, animal migration, water
Outputs – animal migration, water loss, leaching of nutrients
Stores – nutrients held in biomass, litter and soil
Flows- all transfers of energy and nutrients
Each eco-system is in an equilibrium – the balance between biotic (living) and abiotic (non-living)
Trophic levels
Tertiary Consumers Secondary Consumers Primary Consumers Producers Insolation
how do plants grow
Photosynthesis + Chlorophyll covert CO2 + H2O into carbohydrates and tissue
Gersmehl’s Nutrient Cycle
he movement and exchange of organic and inorganic matter back into the production of living matter.
Biomass store
contains all living plant and animal matter
Soil Store
contains minerals from rock in addition to humus from decomposed matter
Litter Store
sits on top of the soil and contains both dead and decaying plants and animal material
What operates at each trophic level
Decomposer- breaks down dead matter (Fungi)
Detritivores – feeds on dead matter
Biome
Ecosystem at continental scale with vegetation characteristics predominately influenced by climate. Can be classified by vegetation growth.
Ecosystem
– dynamic, stable equilibrium between biotic and abiotic at any scale.
Environment
All conditions which an organism lives.
Food Chain
Hierarchy where each member feeds upon another in a chain.
Food Web
When organisms within a community eat more than one type of food and the chain becomes interlinked.
How is energy lost in the food chain
At each trophic level 90 % of energy is lost through life processes-respiration, movement and excretion
This is why there are less organisms at each stage
Examples of the trophic levels
Tertiary consumers (predators or omnivores=plants and meat eaters) Secondary consumers (carnivores) Primary consumers (herbivores) Producers/Autotroph (plants)
Succession and climatic climax
Composition of vegetation depends on interaction between each component
Plants survive on suitable conditions
The change in a plant community through time is succession
If allowed to continue succession will reach climatic climax where species live in perfect balance with conditions
Climate is the major influence as well as drainage, geology and relief affect
Primary Succession
Primary succession occurs on the surfaces that have had no previous vegetation – lava flows, bare rock and sand dunes
Xeroseres
Xeroseres form on dry land – subdividing into lithoseres on rock and psammoseres on sand dunes
Hydroseres
Hydroseres form on water – haloseres on salt water
Secondary Succession
Secondary succession follows the destruction or modification of existing plant community
Naturally- landslide or fire
Human Activity – deforestation or agriculture
Stages of succession
Bare Rock 1 Colonization 2 Establishment 3 Competition 4 Stabilization Seral Climax
Bare Rock Succession
- Bacteria survives on few nutrients
- Mostly survives on energy from sun
- Soil is little more than particles of weathered rock
Seral Stage 1
COLONIZATION
- Pioneers like lichens survive on dry, windy and soil-free conditions
- As they die, simple soils is created, improving water retention
- Mosses develop
Seral Stage 2
ESTABLISHMENT
- Ferns and small bushes appear
- Species diversity increases
- More invertebrates living in the soil, means there is more organic material and more water
Seral Stage 3
COMPETITION
- Larger plants like shrubs and small trees
- Steal light and nutrients so earlier plants die and add to the soil
Seral Stage 4
STABILIZATION
- Fewer species colonize
- Complex food webs
- Dominated growth by birch and rowan
Seral Climax
- Max potential development
- Climatic climax of Ash and Oak
Polyclimax
Environment is influenced by local factors so climatic climax differences within biome are possible
Deciduous Woodland Energy
High energy biome – 1200 NPP (net primary productivity = energy absorbed – energy lost)
Deciduous Woodland Canopy
- Tall tress with large crowns and broad but thin leaves, dominant – Oak 20m+
- Shed leaves in winter reducing transpiration
- Few dominant species
Deciduous Woodland Stratification
Layers- most show
Deciduous Woodland Below the canopy
Below the canopy is a shrub layer with smaller trees- holly, hazel
Deciduous Woodland below the shrub layer
Below the shrub layer is the herb layer which can be dense if enough light filters through – grass, fern, bracken
Deciduous Woodland Epiphytes
Epiphytes – lichens and mosses grow on tree trunks and on the forest flow
Plagioclimax
The resulting vegetation from human interference (de/afforrestaion, grazing) is called the plagioclimax
History of heather moorland
Deforestation led to the deterioration of soils so hardy plants like heather moorland dominates highlands
Sheep grazing became the major form of agriculture and sheep destroy young saplings preventing regeneration of climax
Much of this land is managed by burning to encourage new heather shoots, eliminating less fire-resistant species, leading to further heather dominance
Burnt on average around every 15 years, any more and the fire wood become to hot due to wood matter and nutrients are lost
Each stage of heather moorland
Pioneer Phase (0-6yrs) Building Phase (6-15yrs) Mature Phase (12-28yrs) Degenerate Phase (20-30yrs)
Pioneer Phase
0-6yr
Small shoots among dead heather stems as well as moss and lichen
Building Phase
6-15yrs
Dense dome shaped plant, flowers dominant so little light allows few other plants to grow
