Ecology final
Ecology
Relationships between organisms and their environment (both biotic and abiotic)
Natural history
Predecessor to ecology (knowledge of organisms in thier environment, and describing patterns)
population ecology
studies ecological factors that influence structure and dynamics of a group of organisms
Community ecology
studies how interactions between species influence each other's distribution, abundance, structure, and demography
Ecosystem ecology
studies how entire ecosystems work through the biotic and abiotic components of the system. (nutrient cycling & energy flow)
Landscape ecology
studies ecological process of large heterogenous areas with multiple ecosystems present. Scale is very important
Macroecology
Studies the interactions between organisms and environment at large scales (biomes). E.g latitudinal changes in species richness and
global ecology
ecological study of the entire biosphere. Includes climate change, plate tectonics, extinction events and El Nino
Ecological community
2 or more species inhabit the same geographical area
Eltonian Niche
an animals place in its relationship to food and enemies (biotic environment)
ecological niche
an organisms ecological niche refers to the biotic and abiotic factors required to allow the organism to thrive
Fundamental niche
an organisms potential niche
Realized niche
the organisms actual niche that can be occupied by the organism (they can only thrive in the actual niche)
Ecological community
group or association of populations of two ir more different species occupying the same geographic area at a particular time
Interdependent and Independent distribution
Interdependent: community where species depend on each other in order to exist (common in harsh environments)
Independent: Communities where species don't depend on each other to exist; species co-exist bc they have similar adaptations and habitat reqs
Bottom-up control
Nutrients control plant numbers, which control herbivore abundance, which control pred numbers, the availability of prey limits predator abundance
Top-down control
Predation limits herbivore abundance and structure the community
Kick-it-and-see ecology
Field manipulation on ecological systems that help ius understand ecological processes
How is community structure shaped
By the top predator in the ecological community (keystones species)
Trophic Cascades
Top-down: addition or removal of a predator influences lower trophic levels
Bottom-up: when primary producers or herbivores influence higher trophic levels
Mesopredator release
populations of medium-sized predators start rapidly increasing after removal of the top carnivores. Changes ecosystem structure
Keystone species
unusually strongly interacting species that have a huge effect on community structure than predicted by their abundance/biomass
Ecosystem engineers
Organisms that directly or indirectly modulate the availability of resources by other species by causing physical state changes in biotic or abiotic materials (modify, maintain, and create habitats) e.g Beavers modify water with dams
Mutualistic keystone
Species that have a mutualistic relationship with other species in the system and have a large impact
keystone prey
preferred prey species that can maintain its abundance in the face of predation (via high reproduction)
Disturbance
temporary change in environmental conditions that causes a pronounced change in an ecosystem. Can be natural or human caused, and can vary greatly in temporal and spatial scale. May leave ecosystem in altered but stable state
Ecological succession
Gradual change in plant and animal communities in an area following the creation of new substrate or disturbance
Primary succession
Succession of newly exposed geological substrates not significantly modified by organisms (newly formed volcanic lava)
Secondary succession
Succession where a disturbance has destroyed a community without destroying the soil (forest succession after fire). The system often (not always) returns to its state pre-disturbance
Resistance
Ability of a community or ecosystem to maintain its structure in the face of potential disturbance
Resilience
Ability of a community or ecosystem to return to its original structure following a disturbance
Life History
Significant features of an organism's life cycle, particularly relating to survival and reproduction
Life history strategy
specific suite of traits shaped by natural selection to maximise reproductive output (not conscious decision making)
Trade offs
Organisms cannot maximize all traits simultaneously
Recruitment
The addition of new individuals to a population through survival of juveniles to a critical life stage (eg. sexual maturity)
Semelparity
Reproducing only once per lifetime. They have large litters, smaller offspring and little parental care
Iteroparity
Repeated reproduction. They have smaller litters, larger offspring and more parental investment
Parental Investment
Any investment by a parent in individual offspring increases the offsprings chance of survival at the cost of future reproduction for the parent (trade off)
R selected species
- Fast life history
- Reproduces early
- Produces many offspring
- Unpredictable environments
K selected species
- Delayed reproduction
- Produce few offspring
- Reproduce often
- Predictable environments
Nutrient and Elemental Recycling
All common elements have global cycles that include biotic & abiotic factors
What causes elements to move from one pool to another
Ecological actions and chemical processes, the rate at which this happens can take minutes to millenia
Nutrient cycling at local and global levels
Nutrient cycling at the local level occurs largely through the actions of the decomposers
Nutrient cycling at the global level occurs largely through geological processes, such as atmospheric circulation, erosion and weathering
Nutrients
Elements req for development, maintenance and reproduction in living organisms
Nutrient cycling
The transformation, movement and reuse of nutrients within and among ecosystems
Biogeochemical cycle
The path atoms take from the living (biotic) to the non-living (abiotic) world and back again
Macro and micronutrients
Macro: essential elements req in LARGE concentrations within ecosystem (oxygen, carbon, hydrogen)
Micro: Essential elements that are req in SMALL concentrations
Nutrient cycling is important because...
physiological importance and relative scarcity influence on primary production
Nutrient cycling in terrestrial vs aquatic ecosystems
Terrestrial: plants bridge the separation between the zone of primary productivity and zone of decomposition
Aquatic: no direct link between the zone if primary productivity and decomposition
How does energy travel through ecosystems
Energy makes a one way trip through ecosystems while essential nutrients may be recycled
Nutrient pools in terrestrial vs aquatic
For both:
- Organic pool: consists of living organisms and their detritus
- The available nutrient pool: consists of nutrients held to the surface of soil particles
- Nutrients that are held in soils or roots that are unavailable to living organisms
Terrestrial only:
- The air which can be found in the atmosphere or in the ground
What is the main path of all nutrients (not including CO2 and O2)
From the soil through the roots of producers
Most abundant nutrient in atmosphere, and what is the atmosphere a source of?
Nitrogen, inorganic nutrients
Most abundant nutrient in marine sediments
Phosphorus
What can moderate rates of elemental cycling and move elements across ecosystems
Activities of animals
Phosphorus cycle in an ecosystem
Follows a sedimentary cycle
1. Tectonic uplift and exposure of phosphorus bearing rocks due to the forces of weathering
2. Physical erosion and chemical weathering of rocks producing soils and providing dissolved and particulate phosphorus to rivers
3. Riverine transport of phosphorus through lakes and oceans
4. Sedimentation of phosphorus associated with organic and mineral matter and burial in sediments
Nitrogen cycle in an ecosystem
- Living things cannot use atmospheric nitrogen and are dependent on nitrogen fixing bacteria
Nitrogen fixation: nitrogen is assimilated into organic compounds (ammonia)
Nitrification: Bacteria in the soil transforms ammonia into nitrates and nitrites
Ammonificstion: Conversion of nitrates back into ammonia by bacteria and plants
Denitrification: Return of nitrogen gas back into the atmosphere by certain bacteria
Landscape
A heterogenous area consisting of distinct patches organized into a mosaic-like pattern. Each patch is referred to as a "landscape element" that we can map and quantify.
* Not defined by specific sizes but a spatially heterogenous area relevent to the study
Grain
Size of sample, unit or resolution
Extent
Size of the study area
Corridor
Narrow strips of land which differ from the matrix on either side. Corridors may connect patched
Kinds of corridors
Linear: continuous uniform strip connecting patches
Stepping stone corridor: patches of land facilitating dispersal
Landscape Mosaic corridor: Patches connected by a mosaic of interconnected habitats across a permeable matrix
Habitat corridor: linear landscape element that provides for survivorship, natality and movement
Facilitated movement corridor: linear landscape that allows for survivorship and movement but not necessarily natality
Can humans unintenionally create corridors?
Yes, ex. roadwork connecting two patches
Network
An interconnected system of corridors
Circutscape
A tool for evaluating connectivity across the landscape
Matrix
"Background ecological system" of a landscape with a high degree of connectivity (opposite to patches)
Mosaic
Pattern of patches, corridors, matrix
Fragmentation
A reduction in the connectivity of a landscape mosaic
Conspecifics
The same species
What happens when there's an absence of juveniles and more older numbers of an organim?
Decline of population
Key biological processed often change with
Age
When are geometric, exponential, and logistic growth models used?
Geometric: Abundance of resources and discrete generations
Exponential: Used when there is an abundance of resources and overlapping generations
Logistic: When there is limited resources and overlapping generations
Simpsons Diversity Index
Smallest value is 1
Max value is = to species richness
Species richness
The number of species found in a given community or study area
Shannon Diversity Index
Min value of 0
Max value = natural log of species richness
Evenness (Pielou's J)
Ranges from 0 to 1, lower J value indicates lower evenness
Allopatric and Sympatric
Allopatric: Just one species alone
Sympatric: Multiple species occupying an area