Human influences on Ecosystems ( 2 )

• Pollution is when harmful substances get into the environment and make things dirty or unsafe for living things
• Human activities have led to the pollution of water, land and air
• Eutrophication


  1. Untreated sewage and excess fertilizers get into streams and rivers

  2. Supplies excess nitrates and other ions for microscopic algae

  3. Leads to excessive growth of producers

  4. Producers die and are decomposed by bacteria

  5. Increased decomposition leads to increased aerobic respiration and oxygen depletion

  6. Organisms dependent on dissolved oxygen can't survive
• Non-biodegradable


  Plastics don't break down naturally over time and persist in the environment
• Effects of plastic pollution on aquatic ecosystems

  • Disrupts natural balance
  • Harms marine life habitat
  • Animals get trapped or eat plastic causing injuries or death
  • Plastics release harmful chemicals polluting the water
• Effects of plastic pollution on terrestrial ecosystems

  • Soil contamination
  • Affects plants and nutrient cycles
  • Harms wildlife
  • Spread of microplastics
• Methane and carbon dioxide


  Gases that contribute to the enhanced greenhouse effect and climate change
• Sources of methane and carbon dioxide pollution

  • Livestock
  • Landfills
  • Burning of fossil fuels
• Effects of climate change

  • Altered weather patterns
  • Rising sea levels
  • More frequent and severe extreme weather events
• Conservation methods for forests

  • Education
  • Protected areas
  • Quotas
  • Replanting
• Conservation methods for fish stocks

  • Education
  • Closed seasons
  • Quotas
  • Controlled net types and mesh size
• Endangered species


  A type of plant or animal that has very few of its kind left in the world and is at risk of disappearing forever
• Reasons for species becoming endangered or extinct

  • Climate change
  • Habitat destruction
  • Hunting
  • Over-harvesting
  • Pollution
  • Introduced species
• Methods for conserving endangered species

  • Monitoring and protecting species and habitats
  • Education
  • Captive breeding programs
• Artificial insemination


  Scientists help animals reproduce by collecting sperm from a male and inserting it into a female's body to fertilize her eggs
• In vitro fertilization (IVF)


  Ovum are taken from a female and fertilized with sperm outside her body in a lab, then the fertilized embryo are put back into the female's body or into a surrogate mother
• When a species has fewer and fewer individuals, its genetic variety decreases, making it weaker against diseases and environmental changes, putting it at higher risk of extinction