Ecosystems Flashcards
Define exposure
facing into the sea with prevailing winds
What are the abiotic factors affecting periwinkles on the lower shore?
- harsh winds
- cold temperatures
- tides
What are the abiotic factors affecting periwinkles on the upper shore?
- lack of water
- formations of sand dunes
- litter from humans
What are the biotic factors affecting periwinkles on the upper shore?
- humans destroying habitat
- more predators
What are longworth traps?
Traps for small mammals
What are the limitations of a Longworth trap?
- can become trap happy - not accurate if learn to come back for food
- can’t record smallest mammals like shrews as will die due to high metabolism
- sometimes don’t trip the trap
Define succession
progressive change in a community of organism’s overtime
Define an ecosystem
A community of animals, plants and bacteria integrated with the physical and chemical environment
Define habitat
Place where an organism lives
Define population
All the organisms of one species, who live in the same place at the same time and who can breed together
Define community
All the populations of different species who live in the same place at the same time and who can interact with each other
Define niche
Role of an organism within its habitat
What are examples of biotic factors?
- competition
- disease
- predation
What are the examples of abiotic factors?
- light levels
- wind
- humidity
- soil structure
- PH
- Temperature
What are the 3 kinds of dynamic factors?
- cyclic
- directional
- eratic
What are directional factors?
- go in one direction
- last longer than lifetime of organisms
- e.g. deposition of silt, erosion of a coast line
What are cyclic factors?
- rhythmic changes
- e.g. predator and prey relationship seasons
What are erratic factors?
- no rhythm and no constant direction
- e.g. effects of hurricane and lightning
What are biomass transfers?
- at each trophic levels energy is lost
- lost to life processes, dead organisms and waste material
- represented in pyramid of numbers
How is the efficiency of biomass calculated?
biomass at higher level / biomass at lower level X100
Define gross primary productivity
The rate at which plants convert light energy and chemical energy through photosynthesis
Define net primary productivity
The proportion of energy from the sun available to enter the food chain
What is secondary relating to?
Animals
What are the methods for improving primary productivity?
- plant crops early so there is a longer growing season to harvest more light
- plant drought resistant strains
- grow plants in a green house as it makes it warmer and increases the rate of photosynthesis
- crop rotation to stop reduction of particular ions in the soil
- spraying with pesticides to stop from loosing biomass to insects
- fungicides to stop the plants from dying
What are the methods of improving secondary productivity?
- harvest animals before adulthood to stop energy lost to growth
- selective breeding
- antibiotics to stop the loss of energy to pathogens
- zero grazing/movement to stop energy loss
Define decomposers
Organisms that feed on dead and organic waste material releasing the nutrients and energy
What are the two types of decomposers?
- Detritroves
- Saprotrophs
What are saprotrophs?
They secrete digestive enzymes externally and then absorb the small molecules
What is an example of saprotrophs?
Fungi and bacteria
What are detritroves?
Ingest larger amounts of dead matter and break this into smaller molecules
What are examples of detritroves?
Earthworms and Woodlice
Where is the nitrogen?
- In the air (78%)
- Amino acids/proteins
- Urea
- Ammonia
- Ammonium
- Nitrites
- Nitrates
What are the different processes cycle nitrogen?
- feeding and assimilation
- absorption of nitrates
- deamination
- ammonification
- nitrogen fixation
- nitrification
- denitrification
