Environmental Value Systems & Ecology Summary & Study Notes

🧭 Foundation & EVS

Environmental Value System (EVS) describes how people view environmental issues and decide on action. There are three main EVS: ecocentric, anthropocentric, and technocentric.

🟢 Ecocentric EVS

• Nature at the center of values; intrinsic value of the natural world.
• Favors small-scale, low-technology lifestyles with restraint in resource use.
• Life-centred; respects the rights of nature and takes a holistic view of life.

🔵 Anthropocentric EVS

• Humans central to existence; many views within this category.
• Believes humans should sustainably manage the global system through tools like taxes, regulation, and legislation.
• Nature is valued primarily for the benefits it provides to humans.

🟠 Technocentric EVS

• Belief in technology as the main solution to environmental problems.
• Assumes environmental issues can be resolved through innovation and engineering.
• Often aligns with the idea of potentially unlimited economic growth.

🧩 Key concepts

• A system is a set of inter-related parts working together to form a functioning whole. Example: the Earth’s atmosphere interacts with the biosphere, hydrosphere, and lithosphere to support life.
• Transfers move matter from one reservoir to another; transformations change the form or state of matter.
• Feedback loops:
  • Positive: destabilizing, drives change toward a new state or tipping point, often exponential.
  • Negative: stabilizing, resists change and promotes return to equilibrium.
• Sustainability measures the long-term viability of a system, ensuring conditions for future generations are not diminished.
• Natural income vs natural capital: natural income is the yield from resources (e.g., timber), while natural capital is the stock of resources (the trees themselves).

🌍 Energy, systems & cycles

• The carbon cycle involves stores in soil, biomass, oceans, and the atmosphere, with processes like photosynthesis, respiration, decomposition, combustion, and ocean absorption.
• Photosynthesis (ld):

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$$

• Carbon fixation: CO₂ is converted to organic matter in photosynthesis; carbon returns to the atmosphere via respiration, decomposition, and combustion.

🔗 Ecology basics

• A species is a group of organisms that can interbreed to produce fertile offspring.
• A population is a group of individuals of the same species living in the same area at the same time.
• Biotic factors are living components; abiotic factors are non-living environmental factors.
• Niche describes the specific set of abiotic and biotic conditions a species depends on.
• K-strategists vs R-strategists: K-strategists have longer lifespans, reproduce later, and invest in few offspring; R-strategists reproduce quickly with many offspring.

🧪 Key formulas & terms

• Photosynthesis formula (display):

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$$

• Energy transfer efficiency:

$$\text{efficiency} = \frac{\text{useful output}}{\text{input}} \times 100$$

• Efficiency of transfer between trophic levels:

$$\text{efficiency of assimilation} = \frac{\text{gross productivity}}{\text{food eaten}} \times 100$$

🧭 Climate & Global Systems

• The atmosphere is composed of roughly 78% nitrogen, 21% oxygen, and ~1% other gases including CO₂.
• The greenhouse effect is the trapping of heat by greenhouse gases; the enhanced greenhouse effect from human activities leads to warming.
• Major greenhouse gases include $\mathrm{H_2O}$, $\mathrm{CO_2}$, $\mathrm{CH_4}$, $\mathrm{N_2O}$, chlorofluorocarbons (CFCs), and HCFCs.

🧭 Climate vs Weather

• Weather describes atmospheric conditions over short periods; climate describes conditions over longer timescales.

🧩 Biodiversity & Conservation (glossed reinforcement)

• Biodiversity includes species diversity, genetic diversity, and habitat diversity.
• Endemic species are restricted to specific locations (e.g., lemurs in Madagascar).
• Biodiversity hotspots are regions with high levels of endemism and significant habitat loss, often near the tropics.

🧭 Water, Land & Atmosphere (glossed reinforcement)

• A biome is a region with similar climate patterns and communities.
• Soil is a dynamic system with inputs, outputs, storages and flows; texture (sand, silt, clay) and humus influence fertility.
• The water cycle comprises evaporation, transpiration, condensation, precipitation, runoff, and infiltration.

🌀 Atmospheric Change & Action

• The atmosphere comprises mostly $N_2$ and $O_2$; trace gases drive the greenhouse effect.
• Sustainable management requires balancing human needs with ecological limits.