Ecosystems Flashcards
Define ecosystem
A physical area that Includes all living organisms and non living components and there interactions with each other
Define population
A group of organisms of the same species living in the same area at the same time and can breed together
Define community
Populations of different species living together in the same area area and can interact
Define habitat
A place where an organism lives
Define niche
The role of an organism in its environment includes what it eats, habitat, competition
Define species
A group of similar organisms that can interbreed to produce fertile offspring
Define ecology
The study of interactions between living organisms and their environment
Define biotic factors
Living factors of an ecosystem
Disease, predation, competition
Define abiotic factors
Non living factors
Temp, ph, light intensity, wind velocity
What does it mean if an ecosystem is dynamic
It means they are constantly changing
What is competition exclusion principle
When an organism shares the same niche and they outcompete each other
State and describe three types of ecological interaction that occur between different species in a habitat
Give an example of each
-interspecific competition Grey and red squirrels - predator-prey interaction Lynx and hare -mutualism- both partners benefit Crocodile and Egyptian plover bird
Describe mutualism
Where both partners benefit
Crocodile lies with its mouth open and Egyptian plover flies into the mouth and eats the decaying meat stuck in the teeth
Why is only 2% of the suns energy used by producers
90% reflected by leaf
Only some light wavelengths is used by chlorophyll in plants , most is transmitted
3 reasons why energy is lost at each trophics level
- heat during respiration
- movement contraction
- faeces/ indigestible material
Define the term producer
An organism that converts light energy into chemical energy through photosynthesis
Starts the food chain
Define consumer
Organisms that obtain energy by feeding on other organisms
What is a trophic level
Each stage of a food chain
Describe a pyramid of numbers
Shows the numbers of the different organisms
Producers always at the bottom
Does not account for the size of organism
Caution- parasites have small sizes and large reproductive cycles
What is biomass
Dry mass
What are the measurements for biomass
gym^-2
What’s a disadvantage of a pyramid of biomass
They are difficult to get data for and organisms must be killed to
Explain the process of finding biomass
Takes organism from environment and remove the soil
Dry in a oven at 105°c to evaporate water
Weigh until the mass remains the same
What is the most accurate pyramid
Pyramid of energy
What is the units used in a pyramid of energy
kJm^-2 year^-1
What is the process of finding energy in a pyramid of energy
Takes organism from environment and remove soil
Dry in oven at 105° to evaporate water
Weigh until mass remains the same
Burn in O2 and record temp rise of fixed volume of water using a calorimeter
What percentage of the suns energy is used by producers
2%
Why is the percentage of suns energy so low
90% reflected by leaf
Only some light wavelengths used by chlorophyll
Only some is absorbed most is transmitted
I’m
What is the job of decomposed and detritivores
They break down organic molecules (proteins, carbohydrates) into inorganic molecules (CO2, nitrate and phosphate)
Define gross primary production
The total solar energy that is converted into organic matter in producers
Define net production
What’s left of the gross production after respiration has occurred
What’s the formula for % efficiency
(Energy after transfer / energy before transfer) x 100
What is the formula for net production
Gross production - respiratory loss
How can a plants net production be lowered
How can this be monitored
- eaten by pests- pesticides
- leaves fall off- shelter from wind
- not enough water-irrigation
- not enough light- use artificial light
How could photosynthesis be controlled
Light wave lengths can be controlled if dark
Temperature controlled by heaters and ventilation
C02 controlled by burning fossil fuels
How may productivity of livestock be increased
- prevent predators eating them- keep them fence in
- killed by disease- give them vaccinations
- high protein diets
- restrict movement (avoid energy loss)
Define decomposition
The chemical process where larger organic molecules are broken down into smaller inorganic molecules
What are decomposers
And what do they do
Organisms that feed on and break down plant or animal matter
They turn organic molecules into inorganic molecules
What are saprotrophs
What do they do
Obtain energy from dead or waste organic material
Extracellular digestion which means enzymes are secreted outside the cells
What are detritivores
Organisms that feed on dead and decaying material
They break it down into smaller pieces of organic material
These increase surface area for decompsoers
Speed up the rate of decomposition
Perform internal digestion
Describe the carbon cycle
Carbon compounds in producers➡️carbon in primary consumers➡️ carbon in secondary consumers➡️decomposers
Burn fossil fuels
Decomposers and fossil fuels both release CO2 into air and oceans
What’s the formula for photosynthesis
Carbon dioxide n water= oxygen n glucose
Describe carbon levels during the day and night
During day- less CO2 lots of photosynthesis
Night- more CO2 no photosynthesis
Which biological molecules contain nitrogen
Amino acids
Proteins
DNA
RNA
ATP
What makes nitrogen difficult to break
It is a triple bond
What percentage of nitrogen is in the air
78%
Describe Azobacter
Free living nitrogen fixing bacteria living in the soil
Convert nitrogen in the air into ammonium ions using nitrogen add enzyme in the bacteria
Describe Rhizobium
Nitrogen fixing bacteria that live in root modules of leguminous plants like peas and clover
It’s a mutualistic symbiotic relationship, plants gain amino acids and rhizobium gain glucose from plants from respiration
What does symbiotic mean
Live close to each other
Describe nitrification
An oxidation reaction
Nitrosomonas bacteria oxidise ammonium compounds into nitrites
Nitro after oxidise nitrites into nitrates
Nitrates are highly soluble and are the form in which more nitrogen enters a plant
Describe non living nitrogen fixation
Lightning- electrical energy in lightning combines nitrogen and oxygen in the air to produce nitrites and nitrates
What do denitrifying bacteria do
Convert nitrates back into nitrogen gas
Happens in anaerobic conditions in waterlogged soils
What process do decomposers do
Ammonification
What does succession occur as a result as
Changes in the abiotic factors of an environment
Caused by decomposition of current species making environment suitable for new species
Other species inter specifically outcompete earlier species and the process repeats until a climax community is formed
What is primary succession
Starts with the bare rock or sand
There is no soil or organic material present to begin with
This could occur after a volcanic eruption when all soil and dead matter has been destroyed
Explain secondary succession
Starts with a thin layer of soil such as in a forest clearing after a fire or flood
What’s is the technical term for the states of succession
Seral stages
Name two examples of pioneer species
Name two properties
Lichens and mosses
Can photosynthesis to produce their own food
Can cope with extreme abiotic conditions
How do pioneer species arrive
As spores or seeds carried by winds from nearby land masses or from droppings of birds
What is humus
Dark organic material that forms in the soil when plant and animal matter decays
Contains many useful elements for healthy soil
How do secondary colonisers arrive
Give an example
As spores and seeds
Mosses
Give an example of a tertiary coloniser
Ferns or grasses
What is scrubland
Small trees and shrubs with many deep roots now take over
This changes in abiotic factors and they out compete the earlier species
What does a climax community consist of
Consist of animals and plants that have displaced earlier species
Succession is now stopped, there are a few dominant species
What is animal succession
As the plant species change more habitats and food for consumers are created
What is deflected succession
Where succession is halted
Describe an example of deflected succession
Grouse- we burn the heather to prevent it reaching climax community, grouse shooters lay for heather to be burnt so they can shoot the grouse that depend on the heather
If we didn’t do this, pine and birch would outcompete heather and the grouse would be displaced
