Environmental biology Flashcards
Define ecosystem
A community of plants animals and microorganisms with their environment
4 ecosystem services
- Supporting: required for the production of other services
- Regulating: benefits obtained by regulation of the environment
- Provisioning: material benefits obtained from the environment
- Cultural: non-material benefits obtained from the environment
What is the ecosystem approach
Integrated management of human activities, based off the knowledge about the ecosystem which aims to achieve sustainable use of goods and services
Examples of supporting services
- Nutrient recycling
- Photosynthesis
- water cycling
Examples of regulatory services
- Air quality
- Water quality
- Climate regulation: land cover can affect temp and precipitation
- Natural hazard regulation: soil absorbing water and barrier beaches, wetlands
- Pests and disease regulation: forests reduce standing water
Examples of provisioning services
- Food
- Fibre: wood fuel, timber, cotton and silk
- Water
Examples of cultural services
- Spiritual value
- Inspirational value
- Recreational value
Define biome
Major ecological community classified according to the predominant vegetation, and characterised by adaptions of the organisms
How climate change is affecting the mangrove ecosystem
Climate change effects stability sea level rise and rainfall:
- Increase in rainfall reduces salinity
- Reduced fresh water flow in dry season increase salinity
Ground water storage - 2 zones
- 2 zones unsaturated (upper layer, varying water levels) and saturated
- Saturated zone contains ground water
- Top of ground water is called the water table
Define an aquifer
A water bearing formation which has enough ground water capable to supply to people.
Ground water is a big contributor to public water supply.
Different types of water pollutants
- Inorganic
- Organic sediments
- Chemical plant nutrients
- Pesticides
What is salinisation
An excessive increase of water soluble salts in the soil
Causes of salinisation
- Irrigated areas with low rainfall and high evaporation rates
- Soil has a texture where it cant wash out salts
- Using water with high salt concentrations
- Natural disaster e.g. tsunamis
- De iceing roads with salt
Wetland ecosystem services
- Climate regulation: through sequestering and releasing major portions of fixed carbon in biosphere. Peat bogs hold 30% of carbon.
- Erosion protection
- Natural hazard protection
- Biodiversity
What are EU directives
Certain results that must be achieved by each member of state
What are the UK catchment abstraction management strategies
The amount of water you can take out of an area based on available water
What is artificial recharge
Increase the amount of water that enters a ground water reservoir by artificial means
Define biodiversity
The variety of life forms, the different plants, animals and microorganisms, the genes they contain and the ecosystem they form
Where is biodiversity needed
- Nitrogen cycle
- Pollination
- Agricultural products e.g Brassicaceae
- Medicine
- Cultural services: fishing, gardens and safaris
- Bioremediation
Brassicaceae
- Mustard family and approximately 3,700 species
- Forms 10% of vegetable crop, and a major source of biofuels
- There is a restricted gene poole due to crop domestication and breeding
- Can be bred to use nitogen, phosphorus and water efficiently as well as resist pests and disease, also have a longer shelf life as the c genome brassica have the same number of chromosomes
Define bioremediation
Some bacteria are able to biodegrade organic compounds, converts contaminants to less hazardous substances.
Whats causes changes to biodiversity
- Habitat change/ destruction
- Invasive species
- Pollution
- Climate change: affects distribution and phenology
What causes habitat change and destruction
- Urbanisation
- Fishing
- Fragmentation: populations become small and isolated leading to genetic drift
What is genetic drift
The change in allele frequency with which an allele occurs in a population due to random chance
Define ecology
The scientific study of the distribution and abundance of organisms; and the interactions that determine their distribution and abundance.
Factors that determine abundance and distribution
- Environmental conditions
- Resource availability
- Interaction with other organisms
- Ability to disperse to new areas
- Geographical barriers
- Evolution
Define competition
Interactions between organisms in which the fitness of one or both is lowered by the presence of another when they have a shared resource
Intraspecific competition
Within the same species
Interspecific competition
Between different species with similar ecological requirements
Why is population growth not exponential
- Limited resources
- Competition
- Density dependence
What is density dependence
- Rate of population growth is slowed with increasing population size
- Population is affected according to its size
- Ability to produce new offspring and mortality
What is interference competition
- Individuals interact directly
- Interfere with foraging, reproduction or by directly preventing physical establishment
What is exploitation competition
- Individuals don’t directly interact
- Individuals are affected by what remains after it has been exploited
Define predation
Consumption of one organism by another, prey is alive when the predator attacks
3 categories of predators
- True predators: Kill prey straight after attack
- Grazers: consume only a part of the prey, not usually lethal
- Parasites: consume only part of the prey, not lethal, intimate association with host
How do invasive species cause damage
- Out compete
- Predation
- Transmit pathogens
Characteristics of invasive species
- Tolerate a variety of habitats
- Grow and reproduce rapidly
- Lack natural enemies
- Aggressive for resources
Examples of invasive species
- Grey squirrel out competes the red squirrel as it can digest a wider variety of food sources, also carried a virus
- Himalayan balsam
Control to invasive species
Introducing natural enemies as a biological control agent. Should be specific predators.
e.g. pine martins feed on small mammals such as the grey squirrel as they spend more time on the ground
Define population
Individuals of the same species occupying a defined location at a defined time
Determinants of a population dynamic
- Abiotic conditions
- Intraspecific competition
- Interspecific competition
- Mutualism
- Predation
- Parasitism
Define mortality factor
What was believed to be the main cause of death in each phase of life cycle
How to calculate current population
N = N then + B -D + I + E
Define a patch and what are the key features
A homogeneous area that differs from its surroundings.
- Habitat size
- Dispersal difference
Define a metapopulation
A group of populations separated by space but consists of the same species. They interact as individuals move from one population to another.
Define community
Assemblage of species populations that occur together in space and time.
What determines a community
- Conditions and resources
- Internal dynamics
- Keystone species
- History
What are Gaps
Patches within which many species suffer local extinction at the same time
Types of succession
Primary succession:
- Development of a community new to the location
- Early colonisers tolerate new conditions
Secondary succession:
-Re colonisation of a community after a disturbance
What is systems ecology
How energy moves through an ecosystem to create food webs
How is energy lost through a food web
Energy is lost with each transformation between kinetic and potential forms
Units for energy
- Joules - energy requires to move 1kg through 1 m
2, Calorie - Heat required to raise 1 g of water to 1 degree
What is productivity
The fixing of energy in tissue and gametes
What is gross primary product (GPP)
The total amount of energy assimilated from photosynthesis
What is respiration (R)
The energy used in metabolism
What is net primary productivity (NPP)
The energy available after respiration for growth and reproduction
What is turnover
Time taken to replace the standing crop
What is the compensation point
Where light intensity is such that GPP = R
How do decidous plants reduce there energy expenditure
Shed there expendable tissues in winter to reduce their maintenance
What is a food chain
Transfer of energy down a sequence of trophic levels
How to calculate assimilation efficiency
energy assimilated/ energy consumed
How to calculate production efficiency
Energy fixed to tissue/ energy consumed
How to calculate growth efficiency
Energy fixed to tissue/ energy assimilated
Ectotherms and endotherms efficiencies
- Endotherms have lower efficiencies as they have higher metabolic costs associated with maintaining body temp
- Ectotherms have high efficiencies as they rely on the environment to maintain body temp
What are food chains limited by
- Cant be larger by 5 links
- Not enough territorial space to support the food chain
Sea otter a keystone species
- sea otters eats sea urchin which eats kelp
- Overfishing means whales now eat sea otters meaning less kelp forests
What is a food web
Linked food chains
Characteristics of the food web
- Ratio of predator to prey stays the same for different communities
- Number of linkages is double the number of species
- Length of food chain is independent of habitat type
Uses of food chains
- Wildlife conservation by knowing how they interact
- Agriculture to reduce the number of links
4 electron acceptors
O2, NO3^-, SO4^2-,Fe^3+
3 electron donors
NH4, Fe^2+, H3^-
Where did life begin
Hydrothermal vents:
- Coupled H2 oxidation to CO2 reduction
- Leads to acetyl coA
- Synthesis of acetate and CH4 from H2 and CO2
- CH4 is a greenhouse gas
- Origin of cellular life from self replicating RNA
What is the great oxygenic event
Increase in atmospheric O2
Define weather
The condition of the atmosphere at a particular time and place with regard to temperature, moisture, cloudiness
Define climate
The general condition of atmosphere over the last 30 years
Evidence of climate change
- Glaciers shrinking
- Loss of ice on the mountains
- Fall in arctic sea ice
- Thawing of permafrost
- Sea level rise
- Extreme weather
Summary of temperature change over the past 100 years
- Global temperatures have risen by 1.2 degrees
- Land warms faster than oceans
- Arctic temperatures increase double the rate of the global average
Summary of precipitation change over the last 100 years
-Has increased over land north of 30 degrees north
Long term factors of the climate
Milankovitch cycle: 100,000 years
- Eccentricity: shape of orbit
- Precession: Earths wobble
- Tilt: between 21. 5 and 24.5 degrees
Short term factors of climate
- Sun spots: more spots the more radiation 11 year cycle
- Volcanoes: Ash clouds prevent light reaching the surface
- Ocean oscillation: el nino and la nina
El nino
Weak trade winds bring warm water to the east pacific, effecting the jet stream causing an increase in global temperature
La nina
When strong trade winds causes an upwelling of cold water in the east pacific and a fall in global temperatures
What can you learn from ice core data
- Temperature from oxygen isotope ratios, the warmer it is the greater the depletion of O18 due to evaporation
- CO2 concentration of air trapped in core
- Carbon isotopes used for dating
Origin of antropogenic CO2
- Burning of fossil fuels and deforestation.
- CO2 added by humans
- Burning fossil fuels lower 13C:12C ratios in the atmosphere
What is radiative forcing
A measure of how the energy balance of the earths atmosphere system is influenced when factors that affect climate are altered.
2 sources of methane
Biogenic: ~ 70% global total
-Methanogenesis of acetic acid in livestock, wetlands, landfills and oceans
Non-biogenic:
- Fossil fuels
- Biomass burning
- Waste treatment
Sinks of methane
- Atmosphere
- Soil
- Stratosphere
Different greenhouse gases
Nitrous oxide
Carbon dioxide
Methane
CFCs
Nitrous oxide
230x more potent than CO2
Long lived 110 years
Halocarbons (CFC)
- Leads to the destruction of the ozone
- Limited use to the montreal protocol
What are Aerosols
- Small particles suspended in the atmosphere
- Absorb radiation and scatter it back into space
- Causes overall cooling
- E.g sulphates aerosols from volcanoes
Define albedo
- The fraction of solar energy reflected from the earth back into space.
- Snow and clouds have a high albedo
2 roles of the ozone
- A green house gas
2. Filters out UV radiation
4 storylines from the special report on emission scenarios
A1
A2
B1
B2
A1 storyline
-Rapid economic growth
-Global population peeks in the mid century and declines after
-3 further groups:
Fossil fuel intensive
Non fossil energy sources
Balance across all sources
A2 storyline
- A heterogeneous world
- Continuously increasing global population
- Economic growth is slower
B1 storyline
- Convergent world
- Global population peaks in the mid century and declines after
- Rapid changes to economic structure to services and information
- Introduction of clean and resource efficient technology
B2 storyline
- Local solutions to economic, social and environmental stability
- A continuously increasing global population
- Intermediate levels of economic growth and less rapid and more more diverse technological change
What is the representative concentration pathway
Scenarios based on total radiative forcing in the year 2100 compared to 1750
Impacts on oceans and low lying regions
- Increase in sea surface temp causing coral bleaching, change fish migration and increase disease and algal blooms
- Decrease pH and increase in acidity results in declining calcification
- Increase sea level rise due to thermal expansion and melting of ice caps
- Flooding/ submerged low lying land
- Salination of water and soil so less vegetation
Impacts of food production
- Increase CO2 increases photosynthesis of C3 plants, enhancement of crops
- Increase temp reduces yield of cereal as they develop faster and cant fix as much CO2
- Temperate regions benefit from increased temp due to longer growing season
High temp winter on crops
- May not develop cold hardiness and die due to late frost
- Flowers may not develop the next year
Elevated CO2 levels effects on crops
- Partial close of the stomata
- Reduced C02 diffusion and water loss
- Plant becomes more water efficient
Impacts on livestock
- Thermal stress reduces reproductive potential
- Drought and climate variability might lead to livestock loss
Define mitigation
Actions that reduce greenhouse emissions
Examples of mitigation
- Energy efficiency
- Reducing need to travel, increasing public transport
- Renewable energy
- Reducing biodegradable waste in the landfill
- Promote land use on carbon sinks
- Emission reduction strategies
Adaptions
Actions that minimise or prevent negative impacts of climate change
Impacts of climate change
- Loss of biodiversity
- 10-15% of the worlds species could become extinct over the next 30 years
- Increase temp
- Variable precipitation
- Increase flooding, mass population displacement
Different adaptations for flooding
- Strategic development on locations offering better protection
- Ensuring building are resilient to climate change impacts
- Suitable drainage and water efficiency in buildings
- Increase flood storage capacity and develop new water resources
- Suitable flood management and migration of habitats and species are not foreclosed
Food adaptions to climate
- Increase with irregation, fertiliser and seed development
- Change diet from beef to reduce methane
- Breed crop varieties that are tolerant to heat, drought and water logging
- Protect livestock from heat with shade and air flow
Define conventional farming
Uses all available tools to increase yield
Define organic farming
Natural methods are relied upon to increase yield and control pests and disease. No synthetically produced compounds used.
Define low input agriculture
Uses less synthetic fertilisers and pesticides recommended
Science and technology in agriculture
- Knowledge about crop, pest, weed, disease to manage crops
- Precision farming
- Crop genetics
