Section 3: Ecology and Environment Flashcards
What is Ecology?
“interactions between organisms and
their environments”
What is a Community?
“populations of different species
living in the same area”
What is the order of the ecologies? ( smallest to largest )
Organismal -> Population -> Community -> Ecosystem -> Landscape -> Global
What are two ways to measure diversity? (in ecology)
Species richness
Species evenness
What is the shannon index?
Shannon Diversity Index
H = − sum[ (Pi) × log (Pi) ]
H = Shannon diversity
Pi = proportion of species i in the community
It is Pi not like 3.14
What are the different types of Diversity ?
Diversity may be:
Taxonomic, Phylogenetic, Genetic, Functional, Interaction, Spatial, & Temporal.
What is one way interactions between species can be shown?
Interactions between species can be structured into networks of energy flow - food webs
What are foundation species?
Some species have outsized impacts on ecosystem dynamics. Create the structure or conditions necessary for
the ecosystem to function
3 reasons biodiversity is important?
- Stable
- Resilient
- Productive
What causes the areas around the equator to be more biodiverse?
Abiotic Factors
- Temperature
- Sunlight
- Temperature
- Nutrients
- Water/humidity
Biotic Factors
- Food / prey
- Predators
- Competition
What does species richness depend on?
Species richness dependents on the balance between immigration and extinction
What is fragmentation?
Human activity is creating islands. Dividing habitat creates fragments and multiples the amount of edge. Small fragments suffer the same problems as small islands
What is Disturbance in Dynamic extinction & colonisation?
Natural ecosystems are in a constant state of change
Abiotic, biotic, & anthropogenic factors
What is Succession in Dynamic extinction & colonisation?
After a disruptive event the distribution of resources will differ. Sunlight, nutrients, competition, etc.
Creates a patchwork of conditions
What is the role of ecosystem engineers in Dynamic extinction & colonisation?
Need patchwork of areas to survive. Keystone species can also create these patchworks
Metapopulations example?
GO TO LECTURE 26 - “CONSERVATION”
Extinction has 4 factors, what are they?
Into the population (inflow) - Births, immigration
Out of the population (outflow, causes extinction) - death, emigration
What is important of Most species having small
ranges?
Vulnerable to stochastic events
Fragmentation, and disruption to metapopulations
Risk an ‘Extinction vortex’
What does successful conservation need?
- Connectivity
- Macro-ecological processes
- Foundation & Keystone species
What is the problem with completely stopping habitat management?
Our landscapes have been altered greatly, stopping management will not necessarily return the system to its original state
Invasive species or lost connections/behaviours will reform in new configuration
Rewilding ≠ No Management
What are some misconceptions about rewilding?
We need to understand the natural ecosystem and misplaced rewilding can threaten important
native habitats
e.g., focus on reforestation (for rewilding or carbon capture) can threaten habitats like grassland, wetlands, and bog
Some benefits of Rewilding?
Tourism
Natural flood protection
Natural water purification
Natural pest control
Natural pollinator reservoir
Carbon sequestration
Natural soil
preservation/enrichment
Recreation / healthy living
Resilience to climate change
In Ecosystems as biochemical cycles, what is the order of the flow?
Photosynthetic / chemosynthetic autotrophs convert environmental energy (e.g., sunlight) and inorganic compounds into organic molecules
Heterotrophs feed on producers
Decomposers feed on dead organic matter
What are problems with the biochemical cycle of the ecosystem?
Energy flow is very inefficient (~10%)
Energy lost from the system as heat through respiration and action
Nutrients cannot be created or destroyed, only converted, and so are recycled
Energy flows through the system, being irreversibly lost to the environment as heat at each step
Describe the carbon cycle?
Carbon and other chemical nutrients cycle through the system, changing in form and availability but ultimately being conserved
Explain Energy/Nutrient Budgets:
Energy and nutrients are not equally distributed locally or globally
Abiotic & biotic factors affect where resources are located and how easily they can be extracted / converted
But greater availability does not necessarily mean a more valuable ecosystem…
Define Gross Primary Production (GPP):
Amount of energy converted into organic material by autotrophs
Define Net Primary Production (NPP):
GPP minus the energy used by the autotrophs themselves through respiration etc
Define Net Ecosystem Productivity:
Total amount of biomass added to the ecosystem across all organisms
What are limiting factors?
The resources which prevent continued biomass accumulation. Even if other resources are plentiful, organisms cannot grow if they are missing even just one key resource. Bogs have plentiful water and sunlight, but lack nutrients as low oxygen slows decomposition
(Carbon & nutrients locked away in the peat)
What is a benefit of limiting factors?
Limiting factors often define ecosystems And lead to evolutionary innovation. Specialists often only persist because environmental conditions limit their competition.
Evolution of species specialised to managing a
lack of key resource, e.g.,
- Nitrogen fixing plants capture gaseous nitrogen
rather than relying on soil nitrogen
- Carnivorous plants extract nitrogen from
captured insects
What effect does human activity have on limiting factors?
Human activity can mess with this balance…
- Draining bogs removes limiting factors
- Allows decomposition and biomass turn over
- Bog ecosystem replaced with grassland/forest
- Carbon once locked away returns to circulation
- Nutrient run off affects other ecosystems
What are the Knock - on effects of peat drainage?
Increased water run off
- Increases erosion
- Increases nutrient influx to nearby ecosystems
…leads to Eutrophication
Increased decomposition/respiration
- Returns stored carbon into the atmospheric cycle
…contributes to Climate Change
- Increase growth of generalist species
…leads to loss of species and habitat homogenisation
What are examples of the new ecosystems humans are creating?
Agroecosystems
- Croplands / rangelands
- Dominated by growing crops or livestock
Urban ecosystems
- Cities, towns, villages, etc.
- Dominated by human habitation & industry
Semi-natural ecosystems
- Residential woodlands / parklands
- High levels of human activity / disturbance
Effects of forest clearance:
The majority of modern agricultural land has been created by clearing forests.
Deforestation interrupts the water and carbon cycles, with less photosynthesis and evapotranspiration, and more erosion.
Reducing water retention/availability and increasing temperatures.
Thinner, dustier, soils without roots holding them together are easily washed away
What is Eutrophication?
Agricultural lands are often ‘improved’ by adding fertilisers to promote the growth of crops or livestock forage.
Runoff from agricultural land introduces nutrients into surrounding ecosystems.
Clear water streams, rivers, & lakes are limited by nitrogen & phosphorus – controlling algae growth…
Excess nutrients lead to overgrowth of algae, a loss of light, increased decomposition as plants die, and a lack of oxygen
What are Marine dead zones?
GO TO LECTURE 28 - “Building ecosystems”
Define Bioaccumulation?
Toxins build up in an organism as consumption is greater than excretion
Define Biomagnification?
Toxins build up in higher tropic levels as consuming multiple prey
What are novel communities?
Humans are creating new ecosystems by changing land use, but we are also moving species to create new communities. Introduced species, Accidental or intentional. New predators, diseases, & competitors
What are the two irish examples of novel communities?
Oak processionary moth
Sika Deer
What are Homogenising communities?
Ecosystems around the world are becoming more similar to each other as we move species.
Introduced generalist species outcompete or hybridise with specialist native species. Loss of species & genetic diversity
What are climate changes effects on Phenology?
Timing is very important for many ecological processes.
Organisms need to coordinate their arrival and activity with each other and environmental conditions.
In some species time is measured by temperature whereas in others its daylight Climate change only affect temperature
Examples of phenology?
Bees and birds
More detail : GO TO LECTURE 28 - “Building ecosystems”
What is a population ?
a group of individuals of the same species living in the same area
What makes a species common ?
- Range size
- Local vs global abundance
- Temporal scale
- Local vs global biomass
What is a good example of restricted distribution ?
The Bristol whitebeam is a plant that is only found in the Avon Gorge, within the city of Bristol in the U.K.
What is a good example of global distribution ? (more than 1 example)
Fire moss, this is found on every continent including antarctica, another would be the brown rat or the peregrine falcon
What is a temporal shift ?
not all available patches where that species goes is occupied at once (depends on the time of year)
What dominates the global biomass ?
Humans and livestock dominate global mammal biomass
What is a population ?
a group of individuals of the species that:
-live in the same area
-interact and interbreed
What are the different patterns of dispersion ?
-Clumped
-uniform
random
What creates patterns of dispersion ?
Abiotic factors are:
- temperature, sunlight, nutrients, water/humidity
Biotic factors
-food/prey, predators, competition
What is the concept of density dependent mortality ?
the risk of predation depends on density in some cases (perch is a good example -fish), at higher densities there are fewer places to hide and more likely to be spotted by predators
What is a good example of a boom and bust cycle ?
snowshoe hare and Canadian lynx, sometimes one is doing better/has a bigger population than the other
What are life history traits ?
traits which make up an organism’s schedule of reproduction and survival
e.g. number of offspring age at first reproduction life span
What is Semelparity?
breed just once in life
What is iteroparity?
breed repeatedly through life