ESS Chapter 2: Ecosystem and ecology Flashcards
Species
A group of similar organisms that interbreed and produce fertile offspring.
Population
A group of individuals that belong to the same species and live at the same area at the same time
Habitat
Environment where a species lives
Community
Many different species that lives together in a defined area
Ecosystem
A community of interdependent species and their physical environment. They can be marine, terrestrial and freshwater.
Niche
Abiotic and biotic conditions and resources in which an organism responds to. Includes habitat, interaction & its diet
Fundamental niche
The full range of conditions and resources in which a species could survive and reproduce
Realised niche
The actual conditions and resources in which a species exists in due to biotic conditions
Abiotic factors
The non-living & physical parts of the environment that influence the organisms. Determine the fundamental and realised niche.
E.g temperature, sunlight, acidity, rainfall & salinity
Biotic factors
The living part of the environment, the interaction between organisms
Carrying capacity
The largest population that an area or ecosystem can support over a long period of time
Predation
An interaction in which one animal or plant captures and feeds on a mother organism
Predator-prey relationship
Interaction between two organisms of different species in which one organism, the predator, captures and feeds on another organism, the prey.
Herbivory
An interaction in which a herbivore eats a part of a plant or alga.
Parasitism
A relationship in which an organism lives on or in a host and harms it. Only the parasite benefit from this relationship
Mutualism (Symbiosis)
A relationship between two species in which both species benefit from each other.
Pathogen
An organism that causes disease. E.g bacteria, funguses, fungi.
Competition
A command demand between two or more organisms upon a limited resource.
Intraspecific competition
Competition among the members of the same species
Interspecific competition
Competition between members of different species
S-curve
Shows an initial rapid growth then slows down as it reaches its carrying capacity.
Four phases
1. Lag phase
2. Exponential growth phase
3. Transitional phase
4. Stationary phase
J curve
The rate of growth is always increasing. Starts off slow and becomes increasingly rapid and does not slow down
Density-dependent factors
Factors that decrease the birth rate and increase the death rate as the population grows.
Density-independent factors
Factors that affect the population regardless of the population size.
Photosynthesis
Green plants converting light energy, H20 & CO2 to glucose & oxygen
Respiration
Release of chemical energy inside the cell so it can be used to support life processes
Producers/Autotrophs
Organisms that make their own food
Consumers/Heterotrophs
Organisms that cannot make their own food so they feed on other organisms to obtain energy and matter
Decomposers/Detritivores
Obtain energy by breaking down the remains of other organisms or waste products
Trophic level
The position that an organism occupies in a food chain
Food chain
The flow of energy and matter from organism to organism. The producers always have the first level.
Food webs
Interconnected food chains in an ecosystem
Efficiency of energy transfers through an ecosystem
Energy transfers are not always 100%
It decreases as it travels up the food chain
Pyramid of numbers
The number of individuals at each trophic level coexisting in an ecosystem
Pyramid of biomass
The biological mass of the standing stock at each Trophic level at a particular time
Pyramid of productivity
The flow of energy through a Trophic level over a period of time at which the rate of stock/storage is being generated.
Energy in food chains
Energy is lost through the food chain. Therefore, the top predators are at risk of disturbance further down the food chain
Decrease in producers or consumers can threaten the existence of top predations. That why predations are relatively in small groups
Top predators are the most affected by bioaccumulation
Sunlight % and producers
51% in total doesn’t reach them
19% reflected from cloud
17% absorbed by molecules and dust in the atmosphere
9% reflected from the earth’s surface
3% absorbed from the cloud
3% scattered by aerosols and atmosphere particles
Only 0.06 percent of sunlight is absorbed by plants
Pathways of energy through an ecosystem
1.Conversion of light energy to chemical energy
2. Chemical energy is transferred through each Trophic level with varying efficiencies
1. Overall conversion of ultraviolet and visible light to hear energy by an ecosystem
2. Re-radiation of heat energy to the atmosphere
Productivity
The conversion of energy into biomass for a given period of time
Primary productivity
The gain by producers in energy or biomass per unit area per unit time
Secondary productivity
The biomass gained by by heterotrophs, through feeding or absorption, per unit mass or energy per unit area per unit time
Gross productivity (GP)
The total gain of energy or biomass per unit are per unit time
Net productivity (NP)
The gain in energy or biomass per unit area per unit time remaining after respiratory loss
Gross primary productivity (GPP)
The mass of glucose per unit area per unit time created by photosynthesis in primary producers
Net Primary Producers (NPP)
The gain in energy or biomass per unit are per unit time remaining after allowing for respiratory losses
Gross Secondary Productivity (GSP)
The total energy or biomass gained by consumers per unit area per unit time. This done by subtracting the mass of faeces loss from mass of food eaten
Net Secondary Productivity (NSP)
The energy or biomass gained per unit area per unit time by consumers after allowing for respiratory loss
NSP = GSP - R
Maximum sustainable yield MSY
The maximum amount of resource that can be produce without causing it to decline over time
NSP/NPP
Nutrient cycle
The cyclic movement of nutrient between organisms and the physical environment
Carbon Cycle
The organic circulation of carbon from the atmosphere into organisms and back again.
Nitrogen Cycle
The transfer of nitrogen from the atoms sphere to soil, to living organisms and back to the atmosphere.
Impact of human activities on energy flows
- Deforestation
- Agriculture
- Burning of fossil fuels
- Urbanisation
Impact of human activities on matter cycle
Timber harvesting
Fertiliser runoff
Biomes
A group of ecosystem of climates. There are aquatic, forest, grassland, tundra and desert. Precipitation, insolation and temperature are the factors that control the distribution of biomes
- Topical rainfall (7)
- High temperatures
- High amount of rainfall
- High insolation
- High species diversity
- High levels of photosynthesis
- Near equator
- Growth all year round, evergreen
- Temperate forests (5)
- Common in Europe
- Winters are cold, summers are hot
- Varies in temperature, rainfall & insolation
- Evergreen but deciduous trees
- Lower diversity than rainforests
- Deserts (7)
- Cover 20 - 30% of surface land
- Very high temperatures
- Low rainfall
- Lack of water, low levels of photosynthesis, low NPP
5.Fluctuation in temperature from night to day
6.Cacti is common - Soils are poor in nutrients
- Tundra (7)
- Very low temperatures
- Animal activities increases during summer
- Low insolation due to shorter days.
- Water is a limitation, as water froze into ice. Low rainfalls
- Low nutrient in soils as they are frozen
- High latitudes
- Low photosynthesis due to temp and water
- Grassland (6)
- Found on every continent except for Antarctica.
- High fluctuation in temp makes it hard for organisms to survive.
- Between forest and desert
4.Two types: Topical & Temperate - Low productivity
- Wide diversity
- Tropical coral reefs (7)
Basically rainforest in the ocean.
- Hypothermal vents (5)
- There are no Photosynthetic producers found as sunlight cannot reach the depths of the water.
- Occurs when cold seawater meets with hot rocks below the surface.
- One of the hottest places found on earth.
- Only extremely heat tolerant species can live there, thermophilic species.
- Found in volcanically active areas along tectonic plates.
Tricellular model of atmospheric circulation
It explains the distribution of precipitation and temperature and how it influences the structure and relative productivity of terrestrial biomes.
Zonation
Zonation
The change of community along an environmental gradient due factors such as change in attitude, latitude, tidal level and distance from shore/water coverage.
Succesion
The process of change over time in an ecosystem involving pioneer, intermediate and climax communities. Energy flows, GP, NP, mineral cycling & diversity changes over time.
Pioneer community
The first stage of succession where only hardy species like lichens & mosses can survive harsh conditions. NP is high but GP is low.
Climax community
The last stage of succession where the equilibrium is reached, GP is high and NP is low. There is high species and habitat diversity, the soil quality is better and there are tall and longer-living plant species.
Plagioclimax community
An area or habitat in which the influence of humans have prevented ecosystem from further development and reaching climax community.
Habitat diversity
The range of different habitats or the number of ecological niches per unit area in an ecosystem, biome or community.
R-strategist/species
Grow and mature quickly and produce many small offspring. Found in pioneer communities. They are adaptable and live short and productive lives.
K strategist/species
Grow and mature slowly, produce few but large offspring. Found in climax communities. Dominant species who live a long time
C strategist/species
A mix of R and K strategist, not so extreme.
dichotomous key
A step by step approach to identify an organism using a series of paired descriptions. This usually focuses on characteristics and not behaviour.
Measuring the abiotic factors (1)
Light: Light meter
Temperature: Themometer
Ph: Ph probe/meter
Wind: Anemometer or observations
Particle size: using sieves of various sizes
Measuring abiotic factors (2)
Run-off: measuring slopes
Soil moisture: weighing soils before and after
Mineral content: Heating soil samples
Flow velocity: Timing of floating object from point A to point B
Measuring abiotic factors (3)
Salinity: Electrical conductivity or density of water
Dissolved oxygen: DO meter
Wave action: Dynanometer
Turbidity: Secchi disc
Lincoln index
Pitfall trap
Capture, mark, release, recapture.
N1 x N2/NM
NM: number that was marked in N2
Sampling
- Random sampling: same habitat
- Stratified random sampling: Different habitat
Along an environmental gradient - Systematic sampling: Every 5m
- Continuous sampling: The whole length of the transect
Transect
A line transect: A tape measure laid out in the direction of the gradient
Belt transect: 0.5m to 1m width for larger samples
Population density
Total no. of species in all quadrats divided by area of one quadrat x total no. of quadrats
Percentage frequency
No. of actual occurrences divide by no. of possible occurrences.
7 out of hundred 7%
8 out of 10 quadrats 80%
Limitations on quadrats
- Two or more organisms may be mistakenly identified as the same
- Difficult to use for vv large or vv small plants.
- Difficult to measure outside of the plants main growing season.
Limitation of Lincoln index
- Animal behavior
- Species rarity
Estimation for biomass
- Collect using quadrats
- Weigh sample in previously weighed container
- Oven for 80 degrees Celsius
- Reweighed
- Repeat step 3 and 4 until a constant mass is obtained
- Find average
Estimation for energy
- Organic matter is burned in calorimeter
- Heat released during combustion is measured to determine the energy content
- Extrapolation, measuring to total biomass of organisms and multiplying by the energy content per unit mass
Limitations of calorimeter or oven
- Involves killing animals
- Difficult to measure biomass of very large plants
- Difficult to measure biomass of roots
Species diversity
the no. of diff species compared to the relative no. of individuals of each species
Species richness
the number of species in an area
Simpson index
Total no.(Total no. -1) divide by each no. of species( each -1) sublimation
