ESS Notes: Models, Systems, and Earth's systems - Ecology

Foundations: ============= **[Systems: ]** =========================== Models: ------- A model is a simplified representation of a structure or process. It is a simplified version of reality Models are used to help us understand the world and the world's systems better. - - ### Models ha...

Foundations: ============= **[Systems: ]** =========================== Models: ------- A model is a simplified representation of a structure or process. It is a simplified version of reality Models are used to help us understand the world and the world's systems better. - - ### Models have many different forms: 1. 2. 3. 4. 5. ### Uses and limitations of models: **[Uses:]** 1. 2. 3. 4. 5. 6. 7. **[Limitations:]** In order for models to be simplified, the person making them must leave out information and base the models on assumptions. If these assumptions are incorrect or the missing information is important, the model may lead us to the wrong conclusions - All models are wrong, but some are useful Models are based on what we know about the world and our world values. Our values and knowledge are changing, so we have to update our models when that happens. However, if we become too attached to these models and do not update our models, it can be harmful. Modeles can prevent us from updating our perspectives and worldviews in a way that improves the world. Systems ------- A system is a set of interrelated/interconnected components that work together to form a functional whole. Systems: - - - - **Emergent properties** (a.k.a emergence): Characteristics of a system that appear when the system parts interact with each other but the parts alone do not have these characteristics. Systems have different scales. These include - - - ### Systems approach: - - - - ### System boundaries: The system boundary is a line that separates the system from the external environment that is not apart of the system The external environment is not a part of the system but can affect the system or be affected by the system Systems have boundaries in space and time:\ 1) **Spatially** - The system has boundaries that separate it from its wider, external environment 2\) **Temporally** - The change of the system as time passes; the time you study the system for System boundary also affects the scale of the system we are examining:\ 1) Microscopic scale If we draw our boundaries too narrow, we can miss out on important systems behaviours that affect what we are studying and if we draw our boundaries too widely, then it increases the complexity which can hide valuable information In a systems diagram, it is represented by a cloud. A cloud outline shows the unexplored area outside the boundary and shows the you arent paying attention other things outside the system ### Open and closed systems: **Open system -** A system that exchanges both matter and energy with its external environment. Most natural systems are open, i.e ecosystems like ponds **Closed systems -** A system that exchanges energy but not matter with the external environment - - - ### Earth's systems: - 1. 2. 3. 4. 5. 6. James Lovelock and Lynn Marguils proposed something called the **Gaia hypothesis.** - - Storages and flows: ------------------- ### Storages Storages (stocks and stores) are an accumulation of material, energy or information. Storages can be physical, such as a bathtub, or non-physical like hope In system diagrams, storages are represented via rectangular boxes. The size of the box = size of the storage **Inputs** - Things going into the system and storages **Outputs** - Things going out the system and storages ### Flows: A flow is the movement of matter, energy or information in or out of a storage. - - Flows can be adjusted more quickly than storages. Storages change slowly because flows take time to flow. Because flows take time to flow, there is a delay between changing flows and changing storages. The delay between the changes in storage makes storages a buffer. - **[Principles of inflows and outflows:]** - - - ***[Important:]*** Input ≠ Inflow Output ≠ Outflow **Inputs and outputs** are things that can be accumulated and counted, like water, oil, money, etc.. WHEREAS **Inflows and Outflows** are processes. These are the movements of inputs and outputs ### Transfers and transformations: - **Transfers:** A flow where there is a change in location of energy or matter without a change in its state. I.e water flowing in a river, or heat being moved by wind or ocean currents **Transformation:** A flow where there is a change in location of energy or matter, but whilst that happens, there is change in state as well. I.e. water freezing or plants turning solar energy into glucose ### Simple system diagrams: - - - - Feedback and equilibrium ------------------------ **Feedback** is when the output of a system returns back to the system as an input **[Steady-state equilibrium]** - - **[Stable equilibrium]** The tendency of system to return to its previous equilibrium after a disturbance ### Negative feedback: Stabilising Negative feedback loops are when the output of a system returns back as an input in a way that inhibits or reverses the operations of the system's process. - Examples: - - - It shows that the earth is covered in black and white daisies. These daisies affect the albedo of the earth. **Albedo - reflectivity** If temperature increases, white daisies increase and black daisies decrease. The white daisies reflect sunlight, which decreases the temperatures. This causes the white daisies to decrease and black to increase When black daisies increase, the earth's albedo decreases and the black daisies absorb more sunlight. This makes the temperature increase, thus increasing white daisies and decreasing the number of black daisies. ### Positive feedback: Destabilises Positive feedback loop\[s is when the output of a system returns as an input in such a way that it reinforces the operations of the system. It pushes it in the same directions, moving the system further away from equilibrium Examples: - ### Tipping points: When positive feedback loops are present, it moves the system from its equilibrium until it reaches a tipping point. **Tipping points;** The minimum amount of change that will cause the system to destabilise. The system will shift so far from its stable equilibrium, that it will create a complete new equilibrium state. Once a system moves past its tipping point, it can never reach steady state equilibrium An example would be eutrophication of water systems Positive feedback loops do not allow a system to recover and repair, thus leading it to tipping points. Causal loop diagrams -------------------- Causal loop diagrams show the relationship between variables in a system. A causal loop diagram has 4 elements:\ 1) The variables\ 2) The connection between the variables 3\) The relationship; direct (+) or inverse (-) 4\) The type of loop, where it is negative (B) or positive ® Resilience ---------- Resilience is the system\'s ability to recover after a disturbance A resilient system can avoid tipping points and stay stable due to a balance of positive and negative feedback loops Resilient systems: - - Resilient systems are dynamic, not static. This means that they do face changes in inputs and outputs, however they are still able to reach steady-state equilibrium after the disturbance Resilience can be difficult to see because it requires a holistic, time-consuming understanding of systems ### Factors affecting resilience **1) Diversity** - - - - #### CASE STUDY: North American Prairie systems: - - - - - **2) Size and number of storages** Large storages improve ecosystem resilience. A large storage is more stable than a smaller one (i.e puddle vs lake) Multiple storages within a system mean that if one is depleted another is available for use instead. - - In Human systems, we store water for dry periods, fossil fuels for energy and money for financial securing. - ### Human impact on ecosystem resilience: **[Negative impacts;]** - - - - Feedback about how we are harming ecosystems is often invisible and delayed. We may not respond to the risks as we should. For instance, the impact of biodiversity loss and global warming on rainforests might only be recognised when tipping points are already upon us. By then it may be too late to stop ecosystem collapse. **[Positive impacts:]** - - We can also increase the resilience of human systems. For example, we can plant more trees in cities to cool and shade the urban landscape and people - Water and population [4.1 - Hydrological cycle] -------------------------------------- ### Water sources: 1. Oceans - 96.5% of hydrosphere - not potable Glaciers and ice caps (1.7%) Groundwater (1.7%) - potable --------------------------------------------- ------------------------------ ------------------------------ Surface freshwater (0.02) - potable Atmosphere (0.001%) Organisms (0.0001%) ### ### Hydrological cycle: - - - - ### Flows due to solar radiation: - [Evaporation]: Water from storages like oceans, lakes and rivers is transformed as it changes state by the heat provided by the sun. It evaporates from liquid to gaseous water vapour. [Transpiration]: Water that is taken up by plants from soils is transformed into a gaseous water vapour that is released through their leaves. The total water loss from evaporation and transpiration in plants is known as [evapotranspiration ] [Advection]: Water vapour or condensed water droplets that move location due to wind. The energy of the wind comes from solar radiation [Freezing/melting]: Solar radiation provides heat energy that causes snow or ice to melt into liquid water (transformation). In areas with less solar radiation and heat, water can freeze back into ice [Sublimation]: If air temp too low, gaseous water vapour can directly turn into ice, without becoming liquid first. If, snow and ice absorb so much heat/solar radiation, it can be transformed directly to gaseous water vapour ### Flows due to gravity: [Human impact on water systems ] -------------------------------------------- ### Impact of agriculture - - - - 1. 2. [Ineffective irrigation] - Some irrigation systems such as sprinkler and flood irrigation use large amounts of water, which results in a lot of evaporation as water collected when benign poured rapidly onto the soil surface rather than directly to the roots of the plant. Less water is being absorbed [Effective irrigation systems - ] Drip irrigation- provides water at or below ground level by dripping or trickling instead of watering above the plants. Less water is being used and less water is lost via evaporation and run-off. Water monitoring technologies allow farmers to only water plants when needed, thus avoid waste [Fertiliser use:] 1. [Eutrophication] - excessive nutrients in run-off cause a rapid growth of algae. As bacteria decomposes algae, most oxygen dissolved in the water is consumed The problem is being addressed by avoiding artificial fertilizers and using natural ones like compost and animal manure instead. These release nutrients more slowly and store more water in the soil Machine use: 1. 2. 3. To address the problem, farmers are using other methods of preparing soil and harvesting crops that reduce the compaction of soil. ### Impact of deforestation - 1. 2. 3. Solve this problem: 1. ### Impacts of urbanization 1. [4.2 Water resources ] ---------------------------------- - - - - - ### Factors affecting water access 1. - 2. - - - - - - - - - - - - - - - - [Water management] ------------------------------ ### Increasing supply of water: - \- Increase water supply by capturing and storing rainfall or snow melt in the reservoir behind the dam. Advantages: \- Provides irrigation water for agriculture \- Also generates hydroelectric power \- Can control floods They can provide new fisheries Disadvantages: 1. 2. 3. 4. 5. 6. - - - 1. 2. 3. - - - Advantages 1. 2. 3. - - - 1. 1. 2. 3. ### Reducing demand for water: - - - - - - - - - ### ### ### Water conversation in food production systems: - - - - - - - - - - - - - - - - - - - [8.1 - Human populations ] -------------------------------------- ### Human population as a system: - - #### **Births:** #### **Death:** #### **Immigration** #### **Emigration:** ### ### Net figures and population impact #### **Natural increase rate (NIR)** - - - #### **Net migration:** ### Other population indicators [Population models:] -------------------------------- ### Global population growth curve - - Despite the growth rate falling, the world population is projected to continue to grow until approximately 2100 when it could reach more than 11 billion - - - - - - ### ### Demographic transition models: - - - - - - - - - - - - - - - ### ### Population pyramids - A.K.A Age-gender pyramids The population pyramid is usually represented as a horizontal bar graph, with the age groups displayed along the vertical axis, and the percentage or number of individuals in each age group displayed along the horizontal axis The left side of the graph displays the male population, while the right side shows the females - - - - - - [Managing human population:] ---------------------------------------- ### Factors affecting birth and fertility rates: 1. - - 2. 3. - - - - - 4. - - 5. ### Factors affecting death and life expectancy: - - - ### ### Factors affecting migration: - Push factors are factors of a country that drive people out of their country. These can be due to lack of safety or negative conditions such as unemployment, low wages or natural disasters. ### ### Population management - 1. 2. 3. - - Policy Direct or indirect Explanation Example ------------------------------ -------------------- ---------------------------------------------------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------------------------------- Family planning education direct Free or low-cost birth control; education on family planning Iran encouraged families to delay the first child and space out births (1990s) Media campaigns direct Public campaigns promoting benefits of smaller families; raises awareness of impacts of high population growth, social pressure India has run media campaigns promoting smaller families Laws and financial penalties direct Laws may limit the number of children a family can have, enforced with fines or other penalties China\'s one-child policy (1979--2015) Improving gender equality indirect Improving gender equity with women\'s access to education and employment. Educated women have more independence and power, and often have fewer children Improvement of women\'s education in Ethiopia (Interactive 1) is credited with lowering birth rates (Interactive 2) - - Policy Direct or indirect? Explanation Example ----------------------------------- --------------------- -------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------- Financial incentives Direct Cash bonuses, tax breaks, or subsidies to families with more children, to offset financial burden French government provides proportionally more financial support to families with more than two children Parental leave Direct Extended parental leave with job security makes it easier to balance work and family Sweden offers 480 days of paid parental leave Childcare support Direct Affordable or free childcare helps families have more children and keep careers Japan provides free preschool education Housing assistance Direct Offering large families larger, more affordable housing to address the space and cost challenges of children Singapore\'s Housing Development Board provides priority and grants for larger flats to families with children Fertility treatment Direct Offering free or subsidised fertility treatments to couples Hungary has government owned fertility clinics to help couples conceive Reducing family planning services Direct Countries may cut family planning services, access to contraception and abortion South Korea has removed financial coverage contraception forms from national healthcare provisions Media campaigns Direct Celebrating larger families aims to shift social norms around having children Italy developed a national fertility day in 2016 to raise awareness around fertility - - - ### ### Immigration policies - - - - 1. 2. Soil and Food **[5.1 - Soil ]** ============================= 5.1.1 - The importance of soil ------------------------------ - - ### Plant growth: #### [Soil is a medium for plant stability as the roots of plants ] - - #### [Nutrients: ] - - - - - - \*NOTE - #### [Seedbank: ] - ### Supporting other ecological systems The soil system is called the **pedosphere** - - - - - - These inflows and outflows with other systems make soil an important part of biogeochemical cycles. Contributions to biodiversity - - - 1. 2. Predators: - - Burrow: - - - Soil systems Soil is an open system so it receives and transfers matter and energy from other systems such as the hydrosphere, atmosphere, biosphere and lithosphere. Soil inputs: 1. - - 2. - - 3. - - - - 4. - - - 5. - - 6. - - Storages - 1. - - - 2. - - - Minerals: - - Energy: - Flows: Water: Infiltration: This is a transfer process where water from precipitation or irrigation seeps from the surface into the soil. Percolation: After infiltration, water moves downward through the soil, a transfer that can lead to groundwater flow. Groundwater flow: Water moves horizontally in soils, transferring nutrients and minerals through different soil layers (underground) Erosion: Water transfers soil particles, often leading to loss of top layer of soil. Evaporation: Water is transformed from a liquid to a vapour, and released by soil into the atmosphere due to heating Air: Aeration: This transfer involves the movement of air in, out, and through soil. Erosion: Wind can transfer soil particles and gases, often leading to loss of topsoil Organic matter: - - Minerals: Weathering: This is a transformation process where rocks break down, forming parts of the soil and releasing minerals. Leaching: A transfer where minerals are washed out of the soil by percolating water (diluting it and moving the nutrients to ground water sources) Salinisation: A transformation that results in salts accumulating in soil, often due to poor drainage and evaporation, affecting soil fertility. (Think opposite of desalination) Energy: Energy is transferred through the energy stored in organic matter, that it then released through decomposition and then used up by plants and other organisms. This is called nutrient cycling and it includes transfers and transformations. Outputs: - - 1- Water and minerals: Water and minerals are removed from the soil through plant uptake. This is where the plants absorb water and minerals from the soil through their roots for plant growth. As they take up the ater, dissolved soil also gets carried up Water is also lost through evaporation to the atmosphere Air: Soil releases gases, such as C02 and oxygen, which diffuse into the atmosphere - Organic matter: The erosion of soil from wind and water transports soil particls and organic matter. This eroded soil can be used to reshape the lithosperhe and can affect the composition of the hydropshere Humans also remove organic matter from soils through agriculture and extraction of socil Energy: The energy stored in organic matter is transfer to the biosphere when organisms consume the soil. Thermal energy is also released into the atmosphere over time, which is called infrared radiation. Soil formation and structure: Soil compostion: Soil is made of small particles of rock, minerals, organic matter, water and gases. - - - Inroganic components: - -  Soil formation and structure - - - - - - - \- The different layers in soil are called the soil horizons. When the different layers/horizons are together, it forms soil profiles. - - - - - Soil texture and plant growth The inorganic matter in soil is made of small parcules of rock. These small particls can be sand, silt and clay. Sand - Largest particles so water passess quickly via sandy soil Clay - Smallest particles so it retains water because water pasess through it very slowly Silt - Finely ground particles of parent material/bed rock. Larger particles than clay but smaller than sand - - - - 1. - 2. 3. - - Loam soil is soil that has a balance mixture of sand, silt and clay and it is the most productive (grows most plants).  Tab 5 Tab 3 Class tasks: 9 marker practice: To what extent are water scarcity issues better addressed through changing human behaviour than through technological development?