Comprehensive Notes on Human Impact on Natural Environments

Individuals & Societies - IB MYP 4&5

Key Concepts

  • Time, Place and Space: Human choices across time and locations impact global environmental change, potentially making our current lifestyle unsustainable.
  • Change: Globalization influences development and destruction.
  • Perspective: Considering different viewpoints on sustainability.
  • Sustainability: Balancing resource use with environmental preservation.
  • Globalization: Examining its role as a driver for both progress and harm.

Chapter Overview

  • Focus Question: What impact do humans have on natural environments?
  • Factual Questions:
    • Where are different environments located?
    • What are the characteristics of natural environments?
    • How do humans impact natural environments?
  • Conceptual Question: Can resources ever be exploited sustainably?
  • Debatable Question: To what extent is globalization a driver for development and to what extent a driver for destruction?

Approaches to Learning (ATL) Skills

  • Communication, collaboration, organization, reflection, information literacy, media literacy, critical-thinking, and transfer skills.
  • Learner Profile Attribute: Principled – Examining sustainable resource use with respect for human dignity and rights, and reflecting on responsibility for actions.
  • Assessment Criteria: Knowing and understanding (Criterion A), Investigating (Criterion B), Communicating (Criterion C), Thinking critically (Criterion D).

Major Natural Environments (Ecosystems or Biomes)

  • Forest, desert, grassland, tundra, and aquatic areas.

Location of Natural Environments

  • Using maps and climate graphs to understand the relationship between environments and their climate features.
    • Describing location using hemisphere, distance from equator/prime meridian, continent, neighboring countries, and physical features.
    • Climate graphs: Combination of bar (rainfall) and line (temperature) graphs.

Climate Graphs

  • Temperature on a line graph (right side, °C).
  • Rainfall on a bar graph (left side, mm).
  • Analyzing patterns and relationships between temperature and rainfall.
  • Guiding questions:
    • Temperature consistency throughout the year (seasons)?
    • Warmest season (warm: 10-20°C, hot: 20-30°C, very hot: >30°C)?
    • Coolest season (mild: 0-10°C, cold: -10-0°C, very cold: <-10°C)?
    • Rainfall presence throughout the year?
    • Rainfall patterns (drier/wetter seasons)?
    • Total annual rainfall (sum of monthly totals)?

Characteristics of Natural Environments

Rainforests

  • Covers about 6% of Earth’s surface but home to over half the world’s plant and animal species.
  • Warm, humid climate with abundant rainfall due to location near the equator.
Vegetation
  • Layers: Emergent, canopy, under canopy, forest floor.
    • Emergent Layer: Tallest trees, most sunlight (100%).
    • Canopy Layer: Crowns of most trees, home to insects, birds, mammals (95% sunlight). 30-50m
    • Under Canopy Layer: Woody climbers (lianas), limited sunlight (5%). 1-30m
    • Forest Floor: Dark, little vegetation, prone to flooding (2% sunlight). 50-80m
  • Adaptations to limited light and other environmental factors.
Wildlife
  • Huge variety due to constant water supply and diverse food sources.
  • Large animals (gorillas, jaguars, tigers) and small animals (monkeys, birds, snakes, rodents, frogs, lizards).
  • Adaptations to overcome food competition, e.g., toucan's long bill for reaching fruit.

Deserts

  • Receive less than 250mm of precipitation annually.
  • Can be hot or cold (Antarctica is the largest desert).
Vegetation
  • Adapted to extremes in rainfall and temperature (e.g., cacti).
  • Long, porous roots; shallow, far-reaching roots; thick, waxy skins; spiny leaves; fleshy stems.
  • Seeds lie dormant until heavy rainfall, then germinate and bloom quickly.
Wildlife
  • Many animals are nocturnal, living underground to stay cool.
  • Mostly herbivores that eat desert plants and seeds.
  • Obtain water from insects, bulbs, seeds, or morning dew.
  • Adaptations: light color, ability to provide shade, and conserve water.

Grasslands

  • Distinct wet and dry seasons, located between the Tropics of Capricorn and Cancer.
  • Found in Africa, Australia, South America, and India.
Vegetation
  • Transitional zones between rainforests and deserts.
  • Savanna vegetation includes scrub, grasses, and occasional trees near water.
  • Wet Season: Lush green grasses, wooded areas emerge, baobab trees store water; acacia trees flourish.
  • Dry Season: Plants are xerophytic with small, waxy leaves and thorns to reduce transpiration; long roots reach the water table; grasses turn yellow and wither.
Wildlife
  • Support huge herds of grazing animals during the wet season; many migrate during the dry season.
  • Herbivores and carnivores, including lions, leopards, cheetahs, jackals, wild dogs, and hyenas.
  • Serengeti plains of Tanzania: giraffes, zebras, elephants, lions, and over 2 million wildebeest.

Tundra

  • Arctic areas of Europe, Asia, and North America.
  • Very little precipitation; temperatures below 0°C for most of the year; soil is frozen almost all year.
Vegetation
  • Adapted to cold by remaining close to the ground, growing in clusters, and having small, dark leaves.
  • Cottongrass: short growing season, wind-scattered seeds, dense flower head, shallow roots.
  • Other vegetation: mosses, lichens, low-growing shrubs and grasses.
Wildlife
  • Physical and behavioral adaptations for survival in extreme conditions.
  • Migration: Birds and mammals use the tundra as a summer home.
  • Hibernation: Animals consume food in summer and sleep during winter (e.g. brown bear).
  • Camouflage: Snowshoe hare changes color between seasons.
  • Insulation: Polar bears have thick white fur and layers of fat.
  • Rounded shape with small surface area to volume ratio to minimize heat loss.

Aquatic Environments

  • Water-based environments categorized into freshwater and marine areas.
Freshwater Environments
  • Low salt content, includes lakes/ponds, streams/rivers, and wetlands.
Lakes and Ponds
  • Make up just 3% of Earth's surface.
  • Vary in size from a few square meters to thousands of square kilometers.
  • Limited diversity due to isolation; divided into littoral, limnetic, and profundal zones, each with distinct biodiversity.
Streams and Rivers
  • Bodies of flowing water moving from source to mouth.
  • Temperature cooler at source due to higher altitude and snowmelt; clearer water.
  • Channel widens in the middle course, supporting a wider diversity of species.
  • Water becomes murky in the lower course due to sediments; less plant life; lower oxygen levels.
Wetlands
  • Include bogs, swamps, and marshes; combination of water and land.
  • Saturated with water; may be submerged all year or just at certain times.
  • Often found near other bodies of water; prevent flooding by providing overflow areas.
  • Purify and filter water of excess nutrients and pollutants.
  • High biodiversity: amphibians, birds, reptiles, alligators, crocodiles, beavers, minks, raccoons, deer.
Marine Environments
  • Oceans (cover approximately two-thirds of Earth), estuaries, salt marshes, coral reefs, coastal areas.
  • Home to fish, aquatic plants, seabirds, krill, plankton.
  • Oceans divided into Atlantic, Pacific, Indian, and Arctic.
  • Below 200 meters: dark, cold, murky, similar biodiversity ocean to ocean.
  • Varying salinity based on freshwater input and evaporation rates.
  • Ocean temperature varies with proximity to the equator and poles.
Coral Reefs
  • Found in tropical oceans near the equator.
  • Coral are invertebrate animals known as polyps that live in colonies.
  • Hard skeletons form reefs over time, providing homes for many species.
  • Occur in shallow areas reached by sunlight, which is needed by the algae.

Human Impact on Natural Environments

  • Humans as the dominant species have had a predominantly negative impact.
  • Innovative and technological advances change the planet.

Impact on Rainforests

  • Deforestation: Biggest human threat.
  • Amazon rainforest: High levels of deforestation, especially in Brazil (around 17% lost in the last 50 years).
  • Reasons for deforestation: fuel, slash and burn, food production, commercial farming, logging, mining, hydroelectricity.

Impact on Desert Environments

  • Less severe impact than on other natural environments due to gradual changes and limited human development opportunities.
Desertification
  • Turning of land into desert.
  • Complex causes: climate change, population growth, less rainfall, global warming, more crops grown, increased number of animals, rivers dry up, soils dry out, over-cultivation, over-grazing, increased demand for fuelwood.
  • Primary cause: Increased population leading to increased need for food.

Impact on Grasslands

  • Threats: Poaching and overgrazing.
  • Subject to desertification.
  • Poachers hunt native animals for furs, tusks, and horns.
  • Safaris create problems for the grassland natural environment.

Impact on Tundra Areas

  • Limited direct human impact due to inhospitable conditions.
  • Exploitation of natural minerals (e.g., Trans-Alaska Pipeline).
  • Indirect human impacts: global warming, melting of polar ice, rising sea levels.
  • Global warming: Rise in world’s temperature due to greenhouse gases emitted by humans.
  • Contributing factors include industrialization, deforestation, and pollution.
  • Global emissions of CO_2 have increased significantly since 1990.

Impact on Freshwater Areas

  • Driven by growing demand for fresh water.
  • Farming and irrigation: Affect quality of rivers, lakes and groundwater.
  • Clearance of forests leads to soil erosion and increased sediment in rivers.
  • Intensive agriculture leads to draining of freshwater wetlands.
  • Agro-industrialization: Requires chemicals (fertilizers and pesticides) which lead to eutrophication.
  • Use of dams and reservoirs impacts river conditions.
  • Algal bloom

Impact on Marine Areas

  • Overfishing: Depletion of fish stocks.
  • Coral bleaching: Temperature increases causing polyps to expel algae.
  • Tourism: Damage to reef ecosystems from anchor damage, boat collisions, fin damage, trampling, littering, and pollution.
  • Plastics in the ocean: Harm to animals, environmental damage, health consequences.

Sustainability: Can Resources Be Exploited Sustainably?

Sustainability in Rainforests

  • Sustainable logging schemes: Protecting areas of forest; monitoring with satellite technology; education.
  • Popular procedures: Agro-forestry, selective logging, and afforestation.
  • Global Forest and Trade Network (GFTN): Creating a market for environmentally responsible forest products.
  • restoration plan: replanting, replacing and repairing damaged soil.

Sustainability in Drylands

  • Preventing desertification through small-scale and larger global awareness strategies.
  • Aid agencies and charities educating farmers on productive farming methods.
  • Land restoration and afforestation: 'Great Green Wall' using drought resistant shrubs and grasses.
  • UN decade for Deserts and Fight Against Desertification (2010–2020).
  • 2030 Agenda for Sustainable Development.

Sustainability in Grassland Areas

  • Sustainable management: Improved conservation education programmes for local communities and farmers.

Sustainability in Tundra Areas

  • Efforts to reduce carbon emissions.
  • 2015 Paris climate summit: Limit global temperature rise to well below 2 °C.
  • UN Sustainable Development Goals: Goal 13 – Take urgent action to combat climate change and its impacts.

Sustainability in Marine Areas

  • Great Barrier Reef Marine Park: Zoned areas regulating activities.
  • Reducing carbon dioxide pollution to prevent warming oceans and coral bleaching.
  • Regulating North Sea usage through limiting fishing times and the number of fishing boats.
  • EU Common Fisheries Policy: Setting quotas and encouraging market interventions.
  • Marine Stewardship Council (MSC) ecolabel programme: Certifying sustainable fisheries.

Globalization: Driver for Development or Destruction?

  • Consider human impact on natural environments through the lens of globalization.
  • Explore the notion that global trade brings global responsibilities.